1 <!doctype linuxdoc system>
3 <!-- This is the tutorial marked up in SGML
4 (just to show how to write a comment)
8 <title>GTK v1.1 Tutorial
10 Tony Gale <tt><htmlurl url="mailto:gale@gtk.org"
11 name="<gale@gtk.org>"></tt>
12 Ian Main <tt><htmlurl url="mailto:imain@gtk.org"
13 name="<imain@gtk.org>"></tt>,
14 <date>January 31th, 1999
16 <!-- ***************************************************************** -->
18 <!-- ***************************************************************** -->
20 GTK (GIMP Toolkit) was originally developed as a toolkit for the GIMP
21 (General Image Manipulation Program). GTK is built on top of GDK
22 (GIMP Drawing Kit) which is basically a wrapper around the Xlib
23 functions. It's called the GIMP toolkit because it was originally
24 written for developing the GIMP, but has now been used in several free
25 software projects. The authors are:
27 <item> Peter Mattis <tt><htmlurl url="mailto:petm@xcf.berkeley.edu"
28 name="petm@xcf.berkeley.edu"></tt>
29 <item> Spencer Kimball <tt><htmlurl url="mailto:spencer@xcf.berkeley.edu"
30 name="spencer@xcf.berkeley.edu"></tt>
31 <item> Josh MacDonald <tt><htmlurl url="mailto:jmacd@xcf.berkeley.edu"
32 name="jmacd@xcf.berkeley.edu"></tt>
35 GTK is essentially an object oriented application programmers
36 interface (API). Although written completely in C, it is implemented
37 using the idea of classes and callback functions (pointers to
40 There is also a third component called glib which contains a few
41 replacements for some standard calls, as well as some additional
42 functions for handling linked lists etc. The replacement functions are
43 used to increase GTK's portability, as some of the functions
44 implemented here are not available or are nonstandard on other unixes
45 such as g_strerror(). Some also contain enhancements to the libc
46 versions, such as g_malloc that has enhanced debugging utilities.
48 This tutorial is an attempt to document as much as possible of GTK, it
49 is by no means complete. This tutorial assumes a good understanding of
50 C, and how to create C programs. It would be a great benefit for the
51 reader to have previous X programming experience, but it shouldn't be
52 necessary. If you are learning GTK as your first widget set, please
53 comment on how you found this tutorial, and what you had trouble
54 with. Note that there is also a C++ API for GTK (GTK--) in the works,
55 so if you prefer to use C++, you should look into this
56 instead. There are also Objective C, ADA, Guile and other language
57 bindings available, but I don't follow these.
59 This document is a 'work in progress'. Please look for updates on
60 http://www.gtk.org/ <htmlurl url="http://www.gtk.org/"
61 name="http://www.gtk.org/">.
63 I would very much like to hear of any problems you have learning GTK
64 from this document, and would appreciate input as to how it may be
65 improved. Please see the section on <ref id="sec_Contributing"
66 name="Contributing"> for further information.
68 <!-- ***************************************************************** -->
70 <!-- ***************************************************************** -->
73 The first thing to do of course, is download the GTK source and
74 install it. You can always get the latest version from ftp.gtk.org in
75 /pub/gtk. You can also view other sources of GTK information on
76 http://www.gtk.org/ <htmlurl url="http://www.gtk.org/"
77 name="http://www.gtk.org/">. GTK uses GNU autoconf for configuration.
78 Once untar'd, type ./configure --help to see a list of options.
80 Th GTK source distribution also contains the complete source to all of
81 the examples used in this tutorial, along with Makefiles to aid
84 To begin our introduction to GTK, we'll start with the simplest
85 program possible. This program will create a 200x200 pixel window and
86 has no way of exiting except to be killed using the shell.
89 /* example-start base base.c */
98 gtk_init (&argc, &argv);
100 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
101 gtk_widget_show (window);
110 You can compile the above program with gcc using:
112 gcc base.c -o base `gtk-config --cflags --libs`
115 The meaning of the unusual compilation options is explained below.
117 All programs will of course include gtk/gtk.h which declares the
118 variables, functions, structures etc. that will be used in your GTK
124 gtk_init (&argc, &argv);
127 calls the function gtk_init(gint *argc, gchar ***argv) which will be
128 called in all GTK applications. This sets up a few things for us such
129 as the default visual and color map and then proceeds to call
130 gdk_init(gint *argc, gchar ***argv). This function initializes the
131 library for use, sets up default signal handlers, and checks the
132 arguments passed to your application on the command line, looking for
133 one of the following:
136 <item> <tt/--gtk-module/
137 <item> <tt/--g-fatal-warnings/
138 <item> <tt/--gtk-debug/
139 <item> <tt/--gtk-no-debug/
140 <item> <tt/--gdk-debug/
141 <item> <tt/--gdk-no-debug/
142 <item> <tt/--display/
144 <item> <tt/--no-xshm/
149 It removes these from the argument list, leaving anything it does not
150 recognize for your application to parse or ignore. This creates a set
151 of standard arguments accepted by all GTK applications.
153 The next two lines of code create and display a window.
156 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
157 gtk_widget_show (window);
160 The GTK_WINDOW_TOPLEVEL argument specifies that we want the window to
161 undergo window manager decoration and placement. Rather than create a
162 window of 0x0 size, a window without children is set to 200x200 by
163 default so you can still manipulate it.
165 The gtk_widget_show() function lets GTK know that we are done setting
166 the attributes of this widget, and that it can display it.
168 The last line enters the GTK main processing loop.
174 gtk_main() is another call you will see in every GTK application.
175 When control reaches this point, GTK will sleep waiting for X events
176 (such as button or key presses), timeouts, or file IO notifications to
177 occur. In our simple example however, events are ignored.
179 <!-- ----------------------------------------------------------------- -->
180 <sect1>Hello World in GTK
182 Now for a program with a widget (a button). It's the classic
183 hello world a la GTK.
186 /* example-start helloworld helloworld.c */
190 /* This is a callback function. The data arguments are ignored
191 * in this example. More on callbacks below. */
192 void hello( GtkWidget *widget,
195 g_print ("Hello World\n");
198 gint delete_event( GtkWidget *widget,
202 /* If you return FALSE in the "delete_event" signal handler,
203 * GTK will emit the "destroy" signal. Returning TRUE means
204 * you don't want the window to be destroyed.
205 * This is useful for popping up 'are you sure you want to quit?'
208 g_print ("delete event occurred\n");
210 /* Change TRUE to FALSE and the main window will be destroyed with
211 * a "delete_event". */
216 /* Another callback */
217 void destroy( GtkWidget *widget,
226 /* GtkWidget is the storage type for widgets */
230 /* This is called in all GTK applications. Arguments are parsed
231 * from the command line and are returned to the application. */
232 gtk_init(&argc, &argv);
234 /* create a new window */
235 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
237 /* When the window is given the "delete_event" signal (this is given
238 * by the window manager, usually by the 'close' option, or on the
239 * titlebar), we ask it to call the delete_event () function
240 * as defined above. The data passed to the callback
241 * function is NULL and is ignored in the callback function. */
242 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
243 GTK_SIGNAL_FUNC (delete_event), NULL);
245 /* Here we connect the "destroy" event to a signal handler.
246 * This event occurs when we call gtk_widget_destroy() on the window,
247 * or if we return 'FALSE' in the "delete_event" callback. */
248 gtk_signal_connect (GTK_OBJECT (window), "destroy",
249 GTK_SIGNAL_FUNC (destroy), NULL);
251 /* Sets the border width of the window. */
252 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
254 /* Creates a new button with the label "Hello World". */
255 button = gtk_button_new_with_label ("Hello World");
257 /* When the button receives the "clicked" signal, it will call the
258 * function hello() passing it NULL as its argument. The hello()
259 * function is defined above. */
260 gtk_signal_connect (GTK_OBJECT (button), "clicked",
261 GTK_SIGNAL_FUNC (hello), NULL);
263 /* This will cause the window to be destroyed by calling
264 * gtk_widget_destroy(window) when "clicked". Again, the destroy
265 * signal could come from here, or the window manager. */
266 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
267 GTK_SIGNAL_FUNC (gtk_widget_destroy),
268 GTK_OBJECT (window));
270 /* This packs the button into the window (a gtk container). */
271 gtk_container_add (GTK_CONTAINER (window), button);
273 /* The final step is to display this newly created widget. */
274 gtk_widget_show (button);
277 gtk_widget_show (window);
279 /* All GTK applications must have a gtk_main(). Control ends here
280 * and waits for an event to occur (like a key press or
289 <!-- ----------------------------------------------------------------- -->
290 <sect1>Compiling Hello World
295 gcc -Wall -g helloworld.c -o helloworld `gtk-config --cflags` \
299 This uses the program <tt>gtk-config</>, which comes with gtk. This
300 program 'knows' what compiler switches are needed to compile programs
301 that use gtk. <tt>gtk-config --cflags</> will output a list of include
302 directories for the compiler to look in, and <tt>gtk-config --libs</>
303 will output the list of libraries for the compiler to link with and
304 the directories to find them in. In the aboce example they could have
305 been combined into a single instance, such as
306 `gtk-config --cflags --libs`.
308 Note that the type of single quote used in the compile command above
311 The libraries that are usually linked in are:
313 <item>The GTK library (-lgtk), the widget library, based on top of GDK.
314 <item>The GDK library (-lgdk), the Xlib wrapper.
315 <item>The gmodule library (-lgmodule), which is used to load run time
317 <item>The glib library (-lglib), containing miscellaneous functions, only
318 g_print() is used in this particular example. GTK is built on top
319 of glib so you will always require this library. See the section on
320 <ref id="sec_glib" name="glib"> for details.
321 <item>The Xlib library (-lX11) which is used by GDK.
322 <item>The Xext library (-lXext). This contains code for shared memory
323 pixmaps and other X extensions.
324 <item>The math library (-lm). This is used by GTK for various purposes.
327 <!-- ----------------------------------------------------------------- -->
328 <sect1>Theory of Signals and Callbacks
330 Before we look in detail at <em>helloworld</em>, we'll discuss signals
331 and callbacks. GTK is an event driven toolkit, which means it will
332 sleep in gtk_main until an event occurs and control is passed to the
333 appropriate function.
335 This passing of control is done using the idea of "signals". When an
336 event occurs, such as the press of a mouse button, the appropriate
337 signal will be "emitted" by the widget that was pressed. This is how
338 GTK does most of its useful work. There are a set of signals that all
339 widgets inherit, such as "destroy", and there are signals that are
340 widget specific, such as "toggled" on a toggle button.
342 To make a button perform an action, we set up a signal handler to
343 catch these signals and call the appropriate function. This is done by
344 using a function such as:
347 gint gtk_signal_connect( GtkObject *object,
350 gpointer func_data );
353 Where the first argument is the widget which will be emitting the
354 signal, and the second, the name of the signal you wish to catch. The
355 third is the function you wish to be called when it is caught, and the
356 fourth, the data you wish to have passed to this function.
358 The function specified in the third argument is called a "callback
359 function", and should generally be of the form:
362 void callback_func( GtkWidget *widget,
363 gpointer callback_data );
366 Where the first argument will be a pointer to the widget that emitted
367 the signal, and the second, a pointer to the data given as the last
368 argument to the gtk_signal_connect() function as shown above.
370 Note that the above form for a signal callback function declaration is
371 only a general guide, as some widget specific signals generate
372 different calling parameters. For example, the GtkCList "select_row"
373 signal provides both row and column parameters.
375 Another call used in the <em>helloworld</em> example, is:
378 gint gtk_signal_connect_object( GtkObject *object,
381 GtkObject *slot_object );
384 gtk_signal_connect_object() is the same as gtk_signal_connect() except
385 that the callback function only uses one argument, a pointer to a GTK
386 object. So when using this function to connect signals, the callback
387 should be of the form:
390 void callback_func( GtkObject *object );
393 Where the object is usually a widget. We usually don't setup callbacks
394 for gtk_signal_connect_object however. They are usually used to call a
395 GTK function that accepts a single widget or object as an argument, as
396 is the case in our <em>helloworld</em> example.
398 The purpose of having two functions to connect signals is simply to
399 allow the callbacks to have a different number of arguments. Many
400 functions in the GTK library accept only a single GtkWidget pointer as
401 an argument, so you want to use the gtk_signal_connect_object() for
402 these, whereas for your functions, you may need to have additional
403 data supplied to the callbacks.
405 <!-- ----------------------------------------------------------------- -->
408 In addition to the signal mechanism described above, there are a set
409 of <em>events</em> that reflect the X event mechanism. Callbacks may
410 also be attached to these events. These events are:
414 <item> button_press_event
415 <item> button_release_event
416 <item> motion_notify_event
420 <item> key_press_event
421 <item> key_release_event
422 <item> enter_notify_event
423 <item> leave_notify_event
424 <item> configure_event
425 <item> focus_in_event
426 <item> focus_out_event
429 <item> property_notify_event
430 <item> selection_clear_event
431 <item> selection_request_event
432 <item> selection_notify_event
433 <item> proximity_in_event
434 <item> proximity_out_event
435 <item> drag_begin_event
436 <item> drag_request_event
437 <item> drag_end_event
438 <item> drop_enter_event
439 <item> drop_leave_event
440 <item> drop_data_available_event
444 In order to connect a callback function to one of these events, you
445 use the function gtk_signal_connect, as described above, using one of
446 the above event names as the <tt/name/ parameter. The callback
447 function for events has a slightly different form than that for
451 void callback_func( GtkWidget *widget,
453 gpointer callback_data );
456 GdkEvent is a C <tt/union/ structure whose type will depend upon which
457 of the above events has occurred. In order for us to tell which event
458 has been issued each of the possible alternatives has a <tt/type/
459 parameter which reflects the event being issued. The other components
460 of the event structure will depend upon the type of the
461 event. Possible values for the type are:
483 GDK_SELECTION_REQUEST
493 GDK_VISIBILITY_NOTIFY
495 GDK_OTHER_EVENT /* Deprecated, use filters instead */
498 So, to connect a callback function to one of these events we would use
502 gtk_signal_connect( GTK_OBJECT(button), "button_press_event",
503 GTK_SIGNAL_FUNC(button_press_callback),
507 This assumes that <tt/button/ is a GtkButton widget. Now, when the
508 mouse is over the button and a mouse button is pressed, the function
509 <tt/button_press_callback/ will be called. This function may be
513 static gint button_press_event (GtkWidget *widget,
514 GdkEventButton *event,
518 Note that we can declare the second argument as type
519 <tt/GdkEventButton/ as we know what type of event will occur for this
520 function to be called.
522 The value returned from this function indicates whether the event
523 should be propagated further by the GTK event handling
524 mechanism. Returning TRUE indicates that the event has been handled,
525 and that it should not propagate further. Returning FALSE continues
526 the normal event handling. See the section on
527 <ref id="sec_Adv_Events_and_Signals"
528 name="Advanced Event and Signal Handling"> for more details on this
531 For details on the GdkEvent data types, see the appendix entitled
532 <ref id="sec_GDK_Event_Types" name="GDK Event Types">.
534 <!-- ----------------------------------------------------------------- -->
535 <sect1>Stepping Through Hello World
537 Now that we know the theory behind this, lets clarify by walking through
538 the example <em>helloworld</em> program.
540 Here is the callback function that will be called when the button is
541 "clicked". We ignore both the widget and the data in this example, but
542 it is not hard to do things with them. The next example will use the
543 data argument to tell us which button was pressed.
546 void hello( GtkWidget *widget,
549 g_print ("Hello World\n");
553 The next callback is a bit special. The "delete_event" occurs when the
554 window manager sends this event to the application. We have a choice
555 here as to what to do about these events. We can ignore them, make
556 some sort of response, or simply quit the application.
558 The value you return in this callback lets GTK know what action to
559 take. By returning TRUE, we let it know that we don't want to have
560 the "destroy" signal emitted, keeping our application running. By
561 returning FALSE, we ask that "destroy" is emitted, which in turn will
562 call our "destroy" signal handler.
565 gint delete_event( GtkWidget *widget,
569 g_print ("delete event occurred\n");
575 Here is another callback function which causes the program to quit by
576 calling gtk_main_quit(). This function tells GTK that it is to exit
577 from gtk_main when control is returned to it.
580 void destroy( GtkWidget *widget,
587 I assume you know about the main() function... yes, as with other
588 applications, all GTK applications will also have one of these.
596 This next part, declares a pointer to a structure of type
597 GtkWidget. These are used below to create a window and a button.
604 Here is our gtk_init again. As before, this initializes the toolkit,
605 and parses the arguments found on the command line. Any argument it
606 recognizes from the command line, it removes from the list, and
607 modifies argc and argv to make it look like they never existed,
608 allowing your application to parse the remaining arguments.
611 gtk_init (&argc, &argv);
614 Create a new window. This is fairly straight forward. Memory is
615 allocated for the GtkWidget *window structure so it now points to a
616 valid structure. It sets up a new window, but it is not displayed
617 until we call gtk_widget_show(window) near the end of our program.
620 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
623 Here is an example of connecting a signal handler to an object, in
624 this case, the window. Here, the "destroy" signal is caught. This is
625 emitted when we use the window manager to kill the window (and we
626 return FALSE in the "delete_event" handler), or when we use the
627 gtk_widget_destroy() call passing in the window widget as the object
628 to destroy. By setting this up, we handle both cases with a single
629 call. Here, it just calls the destroy() function defined above with a
630 NULL argument, which quits GTK for us.
632 The GTK_OBJECT and GTK_SIGNAL_FUNC are macros that perform type
633 casting and checking for us, as well as aid the readability of the
637 gtk_signal_connect (GTK_OBJECT (window), "destroy",
638 GTK_SIGNAL_FUNC (destroy), NULL);
641 This next function is used to set an attribute of a container object.
642 This just sets the window so it has a blank area along the inside of
643 it 10 pixels wide where no widgets will go. There are other similar
644 functions which we will look at in the section on
645 <ref id="sec_setting_widget_attributes" name="Setting Widget Attributes">
647 And again, GTK_CONTAINER is a macro to perform type casting.
650 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
653 This call creates a new button. It allocates space for a new GtkWidget
654 structure in memory, initializes it, and makes the button pointer
655 point to it. It will have the label "Hello World" on it when
659 button = gtk_button_new_with_label ("Hello World");
662 Here, we take this button, and make it do something useful. We attach
663 a signal handler to it so when it emits the "clicked" signal, our
664 hello() function is called. The data is ignored, so we simply pass in
665 NULL to the hello() callback function. Obviously, the "clicked" signal
666 is emitted when we click the button with our mouse pointer.
669 gtk_signal_connect (GTK_OBJECT (button), "clicked",
670 GTK_SIGNAL_FUNC (hello), NULL);
673 We are also going to use this button to exit our program. This will
674 illustrate how the "destroy" signal may come from either the window
675 manager, or our program. When the button is "clicked", same as above,
676 it calls the first hello() callback function, and then this one in the
677 order they are set up. You may have as many callback functions as you
678 need, and all will be executed in the order you connected
679 them. Because the gtk_widget_destroy() function accepts only a
680 GtkWidget *widget as an argument, we use the
681 gtk_signal_connect_object() function here instead of straight
682 gtk_signal_connect().
685 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
686 GTK_SIGNAL_FUNC (gtk_widget_destroy),
687 GTK_OBJECT (window));
690 This is a packing call, which will be explained in depth later on. But
691 it is fairly easy to understand. It simply tells GTK that the button
692 is to be placed in the window where it will be displayed. Note that a
693 GTK container can only contain one widget. There are other widgets,
694 that are described later, which are designed to layout multiple
695 widgets in various ways.
698 gtk_container_add (GTK_CONTAINER (window), button);
701 Now we have everything set up the way we want it to be. With all the
702 signal handlers in place, and the button placed in the window where it
703 should be, we ask GTK to "show" the widgets on the screen. The window
704 widget is shown last so the whole window will pop up at once rather
705 than seeing the window pop up, and then the button form inside of
706 it. Although with such a simple example, you'd never notice.
709 gtk_widget_show (button);
711 gtk_widget_show (window);
714 And of course, we call gtk_main() which waits for events to come from
715 the X server and will call on the widgets to emit signals when these
722 And the final return. Control returns here after gtk_quit() is called.
728 Now, when we click the mouse button on a GTK button, the widget emits
729 a "clicked" signal. In order for us to use this information, our
730 program sets up a signal handler to catch that signal, which
731 dispatches the function of our choice. In our example, when the button
732 we created is "clicked", the hello() function is called with a NULL
733 argument, and then the next handler for this signal is called. This
734 calls the gtk_widget_destroy() function, passing it the window widget
735 as its argument, destroying the window widget. This causes the window
736 to emit the "destroy" signal, which is caught, and calls our destroy()
737 callback function, which simply exits GTK.
739 Another course of events, is to use the window manager to kill the
740 window. This will cause the "delete_event" to be emitted. This will
741 call our "delete_event" handler. If we return TRUE here, the window
742 will be left as is and nothing will happen. Returning FALSE will cause
743 GTK to emit the "destroy" signal which of course, calls the "destroy"
744 callback, exiting GTK.
746 Note that these signals are not the same as the Unix system signals,
747 and are not implemented using them, although the terminology is almost
750 <!-- ***************************************************************** -->
752 <!-- ***************************************************************** -->
754 <!-- ----------------------------------------------------------------- -->
757 There are a few things you probably noticed in the previous examples
758 that need explaining. The gint, gchar etc. that you see are typedefs
759 to int and char respectively. This is done to get around that nasty
760 dependency on the size of simple data types when doing calculations.
762 A good example is "gint32" which will be typedef'd to a 32 bit integer
763 for any given platform, whether it be the 64 bit alpha, or the 32 bit
764 i386. The typedefs are very straight forward and intuitive. They are
765 all defined in glib/glib.h (which gets included from gtk.h).
767 You'll also notice the ability to use GtkWidget when the function
768 calls for a GtkObject. GTK is an object oriented design, and a widget
771 <!-- ----------------------------------------------------------------- -->
772 <sect1>More on Signal Handlers
774 Lets take another look at the gtk_signal_connect declaration.
777 gint gtk_signal_connect( GtkObject *object,
780 gpointer func_data );
783 Notice the gint return value? This is a tag that identifies your
784 callback function. As stated above, you may have as many callbacks per
785 signal and per object as you need, and each will be executed in turn,
786 in the order they were attached.
788 This tag allows you to remove this callback from the list by using:
791 void gtk_signal_disconnect( GtkObject *object,
795 So, by passing in the widget you wish to remove the handler from, and
796 the tag returned by one of the signal_connect functions, you can
797 disconnect a signal handler.
799 Another function to remove all the signal handers from an object is:
802 void gtk_signal_handlers_destroy( GtkObject *object );
805 This call is fairly self explanatory. It simply removes all the
806 current signal handlers from the object passed in as the first
809 <!-- ----------------------------------------------------------------- -->
810 <sect1>An Upgraded Hello World
812 Let's take a look at a slightly improved <em>helloworld</em> with
813 better examples of callbacks. This will also introduce us to our next
814 topic, packing widgets.
817 /* example-start helloworld2 helloworld2.c */
821 /* Our new improved callback. The data passed to this function
822 * is printed to stdout. */
823 void callback( GtkWidget *widget,
826 g_print ("Hello again - %s was pressed\n", (char *) data);
829 /* another callback */
830 void delete_event( GtkWidget *widget,
840 /* GtkWidget is the storage type for widgets */
845 /* This is called in all GTK applications. Arguments are parsed
846 * from the command line and are returned to the application. */
847 gtk_init (&argc, &argv);
849 /* Create a new window */
850 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
852 /* This is a new call, this just sets the title of our
853 * new window to "Hello Buttons!" */
854 gtk_window_set_title (GTK_WINDOW (window), "Hello Buttons!");
856 /* Here we just set a handler for delete_event that immediately
858 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
859 GTK_SIGNAL_FUNC (delete_event), NULL);
861 /* Sets the border width of the window. */
862 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
864 /* We create a box to pack widgets into. This is described in detail
865 * in the "packing" section. The box is not really visible, it
866 * is just used as a tool to arrange widgets. */
867 box1 = gtk_hbox_new(FALSE, 0);
869 /* Put the box into the main window. */
870 gtk_container_add (GTK_CONTAINER (window), box1);
872 /* Creates a new button with the label "Button 1". */
873 button = gtk_button_new_with_label ("Button 1");
875 /* Now when the button is clicked, we call the "callback" function
876 * with a pointer to "button 1" as its argument */
877 gtk_signal_connect (GTK_OBJECT (button), "clicked",
878 GTK_SIGNAL_FUNC (callback), (gpointer) "button 1");
880 /* Instead of gtk_container_add, we pack this button into the invisible
881 * box, which has been packed into the window. */
882 gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);
884 /* Always remember this step, this tells GTK that our preparation for
885 * this button is complete, and it can now be displayed. */
886 gtk_widget_show(button);
888 /* Do these same steps again to create a second button */
889 button = gtk_button_new_with_label ("Button 2");
891 /* Call the same callback function with a different argument,
892 * passing a pointer to "button 2" instead. */
893 gtk_signal_connect (GTK_OBJECT (button), "clicked",
894 GTK_SIGNAL_FUNC (callback), (gpointer) "button 2");
896 gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);
898 /* The order in which we show the buttons is not really important, but I
899 * recommend showing the window last, so it all pops up at once. */
900 gtk_widget_show(button);
902 gtk_widget_show(box1);
904 gtk_widget_show (window);
906 /* Rest in gtk_main and wait for the fun to begin! */
914 Compile this program using the same linking arguments as our first
915 example. You'll notice this time there is no easy way to exit the
916 program, you have to use your window manager or command line to kill
917 it. A good exercise for the reader would be to insert a third "Quit"
918 button that will exit the program. You may also wish to play with the
919 options to gtk_box_pack_start() while reading the next section. Try
920 resizing the window, and observe the behavior.
922 Just as a side note, there is another useful define for
923 gtk_window_new() - GTK_WINDOW_DIALOG. This interacts with the window
924 manager a little differently and should be used for transient windows.
926 <!-- ***************************************************************** -->
927 <sect>Packing Widgets
928 <!-- ***************************************************************** -->
930 When creating an application, you'll want to put more than one widget
931 inside a window. Our first <em>helloworld</em> example only used one
932 widget so we could simply use a gtk_container_add call to "pack" the
933 widget into the window. But when you want to put more than one widget
934 into a window, how do you control where that widget is positioned?
935 This is where packing comes in.
937 <!-- ----------------------------------------------------------------- -->
938 <sect1>Theory of Packing Boxes
940 Most packing is done by creating boxes as in the example above. These
941 are invisible widget containers that we can pack our widgets into
942 which come in two forms, a horizontal box, and a vertical box. When
943 packing widgets into a horizontal box, the objects are inserted
944 horizontally from left to right or right to left depending on the call
945 used. In a vertical box, widgets are packed from top to bottom or vice
946 versa. You may use any combination of boxes inside or beside other
947 boxes to create the desired effect.
949 To create a new horizontal box, we use a call to gtk_hbox_new(), and
950 for vertical boxes, gtk_vbox_new().The gtk_box_pack_start() and
951 gtk_box_pack_end() functions are used to place objects inside of these
952 containers. The gtk_box_pack_start() function will start at the top
953 and work its way down in a vbox, and pack left to right in an hbox.
954 gtk_box_pack_end() will do the opposite, packing from bottom to top in
955 a vbox, and right to left in an hbox. Using these functions allow us
956 to right justify or left justify our widgets and may be mixed in any
957 way to achieve the desired effect. We will use gtk_box_pack_start() in
958 most of our examples. An object may be another container or a
959 widget. In fact, many widgets are actually containers themselves,
960 including the button, but we usually only use a label inside a button.
962 By using these calls, GTK knows where you want to place your widgets
963 so it can do automatic resizing and other nifty things. There's also a
964 number of options as to how your widgets should be packed. As you can
965 imagine, this method gives us a quite a bit of flexibility when
966 placing and creating widgets.
968 <!-- ----------------------------------------------------------------- -->
969 <sect1>Details of Boxes
971 Because of this flexibility, packing boxes in GTK can be confusing at
972 first. There are a lot of options, and it's not immediately obvious how
973 they all fit together. In the end however, there are basically five
978 <IMG SRC="gtk_tut_packbox1.gif" VSPACE="15" HSPACE="10" WIDTH="528"
979 HEIGHT="235" ALT="Box Packing Example Image">
983 Each line contains one horizontal box (hbox) with several buttons. The
984 call to gtk_box_pack is shorthand for the call to pack each of the
985 buttons into the hbox. Each of the buttons is packed into the hbox the
986 same way (i.e. same arguments to the gtk_box_pack_start() function).
988 This is the declaration of the gtk_box_pack_start function.
991 void gtk_box_pack_start( GtkBox *box,
998 The first argument is the box you are packing the object into, the
999 second is the object. The objects will all be buttons for now, so
1000 we'll be packing buttons into boxes.
1002 The expand argument to gtk_box_pack_start() and gtk_box_pack_end()
1003 controls whether the widgets are laid out in the box to fill in all
1004 the extra space in the box so the box is expanded to fill the area
1005 alloted to it (TRUE). Or the box is shrunk to just fit the widgets
1006 (FALSE). Setting expand to FALSE will allow you to do right and left
1007 justification of your widgets. Otherwise, they will all expand to fit
1008 into the box, and the same effect could be achieved by using only one
1009 of gtk_box_pack_start or gtk_box_pack_end.
1011 The fill argument to the gtk_box_pack functions control whether the
1012 extra space is allocated to the objects themselves (TRUE), or as extra
1013 padding in the box around these objects (FALSE). It only has an effect
1014 if the expand argument is also TRUE.
1016 When creating a new box, the function looks like this:
1019 GtkWidget *gtk_hbox_new (gint homogeneous,
1023 The homogeneous argument to gtk_hbox_new (and the same for
1024 gtk_vbox_new) controls whether each object in the box has the same
1025 size (i.e. the same width in an hbox, or the same height in a
1026 vbox). If it is set, the expand argument to the gtk_box_pack routines
1027 is always turned on.
1029 What's the difference between spacing (set when the box is created)
1030 and padding (set when elements are packed)? Spacing is added between
1031 objects, and padding is added on either side of an object. The
1032 following figure should make it clearer:
1036 <IMG ALIGN="center" SRC="gtk_tut_packbox2.gif" WIDTH="509"
1037 HEIGHT="213" VSPACE="15" HSPACE="10"
1038 ALT="Box Packing Example Image">
1042 Here is the code used to create the above images. I've commented it
1043 fairly heavily so hopefully you won't have any problems following
1044 it. Compile it yourself and play with it.
1046 <!-- ----------------------------------------------------------------- -->
1047 <sect1>Packing Demonstration Program
1050 /* example-start packbox packbox.c */
1053 #include "gtk/gtk.h"
1055 void delete_event( GtkWidget *widget,
1062 /* Make a new hbox filled with button-labels. Arguments for the
1063 * variables we're interested are passed in to this function.
1064 * We do not show the box, but do show everything inside. */
1065 GtkWidget *make_box( gint homogeneous,
1075 /* Create a new hbox with the appropriate homogeneous
1076 * and spacing settings */
1077 box = gtk_hbox_new (homogeneous, spacing);
1079 /* Create a series of buttons with the appropriate settings */
1080 button = gtk_button_new_with_label ("gtk_box_pack");
1081 gtk_box_pack_start (GTK_BOX (box), button, expand, fill, padding);
1082 gtk_widget_show (button);
1084 button = gtk_button_new_with_label ("(box,");
1085 gtk_box_pack_start (GTK_BOX (box), button, expand, fill, padding);
1086 gtk_widget_show (button);
1088 button = gtk_button_new_with_label ("button,");
1089 gtk_box_pack_start (GTK_BOX (box), button, expand, fill, padding);
1090 gtk_widget_show (button);
1092 /* Create a button with the label depending on the value of
1095 button = gtk_button_new_with_label ("TRUE,");
1097 button = gtk_button_new_with_label ("FALSE,");
1099 gtk_box_pack_start (GTK_BOX (box), button, expand, fill, padding);
1100 gtk_widget_show (button);
1102 /* This is the same as the button creation for "expand"
1103 * above, but uses the shorthand form. */
1104 button = gtk_button_new_with_label (fill ? "TRUE," : "FALSE,");
1105 gtk_box_pack_start (GTK_BOX (box), button, expand, fill, padding);
1106 gtk_widget_show (button);
1108 sprintf (padstr, "%d);", padding);
1110 button = gtk_button_new_with_label (padstr);
1111 gtk_box_pack_start (GTK_BOX (box), button, expand, fill, padding);
1112 gtk_widget_show (button);
1124 GtkWidget *separator;
1129 /* Our init, don't forget this! :) */
1130 gtk_init (&argc, &argv);
1133 fprintf (stderr, "usage: packbox num, where num is 1, 2, or 3.\n");
1134 /* this just does cleanup in GTK, and exits with an exit status of 1. */
1138 which = atoi (argv[1]);
1140 /* Create our window */
1141 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
1143 /* You should always remember to connect the destroy signal to the
1144 * main window. This is very important for proper intuitive
1146 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
1147 GTK_SIGNAL_FUNC (delete_event), NULL);
1148 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
1150 /* We create a vertical box (vbox) to pack the horizontal boxes into.
1151 * This allows us to stack the horizontal boxes filled with buttons one
1152 * on top of the other in this vbox. */
1153 box1 = gtk_vbox_new (FALSE, 0);
1155 /* which example to show. These correspond to the pictures above. */
1158 /* create a new label. */
1159 label = gtk_label_new ("gtk_hbox_new (FALSE, 0);");
1161 /* Align the label to the left side. We'll discuss this function and
1162 * others in the section on Widget Attributes. */
1163 gtk_misc_set_alignment (GTK_MISC (label), 0, 0);
1165 /* Pack the label into the vertical box (vbox box1). Remember that
1166 * widgets added to a vbox will be packed one on top of the other in
1168 gtk_box_pack_start (GTK_BOX (box1), label, FALSE, FALSE, 0);
1170 /* Show the label */
1171 gtk_widget_show (label);
1173 /* Call our make box function - homogeneous = FALSE, spacing = 0,
1174 * expand = FALSE, fill = FALSE, padding = 0 */
1175 box2 = make_box (FALSE, 0, FALSE, FALSE, 0);
1176 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1177 gtk_widget_show (box2);
1179 /* Call our make box function - homogeneous = FALSE, spacing = 0,
1180 * expand = FALSE, fill = FALSE, padding = 0 */
1181 box2 = make_box (FALSE, 0, TRUE, FALSE, 0);
1182 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1183 gtk_widget_show (box2);
1185 /* Args are: homogeneous, spacing, expand, fill, padding */
1186 box2 = make_box (FALSE, 0, TRUE, TRUE, 0);
1187 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1188 gtk_widget_show (box2);
1190 /* Creates a separator, we'll learn more about these later,
1191 * but they are quite simple. */
1192 separator = gtk_hseparator_new ();
1194 /* Cack the separator into the vbox. Remember each of these
1195 * widgets are being packed into a vbox, so they'll be stacked
1197 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 5);
1198 gtk_widget_show (separator);
1200 /* Create another new label, and show it. */
1201 label = gtk_label_new ("gtk_hbox_new (TRUE, 0);");
1202 gtk_misc_set_alignment (GTK_MISC (label), 0, 0);
1203 gtk_box_pack_start (GTK_BOX (box1), label, FALSE, FALSE, 0);
1204 gtk_widget_show (label);
1206 /* Args are: homogeneous, spacing, expand, fill, padding */
1207 box2 = make_box (TRUE, 0, TRUE, FALSE, 0);
1208 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1209 gtk_widget_show (box2);
1211 /* Args are: homogeneous, spacing, expand, fill, padding */
1212 box2 = make_box (TRUE, 0, TRUE, TRUE, 0);
1213 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1214 gtk_widget_show (box2);
1216 /* Another new separator. */
1217 separator = gtk_hseparator_new ();
1218 /* The last 3 arguments to gtk_box_pack_start are: expand, fill, padding. */
1219 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 5);
1220 gtk_widget_show (separator);
1226 /* Create a new label, remember box1 is a vbox as created
1227 * near the beginning of main() */
1228 label = gtk_label_new ("gtk_hbox_new (FALSE, 10);");
1229 gtk_misc_set_alignment (GTK_MISC (label), 0, 0);
1230 gtk_box_pack_start (GTK_BOX (box1), label, FALSE, FALSE, 0);
1231 gtk_widget_show (label);
1233 /* Args are: homogeneous, spacing, expand, fill, padding */
1234 box2 = make_box (FALSE, 10, TRUE, FALSE, 0);
1235 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1236 gtk_widget_show (box2);
1238 /* Args are: homogeneous, spacing, expand, fill, padding */
1239 box2 = make_box (FALSE, 10, TRUE, TRUE, 0);
1240 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1241 gtk_widget_show (box2);
1243 separator = gtk_hseparator_new ();
1244 /* The last 3 arguments to gtk_box_pack_start are: expand, fill, padding. */
1245 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 5);
1246 gtk_widget_show (separator);
1248 label = gtk_label_new ("gtk_hbox_new (FALSE, 0);");
1249 gtk_misc_set_alignment (GTK_MISC (label), 0, 0);
1250 gtk_box_pack_start (GTK_BOX (box1), label, FALSE, FALSE, 0);
1251 gtk_widget_show (label);
1253 /* Args are: homogeneous, spacing, expand, fill, padding */
1254 box2 = make_box (FALSE, 0, TRUE, FALSE, 10);
1255 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1256 gtk_widget_show (box2);
1258 /* Args are: homogeneous, spacing, expand, fill, padding */
1259 box2 = make_box (FALSE, 0, TRUE, TRUE, 10);
1260 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1261 gtk_widget_show (box2);
1263 separator = gtk_hseparator_new ();
1264 /* The last 3 arguments to gtk_box_pack_start are: expand, fill, padding. */
1265 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 5);
1266 gtk_widget_show (separator);
1271 /* This demonstrates the ability to use gtk_box_pack_end() to
1272 * right justify widgets. First, we create a new box as before. */
1273 box2 = make_box (FALSE, 0, FALSE, FALSE, 0);
1275 /* Create the label that will be put at the end. */
1276 label = gtk_label_new ("end");
1277 /* Pack it using gtk_box_pack_end(), so it is put on the right
1278 * side of the hbox created in the make_box() call. */
1279 gtk_box_pack_end (GTK_BOX (box2), label, FALSE, FALSE, 0);
1280 /* Show the label. */
1281 gtk_widget_show (label);
1283 /* Pack box2 into box1 (the vbox remember ? :) */
1284 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, FALSE, 0);
1285 gtk_widget_show (box2);
1287 /* A separator for the bottom. */
1288 separator = gtk_hseparator_new ();
1289 /* This explicitly sets the separator to 400 pixels wide by 5 pixels
1290 * high. This is so the hbox we created will also be 400 pixels wide,
1291 * and the "end" label will be separated from the other labels in the
1292 * hbox. Otherwise, all the widgets in the hbox would be packed as
1293 * close together as possible. */
1294 gtk_widget_set_usize (separator, 400, 5);
1295 /* pack the separator into the vbox (box1) created near the start
1297 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 5);
1298 gtk_widget_show (separator);
1301 /* Create another new hbox.. remember we can use as many as we need! */
1302 quitbox = gtk_hbox_new (FALSE, 0);
1304 /* Our quit button. */
1305 button = gtk_button_new_with_label ("Quit");
1307 /* Setup the signal to destroy the window. Remember that this will send
1308 * the "destroy" signal to the window which will be caught by our signal
1309 * handler as defined above. */
1310 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
1311 GTK_SIGNAL_FUNC (gtk_main_quit),
1312 GTK_OBJECT (window));
1313 /* Pack the button into the quitbox.
1314 * The last 3 arguments to gtk_box_pack_start are: expand, fill, padding. */
1315 gtk_box_pack_start (GTK_BOX (quitbox), button, TRUE, FALSE, 0);
1316 /* pack the quitbox into the vbox (box1) */
1317 gtk_box_pack_start (GTK_BOX (box1), quitbox, FALSE, FALSE, 0);
1319 /* Pack the vbox (box1) which now contains all our widgets, into the
1321 gtk_container_add (GTK_CONTAINER (window), box1);
1323 /* And show everything left */
1324 gtk_widget_show (button);
1325 gtk_widget_show (quitbox);
1327 gtk_widget_show (box1);
1328 /* Showing the window last so everything pops up at once. */
1329 gtk_widget_show (window);
1331 /* And of course, our main function. */
1334 /* Control returns here when gtk_main_quit() is called, but not when
1335 * gtk_exit is used. */
1342 <!-- ----------------------------------------------------------------- -->
1343 <sect1>Packing Using Tables
1345 Let's take a look at another way of packing - Tables. These can be
1346 extremely useful in certain situations.
1348 Using tables, we create a grid that we can place widgets in. The
1349 widgets may take up as many spaces as we specify.
1351 The first thing to look at of course, is the gtk_table_new function:
1354 GtkWidget *gtk_table_new( gint rows,
1359 The first argument is the number of rows to make in the table, while
1360 the second, obviously, is the number of columns.
1362 The homogeneous argument has to do with how the table's boxes are
1363 sized. If homogeneous is TRUE, the table boxes are resized to the size
1364 of the largest widget in the table. If homogeneous is FALSE, the size
1365 of a table boxes is dictated by the tallest widget in its same row,
1366 and the widest widget in its column.
1368 The rows and columns are laid out from 0 to n, where n was the number
1369 specified in the call to gtk_table_new. So, if you specify rows = 2
1370 and columns = 2, the layout would look something like this:
1374 0+----------+----------+
1376 1+----------+----------+
1378 2+----------+----------+
1381 Note that the coordinate system starts in the upper left hand corner.
1382 To place a widget into a box, use the following function:
1385 void gtk_table_attach( GtkTable *table,
1397 Where the first argument ("table") is the table you've created and the
1398 second ("child") the widget you wish to place in the table.
1400 The left and right attach arguments specify where to place the widget,
1401 and how many boxes to use. If you want a button in the lower right
1402 table entry of our 2x2 table, and want it to fill that entry ONLY,
1403 left_attach would be = 1, right_attach = 2, top_attach = 1,
1406 Now, if you wanted a widget to take up the whole top row of our 2x2
1407 table, you'd use left_attach = 0, right_attach = 2, top_attach = 0,
1410 The xoptions and yoptions are used to specify packing options and may
1411 be bitwise OR'ed together to allow multiple options.
1415 <item>GTK_FILL - If the table box is larger than the widget, and
1416 GTK_FILL is specified, the widget will expand to use all the room
1419 <item>GTK_SHRINK - If the table widget was allocated less space then
1420 was requested (usually by the user resizing the window), then the
1421 widgets would normally just be pushed off the bottom of the window and
1422 disappear. If GTK_SHRINK is specified, the widgets will shrink with
1425 <item>GTK_EXPAND - This will cause the table to expand to use up any
1426 remaining space in the window.
1429 Padding is just like in boxes, creating a clear area around the widget
1430 specified in pixels.
1432 gtk_table_attach() has a LOT of options. So, there's a shortcut:
1435 void gtk_table_attach_defaults( GtkTable *table,
1440 gint bottom_attach );
1443 The X and Y options default to GTK_FILL | GTK_EXPAND, and X and Y
1444 padding are set to 0. The rest of the arguments are identical to the
1447 We also have gtk_table_set_row_spacing() and
1448 gtk_table_set_col_spacing(). This places spacing between the rows at
1449 the specified row or column.
1452 void gtk_table_set_row_spacing( GtkTable *table,
1460 void gtk_table_set_col_spacing ( GtkTable *table,
1465 Note that for columns, the space goes to the right of the column, and
1466 for rows, the space goes below the row.
1468 You can also set a consistent spacing of all rows and/or columns with:
1471 void gtk_table_set_row_spacings( GtkTable *table,
1478 void gtk_table_set_col_spacings( GtkTable *table,
1482 Note that with these calls, the last row and last column do not get
1485 <!-- ----------------------------------------------------------------- -->
1486 <sect1>Table Packing Example
1488 Here we make a window with three buttons in a 2x2 table.
1489 The first two buttons will be placed in the upper row.
1490 A third, quit button, is placed in the lower row, spanning both columns.
1491 Which means it should look something like this:
1495 <IMG SRC="gtk_tut_table.gif" VSPACE="15" HSPACE="10"
1496 ALT="Table Packing Example Image" WIDTH="180" HEIGHT="120">
1500 Here's the source code:
1503 /* example-start table table.c */
1505 #include <gtk/gtk.h>
1508 * The data passed to this function is printed to stdout */
1509 void callback( GtkWidget *widget,
1512 g_print ("Hello again - %s was pressed\n", (char *) data);
1515 /* This callback quits the program */
1516 void delete_event( GtkWidget *widget,
1530 gtk_init (&argc, &argv);
1532 /* Create a new window */
1533 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
1535 /* Set the window title */
1536 gtk_window_set_title (GTK_WINDOW (window), "Table");
1538 /* Set a handler for delete_event that immediately
1540 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
1541 GTK_SIGNAL_FUNC (delete_event), NULL);
1543 /* Sets the border width of the window. */
1544 gtk_container_set_border_width (GTK_CONTAINER (window), 20);
1546 /* Create a 2x2 table */
1547 table = gtk_table_new (2, 2, TRUE);
1549 /* Put the table in the main window */
1550 gtk_container_add (GTK_CONTAINER (window), table);
1552 /* Create first button */
1553 button = gtk_button_new_with_label ("button 1");
1555 /* When the button is clicked, we call the "callback" function
1556 * with a pointer to "button 1" as its argument */
1557 gtk_signal_connect (GTK_OBJECT (button), "clicked",
1558 GTK_SIGNAL_FUNC (callback), (gpointer) "button 1");
1561 /* Insert button 1 into the upper left quadrant of the table */
1562 gtk_table_attach_defaults (GTK_TABLE(table), button, 0, 1, 0, 1);
1564 gtk_widget_show (button);
1566 /* Create second button */
1568 button = gtk_button_new_with_label ("button 2");
1570 /* When the button is clicked, we call the "callback" function
1571 * with a pointer to "button 2" as its argument */
1572 gtk_signal_connect (GTK_OBJECT (button), "clicked",
1573 GTK_SIGNAL_FUNC (callback), (gpointer) "button 2");
1574 /* Insert button 2 into the upper right quadrant of the table */
1575 gtk_table_attach_defaults (GTK_TABLE(table), button, 1, 2, 0, 1);
1577 gtk_widget_show (button);
1579 /* Create "Quit" button */
1580 button = gtk_button_new_with_label ("Quit");
1582 /* When the button is clicked, we call the "delete_event" function
1583 * and the program exits */
1584 gtk_signal_connect (GTK_OBJECT (button), "clicked",
1585 GTK_SIGNAL_FUNC (delete_event), NULL);
1587 /* Insert the quit button into the both
1588 * lower quadrants of the table */
1589 gtk_table_attach_defaults (GTK_TABLE(table), button, 0, 2, 1, 2);
1591 gtk_widget_show (button);
1593 gtk_widget_show (table);
1594 gtk_widget_show (window);
1603 <!-- ***************************************************************** -->
1604 <sect>Widget Overview
1605 <!-- ***************************************************************** -->
1607 The general steps to creating a widget in GTK are:
1609 <item> gtk_*_new - one of various functions to create a new widget.
1610 These are all detailed in this section.
1612 <item> Connect all signals and events we wish to use to the
1613 appropriate handlers.
1615 <item> Set the attributes of the widget.
1617 <item> Pack the widget into a container using the appropriate call
1618 such as gtk_container_add() or gtk_box_pack_start().
1620 <item> gtk_widget_show() the widget.
1623 gtk_widget_show() lets GTK know that we are done setting the
1624 attributes of the widget, and it is ready to be displayed. You may
1625 also use gtk_widget_hide to make it disappear again. The order in
1626 which you show the widgets is not important, but I suggest showing the
1627 window last so the whole window pops up at once rather than seeing the
1628 individual widgets come up on the screen as they're formed. The
1629 children of a widget (a window is a widget too) will not be displayed
1630 until the window itself is shown using the gtk_widget_show() function.
1632 <!-- ----------------------------------------------------------------- -->
1635 You'll notice as you go on, that GTK uses a type casting system. This
1636 is always done using macros that both test the ability to cast the
1637 given item, and perform the cast. Some common ones you will see are:
1640 <item> GTK_WIDGET(widget)
1641 <item> GTK_OBJECT(object)
1642 <item> GTK_SIGNAL_FUNC(function)
1643 <item> GTK_CONTAINER(container)
1644 <item> GTK_WINDOW(window)
1648 These are all used to cast arguments in functions. You'll see them in the
1649 examples, and can usually tell when to use them simply by looking at the
1650 function's declaration.
1652 As you can see below in the class hierarchy, all GtkWidgets are
1653 derived from the GtkObject base class. This means you can use a widget
1654 in any place the function asks for an object - simply use the
1660 gtk_signal_connect( GTK_OBJECT(button), "clicked",
1661 GTK_SIGNAL_FUNC(callback_function), callback_data);
1664 This casts the button into an object, and provides a cast for the
1665 function pointer to the callback.
1667 Many widgets are also containers. If you look in the class hierarchy
1668 below, you'll notice that many widgets derive from the GtkContainer
1669 class. Any one of these widgets may be used with the GTK_CONTAINER
1670 macro to pass them to functions that ask for containers.
1672 Unfortunately, these macros are not extensively covered in the
1673 tutorial, but I recommend taking a look through the GTK header
1674 files. It can be very educational. In fact, it's not difficult to
1675 learn how a widget works just by looking at the function declarations.
1677 <!-- ----------------------------------------------------------------- -->
1678 <sect1>Widget Hierarchy
1680 For your reference, here is the class hierarchy tree used to implement widgets.
1687 | | | +GtkAccelLabel
1696 | | | | `GtkAspectFrame
1698 | | | | +GtkToggleButton
1699 | | | | | `GtkCheckButton
1700 | | | | | `GtkRadioButton
1701 | | | | `GtkOptionMenu
1703 | | | | +GtkMenuItem
1704 | | | | | +GtkCheckMenuItem
1705 | | | | | | `GtkRadioMenuItem
1706 | | | | | `GtkTearoffMenuItem
1707 | | | | +GtkListItem
1708 | | | | `GtkTreeItem
1710 | | | | +GtkColorSelectionDialog
1712 | | | | | `GtkInputDialog
1713 | | | | +GtkDrawWindow
1714 | | | | +GtkFileSelection
1715 | | | | +GtkFontSelectionDialog
1719 | | | +GtkScrolledWindow
1723 | | | | +GtkHButtonBox
1724 | | | | `GtkVButtonBox
1726 | | | | +GtkColorSelection
1727 | | | | `GtkGammaCurve
1735 | | | `GtkFontSelection
1754 | | | `GtkSpinButton
1778 <!-- ----------------------------------------------------------------- -->
1779 <sect1>Widgets Without Windows
1781 The following widgets do not have an associated window. If you want to
1782 capture events, you'll have to use the GtkEventBox. See the section on
1783 the <ref id="sec_EventBox" name="EventBox"> widget.
1805 We'll further our exploration of GTK by examining each widget in turn,
1806 creating a few simple functions to display them. Another good source
1807 is the testgtk.c program that comes with GTK. It can be found in
1810 <!-- ***************************************************************** -->
1811 <sect>The Button Widget
1812 <!-- ***************************************************************** -->
1814 <!-- ----------------------------------------------------------------- -->
1815 <sect1>Normal Buttons
1817 We've almost seen all there is to see of the button widget. It's
1818 pretty simple. There are however two ways to create a button. You can
1819 use the gtk_button_new_with_label() to create a button with a label,
1820 or use gtk_button_new() to create a blank button. It's then up to you
1821 to pack a label or pixmap into this new button. To do this, create a
1822 new box, and then pack your objects into this box using the usual
1823 gtk_box_pack_start, and then use gtk_container_add to pack the box
1826 Here's an example of using gtk_button_new to create a button with a
1827 picture and a label in it. I've broken up the code to create a box
1828 from the rest so you can use it in your programs. There are further
1829 examples of using pixmaps later in the tutorial.
1832 /* example-start buttons buttons.c */
1834 #include <gtk/gtk.h>
1836 /* Create a new hbox with an image and a label packed into it
1837 * and return the box. */
1839 GtkWidget *xpm_label_box( GtkWidget *parent,
1840 gchar *xpm_filename,
1845 GtkWidget *pixmapwid;
1850 /* Create box for xpm and label */
1851 box1 = gtk_hbox_new (FALSE, 0);
1852 gtk_container_set_border_width (GTK_CONTAINER (box1), 2);
1854 /* Get the style of the button to get the
1855 * background color. */
1856 style = gtk_widget_get_style(parent);
1858 /* Now on to the xpm stuff */
1859 pixmap = gdk_pixmap_create_from_xpm (parent->window, &mask,
1860 &style->bg[GTK_STATE_NORMAL],
1862 pixmapwid = gtk_pixmap_new (pixmap, mask);
1864 /* Create a label for the button */
1865 label = gtk_label_new (label_text);
1867 /* Pack the pixmap and label into the box */
1868 gtk_box_pack_start (GTK_BOX (box1),
1869 pixmapwid, FALSE, FALSE, 3);
1871 gtk_box_pack_start (GTK_BOX (box1), label, FALSE, FALSE, 3);
1873 gtk_widget_show(pixmapwid);
1874 gtk_widget_show(label);
1879 /* Our usual callback function */
1880 void callback( GtkWidget *widget,
1883 g_print ("Hello again - %s was pressed\n", (char *) data);
1890 /* GtkWidget is the storage type for widgets */
1895 gtk_init (&argc, &argv);
1897 /* Create a new window */
1898 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
1900 gtk_window_set_title (GTK_WINDOW (window), "Pixmap'd Buttons!");
1902 /* It's a good idea to do this for all windows. */
1903 gtk_signal_connect (GTK_OBJECT (window), "destroy",
1904 GTK_SIGNAL_FUNC (gtk_exit), NULL);
1906 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
1907 GTK_SIGNAL_FUNC (gtk_exit), NULL);
1910 /* Sets the border width of the window. */
1911 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
1912 gtk_widget_realize(window);
1914 /* Create a new button */
1915 button = gtk_button_new ();
1917 /* Connect the "clicked" signal of the button to our callback */
1918 gtk_signal_connect (GTK_OBJECT (button), "clicked",
1919 GTK_SIGNAL_FUNC (callback), (gpointer) "cool button");
1921 /* This calls our box creating function */
1922 box1 = xpm_label_box(window, "info.xpm", "cool button");
1924 /* Pack and show all our widgets */
1925 gtk_widget_show(box1);
1927 gtk_container_add (GTK_CONTAINER (button), box1);
1929 gtk_widget_show(button);
1931 gtk_container_add (GTK_CONTAINER (window), button);
1933 gtk_widget_show (window);
1935 /* Rest in gtk_main and wait for the fun to begin! */
1943 The xpm_label_box function could be used to pack xpm's and labels into
1944 any widget that can be a container.
1946 The Button widget has the following signals:
1956 <!-- ----------------------------------------------------------------- -->
1957 <sect1> Toggle Buttons
1959 Toggle buttons are derived from normal buttons and are very similar,
1960 except they will always be in one of two states, alternated by a
1961 click. They may be depressed, and when you click again, they will pop
1962 back up. Click again, and they will pop back down.
1964 Toggle buttons are the basis for check buttons and radio buttons, as
1965 such, many of the calls used for toggle buttons are inherited by radio
1966 and check buttons. I will point these out when we come to them.
1968 Creating a new toggle button:
1971 GtkWidget *gtk_toggle_button_new( void );
1973 GtkWidget *gtk_toggle_button_new_with_label( gchar *label );
1976 As you can imagine, these work identically to the normal button widget
1977 calls. The first creates a blank toggle button, and the second, a
1978 button with a label widget already packed into it.
1980 To retrieve the state of the toggle widget, including radio and check
1981 buttons, we use a GTK macro as shown in our example below. This tests
1982 the state of the toggle in a callback. The signal of interest emitted
1983 to us by toggle buttons (the toggle button, check button, and radio
1984 button widgets), is the "toggled" signal. To check the state of these
1985 buttons, set up a signal handler to catch the toggled signal, and use
1986 the macro to determine its state. The callback will look something
1990 void toggle_button_callback (GtkWidget *widget, gpointer data)
1992 if (GTK_TOGGLE_BUTTON (widget)->active)
1994 /* If control reaches here, the toggle button is down */
1998 /* If control reaches here, the toggle button is up */
2004 void gtk_toggle_button_set_active( GtkToggleButton *toggle_button,
2008 The above call can be used to set the state of the toggle button, and
2009 its children the radio and check buttons. Passing in your created
2010 button as the first argument, and a TRUE or FALSE for the second state
2011 argument to specify whether it should be down (depressed) or up
2012 (released). Default is up, or FALSE.
2014 Note that when you use the gtk_toggle_button_set_active() function, and
2015 the state is actually changed, it causes the "clicked" signal to be
2016 emitted from the button.
2019 void gtk_toggle_button_toggled (GtkToggleButton *toggle_button);
2022 This simply toggles the button, and emits the "toggled" signal.
2024 <!-- ----------------------------------------------------------------- -->
2025 <sect1> Check Buttons
2027 Check buttons inherent many properties and functions from the the
2028 toggle buttons above, but look a little different. Rather than being
2029 buttons with text inside them, they are small squares with the text to
2030 the right of them. These are often used for toggling options on and
2031 off in applications.
2033 The two creation functions are similar to those of the normal button.
2036 GtkWidget *gtk_check_button_new( void );
2038 GtkWidget *gtk_check_button_new_with_label ( gchar *label );
2041 The new_with_label function creates a check button with a label beside
2044 Checking the state of the check button is identical to that of the
2047 <!-- ----------------------------------------------------------------- -->
2048 <sect1> Radio Buttons <label id="sec_Radio_Buttons">
2050 Radio buttons are similar to check buttons except they are grouped so
2051 that only one may be selected/depressed at a time. This is good for
2052 places in your application where you need to select from a short list
2055 Creating a new radio button is done with one of these calls:
2058 GtkWidget *gtk_radio_button_new( GSList *group );
2060 GtkWidget *gtk_radio_button_new_with_label( GSList *group,
2064 You'll notice the extra argument to these calls. They require a group
2065 to perform their duty properly. The first call to
2066 gtk_radio_button_new_with_label or gtk_radio_button_new_with_label
2067 should pass NULL as the first argument. Then create a group using:
2070 GSList *gtk_radio_button_group( GtkRadioButton *radio_button );
2073 The important thing to remember is that gtk_radio_button_group must be
2074 called for each new button added to the group, with the previous
2075 button passed in as an argument. The result is then passed into the
2076 call to gtk_radio_button_new or gtk_radio_button_new_with_label. This
2077 allows a chain of buttons to be established. The example below should
2080 You can shorten this slightly by using the following syntax, which
2081 removes the need for a variable to hold the list of buttons. This form
2082 is used in the example to create the third button:
2085 button2 = gtk_radio_button_new_with_label(
2086 gtk_radio_button_group (GTK_RADIO_BUTTON (button1)),
2090 It is also a good idea to explicitly set which button should be the
2091 default depressed button with:
2094 void gtk_toggle_button_set_active( GtkToggleButton *toggle_button,
2098 This is described in the section on toggle buttons, and works in
2099 exactly the same way.
2101 The following example creates a radio button group with three buttons.
2104 /* example-start radiobuttons radiobuttons.c */
2106 #include <gtk/gtk.h>
2109 void close_application( GtkWidget *widget,
2119 GtkWidget *window = NULL;
2123 GtkWidget *separator;
2126 gtk_init(&argc,&argv);
2128 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
2130 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
2131 GTK_SIGNAL_FUNC(close_application),
2134 gtk_window_set_title (GTK_WINDOW (window), "radio buttons");
2135 gtk_container_set_border_width (GTK_CONTAINER (window), 0);
2137 box1 = gtk_vbox_new (FALSE, 0);
2138 gtk_container_add (GTK_CONTAINER (window), box1);
2139 gtk_widget_show (box1);
2141 box2 = gtk_vbox_new (FALSE, 10);
2142 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2143 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2144 gtk_widget_show (box2);
2146 button = gtk_radio_button_new_with_label (NULL, "button1");
2147 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
2148 gtk_widget_show (button);
2150 group = gtk_radio_button_group (GTK_RADIO_BUTTON (button));
2151 button = gtk_radio_button_new_with_label(group, "button2");
2152 gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (button), TRUE);
2153 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
2154 gtk_widget_show (button);
2156 button = gtk_radio_button_new_with_label(
2157 gtk_radio_button_group (GTK_RADIO_BUTTON (button)),
2159 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
2160 gtk_widget_show (button);
2162 separator = gtk_hseparator_new ();
2163 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 0);
2164 gtk_widget_show (separator);
2166 box2 = gtk_vbox_new (FALSE, 10);
2167 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2168 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, TRUE, 0);
2169 gtk_widget_show (box2);
2171 button = gtk_button_new_with_label ("close");
2172 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
2173 GTK_SIGNAL_FUNC(close_application),
2174 GTK_OBJECT (window));
2175 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
2176 GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
2177 gtk_widget_grab_default (button);
2178 gtk_widget_show (button);
2179 gtk_widget_show (window);
2188 <!-- TODO: check out gtk_radio_button_new_from_widget function - TRG -->
2190 <!-- ***************************************************************** -->
2191 <sect> Adjustments <label id="sec_Adjustment">
2192 <!-- ***************************************************************** -->
2194 GTK+ has various widgets that can be visually adjusted by the user
2195 using the mouse or the keyboard, such as the range widgets, described
2196 in the <ref id="sec_Range_Widgets" name="Range Widgets">
2197 section. There are also a few widgets that display some adjustable
2198 portion of a larger area of data, such as the text widget and the
2201 Obviously, an application needs to be able to react to changes the
2202 user makes in range widgets. One way to do this would be to have each
2203 widget emit its own type of signal when its adjustment changes, and
2204 either pass the new value to the signal handler, or require it to look
2205 inside the widget's data structure in order to ascertain the value.
2206 But you may also want to connect the adjustments of several widgets
2207 together, so that adjusting one adjusts the others. The most obvious
2208 example of this is connecting a scrollbar to a panning viewport or a
2209 scrolling text area. If each widget has its own way of setting or
2210 getting the adjustment value, then the programmer may have to write
2211 their own signal handlers to translate between the output of one
2212 widget's signal and the "input" of another's adjustment setting
2215 GTK+ solves this problem using the GtkAdjustment object, which is a
2216 way for widgets to store and pass adjustment information in an
2217 abstract and flexible form. The most obvious use of GtkAdjustment is
2218 to store the configuration parameters and values of range widgets,
2219 such as scrollbars and scale controls. However, since GtkAdjustments
2220 are derived from GtkObject, they have some special powers beyond those
2221 of normal data structures. Most importantly, they can emit signals,
2222 just like widgets, and these signals can be used not only to allow
2223 your program to react to user input on adjustable widgets, but also to
2224 propagate adjustment values transparently between adjustable widgets.
2226 <sect1> Creating an Adjustment
2228 You create an adjustment using:
2231 GtkObject *gtk_adjustment_new( gfloat value,
2234 gfloat step_increment,
2235 gfloat page_increment,
2239 The <tt/value/ argument is the initial value you want to give to the
2240 adjustment, usually corresponding to the topmost or leftmost position
2241 of an adjustable widget. The <tt/lower/ argument specifies the lowest
2242 value which the adjustment can hold. The <tt/step_increment/ argument
2243 specifies the "smaller" of the two increments by which the user can
2244 change the value, while the <tt/page_increment/ is the "larger" one.
2245 The <tt/page_size/ argument usually corresponds somehow to the visible
2246 area of a panning widget. The <tt/upper/ argument is used to represent
2247 the bottom most or right most coordinate in a panning widget's
2248 child. Therefore it is <em/not/ always the largest number that
2249 <tt/value/ can take, since the <tt/page_size/ of such widgets is
2252 <!-- ----------------------------------------------------------------- -->
2253 <sect1> Using Adjustments the Easy Way
2255 The adjustable widgets can be roughly divided into those which use and
2256 require specific units for these values and those which treat them as
2257 arbitrary numbers. The group which treats the values as arbitrary
2258 numbers includes the range widgets (scrollbars and scales, the
2259 progress bar widget, and the spin button widget). These widgets are
2260 all the widgets which are typically "adjusted" directly by the user
2261 with the mouse or keyboard. They will treat the <tt/lower/ and
2262 <tt/upper/ values of an adjustment as a range within which the user
2263 can manipulate the adjustment's <tt/value/. By default, they will only
2264 modify the <tt/value/ of an adjustment.
2266 The other group includes the text widget, the viewport widget, the
2267 compound list widget, and the scrolled window widget. All of these
2268 widgets use pixel values for their adjustments. These are also all
2269 widgets which are typically "adjusted" indirectly using scrollbars.
2270 While all widgets which use adjustments can either create their own
2271 adjustments or use ones you supply, you'll generally want to let this
2272 particular category of widgets create its own adjustments. Usually,
2273 they will eventually override all the values except the <tt/value/
2274 itself in whatever adjustments you give them, but the results are, in
2275 general, undefined (meaning, you'll have to read the source code to
2276 find out, and it may be different from widget to widget).
2278 Now, you're probably thinking, since text widgets and viewports insist
2279 on setting everything except the <tt/value/ of their adjustments,
2280 while scrollbars will <em/only/ touch the adjustment's <tt/value/, if
2281 you <em/share/ an adjustment object between a scrollbar and a text
2282 widget, manipulating the scrollbar will automagically adjust the text
2283 widget? Of course it will! Just like this:
2286 /* creates its own adjustments */
2287 text = gtk_text_new (NULL, NULL);
2288 /* uses the newly-created adjustment for the scrollbar as well */
2289 vscrollbar = gtk_vscrollbar_new (GTK_TEXT(text)->vadj);
2293 <!-- ----------------------------------------------------------------- -->
2294 <sect1> Adjustment Internals
2296 Ok, you say, that's nice, but what if I want to create my own handlers
2297 to respond when the user adjusts a range widget or a spin button, and
2298 how do I get at the value of the adjustment in these handlers? To
2299 answer these questions and more, let's start by taking a look at
2300 <tt>struct _GtkAdjustment</tt> itself:
2303 struct _GtkAdjustment
2310 gfloat step_increment;
2311 gfloat page_increment;
2316 The first thing you should know is that there aren't any handy-dandy
2317 macros or accessor functions for getting the <tt/value/ out of a
2318 GtkAdjustment, so you'll have to (horror of horrors) do it like a
2319 <em/real/ C programmer. Don't worry - the <tt>GTK_ADJUSTMENT
2320 (Object)</tt> macro does run-time type checking (as do all the GTK+
2321 type-casting macros, actually).
2323 Since, when you set the <tt/value/ of an adjustment, you generally
2324 want the change to be reflected by every widget that uses this
2325 adjustment, GTK+ provides this convenience function to do this:
2328 void gtk_adjustment_set_value( GtkAdjustment *adjustment,
2332 As mentioned earlier, GtkAdjustment is a subclass of GtkObject just
2333 like all the various widgets, and thus it is able to emit signals.
2334 This is, of course, why updates happen automagically when you share an
2335 adjustment object between a scrollbar and another adjustable widget;
2336 all adjustable widgets connect signal handlers to their adjustment's
2337 <tt/value_changed/ signal, as can your program. Here's the definition
2338 of this signal in <tt/struct _GtkAdjustmentClass/:
2341 void (* value_changed) (GtkAdjustment *adjustment);
2344 The various widgets that use the GtkAdjustment object will emit this
2345 signal on an adjustment whenever they change its value. This happens
2346 both when user input causes the slider to move on a range widget, as
2347 well as when the program explicitly changes the value with
2348 <tt/gtk_adjustment_set_value()/. So, for example, if you have a scale
2349 widget, and you want to change the rotation of a picture whenever its
2350 value changes, you would create a callback like this:
2353 void cb_rotate_picture (GtkAdjustment *adj, GtkWidget *picture)
2355 set_picture_rotation (picture, adj->value);
2359 and connect it to the scale widget's adjustment like this:
2362 gtk_signal_connect (GTK_OBJECT (adj), "value_changed",
2363 GTK_SIGNAL_FUNC (cb_rotate_picture), picture);
2366 What about when a widget reconfigures the <tt/upper/ or <tt/lower/
2367 fields of its adjustment, such as when a user adds more text to a text
2368 widget? In this case, it emits the <tt/changed/ signal, which looks
2372 void (* changed) (GtkAdjustment *adjustment);
2375 Range widgets typically connect a handler to this signal, which
2376 changes their appearance to reflect the change - for example, the size
2377 of the slider in a scrollbar will grow or shrink in inverse proportion
2378 to the difference between the <tt/lower/ and <tt/upper/ values of its
2381 You probably won't ever need to attach a handler to this signal,
2382 unless you're writing a new type of range widget. However, if you
2383 change any of the values in a GtkAdjustment directly, you should emit
2384 this signal on it to reconfigure whatever widgets are using it, like
2388 gtk_signal_emit_by_name (GTK_OBJECT (adjustment), "changed");
2391 Now go forth and adjust!
2395 <!-- ***************************************************************** -->
2396 <sect> Range Widgets<label id="sec_Range_Widgets">
2397 <!-- ***************************************************************** -->
2400 The category of range widgets includes the ubiquitous scrollbar widget
2401 and the less common "scale" widget. Though these two types of widgets
2402 are generally used for different purposes, they are quite similar in
2403 function and implementation. All range widgets share a set of common
2404 graphic elements, each of which has its own X window and receives
2405 events. They all contain a "trough" and a "slider" (what is sometimes
2406 called a "thumbwheel" in other GUI environments). Dragging the slider
2407 with the pointer moves it back and forth within the trough, while
2408 clicking in the trough advances the slider towards the location of the
2409 click, either completely, or by a designated amount, depending on
2410 which mouse button is used.
2412 As mentioned in <ref id="sec_Adjustment" name="Adjustments"> above,
2413 all range widgets are associated with an adjustment object, from which
2414 they calculate the length of the slider and it's position within the
2415 trough. When the user manipulates the slider, the range widget will
2416 change the value of the adjustment.
2418 <!-- ----------------------------------------------------------------- -->
2419 <sect1> Scrollbar Widgets
2421 These are your standard, run-of-the-mill scrollbars. These should be
2422 used only for scrolling some other widget, such as a list, a text box,
2423 or a viewport (and it's generally easier to use the scrolled window
2424 widget in most cases). For other purposes, you should use scale
2425 widgets, as they are friendlier and more featureful.
2427 There are separate types for horizontal and vertical scrollbars.
2428 There really isn't much to say about these. You create them with the
2429 following functions, defined in <tt><gtk/gtkhscrollbar.h></tt>
2430 and <tt><gtk/gtkvscrollbar.h></tt>:
2433 GtkWidget *gtk_hscrollbar_new( GtkAdjustment *adjustment );
2435 GtkWidget *gtk_vscrollbar_new( GtkAdjustment *adjustment );
2438 and that's about it (if you don't believe me, look in the header
2439 files!). The <tt/adjustment/ argument can either be a pointer to an
2440 existing GtkAdjustment, or NULL, in which case one will be created for
2441 you. Specifying NULL might actually be useful in this case, if you
2442 wish to pass the newly-created adjustment to the constructor function
2443 of some other widget which will configure it for you, such as a text
2447 <!-- ----------------------------------------------------------------- -->
2448 <sect1> Scale Widgets
2450 Scale widgets are used to allow the user to visually select and
2451 manipulate a value within a specific range. You might want to use a
2452 scale widget, for example, to adjust the magnification level on a
2453 zoomed preview of a picture, or to control the brightness of a colour,
2454 or to specify the number of minutes of inactivity before a screensaver
2455 takes over the screen.
2457 <!-- ----------------------------------------------------------------- -->
2458 <sect2>Creating a Scale Widget
2460 As with scrollbars, there are separate widget types for horizontal and
2461 vertical scale widgets. (Most programmers seem to favour horizontal
2462 scale widgets). Since they work essentially the same way, there's no
2463 need to treat them separately here. The following functions, defined
2464 in <tt><gtk/gtkvscale.h></tt> and
2465 <tt><gtk/gtkhscale.h></tt>, create vertical and horizontal scale
2466 widgets, respectively:
2470 GtkWidget *gtk_vscale_new( GtkAdjustment *adjustment );
2472 GtkWidget *gtk_hscale_new( GtkAdjustment *adjustment );
2476 The <tt/adjustment/ argument can either be an adjustment which has
2477 already been created with <tt/gtk_adjustment_new()/, or <tt/NULL/, in
2478 which case, an anonymous GtkAdjustment is created with all of its
2479 values set to <tt/0.0/ (which isn't very useful in this case). In
2480 order to avoid confusing yourself, you probably want to create your
2481 adjustment with a <tt/page_size/ of <tt/0.0/ so that its <tt/upper/
2482 value actually corresponds to the highest value the user can select.
2483 (If you're <em/already/ thoroughly confused, read the section on <ref
2484 id="sec_Adjustment" name="Adjustments"> again for an explanation of
2485 what exactly adjustments do and how to create and manipulate them).
2487 <!-- ----------------------------------------------------------------- -->
2488 <sect2> Functions and Signals (well, functions, at least)
2490 Scale widgets can display their current value as a number beside the
2491 trough. The default behaviour is to show the value, but you can change
2492 this with this function:
2495 void gtk_scale_set_draw_value( GtkScale *scale,
2499 As you might have guessed, <tt/draw_value/ is either <tt/TRUE/ or
2500 <tt/FALSE/, with predictable consequences for either one.
2502 The value displayed by a scale widget is rounded to one decimal point
2503 by default, as is the <tt/value/ field in its GtkAdjustment. You can
2508 void gtk_scale_set_digits( GtkScale *scale,
2513 where <tt/digits/ is the number of decimal places you want. You can
2514 set <tt/digits/ to anything you like, but no more than 13 decimal
2515 places will actually be drawn on screen.
2517 Finally, the value can be drawn in different positions
2518 relative to the trough:
2522 void gtk_scale_set_value_pos( GtkScale *scale,
2523 GtkPositionType pos );
2527 The argument <tt/pos/ is of type <tt>GtkPositionType</tt>, which is
2528 defined in <tt><gtk/gtkenums.h></tt>, and can take one of the
2533 <item> GTK_POS_RIGHT
2535 <item> GTK_POS_BOTTOM
2538 If you position the value on the "side" of the trough (e.g. on the top
2539 or bottom of a horizontal scale widget), then it will follow the
2540 slider up and down the trough.
2542 All the preceding functions are defined in
2543 <tt><gtk/gtkscale.h></tt>.
2547 <!-- ----------------------------------------------------------------- -->
2548 <sect1> Common Functions <label id="sec_Range_Functions">
2550 The GtkRange widget class is fairly complicated internally, but, like
2551 all the "base class" widgets, most of its complexity is only
2552 interesting if you want to hack on it. Also, almost all of the
2553 functions and signals it defines are only really used in writing
2554 derived widgets. There are, however, a few useful functions that are
2555 defined in <tt><gtk/gtkrange.h></tt> and will work on all range
2558 <!-- ----------------------------------------------------------------- -->
2559 <sect2> Setting the Update Policy
2561 The "update policy" of a range widget defines at what points during
2562 user interaction it will change the <tt/value/ field of its
2563 GtkAdjustment and emit the "value_changed" signal on this
2564 GtkAdjustment. The update policies, defined in
2565 <tt><gtk/gtkenums.h></tt> as type <tt>enum GtkUpdateType</tt>,
2569 <item>GTK_UPDATE_POLICY_CONTINUOUS - This is the default. The
2570 "value_changed" signal is emitted continuously, i.e. whenever the
2571 slider is moved by even the tiniest amount.
2573 <item>GTK_UPDATE_POLICY_DISCONTINUOUS - The "value_changed" signal is
2574 only emitted once the slider has stopped moving and the user has
2575 released the mouse button.
2577 <item>GTK_UPDATE_POLICY_DELAYED - The "value_change" signal is emitted
2578 when the user releases the mouse button, or if the slider stops moving
2579 for a short period of time.
2583 The update policy of a range widget can be set by casting it using the
2584 <tt>GTK_RANGE (Widget)</tt> macro and passing it to this function:
2587 void gtk_range_set_update_policy( GtkRange *range,
2588 GtkUpdateType policy) ;
2591 <!-- ----------------------------------------------------------------- -->
2592 <sect2>Getting and Setting Adjustments
2594 Getting and setting the adjustment for a range widget "on the fly" is
2595 done, predictably, with:
2598 GtkAdjustment* gtk_range_get_adjustment( GtkRange *range );
2600 void gtk_range_set_adjustment( GtkRange *range,
2601 GtkAdjustment *adjustment );
2604 <tt/gtk_range_get_adjustment()/ returns a pointer to the adjustment to
2605 which <tt/range/ is connected.
2607 <tt/gtk_range_set_adjustment()/ does absolutely nothing if you pass it
2608 the adjustment that <tt/range/ is already using, regardless of whether
2609 you changed any of its fields or not. If you pass it a new
2610 GtkAdjustment, it will unreference the old one if it exists (possibly
2611 destroying it), connect the appropriate signals to the new one, and
2612 call the private function <tt/gtk_range_adjustment_changed()/, which
2613 will (or at least, is supposed to...) recalculate the size and/or
2614 position of the slider and redraw if necessary. As mentioned in the
2615 section on adjustments, if you wish to reuse the same GtkAdjustment,
2616 when you modify its values directly, you should emit the "changed"
2617 signal on it, like this:
2620 gtk_signal_emit_by_name (GTK_OBJECT (adjustment), "changed");
2625 <!-- ----------------------------------------------------------------- -->
2626 <sect1> Key and Mouse bindings
2628 All of the GTK+ range widgets react to mouse clicks in more or less
2629 the same way. Clicking button-1 in the trough will cause its
2630 adjustment's <tt/page_increment/ to be added or subtracted from its
2631 <tt/value/, and the slider to be moved accordingly. Clicking mouse
2632 button-2 in the trough will jump the slider to the point at which the
2633 button was clicked. Clicking any button on a scrollbar's arrows will
2634 cause its adjustment's value to change <tt/step_increment/ at a time.
2636 It may take a little while to get used to, but by default, scrollbars
2637 as well as scale widgets can take the keyboard focus in GTK+. If you
2638 think your users will find this too confusing, you can always disable
2639 this by unsetting the GTK_CAN_FOCUS flag on the scrollbar, like this:
2642 GTK_WIDGET_UNSET_FLAGS (scrollbar, GTK_CAN_FOCUS);
2645 The key bindings (which are, of course, only active when the widget
2646 has focus) are slightly different between horizontal and vertical
2647 range widgets, for obvious reasons. They are also not quite the same
2648 for scale widgets as they are for scrollbars, for somewhat less
2649 obvious reasons (possibly to avoid confusion between the keys for
2650 horizontal and vertical scrollbars in scrolled windows, where both
2651 operate on the same area).
2653 <sect2> Vertical Range Widgets
2655 All vertical range widgets can be operated with the up and down arrow
2656 keys, as well as with the <tt/Page Up/ and <tt/Page Down/ keys. The
2657 arrows move the slider up and down by <tt/step_increment/, while
2658 <tt/Page Up/ and <tt/Page Down/ move it by <tt/page_increment/.
2660 The user can also move the slider all the way to one end or the other
2661 of the trough using the keyboard. With the GtkVScale widget, this is
2662 done with the <tt/Home/ and <tt/End/ keys, whereas with the
2663 GtkVScrollbar widget, this is done by typing <tt>Control-Page Up</tt>
2664 and <tt>Control-Page Down</tt>.
2666 <!-- ----------------------------------------------------------------- -->
2667 <sect2> Horizontal Range Widgets
2669 The left and right arrow keys work as you might expect in these
2670 widgets, moving the slider back and forth by <tt/step_increment/. The
2671 <tt/Home/ and <tt/End/ keys move the slider to the ends of the trough.
2672 For the GtkHScale widget, moving the slider by <tt/page_increment/ is
2673 accomplished with <tt>Control-Left</tt> and <tt>Control-Right</tt>,
2674 while for GtkHScrollbar, it's done with <tt>Control-Home</tt> and
2675 <tt>Control-End</tt>.
2679 <!-- ----------------------------------------------------------------- -->
2680 <sect1> Example<label id="sec_Range_Example">
2682 This example is a somewhat modified version of the "range controls"
2683 test from <tt/testgtk.c/. It basically puts up a window with three
2684 range widgets all connected to the same adjustment, and a couple of
2685 controls for adjusting some of the parameters mentioned above and in
2686 the seciton on adjustments, so you can see how they affect the way
2687 these widgets work for the user.
2690 /* example-start rangewidgets rangewidgets.c */
2692 #include <gtk/gtk.h>
2694 GtkWidget *hscale, *vscale;
2696 void cb_pos_menu_select( GtkWidget *item,
2697 GtkPositionType pos )
2699 /* Set the value position on both scale widgets */
2700 gtk_scale_set_value_pos (GTK_SCALE (hscale), pos);
2701 gtk_scale_set_value_pos (GTK_SCALE (vscale), pos);
2704 void cb_update_menu_select( GtkWidget *item,
2705 GtkUpdateType policy )
2707 /* Set the update policy for both scale widgets */
2708 gtk_range_set_update_policy (GTK_RANGE (hscale), policy);
2709 gtk_range_set_update_policy (GTK_RANGE (vscale), policy);
2712 void cb_digits_scale( GtkAdjustment *adj )
2714 /* Set the number of decimal places to which adj->value is rounded */
2715 gtk_scale_set_digits (GTK_SCALE (hscale), (gint) adj->value);
2716 gtk_scale_set_digits (GTK_SCALE (vscale), (gint) adj->value);
2719 void cb_page_size( GtkAdjustment *get,
2720 GtkAdjustment *set )
2722 /* Set the page size and page increment size of the sample
2723 * adjustment to the value specified by the "Page Size" scale */
2724 set->page_size = get->value;
2725 set->page_increment = get->value;
2726 /* Now emit the "changed" signal to reconfigure all the widgets that
2727 * are attached to this adjustment */
2728 gtk_signal_emit_by_name (GTK_OBJECT (set), "changed");
2731 void cb_draw_value( GtkToggleButton *button )
2733 /* Turn the value display on the scale widgets off or on depending
2734 * on the state of the checkbutton */
2735 gtk_scale_set_draw_value (GTK_SCALE (hscale), button->active);
2736 gtk_scale_set_draw_value (GTK_SCALE (vscale), button->active);
2739 /* Convenience functions */
2741 GtkWidget *make_menu_item( gchar *name,
2742 GtkSignalFunc callback,
2747 item = gtk_menu_item_new_with_label (name);
2748 gtk_signal_connect (GTK_OBJECT (item), "activate",
2750 gtk_widget_show (item);
2755 void scale_set_default_values( GtkScale *scale )
2757 gtk_range_set_update_policy (GTK_RANGE (scale),
2758 GTK_UPDATE_CONTINUOUS);
2759 gtk_scale_set_digits (scale, 1);
2760 gtk_scale_set_value_pos (scale, GTK_POS_TOP);
2761 gtk_scale_set_draw_value (scale, TRUE);
2764 /* makes the sample window */
2766 void create_range_controls( void )
2769 GtkWidget *box1, *box2, *box3;
2771 GtkWidget *scrollbar;
2772 GtkWidget *separator;
2773 GtkWidget *opt, *menu, *item;
2776 GtkObject *adj1, *adj2;
2778 /* Standard window-creating stuff */
2779 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
2780 gtk_signal_connect (GTK_OBJECT (window), "destroy",
2781 GTK_SIGNAL_FUNC(gtk_main_quit),
2783 gtk_window_set_title (GTK_WINDOW (window), "range controls");
2785 box1 = gtk_vbox_new (FALSE, 0);
2786 gtk_container_add (GTK_CONTAINER (window), box1);
2787 gtk_widget_show (box1);
2789 box2 = gtk_hbox_new (FALSE, 10);
2790 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2791 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2792 gtk_widget_show (box2);
2794 /* calue, lower, upper, step_increment, page_increment, page_size */
2795 /* Note that the page_size value only makes a difference for
2796 * scrollbar widgets, and the highest value you'll get is actually
2797 * (upper - page_size). */
2798 adj1 = gtk_adjustment_new (0.0, 0.0, 101.0, 0.1, 1.0, 1.0);
2800 vscale = gtk_vscale_new (GTK_ADJUSTMENT (adj1));
2801 scale_set_default_values (GTK_SCALE (vscale));
2802 gtk_box_pack_start (GTK_BOX (box2), vscale, TRUE, TRUE, 0);
2803 gtk_widget_show (vscale);
2805 box3 = gtk_vbox_new (FALSE, 10);
2806 gtk_box_pack_start (GTK_BOX (box2), box3, TRUE, TRUE, 0);
2807 gtk_widget_show (box3);
2809 /* Reuse the same adjustment */
2810 hscale = gtk_hscale_new (GTK_ADJUSTMENT (adj1));
2811 gtk_widget_set_usize (GTK_WIDGET (hscale), 200, 30);
2812 scale_set_default_values (GTK_SCALE (hscale));
2813 gtk_box_pack_start (GTK_BOX (box3), hscale, TRUE, TRUE, 0);
2814 gtk_widget_show (hscale);
2816 /* Reuse the same adjustment again */
2817 scrollbar = gtk_hscrollbar_new (GTK_ADJUSTMENT (adj1));
2818 /* Notice how this causes the scales to always be updated
2819 * continuously when the scrollbar is moved */
2820 gtk_range_set_update_policy (GTK_RANGE (scrollbar),
2821 GTK_UPDATE_CONTINUOUS);
2822 gtk_box_pack_start (GTK_BOX (box3), scrollbar, TRUE, TRUE, 0);
2823 gtk_widget_show (scrollbar);
2825 box2 = gtk_hbox_new (FALSE, 10);
2826 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2827 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2828 gtk_widget_show (box2);
2830 /* A checkbutton to control whether the value is displayed or not */
2831 button = gtk_check_button_new_with_label("Display value on scale widgets");
2832 gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (button), TRUE);
2833 gtk_signal_connect (GTK_OBJECT (button), "toggled",
2834 GTK_SIGNAL_FUNC(cb_draw_value), NULL);
2835 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
2836 gtk_widget_show (button);
2838 box2 = gtk_hbox_new (FALSE, 10);
2839 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2841 /* An option menu to change the position of the value */
2842 label = gtk_label_new ("Scale Value Position:");
2843 gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
2844 gtk_widget_show (label);
2846 opt = gtk_option_menu_new();
2847 menu = gtk_menu_new();
2849 item = make_menu_item ("Top",
2850 GTK_SIGNAL_FUNC(cb_pos_menu_select),
2851 GINT_TO_POINTER (GTK_POS_TOP));
2852 gtk_menu_append (GTK_MENU (menu), item);
2854 item = make_menu_item ("Bottom", GTK_SIGNAL_FUNC (cb_pos_menu_select),
2855 GINT_TO_POINTER (GTK_POS_BOTTOM));
2856 gtk_menu_append (GTK_MENU (menu), item);
2858 item = make_menu_item ("Left", GTK_SIGNAL_FUNC (cb_pos_menu_select),
2859 GINT_TO_POINTER (GTK_POS_LEFT));
2860 gtk_menu_append (GTK_MENU (menu), item);
2862 item = make_menu_item ("Right", GTK_SIGNAL_FUNC (cb_pos_menu_select),
2863 GINT_TO_POINTER (GTK_POS_RIGHT));
2864 gtk_menu_append (GTK_MENU (menu), item);
2866 gtk_option_menu_set_menu (GTK_OPTION_MENU (opt), menu);
2867 gtk_box_pack_start (GTK_BOX (box2), opt, TRUE, TRUE, 0);
2868 gtk_widget_show (opt);
2870 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2871 gtk_widget_show (box2);
2873 box2 = gtk_hbox_new (FALSE, 10);
2874 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2876 /* Yet another option menu, this time for the update policy of the
2878 label = gtk_label_new ("Scale Update Policy:");
2879 gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
2880 gtk_widget_show (label);
2882 opt = gtk_option_menu_new();
2883 menu = gtk_menu_new();
2885 item = make_menu_item ("Continuous",
2886 GTK_SIGNAL_FUNC (cb_update_menu_select),
2887 GINT_TO_POINTER (GTK_UPDATE_CONTINUOUS));
2888 gtk_menu_append (GTK_MENU (menu), item);
2890 item = make_menu_item ("Discontinuous",
2891 GTK_SIGNAL_FUNC (cb_update_menu_select),
2892 GINT_TO_POINTER (GTK_UPDATE_DISCONTINUOUS));
2893 gtk_menu_append (GTK_MENU (menu), item);
2895 item = make_menu_item ("Delayed",
2896 GTK_SIGNAL_FUNC (cb_update_menu_select),
2897 GINT_TO_POINTER (GTK_UPDATE_DELAYED));
2898 gtk_menu_append (GTK_MENU (menu), item);
2900 gtk_option_menu_set_menu (GTK_OPTION_MENU (opt), menu);
2901 gtk_box_pack_start (GTK_BOX (box2), opt, TRUE, TRUE, 0);
2902 gtk_widget_show (opt);
2904 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2905 gtk_widget_show (box2);
2907 box2 = gtk_hbox_new (FALSE, 10);
2908 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2910 /* A GtkHScale widget for adjusting the number of digits on the
2912 label = gtk_label_new ("Scale Digits:");
2913 gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
2914 gtk_widget_show (label);
2916 adj2 = gtk_adjustment_new (1.0, 0.0, 5.0, 1.0, 1.0, 0.0);
2917 gtk_signal_connect (GTK_OBJECT (adj2), "value_changed",
2918 GTK_SIGNAL_FUNC (cb_digits_scale), NULL);
2919 scale = gtk_hscale_new (GTK_ADJUSTMENT (adj2));
2920 gtk_scale_set_digits (GTK_SCALE (scale), 0);
2921 gtk_box_pack_start (GTK_BOX (box2), scale, TRUE, TRUE, 0);
2922 gtk_widget_show (scale);
2924 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2925 gtk_widget_show (box2);
2927 box2 = gtk_hbox_new (FALSE, 10);
2928 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2930 /* And, one last GtkHScale widget for adjusting the page size of the
2932 label = gtk_label_new ("Scrollbar Page Size:");
2933 gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
2934 gtk_widget_show (label);
2936 adj2 = gtk_adjustment_new (1.0, 1.0, 101.0, 1.0, 1.0, 0.0);
2937 gtk_signal_connect (GTK_OBJECT (adj2), "value_changed",
2938 GTK_SIGNAL_FUNC (cb_page_size), adj1);
2939 scale = gtk_hscale_new (GTK_ADJUSTMENT (adj2));
2940 gtk_scale_set_digits (GTK_SCALE (scale), 0);
2941 gtk_box_pack_start (GTK_BOX (box2), scale, TRUE, TRUE, 0);
2942 gtk_widget_show (scale);
2944 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
2945 gtk_widget_show (box2);
2947 separator = gtk_hseparator_new ();
2948 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 0);
2949 gtk_widget_show (separator);
2951 box2 = gtk_vbox_new (FALSE, 10);
2952 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
2953 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, TRUE, 0);
2954 gtk_widget_show (box2);
2956 button = gtk_button_new_with_label ("Quit");
2957 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
2958 GTK_SIGNAL_FUNC(gtk_main_quit),
2960 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
2961 GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
2962 gtk_widget_grab_default (button);
2963 gtk_widget_show (button);
2965 gtk_widget_show (window);
2971 gtk_init(&argc, &argv);
2973 create_range_controls();
2985 <!-- ***************************************************************** -->
2986 <sect> Miscellaneous Widgets
2987 <!-- ***************************************************************** -->
2989 <!-- ----------------------------------------------------------------- -->
2992 Labels are used a lot in GTK, and are relatively simple. Labels emit
2993 no signals as they do not have an associated X window. If you need to
2994 catch signals, or do clipping, use the <ref id="sec_EventBox"
2995 name="EventBox"> widget.
2997 To create a new label, use:
3000 GtkWidget *gtk_label_new( char *str );
3003 Where the sole argument is the string you wish the label to display.
3005 To change the label's text after creation, use the function:
3008 void gtk_label_set_text( GtkLabel *label,
3012 Where the first argument is the label you created previously (cast
3013 using the GTK_LABEL() macro), and the second is the new string.
3015 The space needed for the new string will be automatically adjusted if
3016 needed. You can produce multi-line labels by putting line breaks in
3019 To retrieve the current string, use:
3022 void gtk_label_get( GtkLabel *label,
3026 Where the first argument is the label you've created, and the second,
3027 the return for the string. Do not free the return string, as it is
3028 used internally by GTK.
3030 The label text can be justified using:
3033 void gtk_label_set_justify( GtkLabel *label,
3034 GtkJustification jtype );
3037 Values for <tt/jtype/ are:
3039 <item> GTK_JUSTIFY_LEFT
3040 <item> GTK_JUSTIFY_RIGHT
3041 <item> GTK_JUSTIFY_CENTER (the default)
3042 <item> GTK_JUSTIFY_FILL
3045 The label widget is also capable of line wrapping the text
3046 automatically. This can be activated using:
3049 void gtk_label_set_line_wrap (GtkLabel *label,
3053 The <//wrap/ argument takes a TRUE or FALSE value.
3055 If you want your label underlined, then you can set a pattern on the
3059 void gtk_label_set_pattern (GtkLabel *label,
3060 const gchar *pattern);
3063 The pattern argument indicates how the underlining should look. It
3064 consists of a string of underscore and space characters. An underscore
3065 indicates that the corresponding character in the label should be
3066 underlined. For example, the string <verb/"__ __"/ would underline the
3067 first two characters and eigth and ninth characters.
3069 Below is a short example to illustrate these functions. This example
3070 makes use of the Frame widget to better demonstrate the label
3071 styles. You can ignore this for now as the <ref id="sec_Frames"
3072 name="Frame"> widget is explained later on.
3075 /* example-start label label.c */
3077 #include <gtk/gtk.h>
3082 static GtkWidget *window = NULL;
3088 /* Initialise GTK */
3089 gtk_init(&argc, &argv);
3091 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
3092 gtk_signal_connect (GTK_OBJECT (window), "destroy",
3093 GTK_SIGNAL_FUNC(gtk_main_quit),
3096 gtk_window_set_title (GTK_WINDOW (window), "Label");
3097 vbox = gtk_vbox_new (FALSE, 5);
3098 hbox = gtk_hbox_new (FALSE, 5);
3099 gtk_container_add (GTK_CONTAINER (window), hbox);
3100 gtk_box_pack_start (GTK_BOX (hbox), vbox, FALSE, FALSE, 0);
3101 gtk_container_set_border_width (GTK_CONTAINER (window), 5);
3103 frame = gtk_frame_new ("Normal Label");
3104 label = gtk_label_new ("This is a Normal label");
3105 gtk_container_add (GTK_CONTAINER (frame), label);
3106 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3108 frame = gtk_frame_new ("Multi-line Label");
3109 label = gtk_label_new ("This is a Multi-line label.\nSecond line\n" \
3111 gtk_container_add (GTK_CONTAINER (frame), label);
3112 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3114 frame = gtk_frame_new ("Left Justified Label");
3115 label = gtk_label_new ("This is a Left-Justified\n" \
3116 "Multi-line label.\nThird line");
3117 gtk_label_set_justify (GTK_LABEL (label), GTK_JUSTIFY_LEFT);
3118 gtk_container_add (GTK_CONTAINER (frame), label);
3119 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3121 frame = gtk_frame_new ("Right Justified Label");
3122 label = gtk_label_new ("This is a Right-Justified\nMulti-line label.\n" \
3123 "Fourth line, (j/k)");
3124 gtk_label_set_justify (GTK_LABEL (label), GTK_JUSTIFY_RIGHT);
3125 gtk_container_add (GTK_CONTAINER (frame), label);
3126 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3128 vbox = gtk_vbox_new (FALSE, 5);
3129 gtk_box_pack_start (GTK_BOX (hbox), vbox, FALSE, FALSE, 0);
3130 frame = gtk_frame_new ("Line wrapped label");
3131 label = gtk_label_new ("This is an example of a line-wrapped label. It " \
3132 "should not be taking up the entire " /* big space to test spacing */\
3133 "width allocated to it, but automatically " \
3134 "wraps the words to fit. " \
3135 "The time has come, for all good men, to come to " \
3136 "the aid of their party. " \
3137 "The sixth sheik's six sheep's sick.\n" \
3138 " It supports multiple paragraphs correctly, " \
3139 "and correctly adds "\
3140 "many extra spaces. ");
3141 gtk_label_set_line_wrap (GTK_LABEL (label), TRUE);
3142 gtk_container_add (GTK_CONTAINER (frame), label);
3143 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3145 frame = gtk_frame_new ("Filled, wrapped label");
3146 label = gtk_label_new ("This is an example of a line-wrapped, filled label. " \
3147 "It should be taking "\
3148 "up the entire width allocated to it. " \
3149 "Here is a seneance to prove "\
3150 "my point. Here is another sentence. "\
3151 "Here comes the sun, do de do de do.\n"\
3152 " This is a new paragraph.\n"\
3153 " This is another newer, longer, better " \
3154 "paragraph. It is coming to an end, "\
3156 gtk_label_set_justify (GTK_LABEL (label), GTK_JUSTIFY_FILL);
3157 gtk_label_set_line_wrap (GTK_LABEL (label), TRUE);
3158 gtk_container_add (GTK_CONTAINER (frame), label);
3159 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3161 frame = gtk_frame_new ("Underlined label");
3162 label = gtk_label_new ("This label is underlined!\n"
3163 "This one is underlined in quite a funky fashion");
3164 gtk_label_set_justify (GTK_LABEL (label), GTK_JUSTIFY_LEFT);
3165 gtk_label_set_pattern (GTK_LABEL (label),
3166 "_________________________ _ _________ _ ______ __ _______ ___");
3167 gtk_container_add (GTK_CONTAINER (frame), label);
3168 gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
3170 gtk_widget_show_all (window);
3179 <!-- ----------------------------------------------------------------- -->
3182 The Arrow widget draws an arrowhead, facing in a number of possible
3183 directions and having a number of possible styles. It can be very
3184 useful when placed on a button in many applications.
3186 There are only two functions for manipulating an Arrow widget:
3189 GtkWidget *gtk_arrow_new( GtkArrowType arrow_type,
3190 GtkShadowType shadow_type );
3192 void gtk_arrow_set( GtkArrow *arrow,
3193 GtkArrowType arrow_type,
3194 GtkShadowType shadow_type );
3197 The first creates a new arrow widget with the indicated type and
3198 appearance. The second allows these values to be altered
3199 retrospectively. The <tt/arrow_type/ argument may take one of the
3204 <item> GTK_ARROW_DOWN
3205 <item> GTK_ARROW_LEFT
3206 <item> GTK_ARROW_RIGHT
3209 These values obviously indicate the direction in which the arrow will
3210 point. The <tt/shadow_type/ argument may take one of these values:
3213 <item> GTK_SHADOW_IN
3214 <item> GTK_SHADOW_OUT (the default)
3215 <item> GTK_SHADOW_ETCHED_IN
3216 <item> GTK_SHADOW_ETCHED_OUT
3219 Here's a brief example to illustrate their use.
3222 /* example-start arrow arrow.c */
3224 #include <gtk/gtk.h>
3226 /* Create an Arrow widget with the specified parameters
3227 * and pack it into a button */
3228 GtkWidget *create_arrow_button( GtkArrowType arrow_type,
3229 GtkShadowType shadow_type )
3234 button = gtk_button_new();
3235 arrow = gtk_arrow_new (arrow_type, shadow_type);
3237 gtk_container_add (GTK_CONTAINER (button), arrow);
3239 gtk_widget_show(button);
3240 gtk_widget_show(arrow);
3248 /* GtkWidget is the storage type for widgets */
3253 /* Initialize the toolkit */
3254 gtk_init (&argc, &argv);
3256 /* Create a new window */
3257 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
3259 gtk_window_set_title (GTK_WINDOW (window), "Arrow Buttons");
3261 /* It's a good idea to do this for all windows. */
3262 gtk_signal_connect (GTK_OBJECT (window), "destroy",
3263 GTK_SIGNAL_FUNC (gtk_main_quit), NULL);
3265 /* Sets the border width of the window. */
3266 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
3268 /* Create a box to hold the arrows/buttons */
3269 box = gtk_hbox_new (FALSE, 0);
3270 gtk_container_set_border_width (GTK_CONTAINER (box), 2);
3271 gtk_container_add (GTK_CONTAINER (window), box);
3273 /* Pack and show all our widgets */
3274 gtk_widget_show(box);
3276 button = create_arrow_button(GTK_ARROW_UP, GTK_SHADOW_IN);
3277 gtk_box_pack_start (GTK_BOX (box), button, FALSE, FALSE, 3);
3279 button = create_arrow_button(GTK_ARROW_DOWN, GTK_SHADOW_OUT);
3280 gtk_box_pack_start (GTK_BOX (box), button, FALSE, FALSE, 3);
3282 button = create_arrow_button(GTK_ARROW_LEFT, GTK_SHADOW_ETCHED_IN);
3283 gtk_box_pack_start (GTK_BOX (box), button, FALSE, FALSE, 3);
3285 button = create_arrow_button(GTK_ARROW_RIGHT, GTK_SHADOW_ETCHED_OUT);
3286 gtk_box_pack_start (GTK_BOX (box), button, FALSE, FALSE, 3);
3288 gtk_widget_show (window);
3290 /* Rest in gtk_main and wait for the fun to begin! */
3298 <!-- ----------------------------------------------------------------- -->
3299 <sect1>The Tooltips Widget
3301 These are the little text strings that pop up when you leave your
3302 pointer over a button or other widget for a few seconds. They are easy
3303 to use, so I will just explain them without giving an example. If you
3304 want to see some code, take a look at the testgtk.c program
3305 distributed with GTK.
3307 Widgets that do not receieve events (widgets that do not have their
3308 own window) will not work with tooltips.
3310 The first call you will use creates a new tooltip. You only need to do
3311 this once for a set of tooltips as the <tt/GtkTooltip/ object this
3312 function returns can be used to create multiple tooltips.
3315 GtkTooltips *gtk_tooltips_new( void );
3318 Once you have created a new tooltip, and the widget you wish to use it
3319 on, simply use this call to set it:
3322 void gtk_tooltips_set_tip( GtkTooltips *tooltips,
3324 const gchar *tip_text,
3325 const gchar *tip_private );
3328 The first argument is the tooltip you've already created, followed by
3329 the widget you wish to have this tooltip pop up for, and the text you
3330 wish it to say. The last argument is a text string that can be used as
3331 an identifier when using GtkTipsQuery to implement context sensitive
3332 help. For now, you can set it to NULL.
3334 <!-- TODO: sort out what how to do the context sensitive help -->
3336 Here's a short example:
3339 GtkTooltips *tooltips;
3344 tooltips = gtk_tooltips_new ();
3345 button = gtk_button_new_with_label ("button 1");
3349 gtk_tooltips_set_tip (tooltips, button, "This is button 1", NULL);
3352 There are other calls that can be used with tooltips. I will just list
3353 them with a brief description of what they do.
3356 void gtk_tooltips_enable( GtkTooltips *tooltips );
3359 Enable a disabled set of tooltips.
3362 void gtk_tooltips_disable( GtkTooltips *tooltips );
3365 Disable an enabled set of tooltips.
3368 void gtk_tooltips_set_delay( GtkTooltips *tooltips,
3373 Sets how many milliseconds you have to hold your pointer over the
3374 widget before the tooltip will pop up. The default is 500
3375 milliseconds (half a second).
3378 void gtk_tooltips_set_colors( GtkTooltips *tooltips,
3379 GdkColor *background,
3380 GdkColor *foreground );
3383 Set the foreground and background color of the tooltips.
3385 And that's all the functions associated with tooltips. More than
3386 you'll ever want to know :-)
3388 <!-- ----------------------------------------------------------------- -->
3389 <sect1> Progress Bars <label id="sec_ProgressBar">
3391 Progress bars are used to show the status of an operation. They are
3392 pretty easy to use, as you will see with the code below. But first
3393 lets start out with the calls to create a new progress bar.
3395 There are two ways to create a progress bar, one simple one takes
3396 no arguments, and one that takes a GtkAdjustment object as an
3397 argument. If the former is used, the progress bar creates it's own
3401 GtkWidget *gtk_progress_bar_new( void );
3403 GtkWidget *gtk_progress_bar_new_with_adjustment( GtkAdjustment *adjustment );
3406 The second method has the advantage that we can use the adjustment
3407 object to specify our own range parameters for the progress bar.
3409 Now that the progress bar has been created we can use it.
3412 void gtk_progress_bar_update( GtkProgressBar *pbar,
3413 gfloat percentage );
3416 The first argument is the progress bar you wish to operate on, and the
3417 second argument is the amount 'completed', meaning the amount the
3418 progress bar has been filled from 0-100%. This is passed to the
3419 function as a real number ranging from 0 to 1.
3421 GTK v1.1 has added new functionality to the progress bar that enables
3422 it to display it's value in different ways, and to inform the user of
3423 its current value and its range.
3425 A progress bar may be set to one of a number of orientations using the
3429 void gtk_progress_bar_set_orientation( GtkProgressBar *pbar,
3430 GtkProgressBarOrientation orientation );
3433 Where the <tt/orientation/ argument may take one of the following
3434 values to indicate the direction in which the progress bar moves:
3437 <item> GTK_PROGRESS_LEFT_TO_RIGHT
3438 <item> GTK_PROGRESS_RIGHT_TO_LEFT
3439 <item> GTK_PROGRESS_BOTTOM_TO_TOP
3440 <item> GTK_PROGRESS_TOP_TO_BOTTOM
3443 When used as a measure of how far a process has progressed, the
3444 GtkProgressBar can be set to display it's value in either a continuous
3445 or discrete mode. In continuous mode, the progress bar is updated for
3446 each value. In discrete mode, the progress bar is updated in a number
3447 of discrete blocks. The number of blocks is also configurable.
3449 The style of a progress bar can be set using the following function.
3452 void gtk_progress_bar_set_bar_style( GtkProgressBar *pbar,
3453 GtkProgressBarStyle style );
3456 The <tt/style/ parameter can take one of two values:
3459 <item>GTK_PROGRESS_CONTINUOUS
3460 <item>GTK_PROGRESS_DISCRETE
3463 The number of discrete blocks can be set by calling
3466 void gtk_progress_bar_set_discrete_blocks( GtkProgressBar *pbar,
3470 As well as indicating the amount of progress that has occured, the
3471 progress bar may be set to just indicate that there is some
3472 activity. This can be useful in situations where progress cannot be
3473 measured against a value range. Activity mode is not effected by the
3474 bar style that is described above, and overrides it.This mode is
3475 selected by the following function.
3478 void gtk_progress_set_activity_mode( GtkProgress *progress,
3479 guint activity_mode );
3482 The step size of the activity indicator, and the number of blocks are
3483 set using the following functions.
3486 void gtk_progress_bar_set_activity_step( GtkProgressBar *pbar,
3489 void gtk_progress_bar_set_activity_blocks( GtkProgressBar *pbar,
3493 When in continuous mode, the progress bar can also display a
3494 configurable text string within it's trough, using the following
3498 void gtk_progress_set_format_string( GtkProgress *progress,
3502 The <tt/format/ argument is similiar to one that would be used in a C
3503 <tt/printf/ statement. The following directives may be used within the
3507 <item> %p - percentage
3509 <item> %l - lower range value
3510 <item> %u - upper range value
3513 Progress Bars are usually used with timeouts or other such functions
3514 (see section on <ref id="sec_timeouts" name="Timeouts, I/O and Idle
3515 Functions">) to give the illusion of multitasking. All will employ the
3516 gtk_progress_bar_update function in the same manner.
3518 Here is an example of the progress bar, updated using timeouts. This
3519 code also shows you how to reset the Progress Bar.
3522 /* example-start progressbar progressbar.c */
3524 #include <gtk/gtk.h>
3526 typedef struct _ProgressData {
3532 /* Update the value of the progress bar so that we get
3534 gint progress_timeout( gpointer data )
3539 adj = GTK_PROGRESS (data)->adjustment;
3541 /* Calculate the value of the progress bar using the
3542 * value range set in the adjustment object */
3543 new_val = adj->value + 1;
3544 if (new_val > adj->upper)
3545 new_val = adj->lower;
3547 /* Set the new value */
3548 gtk_progress_set_value (GTK_PROGRESS (data), new_val);
3550 /* As this is a timeout function, return TRUE so that it
3551 * continues to get called */
3555 /* Callback that toggles the text display within the progress
3557 void toggle_show_text( GtkWidget *widget,
3558 ProgressData *pdata )
3560 gtk_progress_set_show_text (GTK_PROGRESS (pdata->pbar),
3561 GTK_TOGGLE_BUTTON (widget)->active);
3564 /* Callback that toggles the activity mode of the progress
3566 void toggle_activity_mode( GtkWidget *widget,
3567 ProgressData *pdata )
3569 gtk_progress_set_activity_mode (GTK_PROGRESS (pdata->pbar),
3570 GTK_TOGGLE_BUTTON (widget)->active);
3573 /* Callback that toggles the continuous mode of the progress
3575 void set_continuous_mode( GtkWidget *widget,
3576 ProgressData *pdata )
3578 gtk_progress_bar_set_bar_style (GTK_PROGRESS_BAR (pdata->pbar),
3579 GTK_PROGRESS_CONTINUOUS);
3582 /* Callback that toggles the discrete mode of the progress
3584 void set_discrete_mode( GtkWidget *widget,
3585 ProgressData *pdata )
3587 gtk_progress_bar_set_bar_style (GTK_PROGRESS_BAR (pdata->pbar),
3588 GTK_PROGRESS_DISCRETE);
3591 /* Clean up allocated memory and remove the timer */
3592 void destroy_progress( GtkWidget *widget,
3593 ProgressData *pdata)
3595 gtk_timeout_remove (pdata->timer);
3597 pdata->window = NULL;
3605 ProgressData *pdata;
3607 GtkWidget *separator;
3614 gtk_init (&argc, &argv);
3616 /* Allocate memory for the data that is passwd to the callbacks */
3617 pdata = g_malloc( sizeof(ProgressData) );
3619 pdata->window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
3620 gtk_window_set_policy (GTK_WINDOW (pdata->window), FALSE, FALSE, TRUE);
3622 gtk_signal_connect (GTK_OBJECT (pdata->window), "destroy",
3623 GTK_SIGNAL_FUNC (destroy_progress),
3625 gtk_window_set_title (GTK_WINDOW (pdata->window), "GtkProgressBar");
3626 gtk_container_set_border_width (GTK_CONTAINER (pdata->window), 0);
3628 vbox = gtk_vbox_new (FALSE, 5);
3629 gtk_container_set_border_width (GTK_CONTAINER (vbox), 10);
3630 gtk_container_add (GTK_CONTAINER (pdata->window), vbox);
3631 gtk_widget_show(vbox);
3633 /* Create a centering alignment object */
3634 align = gtk_alignment_new (0.5, 0.5, 0, 0);
3635 gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 5);
3636 gtk_widget_show(align);
3638 /* Create a GtkAdjusment object to hold the range of the
3640 adj = (GtkAdjustment *) gtk_adjustment_new (0, 1, 150, 0, 0, 0);
3642 /* Create the GtkProgressBar using the adjustment */
3643 pdata->pbar = gtk_progress_bar_new_with_adjustment (adj);
3645 /* Set the format of the string that can be displayed in the
3646 * trough of the progress bar:
3649 * %l - lower range value
3650 * %u - upper range value */
3651 gtk_progress_set_format_string (GTK_PROGRESS (pdata->pbar),
3652 "%v from [%l-%u] (=%p%%)");
3653 gtk_container_add (GTK_CONTAINER (align), pdata->pbar);
3654 gtk_widget_show(pdata->pbar);
3656 /* Add a timer callback to update the value of the progress bar */
3657 pdata->timer = gtk_timeout_add (100, progress_timeout, pdata->pbar);
3659 separator = gtk_hseparator_new ();
3660 gtk_box_pack_start (GTK_BOX (vbox), separator, FALSE, FALSE, 0);
3661 gtk_widget_show(separator);
3663 /* rows, columns, homogeneous */
3664 table = gtk_table_new (2, 3, FALSE);
3665 gtk_box_pack_start (GTK_BOX (vbox), table, FALSE, TRUE, 0);
3666 gtk_widget_show(table);
3668 /* Add a check button to select displaying of the trough text */
3669 check = gtk_check_button_new_with_label ("Show text");
3670 gtk_table_attach (GTK_TABLE (table), check, 0, 1, 0, 1,
3671 GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
3673 gtk_signal_connect (GTK_OBJECT (check), "clicked",
3674 GTK_SIGNAL_FUNC (toggle_show_text),
3676 gtk_widget_show(check);
3678 /* Add a check button to toggle activity mode */
3679 check = gtk_check_button_new_with_label ("Activity mode");
3680 gtk_table_attach (GTK_TABLE (table), check, 0, 1, 1, 2,
3681 GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
3683 gtk_signal_connect (GTK_OBJECT (check), "clicked",
3684 GTK_SIGNAL_FUNC (toggle_activity_mode),
3686 gtk_widget_show(check);
3688 separator = gtk_vseparator_new ();
3689 gtk_table_attach (GTK_TABLE (table), separator, 1, 2, 0, 2,
3690 GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
3692 gtk_widget_show(separator);
3694 /* Add a radio button to select continuous display mode */
3695 button = gtk_radio_button_new_with_label (NULL, "Continuous");
3696 gtk_table_attach (GTK_TABLE (table), button, 2, 3, 0, 1,
3697 GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
3699 gtk_signal_connect (GTK_OBJECT (button), "clicked",
3700 GTK_SIGNAL_FUNC (set_continuous_mode),
3702 gtk_widget_show (button);
3704 /* Add a radio button to select discrete display mode */
3705 button = gtk_radio_button_new_with_label(
3706 gtk_radio_button_group (GTK_RADIO_BUTTON (button)),
3708 gtk_table_attach (GTK_TABLE (table), button, 2, 3, 1, 2,
3709 GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
3711 gtk_signal_connect (GTK_OBJECT (button), "clicked",
3712 GTK_SIGNAL_FUNC (set_discrete_mode),
3714 gtk_widget_show (button);
3716 separator = gtk_hseparator_new ();
3717 gtk_box_pack_start (GTK_BOX (vbox), separator, FALSE, FALSE, 0);
3718 gtk_widget_show(separator);
3720 /* Add a button to exit the program */
3721 button = gtk_button_new_with_label ("close");
3722 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
3723 (GtkSignalFunc) gtk_widget_destroy,
3724 GTK_OBJECT (pdata->window));
3725 gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
3727 /* This makes it so the button is the default. */
3728 GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
3730 /* This grabs this button to be the default button. Simply hitting
3731 * the "Enter" key will cause this button to activate. */
3732 gtk_widget_grab_default (button);
3733 gtk_widget_show(button);
3735 gtk_widget_show (pdata->window);
3744 <!-- ----------------------------------------------------------------- -->
3747 The Dialog widget is very simple, and is actually just a window with a
3748 few things pre-packed into it for you. The structure for a Dialog is:
3756 GtkWidget *action_area;
3760 So you see, it simply creates a window, and then packs a vbox into the
3761 top, then a separator, and then an hbox for the "action_area".
3763 The Dialog widget can be used for pop-up messages to the user, and
3764 other similar tasks. It is really basic, and there is only one
3765 function for the dialog box, which is:
3768 GtkWidget *gtk_dialog_new( void );
3771 So to create a new dialog box, use,
3775 window = gtk_dialog_new ();
3778 This will create the dialog box, and it is now up to you to use it.
3779 you could pack a button in the action_area by doing something like this:
3783 gtk_box_pack_start (GTK_BOX (GTK_DIALOG (window)->action_area),
3784 button, TRUE, TRUE, 0);
3785 gtk_widget_show (button);
3788 And you could add to the vbox area by packing, for instance, a label
3789 in it, try something like this:
3792 label = gtk_label_new ("Dialogs are groovy");
3793 gtk_box_pack_start (GTK_BOX (GTK_DIALOG (window)->vbox),
3794 label, TRUE, TRUE, 0);
3795 gtk_widget_show (label);
3798 As an example in using the dialog box, you could put two buttons in
3799 the action_area, a Cancel button and an Ok button, and a label in the
3800 vbox area, asking the user a question or giving an error etc. Then
3801 you could attach a different signal to each of the buttons and perform
3802 the operation the user selects.
3804 If the simple functionality provided by the default vertical and
3805 horizontal boxes in the two areas does't give you enough control for
3806 your application, then you can simply pack another layout widget into
3807 the boxes provided. For example, you could pack a table into the
3810 <!-- ----------------------------------------------------------------- -->
3811 <sect1> Pixmaps <label id="sec_Pixmaps">
3813 Pixmaps are data structures that contain pictures. These pictures can
3814 be used in various places, but most visibly as icons on the X-Windows
3815 desktop, or as cursors. A bitmap is a 2-color pixmap.
3817 To use pixmaps in GTK, we must first build a GdkPixmap structure using
3818 routines from the GDK layer. Pixmaps can either be created from
3819 in-memory data, or from data read from a file. We'll go through each
3820 of the calls to create a pixmap.
3823 GdkPixmap *gdk_bitmap_create_from_data( GdkWindow *window,
3829 This routine is used to create a single-plane pixmap (2 colors) from
3830 data in memory. Each bit of the data represents whether that pixel is
3831 off or on. Width and height are in pixels. The GdkWindow pointer is
3832 to the current window, since a pixmap resources are meaningful only in
3833 the context of the screen where it is to be displayed.
3836 GdkPixmap *gdk_pixmap_create_from_data( GdkWindow *window,
3845 This is used to create a pixmap of the given depth (number of colors) from
3846 the bitmap data specified. <tt/fg/ and <tt/bg/ are the foreground and
3847 background color to use.
3850 GdkPixmap *gdk_pixmap_create_from_xpm( GdkWindow *window,
3852 GdkColor *transparent_color,
3853 const gchar *filename );
3856 XPM format is a readable pixmap representation for the X Window
3857 System. It is widely used and many different utilities are available
3858 for creating image files in this format. The file specified by
3859 filename must contain an image in that format and it is loaded into
3860 the pixmap structure. The mask specifies which bits of the pixmap are
3861 opaque. All other bits are colored using the color specified by
3862 transparent_color. An example using this follows below.
3865 GdkPixmap *gdk_pixmap_create_from_xpm_d( GdkWindow *window,
3867 GdkColor *transparent_color,
3871 Small images can be incorporated into a program as data in the XPM
3872 format. A pixmap is created using this data, instead of reading it
3873 from a file. An example of such data is
3877 static const char * xpm_data[] = {
3880 ". c #000000000000",
3881 "X c #FFFFFFFFFFFF",
3900 When we're done using a pixmap and not likely to reuse it again soon,
3901 it is a good idea to release the resource using
3902 gdk_pixmap_unref(). Pixmaps should be considered a precious resource.
3904 Once we've created a pixmap, we can display it as a GTK widget. We
3905 must create a GTK pixmap widget to contain the GDK pixmap. This is
3909 GtkWidget *gtk_pixmap_new( GdkPixmap *pixmap,
3913 The other pixmap widget calls are
3916 guint gtk_pixmap_get_type( void );
3918 void gtk_pixmap_set( GtkPixmap *pixmap,
3922 void gtk_pixmap_get( GtkPixmap *pixmap,
3927 gtk_pixmap_set is used to change the pixmap that the widget is currently
3928 managing. Val is the pixmap created using GDK.
3930 The following is an example of using a pixmap in a button.
3933 /* example-start pixmap pixmap.c */
3935 #include <gtk/gtk.h>
3938 /* XPM data of Open-File icon */
3939 static const char * xpm_data[] = {
3942 ". c #000000000000",
3943 "X c #FFFFFFFFFFFF",
3962 /* when invoked (via signal delete_event), terminates the application.
3964 void close_application( GtkWidget *widget, GdkEvent *event, gpointer data ) {
3969 /* is invoked when the button is clicked. It just prints a message.
3971 void button_clicked( GtkWidget *widget, gpointer data ) {
3972 printf( "button clicked\n" );
3975 int main( int argc, char *argv[] )
3977 /* GtkWidget is the storage type for widgets */
3978 GtkWidget *window, *pixmapwid, *button;
3983 /* create the main window, and attach delete_event signal to terminating
3985 gtk_init( &argc, &argv );
3986 window = gtk_window_new( GTK_WINDOW_TOPLEVEL );
3987 gtk_signal_connect( GTK_OBJECT (window), "delete_event",
3988 GTK_SIGNAL_FUNC (close_application), NULL );
3989 gtk_container_set_border_width( GTK_CONTAINER (window), 10 );
3990 gtk_widget_show( window );
3992 /* now for the pixmap from gdk */
3993 style = gtk_widget_get_style( window );
3994 pixmap = gdk_pixmap_create_from_xpm_d( window->window, &mask,
3995 &style->bg[GTK_STATE_NORMAL],
3996 (gchar **)xpm_data );
3998 /* a pixmap widget to contain the pixmap */
3999 pixmapwid = gtk_pixmap_new( pixmap, mask );
4000 gtk_widget_show( pixmapwid );
4002 /* a button to contain the pixmap widget */
4003 button = gtk_button_new();
4004 gtk_container_add( GTK_CONTAINER(button), pixmapwid );
4005 gtk_container_add( GTK_CONTAINER(window), button );
4006 gtk_widget_show( button );
4008 gtk_signal_connect( GTK_OBJECT(button), "clicked",
4009 GTK_SIGNAL_FUNC(button_clicked), NULL );
4011 /* show the window */
4019 To load a file from an XPM data file called icon0.xpm in the current
4020 directory, we would have created the pixmap thus
4023 /* load a pixmap from a file */
4024 pixmap = gdk_pixmap_create_from_xpm( window->window, &mask,
4025 &style->bg[GTK_STATE_NORMAL],
4027 pixmapwid = gtk_pixmap_new( pixmap, mask );
4028 gtk_widget_show( pixmapwid );
4029 gtk_container_add( GTK_CONTAINER(window), pixmapwid );
4032 A disadvantage of using pixmaps is that the displayed object is always
4033 rectangular, regardless of the image. We would like to create desktops
4034 and applications with icons that have more natural shapes. For
4035 example, for a game interface, we would like to have round buttons to
4036 push. The way to do this is using shaped windows.
4038 A shaped window is simply a pixmap where the background pixels are
4039 transparent. This way, when the background image is multi-colored, we
4040 don't overwrite it with a rectangular, non-matching border around our
4041 icon. The following example displays a full wheelbarrow image on the
4045 /* example-start wheelbarrow wheelbarrow.c */
4047 #include <gtk/gtk.h>
4050 static char * WheelbarrowFull_xpm[] = {
4053 ". c #DF7DCF3CC71B",
4054 "X c #965875D669A6",
4055 "o c #71C671C671C6",
4056 "O c #A699A289A699",
4057 "+ c #965892489658",
4058 "@ c #8E38410330C2",
4059 "# c #D75C7DF769A6",
4060 "$ c #F7DECF3CC71B",
4061 "% c #96588A288E38",
4062 "& c #A69992489E79",
4063 "* c #8E3886178E38",
4064 "= c #104008200820",
4065 "- c #596510401040",
4066 "; c #C71B30C230C2",
4067 ": c #C71B9A699658",
4068 "> c #618561856185",
4069 ", c #20811C712081",
4070 "< c #104000000000",
4071 "1 c #861720812081",
4072 "2 c #DF7D4D344103",
4073 "3 c #79E769A671C6",
4074 "4 c #861782078617",
4075 "5 c #41033CF34103",
4076 "6 c #000000000000",
4077 "7 c #49241C711040",
4078 "8 c #492445144924",
4079 "9 c #082008200820",
4080 "0 c #69A618611861",
4081 "q c #B6DA71C65144",
4082 "w c #410330C238E3",
4083 "e c #CF3CBAEAB6DA",
4084 "r c #71C6451430C2",
4085 "t c #EFBEDB6CD75C",
4086 "y c #28A208200820",
4087 "u c #186110401040",
4088 "i c #596528A21861",
4089 "p c #71C661855965",
4090 "a c #A69996589658",
4091 "s c #30C228A230C2",
4092 "d c #BEFBA289AEBA",
4093 "f c #596545145144",
4094 "g c #30C230C230C2",
4095 "h c #8E3882078617",
4096 "j c #208118612081",
4097 "k c #38E30C300820",
4098 "l c #30C2208128A2",
4099 "z c #38E328A238E3",
4100 "x c #514438E34924",
4101 "c c #618555555965",
4102 "v c #30C2208130C2",
4103 "b c #38E328A230C2",
4104 "n c #28A228A228A2",
4105 "m c #41032CB228A2",
4106 "M c #104010401040",
4107 "N c #492438E34103",
4108 "B c #28A2208128A2",
4109 "V c #A699596538E3",
4110 "C c #30C21C711040",
4111 "Z c #30C218611040",
4112 "A c #965865955965",
4113 "S c #618534D32081",
4114 "D c #38E31C711040",
4115 "F c #082000000820",
4124 "ty> 459@>+&& ",
4126 "%$;=* *3:.Xa.dfg> ",
4127 "Oh$;ya *3d.a8j,Xe.d3g8+ ",
4128 " Oh$;ka *3d$a8lz,,xxc:.e3g54 ",
4129 " Oh$;kO *pd$%svbzz,sxxxxfX..&wn> ",
4130 " Oh$@mO *3dthwlsslszjzxxxxxxx3:td8M4 ",
4131 " Oh$@g& *3d$XNlvvvlllm,mNwxxxxxxxfa.:,B* ",
4132 " Oh$@,Od.czlllllzlmmqV@V#V@fxxxxxxxf:%j5& ",
4133 " Oh$1hd5lllslllCCZrV#r#:#2AxxxxxxxxxcdwM* ",
4134 " OXq6c.%8vvvllZZiqqApA:mq:Xxcpcxxxxxfdc9* ",
4135 " 2r<6gde3bllZZrVi7S@SV77A::qApxxxxxxfdcM ",
4136 " :,q-6MN.dfmZZrrSS:#riirDSAX@Af5xxxxxfevo",
4137 " +A26jguXtAZZZC7iDiCCrVVii7Cmmmxxxxxx%3g",
4138 " *#16jszN..3DZZZZrCVSA2rZrV7Dmmwxxxx&en",
4139 " p2yFvzssXe:fCZZCiiD7iiZDiDSSZwwxx8e*>",
4140 " OA1<jzxwwc:$d%NDZZZZCCCZCCZZCmxxfd.B ",
4141 " 3206Bwxxszx%et.eaAp77m77mmmf3&eeeg* ",
4142 " @26MvzxNzvlbwfpdettttttttttt.c,n& ",
4143 " *;16=lsNwwNwgsvslbwwvccc3pcfu<o ",
4144 " p;<69BvwwsszslllbBlllllllu<5+ ",
4145 " OS0y6FBlvvvzvzss,u=Blllj=54 ",
4146 " c1-699Blvlllllu7k96MMMg4 ",
4147 " *10y8n6FjvllllB<166668 ",
4148 " S-kg+>666<M<996-y6n<8* ",
4149 " p71=4 m69996kD8Z-66698&& ",
4150 " &i0ycm6n4 ogk17,0<6666g ",
4151 " N-k-<> >=01-kuu666> ",
4152 " ,6ky& &46-10ul,66, ",
4153 " Ou0<> o66y<ulw<66& ",
4154 " *kk5 >66By7=xu664 ",
4155 " <<M4 466lj<Mxu66o ",
4156 " *>> +66uv,zN666* ",
4166 /* When invoked (via signal delete_event), terminates the application */
4167 void close_application( GtkWidget *widget, GdkEvent *event, gpointer data ) {
4171 int main (int argc, char *argv[])
4173 /* GtkWidget is the storage type for widgets */
4174 GtkWidget *window, *pixmap, *fixed;
4175 GdkPixmap *gdk_pixmap;
4180 /* Create the main window, and attach delete_event signal to terminate
4181 * the application. Note that the main window will not have a titlebar
4182 * since we're making it a popup. */
4183 gtk_init (&argc, &argv);
4184 window = gtk_window_new( GTK_WINDOW_POPUP );
4185 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
4186 GTK_SIGNAL_FUNC (close_application), NULL);
4187 gtk_widget_show (window);
4189 /* Now for the pixmap and the pixmap widget */
4190 style = gtk_widget_get_default_style();
4191 gc = style->black_gc;
4192 gdk_pixmap = gdk_pixmap_create_from_xpm_d( window->window, &mask,
4193 &style->bg[GTK_STATE_NORMAL],
4194 WheelbarrowFull_xpm );
4195 pixmap = gtk_pixmap_new( gdk_pixmap, mask );
4196 gtk_widget_show( pixmap );
4198 /* To display the pixmap, we use a fixed widget to place the pixmap */
4199 fixed = gtk_fixed_new();
4200 gtk_widget_set_usize( fixed, 200, 200 );
4201 gtk_fixed_put( GTK_FIXED(fixed), pixmap, 0, 0 );
4202 gtk_container_add( GTK_CONTAINER(window), fixed );
4203 gtk_widget_show( fixed );
4205 /* This masks out everything except for the image itself */
4206 gtk_widget_shape_combine_mask( window, mask, 0, 0 );
4208 /* show the window */
4209 gtk_widget_set_uposition( window, 20, 400 );
4210 gtk_widget_show( window );
4218 To make the wheelbarrow image sensitive, we could attach the button
4219 press event signal to make it do something. The following few lines
4220 would make the picture sensitive to a mouse button being pressed which
4221 makes the application terminate.
4224 gtk_widget_set_events( window,
4225 gtk_widget_get_events( window ) |
4226 GDK_BUTTON_PRESS_MASK );
4228 gtk_signal_connect( GTK_OBJECT(window), "button_press_event",
4229 GTK_SIGNAL_FUNC(close_application), NULL );
4232 <!-- ----------------------------------------------------------------- -->
4235 Ruler widgets are used to indicate the location of the mouse pointer
4236 in a given window. A window can have a vertical ruler spanning across
4237 the width and a horizontal ruler spanning down the height. A small
4238 triangular indicator on the ruler shows the exact location of the
4239 pointer relative to the ruler.
4241 A ruler must first be created. Horizontal and vertical rulers are
4245 GtkWidget *gtk_hruler_new( void ); /* horizontal ruler */
4247 GtkWidget *gtk_vruler_new( void ); /* vertical ruler */
4250 Once a ruler is created, we can define the unit of measurement. Units
4251 of measure for rulers can be GTK_PIXELS, GTK_INCHES or
4252 GTK_CENTIMETERS. This is set using
4255 void gtk_ruler_set_metric( GtkRuler *ruler,
4256 GtkMetricType metric );
4259 The default measure is GTK_PIXELS.
4262 gtk_ruler_set_metric( GTK_RULER(ruler), GTK_PIXELS );
4265 Other important characteristics of a ruler are how to mark the units
4266 of scale and where the position indicator is initially placed. These
4267 are set for a ruler using
4270 void gtk_ruler_set_range( GtkRuler *ruler,
4277 The lower and upper arguments define the extent of the ruler, and
4278 max_size is the largest possible number that will be displayed.
4279 Position defines the initial position of the pointer indicator within
4282 A vertical ruler can span an 800 pixel wide window thus
4285 gtk_ruler_set_range( GTK_RULER(vruler), 0, 800, 0, 800);
4288 The markings displayed on the ruler will be from 0 to 800, with a
4289 number for every 100 pixels. If instead we wanted the ruler to range
4290 from 7 to 16, we would code
4293 gtk_ruler_set_range( GTK_RULER(vruler), 7, 16, 0, 20);
4296 The indicator on the ruler is a small triangular mark that indicates
4297 the position of the pointer relative to the ruler. If the ruler is
4298 used to follow the mouse pointer, the motion_notify_event signal
4299 should be connected to the motion_notify_event method of the ruler.
4300 To follow all mouse movements within a window area, we would use
4303 #define EVENT_METHOD(i, x) GTK_WIDGET_CLASS(GTK_OBJECT(i)->klass)->x
4305 gtk_signal_connect_object( GTK_OBJECT(area), "motion_notify_event",
4306 (GtkSignalFunc)EVENT_METHOD(ruler, motion_notify_event),
4307 GTK_OBJECT(ruler) );
4310 The following example creates a drawing area with a horizontal ruler
4311 above it and a vertical ruler to the left of it. The size of the
4312 drawing area is 600 pixels wide by 400 pixels high. The horizontal
4313 ruler spans from 7 to 13 with a mark every 100 pixels, while the
4314 vertical ruler spans from 0 to 400 with a mark every 100 pixels.
4315 Placement of the drawing area and the rulers is done using a table.
4318 /* example-start rulers rulers.c */
4320 #include <gtk/gtk.h>
4322 #define EVENT_METHOD(i, x) GTK_WIDGET_CLASS(GTK_OBJECT(i)->klass)->x
4327 /* This routine gets control when the close button is clicked */
4328 void close_application( GtkWidget *widget, GdkEvent *event, gpointer data ) {
4332 /* The main routine */
4333 int main( int argc, char *argv[] ) {
4334 GtkWidget *window, *table, *area, *hrule, *vrule;
4336 /* Initialize GTK and create the main window */
4337 gtk_init( &argc, &argv );
4339 window = gtk_window_new( GTK_WINDOW_TOPLEVEL );
4340 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
4341 GTK_SIGNAL_FUNC( close_application ), NULL);
4342 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
4344 /* Create a table for placing the ruler and the drawing area */
4345 table = gtk_table_new( 3, 2, FALSE );
4346 gtk_container_add( GTK_CONTAINER(window), table );
4348 area = gtk_drawing_area_new();
4349 gtk_drawing_area_size( (GtkDrawingArea *)area, XSIZE, YSIZE );
4350 gtk_table_attach( GTK_TABLE(table), area, 1, 2, 1, 2,
4351 GTK_EXPAND|GTK_FILL, GTK_FILL, 0, 0 );
4352 gtk_widget_set_events( area, GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK );
4354 /* The horizontal ruler goes on top. As the mouse moves across the drawing area,
4355 * a motion_notify_event is passed to the appropriate event handler for the ruler. */
4356 hrule = gtk_hruler_new();
4357 gtk_ruler_set_metric( GTK_RULER(hrule), GTK_PIXELS );
4358 gtk_ruler_set_range( GTK_RULER(hrule), 7, 13, 0, 20 );
4359 gtk_signal_connect_object( GTK_OBJECT(area), "motion_notify_event",
4360 (GtkSignalFunc)EVENT_METHOD(hrule, motion_notify_event),
4361 GTK_OBJECT(hrule) );
4362 /* GTK_WIDGET_CLASS(GTK_OBJECT(hrule)->klass)->motion_notify_event, */
4363 gtk_table_attach( GTK_TABLE(table), hrule, 1, 2, 0, 1,
4364 GTK_EXPAND|GTK_SHRINK|GTK_FILL, GTK_FILL, 0, 0 );
4366 /* The vertical ruler goes on the left. As the mouse moves across the drawing area,
4367 * a motion_notify_event is passed to the appropriate event handler for the ruler. */
4368 vrule = gtk_vruler_new();
4369 gtk_ruler_set_metric( GTK_RULER(vrule), GTK_PIXELS );
4370 gtk_ruler_set_range( GTK_RULER(vrule), 0, YSIZE, 10, YSIZE );
4371 gtk_signal_connect_object( GTK_OBJECT(area), "motion_notify_event",
4373 GTK_WIDGET_CLASS(GTK_OBJECT(vrule)->klass)->motion_notify_event,
4374 GTK_OBJECT(vrule) );
4375 gtk_table_attach( GTK_TABLE(table), vrule, 0, 1, 1, 2,
4376 GTK_FILL, GTK_EXPAND|GTK_SHRINK|GTK_FILL, 0, 0 );
4378 /* Now show everything */
4379 gtk_widget_show( area );
4380 gtk_widget_show( hrule );
4381 gtk_widget_show( vrule );
4382 gtk_widget_show( table );
4383 gtk_widget_show( window );
4391 <!-- ----------------------------------------------------------------- -->
4394 Statusbars are simple widgets used to display a text message. They
4395 keep a stack of the messages pushed onto them, so that popping the
4396 current message will re-display the previous text message.
4398 In order to allow different parts of an application to use the same
4399 statusbar to display messages, the statusbar widget issues Context
4400 Identifiers which are used to identify different 'users'. The message
4401 on top of the stack is the one displayed, no matter what context it is
4402 in. Messages are stacked in last-in-first-out order, not context
4405 A statusbar is created with a call to:
4408 GtkWidget *gtk_statusbar_new( void );
4411 A new Context Identifier is requested using a call to the following
4412 function with a short textual description of the context:
4415 guint gtk_statusbar_get_context_id( GtkStatusbar *statusbar,
4416 const gchar *context_description );
4419 There are three functions that can operate on statusbars:
4422 guint gtk_statusbar_push( GtkStatusbar *statusbar,
4426 void gtk_statusbar_pop( GtkStatusbar *statusbar)
4429 void gtk_statusbar_remove( GtkStatusbar *statusbar,
4434 The first, gtk_statusbar_push, is used to add a new message to the
4435 statusbar. It returns a Message Identifier, which can be passed later
4436 to the function gtk_statusbar_remove to remove the message with the
4437 given Message and Context Identifiers from the statusbar's stack.
4439 The function gtk_statusbar_pop removes the message highest in the
4440 stack with the given Context Identifier.
4442 The following example creates a statusbar and two buttons, one for
4443 pushing items onto the statusbar, and one for popping the last item
4447 /* example-start statusbar statusbar.c */
4449 #include <gtk/gtk.h>
4452 GtkWidget *status_bar;
4454 void push_item (GtkWidget *widget, gpointer data)
4456 static int count = 1;
4459 g_snprintf(buff, 20, "Item %d", count++);
4460 gtk_statusbar_push( GTK_STATUSBAR(status_bar), GPOINTER_TO_INT(data), buff);
4465 void pop_item (GtkWidget *widget, gpointer data)
4467 gtk_statusbar_pop( GTK_STATUSBAR(status_bar), GPOINTER_TO_INT(data) );
4471 int main (int argc, char *argv[])
4480 gtk_init (&argc, &argv);
4482 /* create a new window */
4483 window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
4484 gtk_widget_set_usize( GTK_WIDGET (window), 200, 100);
4485 gtk_window_set_title(GTK_WINDOW (window), "GTK Statusbar Example");
4486 gtk_signal_connect(GTK_OBJECT (window), "delete_event",
4487 (GtkSignalFunc) gtk_exit, NULL);
4489 vbox = gtk_vbox_new(FALSE, 1);
4490 gtk_container_add(GTK_CONTAINER(window), vbox);
4491 gtk_widget_show(vbox);
4493 status_bar = gtk_statusbar_new();
4494 gtk_box_pack_start (GTK_BOX (vbox), status_bar, TRUE, TRUE, 0);
4495 gtk_widget_show (status_bar);
4497 context_id = gtk_statusbar_get_context_id( GTK_STATUSBAR(status_bar), "Statusbar example");
4499 button = gtk_button_new_with_label("push item");
4500 gtk_signal_connect(GTK_OBJECT(button), "clicked",
4501 GTK_SIGNAL_FUNC (push_item), GINT_TO_POINTER(context_id) );
4502 gtk_box_pack_start(GTK_BOX(vbox), button, TRUE, TRUE, 2);
4503 gtk_widget_show(button);
4505 button = gtk_button_new_with_label("pop last item");
4506 gtk_signal_connect(GTK_OBJECT(button), "clicked",
4507 GTK_SIGNAL_FUNC (pop_item), GINT_TO_POINTER(context_id) );
4508 gtk_box_pack_start(GTK_BOX(vbox), button, TRUE, TRUE, 2);
4509 gtk_widget_show(button);
4511 /* always display the window as the last step so it all splashes on
4512 * the screen at once. */
4513 gtk_widget_show(window);
4522 <!-- ----------------------------------------------------------------- -->
4525 The Entry widget allows text to be typed and displayed in a single line
4526 text box. The text may be set with function calls that allow new text
4527 to replace, prepend or append the current contents of the Entry widget.
4529 There are two functions for creating Entry widgets:
4532 GtkWidget *gtk_entry_new( void );
4534 GtkWidget *gtk_entry_new_with_max_length( guint16 max );
4537 The first just creates a new Entry widget, whilst the second creates a
4538 new Entry and sets a limit on the length of the text within the Entry.
4540 There are several functions for altering the text which is currently
4541 within the Entry widget.
4544 void gtk_entry_set_text( GtkEntry *entry,
4545 const gchar *text );
4547 void gtk_entry_append_text( GtkEntry *entry,
4548 const gchar *text );
4550 void gtk_entry_prepend_text( GtkEntry *entry,
4551 const gchar *text );
4554 The function gtk_entry_set_text sets the contents of the Entry widget,
4555 replacing the current contents. The functions gtk_entry_append_text
4556 and gtk_entry_prepend_text allow the current contents to be appended
4559 The next function allows the current insertion point to be set.
4562 void gtk_entry_set_position( GtkEntry *entry,
4566 The contents of the Entry can be retrieved by using a call to the
4567 following function. This is useful in the callback functions described below.
4570 gchar *gtk_entry_get_text( GtkEntry *entry );
4573 If we don't want the contents of the Entry to be changed by someone typing
4574 into it, we can change its editable state.
4577 void gtk_entry_set_editable( GtkEntry *entry,
4578 gboolean editable );
4581 The function above allows us to toggle the editable state of the
4582 Entry widget by passing in a TRUE or FALSE value for the <tt/editable/
4585 If we are using the Entry where we don't want the text entered to be
4586 visible, for example when a password is being entered, we can use the
4587 following function, which also takes a boolean flag.
4590 void gtk_entry_set_visibility( GtkEntry *entry,
4594 A region of the text may be set as selected by using the following
4595 function. This would most often be used after setting some default
4596 text in an Entry, making it easy for the user to remove it.
4599 void gtk_entry_select_region( GtkEntry *entry,
4604 If we want to catch when the user has entered text, we can connect to
4605 the <tt/activate/ or <tt/changed/ signal. Activate is raised when the
4606 user hits the enter key within the Entry widget. Changed is raised
4607 when the text changes at all, e.g. for every character entered or
4610 The following code is an example of using an Entry widget.
4613 /* example-start entry entry.c */
4615 #include <gtk/gtk.h>
4617 void enter_callback(GtkWidget *widget, GtkWidget *entry)
4620 entry_text = gtk_entry_get_text(GTK_ENTRY(entry));
4621 printf("Entry contents: %s\n", entry_text);
4624 void entry_toggle_editable (GtkWidget *checkbutton,
4627 gtk_entry_set_editable(GTK_ENTRY(entry),
4628 GTK_TOGGLE_BUTTON(checkbutton)->active);
4631 void entry_toggle_visibility (GtkWidget *checkbutton,
4634 gtk_entry_set_visibility(GTK_ENTRY(entry),
4635 GTK_TOGGLE_BUTTON(checkbutton)->active);
4638 int main (int argc, char *argv[])
4642 GtkWidget *vbox, *hbox;
4647 gtk_init (&argc, &argv);
4649 /* create a new window */
4650 window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
4651 gtk_widget_set_usize( GTK_WIDGET (window), 200, 100);
4652 gtk_window_set_title(GTK_WINDOW (window), "GTK Entry");
4653 gtk_signal_connect(GTK_OBJECT (window), "delete_event",
4654 (GtkSignalFunc) gtk_exit, NULL);
4656 vbox = gtk_vbox_new (FALSE, 0);
4657 gtk_container_add (GTK_CONTAINER (window), vbox);
4658 gtk_widget_show (vbox);
4660 entry = gtk_entry_new_with_max_length (50);
4661 gtk_signal_connect(GTK_OBJECT(entry), "activate",
4662 GTK_SIGNAL_FUNC(enter_callback),
4664 gtk_entry_set_text (GTK_ENTRY (entry), "hello");
4665 gtk_entry_append_text (GTK_ENTRY (entry), " world");
4666 gtk_entry_select_region (GTK_ENTRY (entry),
4667 0, GTK_ENTRY(entry)->text_length);
4668 gtk_box_pack_start (GTK_BOX (vbox), entry, TRUE, TRUE, 0);
4669 gtk_widget_show (entry);
4671 hbox = gtk_hbox_new (FALSE, 0);
4672 gtk_container_add (GTK_CONTAINER (vbox), hbox);
4673 gtk_widget_show (hbox);
4675 check = gtk_check_button_new_with_label("Editable");
4676 gtk_box_pack_start (GTK_BOX (hbox), check, TRUE, TRUE, 0);
4677 gtk_signal_connect (GTK_OBJECT(check), "toggled",
4678 GTK_SIGNAL_FUNC(entry_toggle_editable), entry);
4679 gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(check), TRUE);
4680 gtk_widget_show (check);
4682 check = gtk_check_button_new_with_label("Visible");
4683 gtk_box_pack_start (GTK_BOX (hbox), check, TRUE, TRUE, 0);
4684 gtk_signal_connect (GTK_OBJECT(check), "toggled",
4685 GTK_SIGNAL_FUNC(entry_toggle_visibility), entry);
4686 gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(check), TRUE);
4687 gtk_widget_show (check);
4689 button = gtk_button_new_with_label ("Close");
4690 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
4691 GTK_SIGNAL_FUNC(gtk_exit),
4692 GTK_OBJECT (window));
4693 gtk_box_pack_start (GTK_BOX (vbox), button, TRUE, TRUE, 0);
4694 GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
4695 gtk_widget_grab_default (button);
4696 gtk_widget_show (button);
4698 gtk_widget_show(window);
4706 <!-- ----------------------------------------------------------------- -->
4707 <sect1> Color Selection
4709 The color selection widget is, not surprisingly, a widget for
4710 interactive selection of colors. This composite widget lets the user
4711 select a color by manipulating RGB (Red, Green, Blue) and HSV (Hue,
4712 Saturation, Value) triples. This is done either by adjusting single
4713 values with sliders or entries, or by picking the desired color from a
4714 hue-saturation wheel/value bar. Optionally, the opacity of the color
4717 The color selection widget currently emits only one signal,
4718 "color_changed", which is emitted whenever the current color in the
4719 widget changes, either when the user changes it or if it's set
4720 explicitly through gtk_color_selection_set_color().
4722 Lets have a look at what the color selection widget has to offer
4723 us. The widget comes in two flavours: gtk_color_selection and
4724 gtk_color_selection_dialog.
4727 GtkWidget *gtk_color_selection_new( void );
4730 You'll probably not be using this constructor directly. It creates an
4731 orphan GtkColorSelection widget which you'll have to parent
4732 yourself. The GtkColorSelection widget inherits from the GtkVBox
4736 GtkWidget *gtk_color_selection_dialog_new( const gchar *title );
4739 This is the most common color selection constructor. It creates a
4740 GtkColorSelectionDialog, which inherits from a GtkDialog. It consists
4741 of a GtkFrame containing a GtkColorSelection widget, a GtkHSeparator
4742 and a GtkHBox with three buttons, "Ok", "Cancel" and "Help". You can
4743 reach these buttons by accessing the "ok_button", "cancel_button" and
4744 "help_button" widgets in the GtkColorSelectionDialog structure,
4745 (i.e. GTK_COLOR_SELECTION_DIALOG(colorseldialog)->ok_button).
4748 void gtk_color_selection_set_update_policy( GtkColorSelection *colorsel,
4749 GtkUpdateType policy );
4752 This function sets the update policy. The default policy is
4753 GTK_UPDATE_CONTINUOUS which means that the current color is updated
4754 continuously when the user drags the sliders or presses the mouse and
4755 drags in the hue-saturation wheel or value bar. If you experience
4756 performance problems, you may want to set the policy to
4757 GTK_UPDATE_DISCONTINUOUS or GTK_UPDATE_DELAYED.
4760 void gtk_color_selection_set_opacity( GtkColorSelection *colorsel,
4764 The color selection widget supports adjusting the opacity of a color
4765 (also known as the alpha channel). This is disabled by
4766 default. Calling this function with use_opacity set to TRUE enables
4767 opacity. Likewise, use_opacity set to FALSE will disable opacity.
4770 void gtk_color_selection_set_color( GtkColorSelection *colorsel,
4774 You can set the current color explicitly by calling this function with
4775 a pointer to an array of colors (gdouble). The length of the array
4776 depends on whether opacity is enabled or not. Position 0 contains the
4777 red component, 1 is green, 2 is blue and opacity is at position 3
4778 (only if opacity is enabled, see
4779 gtk_color_selection_set_opacity()). All values are between 0.0 and
4783 void gtk_color_selection_get_color( GtkColorSelection *colorsel,
4787 When you need to query the current color, typically when you've
4788 received a "color_changed" signal, you use this function. Color is a
4789 pointer to the array of colors to fill in. See the
4790 gtk_color_selection_set_color() function for the description of this
4793 <!-- Need to do a whole section on DnD - TRG
4797 The color sample areas (right under the hue-saturation wheel) supports
4798 drag and drop. The type of drag and drop is "application/x-color". The
4799 message data consists of an array of 4 (or 5 if opacity is enabled)
4800 gdouble values, where the value at position 0 is 0.0 (opacity on) or
4801 1.0 (opacity off) followed by the red, green and blue values at
4802 positions 1,2 and 3 respectively. If opacity is enabled, the opacity
4803 is passed in the value at position 4.
4806 Here's a simple example demonstrating the use of the
4807 GtkColorSelectionDialog. The program displays a window containing a
4808 drawing area. Clicking on it opens a color selection dialog, and
4809 changing the color in the color selection dialog changes the
4813 /* example-start colorsel colorsel.c */
4816 #include <gdk/gdk.h>
4817 #include <gtk/gtk.h>
4819 GtkWidget *colorseldlg = NULL;
4820 GtkWidget *drawingarea = NULL;
4822 /* Color changed handler */
4824 void color_changed_cb (GtkWidget *widget, GtkColorSelection *colorsel)
4828 GdkColormap *colormap;
4830 /* Get drawingarea colormap */
4832 colormap = gdk_window_get_colormap (drawingarea->window);
4834 /* Get current color */
4836 gtk_color_selection_get_color (colorsel,color);
4838 /* Fit to a unsigned 16 bit integer (0..65535) and insert into the GdkColor structure */
4840 gdk_color.red = (guint16)(color[0]*65535.0);
4841 gdk_color.green = (guint16)(color[1]*65535.0);
4842 gdk_color.blue = (guint16)(color[2]*65535.0);
4844 /* Allocate color */
4846 gdk_color_alloc (colormap, &gdk_color);
4848 /* Set window background color */
4850 gdk_window_set_background (drawingarea->window, &gdk_color);
4854 gdk_window_clear (drawingarea->window);
4857 /* Drawingarea event handler */
4859 gint area_event (GtkWidget *widget, GdkEvent *event, gpointer client_data)
4861 gint handled = FALSE;
4862 GtkWidget *colorsel;
4864 /* Check if we've received a button pressed event */
4866 if (event->type == GDK_BUTTON_PRESS && colorseldlg == NULL)
4868 /* Yes, we have an event and there's no colorseldlg yet! */
4872 /* Create color selection dialog */
4874 colorseldlg = gtk_color_selection_dialog_new("Select background color");
4876 /* Get the GtkColorSelection widget */
4878 colorsel = GTK_COLOR_SELECTION_DIALOG(colorseldlg)->colorsel;
4880 /* Connect to the "color_changed" signal, set the client-data to the colorsel widget */
4882 gtk_signal_connect(GTK_OBJECT(colorsel), "color_changed",
4883 (GtkSignalFunc)color_changed_cb, (gpointer)colorsel);
4885 /* Show the dialog */
4887 gtk_widget_show(colorseldlg);
4893 /* Close down and exit handler */
4895 void destroy_window (GtkWidget *widget, gpointer client_data)
4902 gint main (gint argc, gchar *argv[])
4906 /* Initialize the toolkit, remove gtk-related commandline stuff */
4908 gtk_init (&argc,&argv);
4910 /* Create toplevel window, set title and policies */
4912 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
4913 gtk_window_set_title (GTK_WINDOW(window), "Color selection test");
4914 gtk_window_set_policy (GTK_WINDOW(window), TRUE, TRUE, TRUE);
4916 /* Attach to the "delete" and "destroy" events so we can exit */
4918 gtk_signal_connect (GTK_OBJECT(window), "delete_event",
4919 (GtkSignalFunc)destroy_window, (gpointer)window);
4921 gtk_signal_connect (GTK_OBJECT(window), "destroy",
4922 (GtkSignalFunc)destroy_window, (gpointer)window);
4924 /* Create drawingarea, set size and catch button events */
4926 drawingarea = gtk_drawing_area_new ();
4928 gtk_drawing_area_size (GTK_DRAWING_AREA(drawingarea), 200, 200);
4930 gtk_widget_set_events (drawingarea, GDK_BUTTON_PRESS_MASK);
4932 gtk_signal_connect (GTK_OBJECT(drawingarea), "event",
4933 (GtkSignalFunc)area_event, (gpointer)drawingarea);
4935 /* Add drawingarea to window, then show them both */
4937 gtk_container_add (GTK_CONTAINER(window), drawingarea);
4939 gtk_widget_show (drawingarea);
4940 gtk_widget_show (window);
4942 /* Enter the gtk main loop (this never returns) */
4946 /* Satisfy grumpy compilers */
4953 <!-- ----------------------------------------------------------------- -->
4954 <sect1> File Selections
4956 The file selection widget is a quick and simple way to display a File
4957 dialog box. It comes complete with Ok, Cancel, and Help buttons, a
4958 great way to cut down on programming time.
4960 To create a new file selection box use:
4963 GtkWidget *gtk_file_selection_new( gchar *title );
4966 To set the filename, for example to bring up a specific directory, or
4967 give a default filename, use this function:
4970 void gtk_file_selection_set_filename( GtkFileSelection *filesel,
4974 To grab the text that the user has entered or clicked on, use this
4978 gchar *gtk_file_selection_get_filename( GtkFileSelection *filesel );
4981 There are also pointers to the widgets contained within the file
4982 selection widget. These are:
4987 <item>selection_entry
4988 <item>selection_text
4995 Most likely you will want to use the ok_button, cancel_button, and
4996 help_button pointers in signaling their use.
4998 Included here is an example stolen from testgtk.c, modified to run on
4999 its own. As you will see, there is nothing much to creating a file
5000 selection widget. While in this example the Help button appears on the
5001 screen, it does nothing as there is not a signal attached to it.
5004 /* example-start filesel filesel.c */
5006 #include <gtk/gtk.h>
5008 /* Get the selected filename and print it to the console */
5009 void file_ok_sel (GtkWidget *w, GtkFileSelection *fs)
5011 g_print ("%s\n", gtk_file_selection_get_filename (GTK_FILE_SELECTION (fs)));
5014 void destroy (GtkWidget *widget, gpointer data)
5019 int main (int argc, char *argv[])
5023 gtk_init (&argc, &argv);
5025 /* Create a new file selection widget */
5026 filew = gtk_file_selection_new ("File selection");
5028 gtk_signal_connect (GTK_OBJECT (filew), "destroy",
5029 (GtkSignalFunc) destroy, &filew);
5030 /* Connect the ok_button to file_ok_sel function */
5031 gtk_signal_connect (GTK_OBJECT (GTK_FILE_SELECTION (filew)->ok_button),
5032 "clicked", (GtkSignalFunc) file_ok_sel, filew );
5034 /* Connect the cancel_button to destroy the widget */
5035 gtk_signal_connect_object (GTK_OBJECT (GTK_FILE_SELECTION (filew)->cancel_button),
5036 "clicked", (GtkSignalFunc) gtk_widget_destroy,
5037 GTK_OBJECT (filew));
5039 /* Lets set the filename, as if this were a save dialog, and we are giving
5040 a default filename */
5041 gtk_file_selection_set_filename (GTK_FILE_SELECTION(filew),
5044 gtk_widget_show(filew);
5051 <!-- ***************************************************************** -->
5052 <sect> Container Widgets
5053 <!-- ***************************************************************** -->
5055 <!-- ----------------------------------------------------------------- -->
5056 <sect1>The EventBox <label id="sec_EventBox">
5058 Some GTK widgets don't have associated X windows, so they just draw on
5059 their parents. Because of this, they cannot receive events and if they
5060 are incorrectly sized, they don't clip so you can get messy
5061 overwriting etc. If you require more from these widgets, the EventBox
5064 At first glance, the EventBox widget might appear to be totally
5065 useless. It draws nothing on the screen and responds to no
5066 events. However, it does serve a function - it provides an X window
5067 for its child widget. This is important as many GTK widgets do not
5068 have an associated X window. Not having an X window saves memory and
5069 improves performance, but also has some drawbacks. A widget without an
5070 X window cannot receive events, and does not perform any clipping on
5071 its contents. Although the name <em/EventBox/ emphasizes the
5072 event-handling function, the widget can also be used for clipping.
5073 (and more, see the example below).
5075 To create a new EventBox widget, use:
5078 GtkWidget *gtk_event_box_new( void );
5081 A child widget can then be added to this EventBox:
5084 gtk_container_add( GTK_CONTAINER(event_box), child_widget );
5087 The following example demonstrates both uses of an EventBox - a label
5088 is created that is clipped to a small box, and set up so that a
5089 mouse-click on the label causes the program to exit. Resizing the
5090 window reveals varying amounts of the label.
5093 /* example-start eventbox eventbox.c */
5095 #include <gtk/gtk.h>
5098 main (int argc, char *argv[])
5101 GtkWidget *event_box;
5104 gtk_init (&argc, &argv);
5106 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
5108 gtk_window_set_title (GTK_WINDOW (window), "Event Box");
5110 gtk_signal_connect (GTK_OBJECT (window), "destroy",
5111 GTK_SIGNAL_FUNC (gtk_exit), NULL);
5113 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
5115 /* Create an EventBox and add it to our toplevel window */
5117 event_box = gtk_event_box_new ();
5118 gtk_container_add (GTK_CONTAINER(window), event_box);
5119 gtk_widget_show (event_box);
5121 /* Create a long label */
5123 label = gtk_label_new ("Click here to quit, quit, quit, quit, quit");
5124 gtk_container_add (GTK_CONTAINER (event_box), label);
5125 gtk_widget_show (label);
5127 /* Clip it short. */
5128 gtk_widget_set_usize (label, 110, 20);
5130 /* And bind an action to it */
5131 gtk_widget_set_events (event_box, GDK_BUTTON_PRESS_MASK);
5132 gtk_signal_connect (GTK_OBJECT(event_box), "button_press_event",
5133 GTK_SIGNAL_FUNC (gtk_exit), NULL);
5135 /* Yet one more thing you need an X window for ... */
5137 gtk_widget_realize (event_box);
5138 gdk_window_set_cursor (event_box->window, gdk_cursor_new (GDK_HAND1));
5140 gtk_widget_show (window);
5149 <!-- ----------------------------------------------------------------- -->
5150 <sect1>The Alignment widget <label id="sec_Alignment">
5152 The alignment widget allows you to place a widget within its window at
5153 a position and size relative to the size of the Alignment widget
5154 itself. For example, it can be very useful for centering a widget
5157 There are only two functions associated with the Alignment widget:
5160 GtkWidget* gtk_alignment_new( gfloat xalign,
5165 void gtk_alignment_set( GtkAlignment *alignment,
5172 The first function creates a new Alignment widget with the specified
5173 parameters. The second function allows the alignment paramters of an
5174 exisiting Alignment widget to be altered.
5176 All four alignment parameters are floating point numbers which can
5177 range from 0.0 to 1.0. The <tt/xalign/ and <tt/yalign/ arguments
5178 affect the position of the widget placed within the Alignment
5179 widget. The <tt/xscale/ and <tt/yscale/ arguments effect the amount of
5180 space allocated to the widget.
5182 A child widget can be added to this Alignment widget using:
5185 gtk_container_add( GTK_CONTAINER(alignment), child_widget );
5188 For an example of using an Alignment widget, refer to the example for
5189 the <ref id="sec_ProgressBar" name="Progress Bar"> widget.
5191 <!-- ----------------------------------------------------------------- -->
5192 <sect1> Fixed Container
5194 The Fixed container allows you to place widgets at a fixed position
5195 within it's window, relative to it's upper left hand corner. The
5196 position of the widgets can be changed dynamically.
5198 There are only three functions associated with the fixed widget:
5201 GtkWidget* gtk_fixed_new( void );
5203 void gtk_fixed_put( GtkFixed *fixed,
5208 void gtk_fixed_move( GtkFixed *fixed,
5214 The function <tt/gtk_fixed_new/ allows you to create a new Fixed
5217 <tt/gtk_fixed_put/ places <tt/widget/ in the container <tt/fixed/ at
5218 the position specified by <tt/x/ and <tt/y/.
5220 <tt/gtk_fixed_move/ allows the specified widget to be moved to a new
5223 The following example illustrates how to use the Fixed Container.
5226 /* example-start fixed fixed.c */
5228 #include <gtk/gtk.h>
5230 /* I'm going to be lazy and use some global variables to
5231 * store the position of the widget within the fixed
5236 /* This callback function moves the button to a new position
5237 * in the Fixed container. */
5238 void move_button( GtkWidget *widget,
5243 gtk_fixed_move( GTK_FIXED(fixed), widget, x, y);
5249 /* GtkWidget is the storage type for widgets */
5255 /* Initialise GTK */
5256 gtk_init(&argc, &argv);
5258 /* Create a new window */
5259 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
5260 gtk_window_set_title(GTK_WINDOW(window), "Fixed Container");
5262 /* Here we connect the "destroy" event to a signal handler */
5263 gtk_signal_connect (GTK_OBJECT (window), "destroy",
5264 GTK_SIGNAL_FUNC (gtk_main_quit), NULL);
5266 /* Sets the border width of the window. */
5267 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
5269 /* Create a Fixed Container */
5270 fixed = gtk_fixed_new();
5271 gtk_container_add(GTK_CONTAINER(window), fixed);
5272 gtk_widget_show(fixed);
5274 for (i = 1 ; i <= 3 ; i++) {
5275 /* Creates a new button with the label "Press me" */
5276 button = gtk_button_new_with_label ("Press me");
5278 /* When the button receives the "clicked" signal, it will call the
5279 * function move_button() passing it the Fixed Containter as its
5281 gtk_signal_connect (GTK_OBJECT (button), "clicked",
5282 GTK_SIGNAL_FUNC (move_button), fixed);
5284 /* This packs the button into the fixed containers window. */
5285 gtk_fixed_put (GTK_FIXED (fixed), button, i*50, i*50);
5287 /* The final step is to display this newly created widget. */
5288 gtk_widget_show (button);
5291 /* Display the window */
5292 gtk_widget_show (window);
5294 /* Enter the event loop */
5302 <!-- ----------------------------------------------------------------- -->
5303 <sect1> Frames <label id="sec_Frames">
5305 Frames can be used to enclose one or a group of widgets with a box
5306 which can optionally be labelled. The position of the label and the
5307 style of the box can be altered to suit.
5309 A Frame can be created with the following function:
5312 GtkWidget *gtk_frame_new( const gchar *label );
5315 The label is by default placed in the upper left hand corner of the
5316 frame. A value of NULL for the <tt/label/ argument will result in no
5317 label being displayed. The text of the label can be changed using the
5321 void gtk_frame_set_label( GtkFrame *frame,
5322 const gchar *label );
5325 The position of the label can be changed using this function:
5328 void gtk_frame_set_label_align( GtkFrame *frame,
5333 <tt/xalign/ and <tt/yalign/ take values between 0.0 and 1.0. <tt/xalign/
5334 indicates the position of the label along the top horizontal of the
5335 frame. <tt/yalign/ is not currently used. The default value of xalign
5336 is 0.0 which places the label at the left hand end of the frame.
5338 The next function alters the style of the box that is used to outline
5342 void gtk_frame_set_shadow_type( GtkFrame *frame,
5343 GtkShadowType type);
5346 The <tt/type/ argument can take one of the following values:
5348 <item> GTK_SHADOW_NONE
5349 <item> GTK_SHADOW_IN
5350 <item> GTK_SHADOW_OUT
5351 <item> GTK_SHADOW_ETCHED_IN (the default)
5352 <item> GTK_SHADOW_ETCHED_OUT
5355 The following code example illustrates the use of the Frame widget.
5358 /* example-start frame frame.c */
5360 #include <gtk/gtk.h>
5365 /* GtkWidget is the storage type for widgets */
5371 /* Initialise GTK */
5372 gtk_init(&argc, &argv);
5374 /* Create a new window */
5375 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
5376 gtk_window_set_title(GTK_WINDOW(window), "Frame Example");
5378 /* Here we connect the "destroy" event to a signal handler */
5379 gtk_signal_connect (GTK_OBJECT (window), "destroy",
5380 GTK_SIGNAL_FUNC (gtk_main_quit), NULL);
5382 gtk_widget_set_usize(window, 300, 300);
5383 /* Sets the border width of the window. */
5384 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
5386 /* Create a Frame */
5387 frame = gtk_frame_new(NULL);
5388 gtk_container_add(GTK_CONTAINER(window), frame);
5390 /* Set the frames label */
5391 gtk_frame_set_label( GTK_FRAME(frame), "GTK Frame Widget" );
5393 /* Align the label at the right of the frame */
5394 gtk_frame_set_label_align( GTK_FRAME(frame), 1.0, 0.0);
5396 /* Set the style of the frame */
5397 gtk_frame_set_shadow_type( GTK_FRAME(frame), GTK_SHADOW_ETCHED_OUT);
5399 gtk_widget_show(frame);
5401 /* Display the window */
5402 gtk_widget_show (window);
5404 /* Enter the event loop */
5413 <!-- ----------------------------------------------------------------- -->
5414 <sect1> Aspect Frames
5416 The aspect frame widget is like a frame widget, except that it also
5417 enforces the aspect ratio (that is, the ratio of the width to the
5418 height) of the child widget to have a certain value, adding extra
5419 space if necessary. This is useful, for instance, if you want to
5420 preview a larger image. The size of the preview should vary when the
5421 user resizes the window, but the aspect ratio needs to always match
5424 To create a new aspect frame use:
5427 GtkWidget *gtk_aspect_frame_new( const gchar *label,
5434 <tt/xalign/ and <tt/yalign/ specify alignment as with Alignment
5435 widgets. If <tt/obey_child/ is true, the aspect ratio of a child
5436 widget will match the aspect ratio of the ideal size it requests.
5437 Otherwise, it is given by <tt/ratio/.
5439 To change the options of an existing aspect frame, you can use:
5442 void gtk_aspect_frame_set( GtkAspectFrame *aspect_frame,
5449 As an example, the following program uses an AspectFrame to present a
5450 drawing area whose aspect ratio will always be 2:1, no matter how the
5451 user resizes the top-level window.
5454 /* example-start aspectframe aspectframe.c */
5456 #include <gtk/gtk.h>
5459 main (int argc, char *argv[])
5462 GtkWidget *aspect_frame;
5463 GtkWidget *drawing_area;
5464 gtk_init (&argc, &argv);
5466 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
5467 gtk_window_set_title (GTK_WINDOW (window), "Aspect Frame");
5468 gtk_signal_connect (GTK_OBJECT (window), "destroy",
5469 GTK_SIGNAL_FUNC (gtk_main_quit), NULL);
5470 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
5472 /* Create an aspect_frame and add it to our toplevel window */
5474 aspect_frame = gtk_aspect_frame_new ("2x1", /* label */
5477 2, /* xsize/ysize = 2 */
5478 FALSE /* ignore child's aspect */);
5480 gtk_container_add (GTK_CONTAINER(window), aspect_frame);
5481 gtk_widget_show (aspect_frame);
5483 /* Now add a child widget to the aspect frame */
5485 drawing_area = gtk_drawing_area_new ();
5487 /* Ask for a 200x200 window, but the AspectFrame will give us a 200x100
5488 * window since we are forcing a 2x1 aspect ratio */
5489 gtk_widget_set_usize (drawing_area, 200, 200);
5490 gtk_container_add (GTK_CONTAINER(aspect_frame), drawing_area);
5491 gtk_widget_show (drawing_area);
5493 gtk_widget_show (window);
5500 <!-- ----------------------------------------------------------------- -->
5501 <sect1> Paned Window Widgets
5503 The paned window widgets are useful when you want to divide an area
5504 into two parts, with the relative size of the two parts controlled by
5505 the user. A groove is drawn between the two portions with a handle
5506 that the user can drag to change the ratio. The division can either be
5507 horizontal (HPaned) or vertical (VPaned).
5509 To create a new paned window, call one of:
5512 GtkWidget *gtk_hpaned_new (void);
5514 GtkWidget *gtk_vpaned_new (void);
5517 After creating the paned window widget, you need to add child widgets
5518 to its two halves. To do this, use the functions:
5521 void gtk_paned_add1 (GtkPaned *paned, GtkWidget *child);
5523 void gtk_paned_add2 (GtkPaned *paned, GtkWidget *child);
5526 <tt/gtk_paned_add1()/ adds the child widget to the left or top half of
5527 the paned window. <tt/gtk_paned_add2()/ adds the child widget to the
5528 right or bottom half of the paned window.
5530 A paned widget can be changed visually using the following two
5534 void gtk_paned_set_handle_size( GtkPaned *paned,
5537 void gtk_paned_set_gutter_size( GtkPaned *paned,
5541 The first of these sets the size of the handle and the second sets the
5542 size of the gutter that is between the two parts of the paned window.
5544 As an example, we will create part of the user interface of an
5545 imaginary email program. A window is divided into two portions
5546 vertically, with the top portion being a list of email messages and
5547 the bottom portion the text of the email message. Most of the program
5548 is pretty straightforward. A couple of points to note: text can't be
5549 added to a Text widget until it is realized. This could be done by
5550 calling <tt/gtk_widget_realize()/, but as a demonstration of an
5551 alternate technique, we connect a handler to the "realize" signal to
5552 add the text. Also, we need to add the <tt/GTK_SHRINK/ option to some
5553 of the items in the table containing the text window and its
5554 scrollbars, so that when the bottom portion is made smaller, the
5555 correct portions shrink instead of being pushed off the bottom of the
5559 /* example-start paned paned.c */
5561 #include <gtk/gtk.h>
5563 /* Create the list of "messages" */
5568 GtkWidget *scrolled_window;
5570 GtkWidget *list_item;
5575 /* Create a new scrolled window, with scrollbars only if needed */
5576 scrolled_window = gtk_scrolled_window_new (NULL, NULL);
5577 gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window),
5578 GTK_POLICY_AUTOMATIC,
5579 GTK_POLICY_AUTOMATIC);
5581 /* Create a new list and put it in the scrolled window */
5582 list = gtk_list_new ();
5583 gtk_scrolled_window_add_with_viewport (GTK_SCROLLED_WINDOW (scrolled_window),
5585 gtk_widget_show (list);
5587 /* Add some messages to the window */
5588 for (i=0; i<10; i++) {
5590 sprintf(buffer,"Message #%d",i);
5591 list_item = gtk_list_item_new_with_label (buffer);
5592 gtk_container_add (GTK_CONTAINER(list), list_item);
5593 gtk_widget_show (list_item);
5597 return scrolled_window;
5600 /* Add some text to our text widget - this is a callback that is invoked
5601 when our window is realized. We could also force our window to be
5602 realized with gtk_widget_realize, but it would have to be part of
5603 a hierarchy first */
5606 realize_text (GtkWidget *text, gpointer data)
5608 gtk_text_freeze (GTK_TEXT (text));
5609 gtk_text_insert (GTK_TEXT (text), NULL, &text->style->black, NULL,
5610 "From: pathfinder@nasa.gov\n"
5611 "To: mom@nasa.gov\n"
5612 "Subject: Made it!\n"
5614 "We just got in this morning. The weather has been\n"
5615 "great - clear but cold, and there are lots of fun sights.\n"
5616 "Sojourner says hi. See you soon.\n"
5619 gtk_text_thaw (GTK_TEXT (text));
5622 /* Create a scrolled text area that displays a "message" */
5628 GtkWidget *hscrollbar;
5629 GtkWidget *vscrollbar;
5631 /* Create a table to hold the text widget and scrollbars */
5632 table = gtk_table_new (2, 2, FALSE);
5634 /* Put a text widget in the upper left hand corner. Note the use of
5635 * GTK_SHRINK in the y direction */
5636 text = gtk_text_new (NULL, NULL);
5637 gtk_table_attach (GTK_TABLE (table), text, 0, 1, 0, 1,
5638 GTK_FILL | GTK_EXPAND,
5639 GTK_FILL | GTK_EXPAND | GTK_SHRINK, 0, 0);
5640 gtk_widget_show (text);
5642 /* Put a HScrollbar in the lower left hand corner */
5643 hscrollbar = gtk_hscrollbar_new (GTK_TEXT (text)->hadj);
5644 gtk_table_attach (GTK_TABLE (table), hscrollbar, 0, 1, 1, 2,
5645 GTK_EXPAND | GTK_FILL, GTK_FILL, 0, 0);
5646 gtk_widget_show (hscrollbar);
5648 /* And a VScrollbar in the upper right */
5649 vscrollbar = gtk_vscrollbar_new (GTK_TEXT (text)->vadj);
5650 gtk_table_attach (GTK_TABLE (table), vscrollbar, 1, 2, 0, 1,
5651 GTK_FILL, GTK_EXPAND | GTK_FILL | GTK_SHRINK, 0, 0);
5652 gtk_widget_show (vscrollbar);
5654 /* Add a handler to put a message in the text widget when it is realized */
5655 gtk_signal_connect (GTK_OBJECT (text), "realize",
5656 GTK_SIGNAL_FUNC (realize_text), NULL);
5662 main (int argc, char *argv[])
5669 gtk_init (&argc, &argv);
5671 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
5672 gtk_window_set_title (GTK_WINDOW (window), "Paned Windows");
5673 gtk_signal_connect (GTK_OBJECT (window), "destroy",
5674 GTK_SIGNAL_FUNC (gtk_main_quit), NULL);
5675 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
5676 gtk_widget_set_usize (GTK_WIDGET(window), 450, 400);
5678 /* create a vpaned widget and add it to our toplevel window */
5680 vpaned = gtk_vpaned_new ();
5681 gtk_container_add (GTK_CONTAINER(window), vpaned);
5682 gtk_paned_set_handle_size (GTK_PANED(vpaned),
5684 gtk_paned_set_gutter_size (GTK_PANED(vpaned),
5686 gtk_widget_show (vpaned);
5688 /* Now create the contents of the two halves of the window */
5690 list = create_list ();
5691 gtk_paned_add1 (GTK_PANED(vpaned), list);
5692 gtk_widget_show (list);
5694 text = create_text ();
5695 gtk_paned_add2 (GTK_PANED(vpaned), text);
5696 gtk_widget_show (text);
5697 gtk_widget_show (window);
5704 <!-- ----------------------------------------------------------------- -->
5705 <sect1>Viewports <label id="sec_Viewports">
5707 It is unlikely that you will ever need to use the Viewport widget
5708 directly. You are much more likely to use the
5709 <ref id="sec_ScrolledWindows" name="Scrolled Windows"> widget which
5710 itself uses the Viewport.
5712 A viewport widget allows you to place a larger widget within it such
5713 that you can view a part of it at a time. It uses
5714 <ref id="sec_Adjustment" name="Adjustments"> to define the area that
5715 is currently in view.
5717 A Viewport is created with the function
5720 GtkWidget *gtk_viewport_new( GtkAdjustment *hadjustment,
5721 GtkAdjustment *vadjustment );
5724 As you can see you can specify the horizontal and vertical Adjustments
5725 that the widget is to use when you create the widget. It will create
5726 it's own if you pass NULL as the value of the arguments.
5728 You can get and set the adjustments after the widget has been created
5729 using the following four functions:
5732 GtkAdjustment *gtk_viewport_get_hadjustment (GtkViewport *viewport );
5734 GtkAdjustment *gtk_viewport_get_vadjustment (GtkViewport *viewport );
5736 void gtk_viewport_set_hadjustment( GtkViewport *viewport,
5737 GtkAdjustment *adjustment );
5739 void gtk_viewport_set_vadjustment( GtkViewport *viewport,
5740 GtkAdjustment *adjustment );
5743 The only other viewport function is used to alter its appearance:
5746 void gtk_viewport_set_shadow_type( GtkViewport *viewport,
5747 GtkShadowType type );
5750 Possible values for the <tt/type/ parameter are:
5752 <item> GTK_SHADOW_NONE,
5753 <item> GTK_SHADOW_IN,
5754 <item> GTK_SHADOW_OUT,
5755 <item> GTK_SHADOW_ETCHED_IN,
5756 <item> GTK_SHADOW_ETCHED_OUT
5759 <!-- ----------------------------------------------------------------- -->
5760 <sect1>Scrolled Windows <label id="sec_ScrolledWindows">
5762 Scrolled windows are used to create a scrollable area inside a real
5763 window. You may insert any type of widget into a scrolled window, and
5764 it will be accessible regardless of the size by using the scrollbars.
5766 The following function is used to create a new scrolled window.
5769 GtkWidget *gtk_scrolled_window_new( GtkAdjustment *hadjustment,
5770 GtkAdjustment *vadjustment );
5773 Where the first argument is the adjustment for the horizontal
5774 direction, and the second, the adjustment for the vertical direction.
5775 These are almost always set to NULL.
5778 void gtk_scrolled_window_set_policy( GtkScrolledWindow *scrolled_window,
5779 GtkPolicyType hscrollbar_policy,
5780 GtkPolicyType vscrollbar_policy );
5783 This sets the policy to be used with respect to the scrollbars.
5784 The first argument is the scrolled window you wish to change. The second
5785 sets the policy for the horizontal scrollbar, and the third the policy for
5786 the vertical scrollbar.
5788 The policy may be one of GTK_POLICY_AUTOMATIC, or GTK_POLICY_ALWAYS.
5789 GTK_POLICY_AUTOMATIC will automatically decide whether you need
5790 scrollbars, whereas GTK_POLICY_ALWAYS will always leave the scrollbars
5793 You can then place your object into the scrolled window using the
5797 void gtk_scrolled_window_add_with_viewport( GtkScrolledWindow *scrolled_window,
5801 Here is a simple example that packs 100 toggle buttons into a scrolled
5802 window. I've only commented on the parts that may be new to you.
5805 /* example-start scrolledwin scrolledwin.c */
5807 #include <gtk/gtk.h>
5809 void destroy(GtkWidget *widget, gpointer data)
5814 int main (int argc, char *argv[])
5816 static GtkWidget *window;
5817 GtkWidget *scrolled_window;
5823 gtk_init (&argc, &argv);
5825 /* Create a new dialog window for the scrolled window to be
5826 * packed into. A dialog is just like a normal window except it has a
5827 * vbox and a horizontal separator packed into it. It's just a shortcut
5828 * for creating dialogs */
5829 window = gtk_dialog_new ();
5830 gtk_signal_connect (GTK_OBJECT (window), "destroy",
5831 (GtkSignalFunc) destroy, NULL);
5832 gtk_window_set_title (GTK_WINDOW (window), "GtkScrolledWindow example");
5833 gtk_container_set_border_width (GTK_CONTAINER (window), 0);
5834 gtk_widget_set_usize(window, 300, 300);
5836 /* create a new scrolled window. */
5837 scrolled_window = gtk_scrolled_window_new (NULL, NULL);
5839 gtk_container_set_border_width (GTK_CONTAINER (scrolled_window), 10);
5841 /* the policy is one of GTK_POLICY AUTOMATIC, or GTK_POLICY_ALWAYS.
5842 * GTK_POLICY_AUTOMATIC will automatically decide whether you need
5843 * scrollbars, whereas GTK_POLICY_ALWAYS will always leave the scrollbars
5844 * there. The first one is the horizontal scrollbar, the second,
5846 gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window),
5847 GTK_POLICY_AUTOMATIC, GTK_POLICY_ALWAYS);
5848 /* The dialog window is created with a vbox packed into it. */
5849 gtk_box_pack_start (GTK_BOX (GTK_DIALOG(window)->vbox), scrolled_window,
5851 gtk_widget_show (scrolled_window);
5853 /* create a table of 10 by 10 squares. */
5854 table = gtk_table_new (10, 10, FALSE);
5856 /* set the spacing to 10 on x and 10 on y */
5857 gtk_table_set_row_spacings (GTK_TABLE (table), 10);
5858 gtk_table_set_col_spacings (GTK_TABLE (table), 10);
5860 /* pack the table into the scrolled window */
5861 gtk_scrolled_window_add_with_viewport (GTK_SCROLLED_WINDOW (scrolled_window),
5863 gtk_widget_show (table);
5865 /* this simply creates a grid of toggle buttons on the table
5866 * to demonstrate the scrolled window. */
5867 for (i = 0; i < 10; i++)
5868 for (j = 0; j < 10; j++) {
5869 sprintf (buffer, "button (%d,%d)\n", i, j);
5870 button = gtk_toggle_button_new_with_label (buffer);
5871 gtk_table_attach_defaults (GTK_TABLE (table), button,
5873 gtk_widget_show (button);
5876 /* Add a "close" button to the bottom of the dialog */
5877 button = gtk_button_new_with_label ("close");
5878 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
5879 (GtkSignalFunc) gtk_widget_destroy,
5880 GTK_OBJECT (window));
5882 /* this makes it so the button is the default. */
5884 GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
5885 gtk_box_pack_start (GTK_BOX (GTK_DIALOG (window)->action_area), button, TRUE, TRUE, 0);
5887 /* This grabs this button to be the default button. Simply hitting
5888 * the "Enter" key will cause this button to activate. */
5889 gtk_widget_grab_default (button);
5890 gtk_widget_show (button);
5892 gtk_widget_show (window);
5901 Try playing with resizing the window. You'll notice how the scrollbars
5902 react. You may also wish to use the gtk_widget_set_usize() call to set
5903 the default size of the window or other widgets.
5905 <!-- ----------------------------------------------------------------- -->
5908 Button Boxes are a convenient way to quickly layout a group of
5909 buttons. They come in both horizontal and vertical flavours. You
5910 create a new Button Box with one of the following calls, which create
5911 a horizontal or vertical box, respectively:
5914 GtkWidget *gtk_hbutton_box_new( void );
5916 GtkWidget *gtk_vbutton_box_new( void );
5919 The only attributes pertaining to button boxes effect how the buttons
5920 are layed out. You can change the spacing between the buttons with:
5923 void gtk_hbutton_box_set_spacing_default( gint spacing );
5925 void gtk_vbutton_box_set_spacing_default( gint spacing );
5928 Similarly, the current spacing values can be queried using:
5931 gint gtk_hbutton_box_get_spacing_default( void );
5933 gint gtk_vbutton_box_get_spacing_default( void );
5936 The second attribute that we can access effects the layour of the
5937 buttons within the box. It is set using one of:
5940 void gtk_hbutton_box_set_layout_default( GtkButtonBoxStyle layout );
5942 void gtk_vbutton_box_set_layout_default( GtkButtonBoxStyle layout );
5945 The <tt/layout/ argument can take one of the following values:
5948 <item> GTK_BUTTONBOX_DEFAULT_STYLE
5949 <item> GTK_BUTTONBOX_SPREAD
5950 <item> GTK_BUTTONBOX_EDGE
5951 <item> GTK_BUTTONBOX_START
5952 <item> GTK_BUTTONBOX_END
5955 The current layout setting can be retrieved using:
5958 GtkButtonBoxStyle gtk_hbutton_box_get_layout_default( void );
5960 GtkButtonBoxStyle gtk_vbutton_box_get_layout_default( void );
5963 Buttons are added to a Button Box using the usual function:
5966 gtk_container_add( GTK_CONTAINER(button_box), child_widget );
5969 Here's an example that illustrates all the different layout settings
5973 /* example-start buttonbox buttonbox.c */
5975 #include <gtk/gtk.h>
5977 /* Create a Button Box with the specified parameters */
5978 GtkWidget *create_bbox (gint horizontal,
5989 frame = gtk_frame_new (title);
5992 bbox = gtk_hbutton_box_new ();
5994 bbox = gtk_vbutton_box_new ();
5996 gtk_container_set_border_width (GTK_CONTAINER (bbox), 5);
5997 gtk_container_add (GTK_CONTAINER (frame), bbox);
5999 /* Set the appearance of the Button Box */
6000 gtk_button_box_set_layout (GTK_BUTTON_BOX (bbox), layout);
6001 gtk_button_box_set_spacing (GTK_BUTTON_BOX (bbox), spacing);
6002 gtk_button_box_set_child_size (GTK_BUTTON_BOX (bbox), child_w, child_h);
6004 button = gtk_button_new_with_label ("OK");
6005 gtk_container_add (GTK_CONTAINER (bbox), button);
6007 button = gtk_button_new_with_label ("Cancel");
6008 gtk_container_add (GTK_CONTAINER (bbox), button);
6010 button = gtk_button_new_with_label ("Help");
6011 gtk_container_add (GTK_CONTAINER (bbox), button);
6019 static GtkWidget* window = NULL;
6020 GtkWidget *main_vbox;
6023 GtkWidget *frame_horz;
6024 GtkWidget *frame_vert;
6026 /* Initialize GTK */
6027 gtk_init( &argc, &argv );
6029 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
6030 gtk_window_set_title (GTK_WINDOW (window), "Button Boxes");
6032 gtk_signal_connect (GTK_OBJECT (window), "destroy",
6033 GTK_SIGNAL_FUNC(gtk_main_quit),
6036 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
6038 main_vbox = gtk_vbox_new (FALSE, 0);
6039 gtk_container_add (GTK_CONTAINER (window), main_vbox);
6041 frame_horz = gtk_frame_new ("Horizontal Button Boxes");
6042 gtk_box_pack_start (GTK_BOX (main_vbox), frame_horz, TRUE, TRUE, 10);
6044 vbox = gtk_vbox_new (FALSE, 0);
6045 gtk_container_set_border_width (GTK_CONTAINER (vbox), 10);
6046 gtk_container_add (GTK_CONTAINER (frame_horz), vbox);
6048 gtk_box_pack_start (GTK_BOX (vbox),
6049 create_bbox (TRUE, "Spread (spacing 40)", 40, 85, 20, GTK_BUTTONBOX_SPREAD),
6052 gtk_box_pack_start (GTK_BOX (vbox),
6053 create_bbox (TRUE, "Edge (spacing 30)", 30, 85, 20, GTK_BUTTONBOX_EDGE),
6056 gtk_box_pack_start (GTK_BOX (vbox),
6057 create_bbox (TRUE, "Start (spacing 20)", 20, 85, 20, GTK_BUTTONBOX_START),
6060 gtk_box_pack_start (GTK_BOX (vbox),
6061 create_bbox (TRUE, "End (spacing 10)", 10, 85, 20, GTK_BUTTONBOX_END),
6064 frame_vert = gtk_frame_new ("Vertical Button Boxes");
6065 gtk_box_pack_start (GTK_BOX (main_vbox), frame_vert, TRUE, TRUE, 10);
6067 hbox = gtk_hbox_new (FALSE, 0);
6068 gtk_container_set_border_width (GTK_CONTAINER (hbox), 10);
6069 gtk_container_add (GTK_CONTAINER (frame_vert), hbox);
6071 gtk_box_pack_start (GTK_BOX (hbox),
6072 create_bbox (FALSE, "Spread (spacing 5)", 5, 85, 20, GTK_BUTTONBOX_SPREAD),
6075 gtk_box_pack_start (GTK_BOX (hbox),
6076 create_bbox (FALSE, "Edge (spacing 30)", 30, 85, 20, GTK_BUTTONBOX_EDGE),
6079 gtk_box_pack_start (GTK_BOX (hbox),
6080 create_bbox (FALSE, "Start (spacing 20)", 20, 85, 20, GTK_BUTTONBOX_START),
6083 gtk_box_pack_start (GTK_BOX (hbox),
6084 create_bbox (FALSE, "End (spacing 20)", 20, 85, 20, GTK_BUTTONBOX_END),
6087 gtk_widget_show_all (window);
6089 /* Enter the event loop */
6097 <!-- ----------------------------------------------------------------- -->
6100 Toolbars are usually used to group some number of widgets in order to
6101 simplify customization of their look and layout. Typically a toolbar
6102 consists of buttons with icons, labels and tooltips, but any other
6103 widget can also be put inside a toolbar. Finally, items can be
6104 arranged horizontally or vertically and buttons can be displayed with
6105 icons, labels or both.
6107 Creating a toolbar is (as one may already suspect) done with the
6111 GtkWidget *gtk_toolbar_new( GtkOrientation orientation,
6112 GtkToolbarStyle style );
6115 where orientation may be one of:
6118 GTK_ORIENTATION_HORIZONTAL
6119 GTK_ORIENTATION_VERTICAL
6130 The style applies to all the buttons created with the `item' functions
6131 (not to buttons inserted into toolbar as separate widgets).
6133 After creating a toolbar one can append, prepend and insert items
6134 (that means simple buttons) into the toolbar. To describe an item we
6135 need a label text, a tooltip text, a private tooltip text, an icon for
6136 the button and a callback function for it. For example, to append or
6137 prepend an item you may use the following functions:
6140 GtkWidget *gtk_toolbar_append_item( GtkToolbar *toolbar,
6142 const char *tooltip_text,
6143 const char *tooltip_private_text,
6145 GtkSignalFunc callback,
6146 gpointer user_data );
6148 GtkWidget *gtk_toolbar_prepend_item( GtkToolbar *toolbar,
6150 const char *tooltip_text,
6151 const char *tooltip_private_text,
6153 GtkSignalFunc callback,
6154 gpointer user_data );
6157 If you want to use gtk_toolbar_insert_item, the only additional
6158 parameter which must be specified is the position in which the item
6159 should be inserted, thus:
6162 GtkWidget *gtk_toolbar_insert_item( GtkToolbar *toolbar,
6164 const char *tooltip_text,
6165 const char *tooltip_private_text,
6167 GtkSignalFunc callback,
6172 To simplify adding spaces between toolbar items, you may use the
6173 following functions:
6176 void gtk_toolbar_append_space( GtkToolbar *toolbar );
6178 void gtk_toolbar_prepend_space( GtkToolbar *toolbar );
6180 void gtk_toolbar_insert_space( GtkToolbar *toolbar,
6185 While the size of the added space can be set globally for a
6186 whole toolbar with the function:
6189 void gtk_toolbar_set_space_size( GtkToolbar *toolbar,
6193 If it's required, the orientation of a toolbar and its style can be
6194 changed `on the fly' using the following functions:
6197 void gtk_toolbar_set_orientation( GtkToolbar *toolbar,
6198 GtkOrientation orientation );
6200 void gtk_toolbar_set_style( GtkToolbar *toolbar,
6201 GtkToolbarStyle style );
6203 void gtk_toolbar_set_tooltips( GtkToolbar *toolbar,
6207 Where <tt/orientation/ is one of GTK_ORIENTATION_HORIZONTAL or
6208 GTK_ORIENTATION_VERTICAL. The <tt/style/ is used to set appearance of
6209 the toolbar items by using one of GTK_TOOLBAR_ICONS, GTK_TOOLBAR_TEXT
6210 or GTK_TOOLBAR_BOTH.
6212 To show some other things that can be done with a toolbar, let's take
6213 the following program (we'll interrupt the listing with some
6214 additional explanations):
6217 #include <gtk/gtk.h>
6221 /* This function is connected to the Close button or
6222 * closing the window from the WM */
6223 void delete_event (GtkWidget *widget, GdkEvent *event, gpointer data)
6229 The above beginning seems for sure familiar to you if it's not your first
6230 GTK program. There is one additional thing though, we include a nice XPM
6231 picture to serve as an icon for all of the buttons.
6234 GtkWidget* close_button; // this button will emit signal to close application
6235 GtkWidget* tooltips_button; // to enable/disable tooltips
6236 GtkWidget* text_button,
6238 * both_button; // radio buttons for toolbar style
6239 GtkWidget* entry; // a text entry to show packing any widget into toolbar
6242 In fact not all of the above widgets are needed here, but to make things
6243 clearer I put them all together.
6246 /* that's easy... when one of the buttons is toggled, we just
6247 * check which one is active and set the style of the toolbar
6249 * ATTENTION: our toolbar is passed as data to callback ! */
6250 void radio_event (GtkWidget *widget, gpointer data)
6252 if (GTK_TOGGLE_BUTTON (text_button)->active)
6253 gtk_toolbar_set_style(GTK_TOOLBAR ( data ), GTK_TOOLBAR_TEXT);
6254 else if (GTK_TOGGLE_BUTTON (icon_button)->active)
6255 gtk_toolbar_set_style(GTK_TOOLBAR ( data ), GTK_TOOLBAR_ICONS);
6256 else if (GTK_TOGGLE_BUTTON (both_button)->active)
6257 gtk_toolbar_set_style(GTK_TOOLBAR ( data ), GTK_TOOLBAR_BOTH);
6260 /* even easier, just check given toggle button and enable/disable
6262 void toggle_event (GtkWidget *widget, gpointer data)
6264 gtk_toolbar_set_tooltips (GTK_TOOLBAR ( data ),
6265 GTK_TOGGLE_BUTTON (widget)->active );
6269 The above are just two callback functions that will be called when
6270 one of the buttons on a toolbar is pressed. You should already be
6271 familiar with things like this if you've already used toggle buttons (and
6275 int main (int argc, char *argv[])
6277 /* Here is our main window (a dialog) and a handle for the handlebox */
6279 GtkWidget* handlebox;
6281 /* Ok, we need a toolbar, an icon with a mask (one for all of
6282 the buttons) and an icon widget to put this icon in (but
6283 we'll create a separate widget for each button) */
6284 GtkWidget * toolbar;
6289 /* this is called in all GTK application. */
6290 gtk_init (&argc, &argv);
6292 /* create a new window with a given title, and nice size */
6293 dialog = gtk_dialog_new ();
6294 gtk_window_set_title ( GTK_WINDOW ( dialog ) , "GTKToolbar Tutorial");
6295 gtk_widget_set_usize( GTK_WIDGET ( dialog ) , 600 , 300 );
6296 GTK_WINDOW ( dialog ) ->allow_shrink = TRUE;
6298 /* typically we quit if someone tries to close us */
6299 gtk_signal_connect ( GTK_OBJECT ( dialog ), "delete_event",
6300 GTK_SIGNAL_FUNC ( delete_event ), NULL);
6302 /* we need to realize the window because we use pixmaps for
6303 * items on the toolbar in the context of it */
6304 gtk_widget_realize ( dialog );
6306 /* to make it nice we'll put the toolbar into the handle box,
6307 * so that it can be detached from the main window */
6308 handlebox = gtk_handle_box_new ();
6309 gtk_box_pack_start ( GTK_BOX ( GTK_DIALOG(dialog)->vbox ),
6310 handlebox, FALSE, FALSE, 5 );
6313 The above should be similar to any other GTK application. Just
6314 initialization of GTK, creating the window etc.. There is only one
6315 thing that probably needs some explanation: a handle box. A handle box
6316 is just another box that can be used to pack widgets in to. The
6317 difference between it and typical boxes is that it can be detached
6318 from a parent window (or, in fact, the handle box remains in the
6319 parent, but it is reduced to a very small rectangle, while all of its
6320 contents are reparented to a new freely floating window). It is
6321 usually nice to have a detachable toolbar, so these two widgets occur
6322 together quite often.
6325 /* toolbar will be horizontal, with both icons and text, and
6326 * with 5pxl spaces between items and finally,
6327 * we'll also put it into our handlebox */
6328 toolbar = gtk_toolbar_new ( GTK_ORIENTATION_HORIZONTAL,
6330 gtk_container_set_border_width ( GTK_CONTAINER ( toolbar ) , 5 );
6331 gtk_toolbar_set_space_size ( GTK_TOOLBAR ( toolbar ), 5 );
6332 gtk_container_add ( GTK_CONTAINER ( handlebox ) , toolbar );
6334 /* now we create icon with mask: we'll reuse it to create
6335 * icon widgets for toolbar items */
6336 icon = gdk_pixmap_create_from_xpm_d ( dialog->window, &mask,
6337 &dialog->style->white, gtk_xpm );
6340 Well, what we do above is just a straight-forward initialization of
6341 the toolbar widget and creation of a GDK pixmap with its mask. If you
6342 want to know something more about using pixmaps, refer to GDK
6343 documentation or to the <ref id="sec_Pixmaps" name="Pixmaps"> section
6344 earlier in this tutorial.
6347 /* our first item is <close> button */
6348 iconw = gtk_pixmap_new ( icon, mask ); // icon widget
6350 gtk_toolbar_append_item ( GTK_TOOLBAR (toolbar), // our toolbar
6351 "Close", // button label
6352 "Closes this app", // tooltip for this button
6353 "Private", // tooltip private string
6354 iconw, // icon widget
6355 GTK_SIGNAL_FUNC (delete_event), // a signal
6357 gtk_toolbar_append_space ( GTK_TOOLBAR ( toolbar ) ); // space after item
6360 In the above code you see the simplest case: adding a button to
6361 toolbar. Just before appending a new item, we have to construct a
6362 pixmap widget to serve as an icon for this item; this step will have
6363 to be repeated for each new item. Just after the item we also add a
6364 space, so the following items will not touch each other. As you see
6365 gtk_toolbar_append_item returns a pointer to our newly created button
6366 widget, so that we can work with it in the normal way.
6369 /* now, let's make our radio buttons group... */
6370 iconw = gtk_pixmap_new ( icon, mask );
6372 gtk_toolbar_append_element(GTK_TOOLBAR(toolbar),
6373 GTK_TOOLBAR_CHILD_RADIOBUTTON, // a type of element
6374 NULL, // pointer to widget
6376 "Only icons in toolbar", // tooltip
6377 "Private", // tooltip private string
6379 GTK_SIGNAL_FUNC (radio_event), // signal
6380 toolbar); // data for signal
6381 gtk_toolbar_append_space ( GTK_TOOLBAR ( toolbar ) );
6384 Here we begin creating a radio buttons group. To do this we use
6385 gtk_toolbar_append_element. In fact, using this function one can also
6386 add simple items or even spaces (type = GTK_TOOLBAR_CHILD_SPACE or
6387 GTK_TOOLBAR_CHILD_BUTTON). In the above case we start creating a radio
6388 group. In creating other radio buttons for this group a pointer to the
6389 previous button in the group is required, so that a list of buttons
6390 can be easily constructed (see the section on <ref
6391 id="sec_Radio_Buttons" name="Radio Buttons"> earlier in this
6395 /* following radio buttons refer to previous ones */
6396 iconw = gtk_pixmap_new ( icon, mask );
6398 gtk_toolbar_append_element(GTK_TOOLBAR(toolbar),
6399 GTK_TOOLBAR_CHILD_RADIOBUTTON,
6402 "Only texts in toolbar",
6405 GTK_SIGNAL_FUNC (radio_event),
6407 gtk_toolbar_append_space ( GTK_TOOLBAR ( toolbar ) );
6409 iconw = gtk_pixmap_new ( icon, mask );
6411 gtk_toolbar_append_element(GTK_TOOLBAR(toolbar),
6412 GTK_TOOLBAR_CHILD_RADIOBUTTON,
6415 "Icons and text in toolbar",
6418 GTK_SIGNAL_FUNC (radio_event),
6420 gtk_toolbar_append_space ( GTK_TOOLBAR ( toolbar ) );
6421 gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(both_button),TRUE);
6424 In the end we have set the state of one of the buttons manually (otherwise
6425 they all stay in active state, preventing us from switching between them).
6428 /* here we have just a simple toggle button */
6429 iconw = gtk_pixmap_new ( icon, mask );
6431 gtk_toolbar_append_element(GTK_TOOLBAR(toolbar),
6432 GTK_TOOLBAR_CHILD_TOGGLEBUTTON,
6435 "Toolbar with or without tips",
6438 GTK_SIGNAL_FUNC (toggle_event),
6440 gtk_toolbar_append_space ( GTK_TOOLBAR ( toolbar ) );
6441 gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(tooltips_button),TRUE);
6444 A toggle button can be created in the obvious way (if one knows how to create
6445 radio buttons already).
6448 /* to pack a widget into toolbar, we only have to
6449 * create it and append it with an appropriate tooltip */
6450 entry = gtk_entry_new ();
6451 gtk_toolbar_append_widget( GTK_TOOLBAR (toolbar),
6453 "This is just an entry",
6456 /* well, it isn't created within thetoolbar, so we must still show it */
6457 gtk_widget_show ( entry );
6460 As you see, adding any kind of widget to a toolbar is simple. The
6461 one thing you have to remember is that this widget must be shown manually
6462 (contrary to other items which will be shown together with the toolbar).
6465 /* that's it ! let's show everything. */
6466 gtk_widget_show ( toolbar );
6467 gtk_widget_show (handlebox);
6468 gtk_widget_show ( dialog );
6470 /* rest in gtk_main and wait for the fun to begin! */
6477 So, here we are at the end of toolbar tutorial. Of course, to appreciate
6478 it in full you need also this nice XPM icon, so here it is:
6482 static char * gtk_xpm[] = {
6489 "................+...............",
6490 "..............+++++.............",
6491 "............+++++@@++...........",
6492 "..........+++++@@@@@@++.........",
6493 "........++++@@@@@@@@@@++........",
6494 "......++++@@++++++++@@@++.......",
6495 ".....+++@@@+++++++++++@@@++.....",
6496 "...+++@@@@+++@@@@@@++++@@@@+....",
6497 "..+++@@@@+++@@@@@@@@+++@@@@@++..",
6498 ".++@@@@@@+++@@@@@@@@@@@@@@@@@@++",
6499 ".+#+@@@@@@++@@@@+++@@@@@@@@@@@@+",
6500 ".+##++@@@@+++@@@+++++@@@@@@@@$@.",
6501 ".+###++@@@@+++@@@+++@@@@@++$$$@.",
6502 ".+####+++@@@+++++++@@@@@+@$$$$@.",
6503 ".+#####+++@@@@+++@@@@++@$$$$$$+.",
6504 ".+######++++@@@@@@@++@$$$$$$$$+.",
6505 ".+#######+##+@@@@+++$$$$$$@@$$+.",
6506 ".+###+++##+##+@@++@$$$$$$++$$$+.",
6507 ".+###++++##+##+@@$$$$$$$@+@$$@+.",
6508 ".+###++++++#+++@$$@+@$$@++$$$@+.",
6509 ".+####+++++++#++$$@+@$$++$$$$+..",
6510 ".++####++++++#++$$@+@$++@$$$$+..",
6511 ".+#####+++++##++$$++@+++$$$$$+..",
6512 ".++####+++##+#++$$+++++@$$$$$+..",
6513 ".++####+++####++$$++++++@$$$@+..",
6514 ".+#####++#####++$$+++@++++@$@+..",
6515 ".+#####++#####++$$++@$$@+++$@@..",
6516 ".++####++#####++$$++$$$$$+@$@++.",
6517 ".++####++#####++$$++$$$$$$$$+++.",
6518 ".+++####+#####++$$++$$$$$$$@+++.",
6519 "..+++#########+@$$+@$$$$$$+++...",
6520 "...+++########+@$$$$$$$$@+++....",
6521 ".....+++######+@$$$$$$$+++......",
6522 "......+++#####+@$$$$$@++........",
6523 ".......+++####+@$$$$+++.........",
6524 ".........++###+$$$@++...........",
6525 "..........++##+$@+++............",
6526 "...........+++++++..............",
6527 ".............++++..............."};
6530 <!-- ----------------------------------------------------------------- -->
6533 The NoteBook Widget is a collection of 'pages' that overlap each
6534 other, each page contains different information. This widget has
6535 become more common lately in GUI programming, and it is a good way to
6536 show blocks of similar information that warrant separation in their
6539 The first function call you will need to know, as you can probably
6540 guess by now, is used to create a new notebook widget.
6543 GtkWidget *gtk_notebook_new( void );
6546 Once the notebook has been created, there are a number of functions
6547 that operate on the notebook widget. Let's look at them individually.
6549 The first one we will look at is how to position the page indicators.
6550 These page indicators or 'tabs' as they are referred to, can be
6551 positioned in four ways: top, bottom, left, or right.
6554 void gtk_notebook_set_tab_pos( GtkNotebook *notebook,
6555 GtkPositionType pos );
6558 GtkPostionType will be one of the following, and they are pretty self explanatory:
6561 <item> GTK_POS_RIGHT
6563 <item> GTK_POS_BOTTOM
6566 GTK_POS_TOP is the default.
6568 Next we will look at how to add pages to the notebook. There are three
6569 ways to add pages to the NoteBook. Let's look at the first two
6570 together as they are quite similar.
6573 void gtk_notebook_append_page( GtkNotebook *notebook,
6575 GtkWidget *tab_label );
6577 void gtk_notebook_prepend_page( GtkNotebook *notebook,
6579 GtkWidget *tab_label );
6582 These functions add pages to the notebook by inserting them from the
6583 back of the notebook (append), or the front of the notebook (prepend).
6584 <tt/child/ is the widget that is placed within the notebook page, and
6585 <tt/tab_label/ is the label for the page being added. The <tt/child/
6586 widget must be created separately, and is typically a set of options
6587 setout witin one of the other container widgets, such as a table.
6589 The final function for adding a page to the notebook contains all of
6590 the properties of the previous two, but it allows you to specify what
6591 position you want the page to be in the notebook.
6594 void gtk_notebook_insert_page( GtkNotebook *notebook,
6596 GtkWidget *tab_label,
6600 The parameters are the same as _append_ and _prepend_ except it
6601 contains an extra parameter, <tt/position/. This parameter is used to
6602 specify what place this page will be inserted into.
6604 Now that we know how to add a page, lets see how we can remove a page
6608 void gtk_notebook_remove_page( GtkNotebook *notebook,
6612 This function takes the page specified by <tt/page_num/ and removes it
6613 from the widget pointed to by <tt/notebook/.
6615 To find out what the current page is in a notebook use the function:
6618 gint gtk_notebook_get_current_page( GtkNotebook *notebook );
6621 These next two functions are simple calls to move the notebook page
6622 forward or backward. Simply provide the respective function call with
6623 the notebook widget you wish to operate on. Note: when the NoteBook is
6624 currently on the last page, and gtk_notebook_next_page is called, the
6625 notebook will wrap back to the first page. Likewise, if the NoteBook
6626 is on the first page, and gtk_notebook_prev_page is called, the
6627 notebook will wrap to the last page.
6630 void gtk_notebook_next_page( GtkNoteBook *notebook );
6632 void gtk_notebook_prev_page( GtkNoteBook *notebook );
6635 This next function sets the 'active' page. If you wish the notebook to
6636 be opened to page 5 for example, you would use this function. Without
6637 using this function, the notebook defaults to the first page.
6640 void gtk_notebook_set_page( GtkNotebook *notebook,
6644 The next two functions add or remove the notebook page tabs and the
6645 notebook border respectively.
6648 void gtk_notebook_set_show_tabs( GtkNotebook *notebook,
6649 gboolean show_tabs);
6651 void gtk_notebook_set_show_border( GtkNotebook *notebook,
6652 gboolean show_border );
6655 The next function is useful when the you have a large number of pages,
6656 and the tabs don't fit on the page. It allows the tabs to be scrolled
6657 through using two arrow buttons.
6660 void gtk_notebook_set_scrollable( GtkNotebook *notebook,
6661 gboolean scrollable );
6664 <tt/show_tabs/, <tt/show_border/ and <tt/scrollable/ can be either
6667 Now lets look at an example, it is expanded from the testgtk.c code
6668 that comes with the GTK distribution. This small program creates a
6669 window with a notebook and six buttons. The notebook contains 11
6670 pages, added in three different ways, appended, inserted, and
6671 prepended. The buttons allow you rotate the tab positions, add/remove
6672 the tabs and border, remove a page, change pages in both a forward and
6673 backward manner, and exit the program.
6676 /* example-start notebook notebook.c */
6678 #include <gtk/gtk.h>
6680 /* This function rotates the position of the tabs */
6681 void rotate_book (GtkButton *button, GtkNotebook *notebook)
6683 gtk_notebook_set_tab_pos (notebook, (notebook->tab_pos +1) %4);
6686 /* Add/Remove the page tabs and the borders */
6687 void tabsborder_book (GtkButton *button, GtkNotebook *notebook)
6691 if (notebook->show_tabs == 0)
6693 if (notebook->show_border == 0)
6696 gtk_notebook_set_show_tabs (notebook, tval);
6697 gtk_notebook_set_show_border (notebook, bval);
6700 /* Remove a page from the notebook */
6701 void remove_book (GtkButton *button, GtkNotebook *notebook)
6705 page = gtk_notebook_get_current_page(notebook);
6706 gtk_notebook_remove_page (notebook, page);
6707 /* Need to refresh the widget --
6708 This forces the widget to redraw itself. */
6709 gtk_widget_draw(GTK_WIDGET(notebook), NULL);
6712 void delete (GtkWidget *widget, GtkWidget *event, gpointer data)
6717 int main (int argc, char *argv[])
6722 GtkWidget *notebook;
6725 GtkWidget *checkbutton;
6730 gtk_init (&argc, &argv);
6732 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
6734 gtk_signal_connect (GTK_OBJECT (window), "delete_event",
6735 GTK_SIGNAL_FUNC (delete), NULL);
6737 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
6739 table = gtk_table_new(3,6,FALSE);
6740 gtk_container_add (GTK_CONTAINER (window), table);
6742 /* Create a new notebook, place the position of the tabs */
6743 notebook = gtk_notebook_new ();
6744 gtk_notebook_set_tab_pos (GTK_NOTEBOOK (notebook), GTK_POS_TOP);
6745 gtk_table_attach_defaults(GTK_TABLE(table), notebook, 0,6,0,1);
6746 gtk_widget_show(notebook);
6748 /* Lets append a bunch of pages to the notebook */
6749 for (i=0; i < 5; i++) {
6750 sprintf(bufferf, "Append Frame %d", i+1);
6751 sprintf(bufferl, "Page %d", i+1);
6753 frame = gtk_frame_new (bufferf);
6754 gtk_container_set_border_width (GTK_CONTAINER (frame), 10);
6755 gtk_widget_set_usize (frame, 100, 75);
6756 gtk_widget_show (frame);
6758 label = gtk_label_new (bufferf);
6759 gtk_container_add (GTK_CONTAINER (frame), label);
6760 gtk_widget_show (label);
6762 label = gtk_label_new (bufferl);
6763 gtk_notebook_append_page (GTK_NOTEBOOK (notebook), frame, label);
6766 /* Now lets add a page to a specific spot */
6767 checkbutton = gtk_check_button_new_with_label ("Check me please!");
6768 gtk_widget_set_usize(checkbutton, 100, 75);
6769 gtk_widget_show (checkbutton);
6771 label = gtk_label_new ("Add page");
6772 gtk_notebook_insert_page (GTK_NOTEBOOK (notebook), checkbutton, label, 2);
6774 /* Now finally lets prepend pages to the notebook */
6775 for (i=0; i < 5; i++) {
6776 sprintf(bufferf, "Prepend Frame %d", i+1);
6777 sprintf(bufferl, "PPage %d", i+1);
6779 frame = gtk_frame_new (bufferf);
6780 gtk_container_set_border_width (GTK_CONTAINER (frame), 10);
6781 gtk_widget_set_usize (frame, 100, 75);
6782 gtk_widget_show (frame);
6784 label = gtk_label_new (bufferf);
6785 gtk_container_add (GTK_CONTAINER (frame), label);
6786 gtk_widget_show (label);
6788 label = gtk_label_new (bufferl);
6789 gtk_notebook_prepend_page (GTK_NOTEBOOK(notebook), frame, label);
6792 /* Set what page to start at (page 4) */
6793 gtk_notebook_set_page (GTK_NOTEBOOK(notebook), 3);
6795 /* Create a bunch of buttons */
6796 button = gtk_button_new_with_label ("close");
6797 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
6798 GTK_SIGNAL_FUNC (delete), NULL);
6799 gtk_table_attach_defaults(GTK_TABLE(table), button, 0,1,1,2);
6800 gtk_widget_show(button);
6802 button = gtk_button_new_with_label ("next page");
6803 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
6804 (GtkSignalFunc) gtk_notebook_next_page,
6805 GTK_OBJECT (notebook));
6806 gtk_table_attach_defaults(GTK_TABLE(table), button, 1,2,1,2);
6807 gtk_widget_show(button);
6809 button = gtk_button_new_with_label ("prev page");
6810 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
6811 (GtkSignalFunc) gtk_notebook_prev_page,
6812 GTK_OBJECT (notebook));
6813 gtk_table_attach_defaults(GTK_TABLE(table), button, 2,3,1,2);
6814 gtk_widget_show(button);
6816 button = gtk_button_new_with_label ("tab position");
6817 gtk_signal_connect (GTK_OBJECT (button), "clicked",
6818 (GtkSignalFunc) rotate_book, GTK_OBJECT(notebook));
6819 gtk_table_attach_defaults(GTK_TABLE(table), button, 3,4,1,2);
6820 gtk_widget_show(button);
6822 button = gtk_button_new_with_label ("tabs/border on/off");
6823 gtk_signal_connect (GTK_OBJECT (button), "clicked",
6824 (GtkSignalFunc) tabsborder_book,
6825 GTK_OBJECT (notebook));
6826 gtk_table_attach_defaults(GTK_TABLE(table), button, 4,5,1,2);
6827 gtk_widget_show(button);
6829 button = gtk_button_new_with_label ("remove page");
6830 gtk_signal_connect (GTK_OBJECT (button), "clicked",
6831 (GtkSignalFunc) remove_book,
6832 GTK_OBJECT(notebook));
6833 gtk_table_attach_defaults(GTK_TABLE(table), button, 5,6,1,2);
6834 gtk_widget_show(button);
6836 gtk_widget_show(table);
6837 gtk_widget_show(window);
6846 Hopefully this helps you on your way with creating notebooks for your
6849 <!-- ***************************************************************** -->
6851 <!-- ***************************************************************** -->
6853 <!-- ----------------------------------------------------------------- -->
6855 The GtkCList widget has replaced the GtkList widget (which is still
6858 The GtkCList widget is a multi-column list widget that is capable of
6859 handling literally thousands of rows of information. Each column can
6860 optionally have a title, which itself is optionally active, allowing
6861 us to bind a function to its selection.
6863 <!-- ----------------------------------------------------------------- -->
6864 <sect1>Creating a GtkCList widget
6866 Creating a GtkCList is quite straightforward, once you have learned
6867 about widgets in general. It provides the almost standard two ways,
6868 that is the hard way, and the easy way. But before we create it, there
6869 is one thing we should figure out beforehand: how many columns should
6872 Not all columns have to be visible and can be used to store data that
6873 is related to a certain cell in the list.
6876 GtkWidget *gtk_clist_new ( gint columns );
6878 GtkWidget *gtk_clist_new_with_titles( gint columns,
6882 The first form is very straight forward, the second might require some
6883 explanation. Each column can have a title associated with it, and this
6884 title can be a label or a button that reacts when we click on it. If
6885 we use the second form, we must provide pointers to the title texts,
6886 and the number of pointers should equal the number of columns
6887 specified. Of course we can always use the first form, and manually
6890 Note: the GtkCList widget does not have it's own scrollbars and should
6891 be placed within a GtkScrolledWindow widget if your require this
6892 functionality. This is a change from the GTK 1.0 implementation.
6894 <!-- ----------------------------------------------------------------- -->
6895 <sect1>Modes of operation
6897 There are several attributes that can be used to alter the behaviour of
6898 a GtkCList. First there is
6901 void gtk_clist_set_selection_mode( GtkCList *clist,
6902 GtkSelectionMode mode );
6905 which, as the name implies, sets the selection mode of the GtkCList. The first
6906 argument is the GtkCList widget, and the second specifies the cell selection
6907 mode (they are defined in gtkenums.h). At the time of this writing, the following
6908 modes are available to us:
6911 <item> GTK_SELECTION_SINGLE - The selection is either NULL or contains a GList
6912 pointer for a single selected item.
6914 <item> GTK_SELECTION_BROWSE - The selection is NULL if the list contains no
6915 widgets or insensitive ones only, otherwise it contains a GList pointer for
6916 one GList structure, and therefore exactly one list item.
6918 <item> GTK_SELECTION_MULTIPLE - The selection is NULL if no list items are
6919 selected or a GList pointer for the first selected item. That in turn points
6920 to a GList structure for the second selected item and so on. This is currently
6921 the <bf>default</bf> for the GtkCList widget.
6923 <item> GTK_SELECTION_EXTENDED - The selection is always NULL.
6926 Others might be added in later revisions of GTK.
6928 We can also define what the border of the GtkCList widget should look
6929 like. It is done through
6932 void gtk_clist_set_shadow_type( GtkCList *clist,
6933 GtkShadowType border );
6936 And the possible values for the second argument are
6939 <item> GTK_SHADOW_NONE
6941 <item> GTK_SHADOW_IN
6943 <item> GTK_SHADOW_OUT
6945 <item> GTK_SHADOW_ETCHED_IN
6947 <item> GTK_SHADOW_ETCHED_OUT
6950 <!-- ----------------------------------------------------------------- -->
6951 <sect1>Working with titles
6953 When you create a GtkCList widget, you will also get a set of title
6954 buttons automatically. They live in the top of the CList window, and
6955 can act either as normal buttons that respond to being pressed, or
6956 they can be passive, in which case they are nothing more than a
6957 title. There are four different calls that aid us in setting the
6958 status of the title buttons.
6961 void gtk_clist_column_title_active( GtkCList *clist,
6964 void gtk_clist_column_title_passive( GtkCList *clist,
6967 void gtk_clist_column_titles_active( GtkCList *clist );
6969 void gtk_clist_column_titles_passive( GtkCList *clist );
6972 An active title is one which acts as a normal button, a passive one is
6973 just a label. The first two calls above will activate/deactivate the
6974 title button above the specific column, while the last two calls
6975 activate/deactivate all title buttons in the supplied clist widget.
6977 But of course there are those cases when we don't want them at all,
6978 and so they can be hidden and shown at will using the following two
6982 void gtk_clist_column_titles_show( GtkCList *clist );
6984 void gtk_clist_column_titles_hide( GtkCList *clist );
6987 For titles to be really useful we need a mechanism to set and change
6988 them, and this is done using
6991 void gtk_clist_set_column_title( GtkCList *clist,
6996 Note that only the title of one column can be set at a time, so if all
6997 the titles are known from the beginning, then I really suggest using
6998 gtk_clist_new_with_titles (as described above) to set them. Saves you
6999 coding time, and makes your program smaller. There are some cases
7000 where getting the job done the manual way is better, and that's when
7001 not all titles will be text. GtkCList provides us with title buttons
7002 that can in fact incorporate whole widgets, for example a pixmap. It's
7006 void gtk_clist_set_column_widget( GtkCList *clist,
7008 GtkWidget *widget );
7011 which should require no special explanation.
7013 <!-- ----------------------------------------------------------------- -->
7014 <sect1>Manipulating the list itself
7016 It is possible to change the justification for a column, and it is
7020 void gtk_clist_set_column_justification( GtkCList *clist,
7022 GtkJustification justification );
7025 The GtkJustification type can take the following values:
7028 <item>GTK_JUSTIFY_LEFT - The text in the column will begin from the
7031 <item>GTK_JUSTIFY_RIGHT - The text in the column will begin from the
7034 <item>GTK_JUSTIFY_CENTER - The text is placed in the center of the
7037 <item>GTK_JUSTIFY_FILL - The text will use up all available space in
7038 the column. It is normally done by inserting extra blank spaces
7039 between words (or between individual letters if it's a single
7040 word). Much in the same way as any ordinary WYSIWYG text editor.
7043 The next function is a very important one, and should be standard in
7044 the setup of all GtkCList widgets. When the list is created, the width
7045 of the various columns are chosen to match their titles, and since
7046 this is seldom the right width we have to set it using
7049 void gtk_clist_set_column_width( GtkCList *clist,
7054 Note that the width is given in pixels and not letters. The same goes
7055 for the height of the cells in the columns, but as the default value
7056 is the height of the current font this isn't as critical to the
7057 application. Still, it is done through
7060 void gtk_clist_set_row_height( GtkCList *clist,
7064 Again, note that the height is given in pixels.
7066 We can also move the list around without user interaction, however, it
7067 does require that we know what we are looking for. Or in other words,
7068 we need the row and column of the item we want to scroll to.
7071 void gtk_clist_moveto( GtkCList *clist,
7078 The gfloat row_align is pretty important to understand. It's a value
7079 between 0.0 and 1.0, where 0.0 means that we should scroll the list so
7080 the row appears at the top, while if the value of row_align is 1.0,
7081 the row will appear at the bottom instead. All other values between
7082 0.0 and 1.0 are also valid and will place the row between the top and
7083 the bottom. The last argument, gfloat col_align works in the same way,
7084 though 0.0 marks left and 1.0 marks right instead.
7086 Depending on the application's needs, we don't have to scroll to an
7087 item that is already visible to us. So how do we know if it is
7088 visible? As usual, there is a function to find that out as well.
7091 GtkVisibility gtk_clist_row_is_visible( GtkCList *clist,
7095 The return value is is one of the following:
7098 <item>GTK_VISIBILITY_NONE
7100 <item>GTK_VISIBILITY_PARTIAL
7102 <item>GTK_VISIBILITY_FULL
7105 Note that it will only tell us if a row is visible. Currently there is
7106 no way to determine this for a column. We can get partial information
7107 though, because if the return is GTK_VISIBILITY_PARTIAL, then some of
7108 it is hidden, but we don't know if it is the row that is being cut by
7109 the lower edge of the listbox, or if the row has columns that are
7112 We can also change both the foreground and background colors of a
7113 particular row. This is useful for marking the row selected by the
7114 user, and the two functions that is used to do it are
7117 void gtk_clist_set_foreground( GtkCList *clist,
7121 void gtk_clist_set_background( GtkCList *clist,
7126 Please note that the colors must have been previously allocated.
7128 <!-- ----------------------------------------------------------------- -->
7129 <sect1>Adding rows to the list
7131 We can add rows in three ways. They can be prepended or appended to
7135 gint gtk_clist_prepend( GtkCList *clist,
7138 gint gtk_clist_append( GtkCList *clist,
7142 The return value of these two functions indicate the index of the row
7143 that was just added. We can insert a row at a given place using
7146 void gtk_clist_insert( GtkCList *clist,
7151 In these calls we have to provide a collection of pointers that are
7152 the texts we want to put in the columns. The number of pointers should
7153 equal the number of columns in the list. If the text[] argument is
7154 NULL, then there will be no text in the columns of the row. This is
7155 useful, for example, if we want to add pixmaps instead (something that
7156 has to be done manually).
7158 Also, please note that the numbering of both rows and columns start at 0.
7160 To remove an individual row we use
7163 void gtk_clist_remove( GtkCList *clist,
7167 There is also a call that removes all rows in the list. This is a lot
7168 faster than calling gtk_clist_remove once for each row, which is the
7172 void gtk_clist_clear( GtkCList *clist );
7175 There are also two convenience functions that should be used when a
7176 lot of changes have to be made to the list. This is to prevent the
7177 list flickering while being repeatedly updated, which may be highly
7178 annoying to the user. So instead it is a good idea to freeze the list,
7179 do the updates to it, and finally thaw it which causes the list to be
7180 updated on the screen.
7183 void gtk_clist_freeze( GtkCList * clist );
7185 void gtk_clist_thaw( GtkCList * clist );
7188 <!-- ----------------------------------------------------------------- -->
7189 <sect1>Setting text and pixmaps in the cells
7191 A cell can contain a pixmap, text or both. To set them the following
7195 void gtk_clist_set_text( GtkCList *clist,
7200 void gtk_clist_set_pixmap( GtkCList *clist,
7206 void gtk_clist_set_pixtext( GtkCList *clist,
7215 It's quite straightforward. All the calls have the GtkCList as the
7216 first argument, followed by the row and column of the cell, followed
7217 by the data to be set. The <tt/spacing/ argument in
7218 gtk_clist_set_pixtext is the number of pixels between the pixmap and
7219 the beginning of the text.
7221 To read back the data, we instead use
7224 gint gtk_clist_get_text( GtkCList *clist,
7229 gint gtk_clist_get_pixmap( GtkCList *clist,
7235 gint gtk_clist_get_pixtext( GtkCList *clist,
7244 It isn't necessary to read it all back in case you aren't
7245 interested. Any of the pointers that are meant for return values (all
7246 except the clist) can be NULL. So if we want to read back only the
7247 text from a cell that is of type pixtext, then we would do the
7248 following, assuming that clist, row and column already exist:
7253 gtk_clist_get_pixtext(clist, row, column, &mytext, NULL, NULL, NULL);
7256 There is one more call that is related to what's inside a cell in the
7260 GtkCellType gtk_clist_get_cell_type( GtkCList *clist,
7265 which returns the type of data in a cell. The return value is one of
7268 <item>GTK_CELL_EMPTY
7272 <item>GTK_CELL_PIXMAP
7274 <item>GTK_CELL_PIXTEXT
7276 <item>GTK_CELL_WIDGET
7279 There is also a function that will let us set the indentation, both
7280 vertical and horizontal, of a cell. The indentation value is of type
7281 gint, given in pixels, and can be both positive and negative.
7284 void gtk_clist_set_shift( GtkCList *clist,
7291 <!-- ----------------------------------------------------------------- -->
7292 <sect1>Storing data pointers
7294 With a GtkCList it is possible to set a data pointer for a row. This
7295 pointer will not be visible for the user, but is merely a convenience
7296 for the programmer to associate a row with a pointer to some
7299 The functions should be fairly self-explanatory by now
7302 void gtk_clist_set_row_data( GtkCList *clist,
7306 void gtk_clist_set_row_data_full( GtkCList *clist,
7309 GtkDestroyNotify destroy );
7311 gpointer gtk_clist_get_row_data( GtkCList *clist,
7314 gint gtk_clist_find_row_from_data( GtkCList *clist,
7318 <!-- ----------------------------------------------------------------- -->
7319 <sect1>Working with selections
7321 There are also functions available that let us force the (un)selection
7325 void gtk_clist_select_row( GtkCList *clist,
7329 void gtk_clist_unselect_row( GtkCList *clist,
7334 And also a function that will take x and y coordinates (for example,
7335 read from the mousepointer), and map that onto the list, returning the
7336 corresponding row and column.
7339 gint gtk_clist_get_selection_info( GtkCList *clist,
7346 When we detect something of interest, it might be movement of the
7347 pointer, a click somewhere in the list, we can read the pointer
7348 coordinates and find out where in the list the pointer is. Cumbersome?
7349 Luckily, there is a simpler way...
7351 <!-- ----------------------------------------------------------------- -->
7352 <sect1>The signals that bring it together
7354 As with all other widgets, there are a few signals that can be used. The
7355 GtkCList widget is derived from the GtkContainer widget, and so has all the
7356 same signals, but also the adds following:
7359 <item>select_row - This signal will send the following information, in
7360 order: GtkCList *clist, gint row, gint column, GtkEventButton *event
7362 <item>unselect_row - When the user unselects a row, this signal is
7363 activated. It sends the same information as select_row
7365 <item>click_column - Send GtkCList *clist, gint column
7368 So if we want to connect a callback to select_row, the callback
7369 function would be declared like this
7372 void select_row_callback(GtkWidget *widget,
7375 GdkEventButton *event,
7379 The callback is connected as usual with
7382 gtk_signal_connect(GTK_OBJECT( clist),
7384 GTK_SIGNAL_FUNC(select_row_callback),
7388 <!-- ----------------------------------------------------------------- -->
7389 <sect1>A GtkCList example
7393 /* example-start clist clist.c */
7395 #include <gtk/gtk.h>
7398 /* These are just the prototypes of the various callbacks */
7399 void button_add_clicked( GtkWidget *button, gpointer data);
7400 void button_clear_clicked( GtkWidget *button, gpointer data);
7401 void button_hide_show_clicked( GtkWidget *button, gpointer data);
7402 void selection_made( GtkWidget *clist, gint row, gint column,
7403 GdkEventButton *event, gpointer data);
7405 gint main (int argc, gchar *argv[])
7408 GtkWidget *vbox, *hbox;
7410 GtkWidget *button_add, *button_clear, *button_hide_show;
7411 gchar *titles[2] = {"Ingredients","Amount"};
7413 gtk_init(&argc, &argv);
7416 window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
7417 gtk_widget_set_usize(GTK_WIDGET(window), 300, 150);
7419 gtk_window_set_title(GTK_WINDOW(window), "GtkCList Example");
7420 gtk_signal_connect(GTK_OBJECT(window),
7422 GTK_SIGNAL_FUNC(gtk_main_quit),
7425 vbox=gtk_vbox_new(FALSE, 5);
7426 gtk_container_set_border_width(GTK_CONTAINER(vbox), 5);
7427 gtk_container_add(GTK_CONTAINER(window), vbox);
7428 gtk_widget_show(vbox);
7430 /* Create the GtkCList. For this example we use 2 columns */
7431 clist = gtk_clist_new_with_titles( 2, titles);
7433 /* When a selection is made, we want to know about it. The callback
7434 * used is selection_made, and its code can be found further down */
7435 gtk_signal_connect(GTK_OBJECT(clist), "select_row",
7436 GTK_SIGNAL_FUNC(selection_made),
7439 /* It isn't necessary to shadow the border, but it looks nice :) */
7440 gtk_clist_set_shadow_type (GTK_CLIST(clist), GTK_SHADOW_OUT);
7442 /* What however is important, is that we set the column widths as
7443 * they will never be right otherwise. Note that the columns are
7444 * numbered from 0 and up (to 1 in this case).
7446 gtk_clist_set_column_width (GTK_CLIST(clist), 0, 150);
7448 /* Add the GtkCList widget to the vertical box and show it. */
7449 gtk_box_pack_start(GTK_BOX(vbox), clist, TRUE, TRUE, 0);
7450 gtk_widget_show(clist);
7452 /* Create the buttons and add them to the window. See the button
7453 * tutorial for more examples and comments on this.
7455 hbox = gtk_hbox_new(FALSE, 0);
7456 gtk_box_pack_start(GTK_BOX(vbox), hbox, FALSE, TRUE, 0);
7457 gtk_widget_show(hbox);
7459 button_add = gtk_button_new_with_label("Add List");
7460 button_clear = gtk_button_new_with_label("Clear List");
7461 button_hide_show = gtk_button_new_with_label("Hide/Show titles");
7463 gtk_box_pack_start(GTK_BOX(hbox), button_add, TRUE, TRUE, 0);
7464 gtk_box_pack_start(GTK_BOX(hbox), button_clear, TRUE, TRUE, 0);
7465 gtk_box_pack_start(GTK_BOX(hbox), button_hide_show, TRUE, TRUE, 0);
7467 /* Connect our callbacks to the three buttons */
7468 gtk_signal_connect_object(GTK_OBJECT(button_add), "clicked",
7469 GTK_SIGNAL_FUNC(button_add_clicked),
7471 gtk_signal_connect_object(GTK_OBJECT(button_clear), "clicked",
7472 GTK_SIGNAL_FUNC(button_clear_clicked),
7474 gtk_signal_connect_object(GTK_OBJECT(button_hide_show), "clicked",
7475 GTK_SIGNAL_FUNC(button_hide_show_clicked),
7478 gtk_widget_show(button_add);
7479 gtk_widget_show(button_clear);
7480 gtk_widget_show(button_hide_show);
7482 /* The interface is completely set up so we show the window and
7483 * enter the gtk_main loop.
7485 gtk_widget_show(window);
7491 /* User clicked the "Add List" button. */
7492 void button_add_clicked( GtkWidget *button, gpointer data)
7496 /* Something silly to add to the list. 4 rows of 2 columns each */
7497 gchar *drink[4][2] = {{"Milk", "3 Oz"},
7502 /* Here we do the actual adding of the text. It's done once for
7505 for( indx=0; indx < 4; indx++)
7506 gtk_clist_append( (GtkCList*) data, drink[indx]);
7511 /* User clicked the "Clear List" button. */
7512 void button_clear_clicked( GtkWidget *button, gpointer data)
7514 /* Clear the list using gtk_clist_clear. This is much faster than
7515 * calling gtk_clist_remove once for each row.
7517 gtk_clist_clear((GtkCList*) data);
7522 /* The user clicked the "Hide/Show titles" button. */
7523 void button_hide_show_clicked( GtkWidget *button, gpointer data)
7525 /* Just a flag to remember the status. 0 = currently visible */
7526 static short int flag = 0;
7530 /* Hide the titles and set the flag to 1 */
7531 gtk_clist_column_titles_hide((GtkCList*) data);
7536 /* Show the titles and reset flag to 0 */
7537 gtk_clist_column_titles_show((GtkCList*) data);
7544 /* If we come here, then the user has selected a row in the list. */
7545 void selection_made( GtkWidget *clist, gint row, gint column,
7546 GdkEventButton *event, gpointer data)
7550 /* Get the text that is stored in the selected row and column
7551 * which was clicked in. We will receive it as a pointer in the
7554 gtk_clist_get_text(GTK_CLIST(clist), row, column, &text);
7556 /* Just prints some information about the selected row */
7557 g_print("You selected row %d. More specifically you clicked in column %d, and the text in this cell is %s\n\n", row, column, text);
7564 <!-- ***************************************************************** -->
7565 <sect> Tree Widget <label id="sec_Tree_Widgets">
7566 <!-- ***************************************************************** -->
7568 The purpose of tree widgets is to display hierarchically-organized
7569 data. The GtkTree widget itself is a vertical container for widgets of
7570 type GtkTreeItem. GtkTree itself is not terribly different from
7571 GtkList - both are derived directly from GtkContainer, and the
7572 GtkContainer methods work in the same way on GtkTree widgets as on
7573 GtkList widgets. The difference is that GtkTree widgets can be nested
7574 within other GtkTree widgets. We'll see how to do this shortly.
7576 The GtkTree widget has its own window, and defaults to a white
7577 background, as does GtkList. Also, most of the GtkTree methods work in
7578 the same way as the corresponding GtkList ones. However, GtkTree is
7579 not derived from GtkList, so you cannot use them interchangeably.
7581 <sect1> Creating a Tree
7583 A GtkTree is created in the usual way, using:
7586 GtkWidget* gtk_tree_new( void );
7589 Like the GtkList widget, a GtkTree will simply keep growing as more
7590 items are added to it, as well as when subtrees are expanded. For
7591 this reason, they are almost always packed into a
7592 GtkScrolledWindow. You might want to use gtk_widget_set_usize() on the
7593 scrolled window to ensure that it is big enough to see the tree's
7594 items, as the default size for GtkScrolledWindow is quite small.
7596 Now that you have a tree, you'll probably want to add some items to
7597 it. <ref id="sec_Tree_Item_Widget" name="The Tree Item Widget"> below
7598 explains the gory details of GtkTreeItem. For now, it'll suffice to
7602 GtkWidget* gtk_tree_item_new_with_label( gchar *label );
7605 You can then add it to the tree using one of the following (see
7606 <ref id="sec_GtkTree_Functions" name="Functions and Macros">
7607 below for more options):
7610 void gtk_tree_append( GtkTree *tree,
7611 GtkWidget *tree_item );
7613 void gtk_tree_prepend( GtkTree *tree,
7614 GtkWidget *tree_item );
7617 Note that you must add items to a GtkTree one at a time - there is no
7618 equivalent to gtk_list_*_items().
7620 <!-- ----------------------------------------------------------------- -->
7621 <sect1> Adding a Subtree
7623 A subtree is created like any other GtkTree widget. A subtree is added
7624 to another tree beneath a tree item, using:
7627 void gtk_tree_item_set_subtree( GtkTreeItem *tree_item,
7628 GtkWidget *subtree );
7631 You do not need to call gtk_widget_show() on a subtree before or after
7632 adding it to a GtkTreeItem. However, you <em>must</em> have added the
7633 GtkTreeItem in question to a parent tree before calling
7634 gtk_tree_item_set_subtree(). This is because, technically, the parent
7635 of the subtree is <em>not</em> the GtkTreeItem which "owns" it, but
7636 rather the GtkTree which holds that GtkTreeItem.
7638 When you add a subtree to a GtkTreeItem, a plus or minus sign appears
7639 beside it, which the user can click on to "expand" or "collapse" it,
7640 meaning, to show or hide its subtree. GtkTreeItems are collapsed by
7641 default. Note that when you collapse a GtkTreeItem, any selected
7642 items in its subtree remain selected, which may not be what the user
7645 <!-- ----------------------------------------------------------------- -->
7646 <sect1> Handling the Selection List
7648 As with GtkList, the GtkTree type has a <tt>selection</tt> field, and
7649 it is possible to control the behaviour of the tree (somewhat) by
7650 setting the selection type using:
7653 void gtk_tree_set_selection_mode( GtkTree *tree,
7654 GtkSelectionMode mode );
7657 The semantics associated with the various selection modes are
7658 described in the section on the GtkList widget. As with the GtkList
7659 widget, the "select_child", "unselect_child" (not really - see <ref
7660 id="sec_GtkTree_Signals" name="Signals"> below for an explanation),
7661 and "selection_changed" signals are emitted when list items are
7662 selected or unselected. However, in order to take advantage of these
7663 signals, you need to know <em>which</em> GtkTree widget they will be
7664 emitted by, and where to find the list of selected items.
7666 This is a source of potential confusion. The best way to explain this
7667 is that though all GtkTree widgets are created equal, some are more
7668 equal than others. All GtkTree widgets have their own X window, and
7669 can therefore receive events such as mouse clicks (if their
7670 GtkTreeItems or their children don't catch them first!). However, to
7671 make GTK_SELECTION_SINGLE and GTK_SELECTION_BROWSE selection types
7672 behave in a sane manner, the list of selected items is specific to the
7673 topmost GtkTree widget in a hierarchy, known as the "root tree".
7675 Thus, accessing the <tt>selection</tt>field directly in an arbitrary
7676 GtkTree widget is not a good idea unless you <em>know</em> it's the
7677 root tree. Instead, use the GTK_TREE_SELECTION (Tree) macro, which
7678 gives the root tree's selection list as a GList pointer. Of course,
7679 this list can include items that are not in the subtree in question if
7680 the selection type is GTK_SELECTION_MULTIPLE.
7682 Finally, the "select_child" (and "unselect_child", in theory) signals
7683 are emitted by all trees, but the "selection_changed" signal is only
7684 emitted by the root tree. Consequently, if you want to handle the
7685 "select_child" signal for a tree and all its subtrees, you will have
7686 to call gtk_signal_connect() for every subtree.
7688 <sect1> Tree Widget Internals
7690 The GtkTree's struct definition looks like this:
7695 GtkContainer container;
7699 GtkTree* root_tree; /* owner of selection list */
7700 GtkWidget* tree_owner;
7704 guint current_indent;
7705 guint selection_mode : 2;
7706 guint view_mode : 1;
7707 guint view_line : 1;
7711 The perils associated with accessing the <tt>selection</tt> field
7712 directly have already been mentioned. The other important fields of
7713 the struct can also be accessed with handy macros or class functions.
7714 GTK_TREE_IS_ROOT_TREE (Tree) returns a boolean value which indicates
7715 whether a tree is the root tree in a GtkTree hierarchy, while
7716 GTK_TREE_ROOT_TREE (Tree) returns the root tree, an object of type
7717 GtkTree (so, remember to cast it using GTK_WIDGET (Tree) if you want
7718 to use one of the gtk_widget_*() functions on it).
7720 Instead of directly accessing the children field of a GtkTree widget,
7721 it's probably best to cast it using GTK_CONTAINER (Tree), and pass it
7722 to the gtk_container_children() function. This creates a duplicate of
7723 the original list, so it's advisable to free it up using g_list_free()
7724 after you're done with it, or to iterate on it destructively, like
7728 children = gtk_container_children (GTK_CONTAINER (tree));
7730 do_something_nice (GTK_TREE_ITEM (children->data));
7731 children = g_list_remove_link (children, children);
7735 The <tt>tree_owner</tt> field is defined only in subtrees, where it
7736 points to the GtkTreeItem widget which holds the tree in question.
7737 The <tt>level</tt> field indicates how deeply nested a particular tree
7738 is; root trees have level 0, and each successive level of subtrees has
7739 a level one greater than the parent level. This field is set only
7740 after a GtkTree widget is actually mapped (i.e. drawn on the screen).
7742 <sect2> Signals<label id="sec_GtkTree_Signals">
7745 void selection_changed( GtkTree *tree );
7748 This signal will be emitted whenever the <tt>selection</tt> field of a
7749 GtkTree has changed. This happens when a child of the GtkTree is
7750 selected or deselected.
7753 void select_child( GtkTree *tree,
7757 This signal is emitted when a child of the GtkTree is about to get
7758 selected. This happens on calls to gtk_tree_select_item(),
7759 gtk_tree_select_child(), on <em>all</em> button presses and calls to
7760 gtk_tree_item_toggle() and gtk_item_toggle(). It may sometimes be
7761 indirectly triggered on other occasions where children get added to or
7762 removed from the GtkTree.
7765 void unselect_child (GtkTree *tree,
7769 This signal is emitted when a child of the GtkTree is about to get
7770 deselected. As of GTK+ 1.0.4, this seems to only occur on calls to
7771 gtk_tree_unselect_item() or gtk_tree_unselect_child(), and perhaps on
7772 other occasions, but <em>not</em> when a button press deselects a
7773 child, nor on emission of the "toggle" signal by gtk_item_toggle().
7775 <sect2> Functions and Macros<label id="sec_GtkTree_Functions">
7778 guint gtk_tree_get_type( void );
7781 Returns the `GtkTree' type identifier.
7784 GtkWidget* gtk_tree_new( void );
7787 Create a new GtkTree object. The new widget is returned as a pointer
7788 to a GtkWidget object. NULL is returned on failure.
7791 void gtk_tree_append( GtkTree *tree,
7792 GtkWidget *tree_item );
7795 Append a tree item to a GtkTree.
7798 void gtk_tree_prepend( GtkTree *tree,
7799 GtkWidget *tree_item );
7802 Prepend a tree item to a GtkTree.
7805 void gtk_tree_insert( GtkTree *tree,
7806 GtkWidget *tree_item,
7810 Insert a tree item into a GtkTree at the position in the list
7811 specified by <tt>position.</tt>
7814 void gtk_tree_remove_items( GtkTree *tree,
7818 Remove a list of items (in the form of a GList *) from a GtkTree.
7819 Note that removing an item from a tree dereferences (and thus usually)
7820 destroys it <em>and</em> its subtree, if it has one, <em>and</em> all
7821 subtrees in that subtree. If you want to remove only one item, you
7822 can use gtk_container_remove().
7825 void gtk_tree_clear_items( GtkTree *tree,
7830 Remove the items from position <tt>start</tt> to position <tt>end</tt>
7831 from a GtkTree. The same warning about dereferencing applies here, as
7832 gtk_tree_clear_items() simply constructs a list and passes it to
7833 gtk_tree_remove_items().
7836 void gtk_tree_select_item( GtkTree *tree,
7840 Emits the "select_item" signal for the child at position
7841 <tt>item</tt>, thus selecting the child (unless you unselect it in a
7845 void gtk_tree_unselect_item( GtkTree *tree,
7849 Emits the "unselect_item" signal for the child at position
7850 <tt>item</tt>, thus unselecting the child.
7853 void gtk_tree_select_child( GtkTree *tree,
7854 GtkWidget *tree_item );
7857 Emits the "select_item" signal for the child <tt>tree_item</tt>, thus
7861 void gtk_tree_unselect_child( GtkTree *tree,
7862 GtkWidget *tree_item );
7865 Emits the "unselect_item" signal for the child <tt>tree_item</tt>,
7866 thus unselecting it.
7869 gint gtk_tree_child_position( GtkTree *tree,
7873 Returns the position in the tree of <tt>child</tt>, unless
7874 <tt>child</tt> is not in the tree, in which case it returns -1.
7877 void gtk_tree_set_selection_mode( GtkTree *tree,
7878 GtkSelectionMode mode );
7881 Sets the selection mode, which can be one of GTK_SELECTION_SINGLE (the
7882 default), GTK_SELECTION_BROWSE, GTK_SELECTION_MULTIPLE, or
7883 GTK_SELECTION_EXTENDED. This is only defined for root trees, which
7884 makes sense, since the root tree "owns" the selection. Setting it for
7885 subtrees has no effect at all; the value is simply ignored.
7888 void gtk_tree_set_view_mode( GtkTree *tree,
7889 GtkTreeViewMode mode );
7892 Sets the "view mode", which can be either GTK_TREE_VIEW_LINE (the
7893 default) or GTK_TREE_VIEW_ITEM. The view mode propagates from a tree
7894 to its subtrees, and can't be set exclusively to a subtree (this is
7895 not exactly true - see the example code comments).
7897 The term "view mode" is rather ambiguous - basically, it controls the
7898 way the highlight is drawn when one of a tree's children is selected.
7899 If it's GTK_TREE_VIEW_LINE, the entire GtkTreeItem widget is
7900 highlighted, while for GTK_TREE_VIEW_ITEM, only the child widget
7901 (i.e. usually the label) is highlighted.
7904 void gtk_tree_set_view_lines( GtkTree *tree,
7908 Controls whether connecting lines between tree items are drawn.
7909 <tt>flag</tt> is either TRUE, in which case they are, or FALSE, in
7910 which case they aren't.
7913 GtkTree *GTK_TREE (gpointer obj);
7916 Cast a generic pointer to `GtkTree *'.
7919 GtkTreeClass *GTK_TREE_CLASS (gpointer class);
7922 Cast a generic pointer to `GtkTreeClass*'.
7925 gint GTK_IS_TREE (gpointer obj);
7928 Determine if a generic pointer refers to a `GtkTree' object.
7931 gint GTK_IS_ROOT_TREE (gpointer obj)
7934 Determine if a generic pointer refers to a `GtkTree' object
7935 <em>and</em> is a root tree. Though this will accept any pointer, the
7936 results of passing it a pointer that does not refer to a GtkTree are
7937 undefined and possibly harmful.
7940 GtkTree *GTK_TREE_ROOT_TREE (gpointer obj)
7943 Return the root tree of a pointer to a `GtkTree' object. The above
7947 GList *GTK_TREE_SELECTION( gpointer obj)
7950 Return the selection list of the root tree of a `GtkTree' object. The
7951 above warning applies here, too.
7953 <sect1> Tree Item Widget<label id="sec_Tree_Item_Widget">
7955 The GtkTreeItem widget, like GtkListItem, is derived from GtkItem,
7956 which in turn is derived from GtkBin. Therefore, the item itself is a
7957 generic container holding exactly one child widget, which can be of
7958 any type. The GtkTreeItem widget has a number of extra fields, but
7959 the only one we need be concerned with is the <tt>subtree</tt> field.
7961 The definition for the GtkTreeItem struct looks like this:
7969 GtkWidget *pixmaps_box;
7970 GtkWidget *plus_pix_widget, *minus_pix_widget;
7972 GList *pixmaps; /* pixmap node for this items color depth */
7978 The <tt>pixmaps_box</tt> field is a GtkEventBox which catches clicks
7979 on the plus/minus symbol which controls expansion and collapsing. The
7980 <tt>pixmaps</tt> field points to an internal data structure. Since
7981 you can always obtain the subtree of a GtkTreeItem in a (relatively)
7982 type-safe manner with the GTK_TREE_ITEM_SUBTREE (Item) macro, it's
7983 probably advisable never to touch the insides of a GtkTreeItem unless
7984 you <em>really</em> know what you're doing.
7986 Since it is directly derived from a GtkItem it can be treated as such
7987 by using the GTK_ITEM (TreeItem) macro. A GtkTreeItem usually holds a
7988 label, so the convenience function gtk_list_item_new_with_label() is
7989 provided. The same effect can be achieved using code like the
7990 following, which is actually copied verbatim from
7991 gtk_tree_item_new_with_label():
7994 tree_item = gtk_tree_item_new ();
7995 label_widget = gtk_label_new (label);
7996 gtk_misc_set_alignment (GTK_MISC (label_widget), 0.0, 0.5);
7998 gtk_container_add (GTK_CONTAINER (tree_item), label_widget);
7999 gtk_widget_show (label_widget);
8002 As one is not forced to add a GtkLabel to a GtkTreeItem, you could
8003 also add a GtkHBox or a GtkArrow, or even a GtkNotebook (though your
8004 app will likely be quite unpopular in this case) to the GtkTreeItem.
8006 If you remove all the items from a subtree, it will be destroyed and
8007 unparented, unless you reference it beforehand, and the GtkTreeItem
8008 which owns it will be collapsed. So, if you want it to stick around,
8009 do something like the following:
8012 gtk_widget_ref (tree);
8013 owner = GTK_TREE(tree)->tree_owner;
8014 gtk_container_remove (GTK_CONTAINER(tree), item);
8015 if (tree->parent == NULL){
8016 gtk_tree_item_expand (GTK_TREE_ITEM(owner));
8017 gtk_tree_item_set_subtree (GTK_TREE_ITEM(owner), tree);
8020 gtk_widget_unref (tree);
8023 Finally, drag-n-drop <em>does</em> work with GtkTreeItems. You just
8024 have to make sure that the GtkTreeItem you want to make into a drag
8025 item or a drop site has not only been added to a GtkTree, but that
8026 each successive parent widget has a parent itself, all the way back to
8027 a toplevel or dialog window, when you call gtk_widget_dnd_drag_set()
8028 or gtk_widget_dnd_drop_set(). Otherwise, strange things will happen.
8032 GtkTreeItem inherits the "select", "deselect", and "toggle" signals
8033 from GtkItem. In addition, it adds two signals of its own, "expand"
8037 void select( GtkItem *tree_item );
8040 This signal is emitted when an item is about to be selected, either
8041 after it has been clicked on by the user, or when the program calls
8042 gtk_tree_item_select(), gtk_item_select(), or gtk_tree_select_child().
8045 void deselect( GtkItem *tree_item );
8048 This signal is emitted when an item is about to be unselected, either
8049 after it has been clicked on by the user, or when the program calls
8050 gtk_tree_item_deselect() or gtk_item_deselect(). In the case of
8051 GtkTreeItems, it is also emitted by gtk_tree_unselect_child(), and
8052 sometimes gtk_tree_select_child().
8055 void toggle( GtkItem *tree_item );
8058 This signal is emitted when the program calls gtk_item_toggle(). The
8059 effect it has when emitted on a GtkTreeItem is to call
8060 gtk_tree_select_child() (and never gtk_tree_unselect_child()) on the
8061 item's parent tree, if the item has a parent tree. If it doesn't,
8062 then the highlight is reversed on the item.
8065 void expand( GtkTreeItem *tree_item );
8068 This signal is emitted when the tree item's subtree is about to be
8069 expanded, that is, when the user clicks on the plus sign next to the
8070 item, or when the program calls gtk_tree_item_expand().
8073 void collapse( GtkTreeItem *tree_item );
8076 This signal is emitted when the tree item's subtree is about to be
8077 collapsed, that is, when the user clicks on the minus sign next to the
8078 item, or when the program calls gtk_tree_item_collapse().
8080 <sect2> Functions and Macros
8083 guint gtk_tree_item_get_type( void );
8086 Returns the `GtkTreeItem' type identifier.
8089 GtkWidget* gtk_tree_item_new( void );
8092 Create a new GtkTreeItem object. The new widget is returned as a
8093 pointer to a GtkWidget object. NULL is returned on failure.
8096 GtkWidget* gtk_tree_item_new_with_label (gchar *label);
8099 Create a new GtkTreeItem object, having a single GtkLabel as the sole
8100 child. The new widget is returned as a pointer to a GtkWidget
8101 object. NULL is returned on failure.
8104 void gtk_tree_item_select( GtkTreeItem *tree_item );
8107 This function is basically a wrapper around a call to gtk_item_select
8108 (GTK_ITEM (tree_item)) which will emit the select signal.
8111 void gtk_tree_item_deselect( GtkTreeItem *tree_item );
8114 This function is basically a wrapper around a call to
8115 gtk_item_deselect (GTK_ITEM (tree_item)) which will emit the deselect
8119 void gtk_tree_item_set_subtree( GtkTreeItem *tree_item,
8120 GtkWidget *subtree );
8123 This function adds subtree to tree_item, showing it if tree_item is
8124 expanded, or hiding it if tree_item is collapsed. Again, remember that
8125 the tree_item must have already been added to a tree for this to work.
8128 void gtk_tree_item_remove_subtree( GtkTreeItem *tree_item );
8131 This removes all of tree_item's subtree's children (thus unreferencing
8132 and destroying it, any of its children's subtrees, and so on...), then
8133 removes the subtree itself, and hides the plus/minus sign.
8136 void gtk_tree_item_expand( GtkTreeItem *tree_item );
8139 This emits the "expand" signal on tree_item, which expands it.
8142 void gtk_tree_item_collapse( GtkTreeItem *tree_item );
8145 This emits the "collapse" signal on tree_item, which collapses it.
8148 GtkTreeItem *GTK_TREE_ITEM (gpointer obj)
8151 Cast a generic pointer to `GtkTreeItem*'.
8154 GtkTreeItemClass *GTK_TREE_ITEM_CLASS (gpointer obj)
8157 Cast a generic pointer to `GtkTreeItemClass'.
8160 gint GTK_IS_TREE_ITEM (gpointer obj)
8163 Determine if a generic pointer refers to a `GtkTreeItem' object.
8166 GtkWidget GTK_TREE_ITEM_SUBTREE (gpointer obj)
8169 Returns a tree item's subtree (obj should point to a `GtkTreeItem'
8172 <sect1> Tree Example
8174 This is somewhat like the tree example in testgtk.c, but a lot less
8175 complete (although much better commented). It puts up a window with a
8176 tree, and connects all the signals for the relevant objects, so you
8177 can see when they are emitted.
8180 /* example-start tree tree.c */
8182 #include <gtk/gtk.h>
8184 /* for all the GtkItem:: and GtkTreeItem:: signals */
8185 static void cb_itemsignal (GtkWidget *item, gchar *signame)
8190 /* It's a GtkBin, so it has one child, which we know to be a
8191 label, so get that */
8192 label = GTK_LABEL (GTK_BIN (item)->child);
8193 /* Get the text of the label */
8194 gtk_label_get (label, &name);
8195 /* Get the level of the tree which the item is in */
8196 g_print ("%s called for item %s->%p, level %d\n", signame, name,
8197 item, GTK_TREE (item->parent)->level);
8200 /* Note that this is never called */
8201 static void cb_unselect_child (GtkWidget *root_tree, GtkWidget *child,
8204 g_print ("unselect_child called for root tree %p, subtree %p, child %p\n",
8205 root_tree, subtree, child);
8208 /* Note that this is called every time the user clicks on an item,
8209 whether it is already selected or not. */
8210 static void cb_select_child (GtkWidget *root_tree, GtkWidget *child,
8213 g_print ("select_child called for root tree %p, subtree %p, child %p\n",
8214 root_tree, subtree, child);
8217 static void cb_selection_changed (GtkWidget *tree)
8221 g_print ("selection_change called for tree %p\n", tree);
8222 g_print ("selected objects are:\n");
8224 i = GTK_TREE_SELECTION(tree);
8230 /* Get a GtkWidget pointer from the list node */
8231 item = GTK_WIDGET (i->data);
8232 label = GTK_LABEL (GTK_BIN (item)->child);
8233 gtk_label_get (label, &name);
8234 g_print ("\t%s on level %d\n", name, GTK_TREE
8235 (item->parent)->level);
8240 int main (int argc, char *argv[])
8242 GtkWidget *window, *scrolled_win, *tree;
8243 static gchar *itemnames[] = {"Foo", "Bar", "Baz", "Quux",
8247 gtk_init (&argc, &argv);
8249 /* a generic toplevel window */
8250 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
8251 gtk_signal_connect (GTK_OBJECT(window), "delete_event",
8252 GTK_SIGNAL_FUNC (gtk_main_quit), NULL);
8253 gtk_container_set_border_width (GTK_CONTAINER(window), 5);
8255 /* A generic scrolled window */
8256 scrolled_win = gtk_scrolled_window_new (NULL, NULL);
8257 gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_win),
8258 GTK_POLICY_AUTOMATIC,
8259 GTK_POLICY_AUTOMATIC);
8260 gtk_widget_set_usize (scrolled_win, 150, 200);
8261 gtk_container_add (GTK_CONTAINER(window), scrolled_win);
8262 gtk_widget_show (scrolled_win);
8264 /* Create the root tree */
8265 tree = gtk_tree_new();
8266 g_print ("root tree is %p\n", tree);
8267 /* connect all GtkTree:: signals */
8268 gtk_signal_connect (GTK_OBJECT(tree), "select_child",
8269 GTK_SIGNAL_FUNC(cb_select_child), tree);
8270 gtk_signal_connect (GTK_OBJECT(tree), "unselect_child",
8271 GTK_SIGNAL_FUNC(cb_unselect_child), tree);
8272 gtk_signal_connect (GTK_OBJECT(tree), "selection_changed",
8273 GTK_SIGNAL_FUNC(cb_selection_changed), tree);
8274 /* Add it to the scrolled window */
8275 gtk_scrolled_window_add_with_viewport (GTK_SCROLLED_WINDOW(scrolled_win),
8277 /* Set the selection mode */
8278 gtk_tree_set_selection_mode (GTK_TREE(tree),
8279 GTK_SELECTION_MULTIPLE);
8281 gtk_widget_show (tree);
8283 for (i = 0; i < 5; i++){
8284 GtkWidget *subtree, *item;
8287 /* Create a tree item */
8288 item = gtk_tree_item_new_with_label (itemnames[i]);
8289 /* Connect all GtkItem:: and GtkTreeItem:: signals */
8290 gtk_signal_connect (GTK_OBJECT(item), "select",
8291 GTK_SIGNAL_FUNC(cb_itemsignal), "select");
8292 gtk_signal_connect (GTK_OBJECT(item), "deselect",
8293 GTK_SIGNAL_FUNC(cb_itemsignal), "deselect");
8294 gtk_signal_connect (GTK_OBJECT(item), "toggle",
8295 GTK_SIGNAL_FUNC(cb_itemsignal), "toggle");
8296 gtk_signal_connect (GTK_OBJECT(item), "expand",
8297 GTK_SIGNAL_FUNC(cb_itemsignal), "expand");
8298 gtk_signal_connect (GTK_OBJECT(item), "collapse",
8299 GTK_SIGNAL_FUNC(cb_itemsignal), "collapse");
8300 /* Add it to the parent tree */
8301 gtk_tree_append (GTK_TREE(tree), item);
8302 /* Show it - this can be done at any time */
8303 gtk_widget_show (item);
8304 /* Create this item's subtree */
8305 subtree = gtk_tree_new();
8306 g_print ("-> item %s->%p, subtree %p\n", itemnames[i], item,
8309 /* This is still necessary if you want these signals to be called
8310 for the subtree's children. Note that selection_change will be
8311 signalled for the root tree regardless. */
8312 gtk_signal_connect (GTK_OBJECT(subtree), "select_child",
8313 GTK_SIGNAL_FUNC(cb_select_child), subtree);
8314 gtk_signal_connect (GTK_OBJECT(subtree), "unselect_child",
8315 GTK_SIGNAL_FUNC(cb_unselect_child), subtree);
8316 /* This has absolutely no effect, because it is completely ignored
8318 gtk_tree_set_selection_mode (GTK_TREE(subtree),
8319 GTK_SELECTION_SINGLE);
8320 /* Neither does this, but for a rather different reason - the
8321 view_mode and view_line values of a tree are propagated to
8322 subtrees when they are mapped. So, setting it later on would
8323 actually have a (somewhat unpredictable) effect */
8324 gtk_tree_set_view_mode (GTK_TREE(subtree), GTK_TREE_VIEW_ITEM);
8325 /* Set this item's subtree - note that you cannot do this until
8326 AFTER the item has been added to its parent tree! */
8327 gtk_tree_item_set_subtree (GTK_TREE_ITEM(item), subtree);
8329 for (j = 0; j < 5; j++){
8332 /* Create a subtree item, in much the same way */
8333 subitem = gtk_tree_item_new_with_label (itemnames[j]);
8334 /* Connect all GtkItem:: and GtkTreeItem:: signals */
8335 gtk_signal_connect (GTK_OBJECT(subitem), "select",
8336 GTK_SIGNAL_FUNC(cb_itemsignal), "select");
8337 gtk_signal_connect (GTK_OBJECT(subitem), "deselect",
8338 GTK_SIGNAL_FUNC(cb_itemsignal), "deselect");
8339 gtk_signal_connect (GTK_OBJECT(subitem), "toggle",
8340 GTK_SIGNAL_FUNC(cb_itemsignal), "toggle");
8341 gtk_signal_connect (GTK_OBJECT(subitem), "expand",
8342 GTK_SIGNAL_FUNC(cb_itemsignal), "expand");
8343 gtk_signal_connect (GTK_OBJECT(subitem), "collapse",
8344 GTK_SIGNAL_FUNC(cb_itemsignal), "collapse");
8345 g_print ("-> -> item %s->%p\n", itemnames[j], subitem);
8346 /* Add it to its parent tree */
8347 gtk_tree_append (GTK_TREE(subtree), subitem);
8349 gtk_widget_show (subitem);
8353 /* Show the window and loop endlessly */
8354 gtk_widget_show (window);
8361 <!-- ***************************************************************** -->
8363 <!-- ***************************************************************** -->
8365 There are two ways to create menus, there's the easy way, and there's
8366 the hard way. Both have their uses, but you can usually use the
8367 itemfactory (the easy way). The "hard" way is to create all the menus
8368 using the calls directly. The easy way is to use the gtk_item_factory
8369 calls. This is much simpler, but there are advantages and
8370 disadvantages to each approach.
8372 The itemfactory is much easier to use, and to add new menus to,
8373 although writing a few wrapper functions to create menus using the
8374 manual method could go a long way towards usability. With the
8375 menufactory, it is not possible to add images or the character '/' to
8378 <!-- ----------------------------------------------------------------- -->
8379 <sect1>Manual Menu Creation
8381 In the true tradition of teaching, we'll show you the hard way
8384 There are three widgets that go into making a menubar and submenus:
8386 <item>a menu item, which is what the user wants to select, e.g. 'Save'
8387 <item>a menu, which acts as a container for the menu items, and
8388 <item>a menubar, which is a container for each of the individual
8392 This is slightly complicated by the fact that menu item widgets are
8393 used for two different things. They are both the widgets that are
8394 packed into the menu, and the widget that is packed into the menubar,
8395 which, when selected, activates the menu.
8397 Let's look at the functions that are used to create menus and
8398 menubars. This first function is used to create a new menubar.
8402 GtkWidget *gtk_menu_bar_new( void );
8406 This rather self explanatory function creates a new menubar. You use
8407 gtk_container_add to pack this into a window, or the box_pack
8408 functions to pack it into a box - the same as buttons.
8411 GtkWidget *gtk_menu_new( void );
8414 This function returns a pointer to a new menu, it is never actually
8415 shown (with gtk_widget_show), it is just a container for the menu
8416 items. Hopefully this will become more clear when you look at the
8419 The next two calls are used to create menu items that are packed into
8420 the menu (and menubar).
8423 GtkWidget *gtk_menu_item_new( void );
8429 GtkWidget *gtk_menu_item_new_with_label( const char *label );
8432 These calls are used to create the menu items that are to be
8433 displayed. Remember to differentiate between a "menu" as created with
8434 gtk_menu_new and a "menu item" as created by the gtk_menu_item_new
8435 functions. The menu item will be an actual button with an associated
8436 action, whereas a menu will be a container holding menu items.
8438 The gtk_menu_new_with_label and gtk_menu_new functions are just as
8439 you'd expect after reading about the buttons. One creates a new menu
8440 item with a label already packed into it, and the other just creates a
8443 Once you've created a menu item you have to put it into a menu. This
8444 is done using the function gtk_menu_append. In order to capture when
8445 the item is selected by the user, we need to connect to the
8446 <tt/activate/ signal in the usual way. So, if we wanted to create a
8447 standard <tt/File/ menu, with the options <tt/Open/, <tt/Save/ and
8448 <tt/Quit/ the code would look something like:
8451 file_menu = gtk_menu_new(); /* Don't need to show menus */
8453 /* Create the menu items */
8454 open_item = gtk_menu_item_new_with_label("Open");
8455 save_item = gtk_menu_item_new_with_label("Save");
8456 quit_item = gtk_menu_item_new_with_label("Quit");
8458 /* Add them to the menu */
8459 gtk_menu_append( GTK_MENU(file_menu), open_item);
8460 gtk_menu_append( GTK_MENU(file_menu), save_item);
8461 gtk_menu_append( GTK_MENU(file_menu), quit_item);
8463 /* Attach the callback functions to the activate signal */
8464 gtk_signal_connect_object( GTK_OBJECT(open_items), "activate",
8465 GTK_SIGNAL_FUNC(menuitem_response),
8466 (gpointer) "file.open");
8467 gtk_signal_connect_object( GTK_OBJECT(save_items), "activate",
8468 GTK_SIGNAL_FUNC(menuitem_response),
8469 (gpointer) "file.save");
8471 /* We can attach the Quit menu item to our exit function */
8472 gtk_signal_connect_object( GTK_OBJECT(quit_items), "activate",
8473 GTK_SIGNAL_FUNC(destroy),
8474 (gpointer) "file.quit");
8476 /* We do need to show menu items */
8477 gtk_widget_show( open_item );
8478 gtk_widget_show( save_item );
8479 gtk_widget_show( quit_item );
8482 At this point we have our menu. Now we need to create a menubar and a
8483 menu item for the <tt/File/ entry, to which we add our menu. The code
8487 menu_bar = gtk_menu_bar_new();
8488 gtk_container_add( GTK_CONTAINER(window), menu_bar);
8489 gtk_widget_show( menu_bar );
8491 file_item = gtk_menu_item_new_with_label("File");
8492 gtk_widget_show(file_item);
8495 Now we need to associate the menu with <tt/file_item/. This is done
8499 void gtk_menu_item_set_submenu( GtkMenuItem *menu_item,
8500 GtkWidget *submenu );
8503 So, our example would continue with
8506 gtk_menu_item_set_submenu( GTK_MENU_ITEM(file_item), file_menu );
8509 All that is left to do is to add the menu to the menubar, which is
8510 accomplished using the function
8513 void gtk_menu_bar_append( GtkMenuBar *menu_bar, GtkWidget *menu_item);
8516 which in our case looks like this:
8519 gtk_menu_bar_append( GTK_MENU_BAR (menu_bar), file_item );
8522 If we wanted the menu right justified on the menubar, such as help
8523 menus often are, we can use the following function (again on
8524 <tt/file_item/ in the current example) before attaching it to the
8528 void gtk_menu_item_right_justify( GtkMenuItem *menu_item );
8531 Here is a summary of the steps needed to create a menu bar with menus
8535 <item> Create a new menu using gtk_menu_new()
8536 <item> Use multiple calls to gtk_menu_item_new() for each item you
8537 wish to have on your menu. And use gtk_menu_append() to put each of
8538 these new items on to the menu.
8539 <item> Create a menu item using gtk_menu_item_new(). This will be the
8540 root of the menu, the text appearing here will be on the menubar
8542 <item>Use gtk_menu_item_set_submenu() to attach the menu to the root
8543 menu item (the one created in the above step).
8544 <item> Create a new menubar using gtk_menu_bar_new. This step only
8545 needs to be done once when creating a series of menus on one menu bar.
8546 <item> Use gtk_menu_bar_append to put the root menu onto the menubar.
8549 Creating a popup menu is nearly the same. The difference is that the
8550 menu is not posted `automatically' by a menubar, but explicitly by
8551 calling the function gtk_menu_popup() from a button-press event, for
8552 example. Take these steps:
8555 <item>Create an event handling function. It needs to have the
8558 static gint handler( GtkWidget *widget,
8561 and it will use the event to find out where to pop up the menu.
8562 <item>In the event handler, if the event is a mouse button press,
8563 treat <tt>event</tt> as a button event (which it is) and use it as
8564 shown in the sample code to pass information to gtk_menu_popup().
8565 <item>Bind that event handler to a widget with
8567 gtk_signal_connect_object(GTK_OBJECT(widget), "event",
8568 GTK_SIGNAL_FUNC (handler),
8571 where <tt>widget</tt> is the widget you are binding to,
8572 <tt>handler</tt> is the handling function, and <tt>menu</tt> is a menu
8573 created with gtk_menu_new(). This can be a menu which is also posted
8574 by a menu bar, as shown in the sample code.
8577 <!-- ----------------------------------------------------------------- -->
8578 <sect1>Manual Menu Example
8580 That should about do it. Let's take a look at an example to help clarify.
8583 /* example-start menu menu.c */
8585 #include <gtk/gtk.h>
8587 static gint button_press (GtkWidget *, GdkEvent *);
8588 static void menuitem_response (gchar *);
8590 int main (int argc, char *argv[])
8595 GtkWidget *menu_bar;
8596 GtkWidget *root_menu;
8597 GtkWidget *menu_items;
8603 gtk_init (&argc, &argv);
8605 /* create a new window */
8606 window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
8607 gtk_widget_set_usize( GTK_WIDGET (window), 200, 100);
8608 gtk_window_set_title(GTK_WINDOW (window), "GTK Menu Test");
8609 gtk_signal_connect(GTK_OBJECT (window), "delete_event",
8610 (GtkSignalFunc) gtk_main_quit, NULL);
8612 /* Init the menu-widget, and remember -- never
8613 * gtk_show_widget() the menu widget!!
8614 * This is the menu that holds the menu items, the one that
8615 * will pop up when you click on the "Root Menu" in the app */
8616 menu = gtk_menu_new();
8618 /* Next we make a little loop that makes three menu-entries for "test-menu".
8619 * Notice the call to gtk_menu_append. Here we are adding a list of
8620 * menu items to our menu. Normally, we'd also catch the "clicked"
8621 * signal on each of the menu items and setup a callback for it,
8622 * but it's omitted here to save space. */
8624 for(i = 0; i < 3; i++)
8626 /* Copy the names to the buf. */
8627 sprintf(buf, "Test-undermenu - %d", i);
8629 /* Create a new menu-item with a name... */
8630 menu_items = gtk_menu_item_new_with_label(buf);
8632 /* ...and add it to the menu. */
8633 gtk_menu_append(GTK_MENU (menu), menu_items);
8635 /* Do something interesting when the menuitem is selected */
8636 gtk_signal_connect_object(GTK_OBJECT(menu_items), "activate",
8637 GTK_SIGNAL_FUNC(menuitem_response), (gpointer) g_strdup(buf));
8639 /* Show the widget */
8640 gtk_widget_show(menu_items);
8643 /* This is the root menu, and will be the label
8644 * displayed on the menu bar. There won't be a signal handler attached,
8645 * as it only pops up the rest of the menu when pressed. */
8646 root_menu = gtk_menu_item_new_with_label("Root Menu");
8648 gtk_widget_show(root_menu);
8650 /* Now we specify that we want our newly created "menu" to be the menu
8651 * for the "root menu" */
8652 gtk_menu_item_set_submenu(GTK_MENU_ITEM (root_menu), menu);
8654 /* A vbox to put a menu and a button in: */
8655 vbox = gtk_vbox_new(FALSE, 0);
8656 gtk_container_add(GTK_CONTAINER(window), vbox);
8657 gtk_widget_show(vbox);
8659 /* Create a menu-bar to hold the menus and add it to our main window */
8660 menu_bar = gtk_menu_bar_new();
8661 gtk_box_pack_start(GTK_BOX(vbox), menu_bar, FALSE, FALSE, 2);
8662 gtk_widget_show(menu_bar);
8664 /* Create a button to which to attach menu as a popup */
8665 button = gtk_button_new_with_label("press me");
8666 gtk_signal_connect_object(GTK_OBJECT(button), "event",
8667 GTK_SIGNAL_FUNC (button_press), GTK_OBJECT(menu));
8668 gtk_box_pack_end(GTK_BOX(vbox), button, TRUE, TRUE, 2);
8669 gtk_widget_show(button);
8671 /* And finally we append the menu-item to the menu-bar -- this is the
8672 * "root" menu-item I have been raving about =) */
8673 gtk_menu_bar_append(GTK_MENU_BAR (menu_bar), root_menu);
8675 /* always display the window as the last step so it all splashes on
8676 * the screen at once. */
8677 gtk_widget_show(window);
8684 /* Respond to a button-press by posting a menu passed in as widget.
8686 * Note that the "widget" argument is the menu being posted, NOT
8687 * the button that was pressed.
8690 static gint button_press (GtkWidget *widget, GdkEvent *event)
8693 if (event->type == GDK_BUTTON_PRESS) {
8694 GdkEventButton *bevent = (GdkEventButton *) event;
8695 gtk_menu_popup (GTK_MENU(widget), NULL, NULL, NULL, NULL,
8696 bevent->button, bevent->time);
8697 /* Tell calling code that we have handled this event; the buck
8702 /* Tell calling code that we have not handled this event; pass it on. */
8707 /* Print a string when a menu item is selected */
8709 static void menuitem_response (gchar *string)
8711 printf("%s\n", string);
8716 You may also set a menu item to be insensitive and, using an accelerator
8717 table, bind keys to menu functions.
8719 <!-- ----------------------------------------------------------------- -->
8720 <sect1>Using GtkItemFactory
8722 Now that we've shown you the hard way, here's how you do it using the
8723 gtk_item_factory calls.
8725 <!-- ----------------------------------------------------------------- -->
8726 <sect1>Item Factory Example
8728 Here is an example using the GTK item factory.
8731 /* example-start menu itemfactory.c */
8733 #include <gtk/gtk.h>
8734 #include <strings.h>
8736 /* Obligatory basic callback */
8737 static void print_hello(GtkWidget *w, gpointer data) {
8738 g_message("Hello, World!\n");
8741 /* This is the GtkItemFactoryEntry structure used to generate new menus.
8742 Item 1: The menu path. The letter after the underscore indicates an
8743 accelerator key once the menu is open.
8744 Item 2: The accelerator key for the entry
8745 Item 3: The callback function.
8746 Item 4: The callback action. This changes the parameters with
8747 which the function is called. The default is 0.
8748 Item 5: The item type, used to define what kind of an item it is.
8749 Here are the possible values:
8753 "<Title>" -> create a title item
8754 "<Item>" -> create a simple item
8755 "<CheckItem>" -> create a check item
8756 "<ToggleItem>" -> create a toggle item
8757 "<RadioItem>" -> create a radio item
8758 <path> -> path of a radio item to link against
8759 "<Separator>" -> create a separator
8760 "<Branch>" -> create an item to hold sub items
8761 "<LastBranch>" -> create a right justified branch
8764 static GtkItemFactoryEntry menu_items[] = {
8765 {"/_File", NULL, NULL, 0, "<Branch>"},
8766 {"/File/_New", "<control>N", print_hello, 0, NULL},
8767 {"/File/_Open", "<control>O", print_hello, 0, NULL},
8768 {"/File/_Save", "<control>S", print_hello, 0, NULL},
8769 {"/File/Save _As", NULL, NULL, 0, NULL},
8770 {"/File/sep1", NULL, NULL, 0, "<Separator>"},
8771 {"/File/Quit", "<control>Q", gtk_main_quit, 0, NULL},
8772 {"/_Options", NULL, NULL, 0, "<Branch>"},
8773 {"/Options/Test", NULL, NULL, 0, NULL},
8774 {"/_Help", NULL, NULL, 0, "<LastBranch>"},
8775 {"/_Help/About", NULL, NULL, 0, NULL},
8779 void get_main_menu(GtkWidget *window, GtkWidget ** menubar) {
8780 int nmenu_items = sizeof(menu_items) / sizeof(menu_items[0]);
8781 GtkItemFactory *item_factory;
8782 GtkAccelGroup *accel_group;
8784 accel_group = gtk_accel_group_new();
8786 /* This function initializes the item factory.
8787 Param 1: The type of menu - can be GTK_TYPE_MENU_BAR, GTK_TYPE_MENU,
8788 or GTK_TYPE_OPTION_MENU.
8789 Param 2: The path of the menu.
8790 Param 3: A pointer to a gtk_accel_group. The item factory sets up
8791 the accelerator table while generating menus.
8794 item_factory = gtk_item_factory_new(GTK_TYPE_MENU_BAR, "<main>",
8797 /* This function generates the menu items. Pass the item factory,
8798 the number of items in the array, the array itself, and any
8799 callback data for the the menu items. */
8800 gtk_item_factory_create_items(item_factory, nmenu_items, menu_items, NULL);
8802 /* Attach the new accelerator group to the window. */
8803 gtk_accel_group_attach (accel_group, GTK_OBJECT (window));
8806 /* Finally, return the actual menu bar created by the item factory. */
8807 *menubar = gtk_item_factory_get_widget(item_factory, "<main>");
8810 int main(int argc, char *argv[]) {
8812 GtkWidget *main_vbox;
8815 gtk_init(&argc, &argv);
8817 window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
8818 gtk_signal_connect(GTK_OBJECT(window), "destroy",
8819 GTK_SIGNAL_FUNC(gtk_main_quit),
8821 gtk_window_set_title(GTK_WINDOW(window), "Item Factory");
8822 gtk_widget_set_usize(GTK_WIDGET(window), 300, 200);
8824 main_vbox = gtk_vbox_new(FALSE, 1);
8825 gtk_container_border_width(GTK_CONTAINER(main_vbox), 1);
8826 gtk_container_add(GTK_CONTAINER(window), main_vbox);
8827 gtk_widget_show(main_vbox);
8829 get_main_menu(window, &menubar);
8830 gtk_box_pack_start(GTK_BOX(main_vbox), menubar, FALSE, TRUE, 0);
8831 gtk_widget_show(menubar);
8833 gtk_widget_show(window);
8842 For now, there's only this example. An explanation and lots 'o' comments
8845 <!-- ***************************************************************** -->
8847 <!-- ***************************************************************** -->
8849 The Text widget allows multiple lines of text to be displayed and
8850 edited. It supports both multi-colored and multi-font text, allowing
8851 them to be mixed in any way we wish. It also has a wide set of key
8852 based text editing commands, which are compatible with Emacs.
8854 The text widget supports full cut-and-paste facilities, including the
8855 use of double- and triple-click to select a word and a whole line,
8858 <!-- ----------------------------------------------------------------- -->
8859 <sect1>Creating and Configuring a Text box
8861 There is only one function for creating a new Text widget.
8864 GtkWidget *gtk_text_new( GtkAdjustment *hadj,
8865 GtkAdjustment *vadj );
8868 The arguments allow us to give the Text widget pointers to Adjustments
8869 that can be used to track the viewing position of the widget. Passing
8870 NULL values to either or both of these arguments will cause the
8871 gtk_text_new function to create its own.
8874 void gtk_text_set_adjustments( GtkText *text,
8875 GtkAdjustment *hadj,
8876 GtkAdjustment *vadj );
8879 The above function allows the horizontal and vertical adjustments of a
8880 text widget to be changed at any time.
8882 The text widget will not automatically create its own scrollbars when
8883 the amount of text to be displayed is too long for the display
8884 window. We therefore have to create and add them to the display layout
8888 vscrollbar = gtk_vscrollbar_new (GTK_TEXT(text)->vadj);
8889 gtk_box_pack_start(GTK_BOX(hbox), vscrollbar, FALSE, FALSE, 0);
8890 gtk_widget_show (vscrollbar);
8893 The above code snippet creates a new vertical scrollbar, and attaches
8894 it to the vertical adjustment of the text widget, <tt/text/. It then
8895 packs it into a box in the normal way.
8897 Note, currently the GtkText widget does not support horizontal
8900 There are two main ways in which a Text widget can be used: to allow
8901 the user to edit a body of text, or to allow us to display multiple
8902 lines of text to the user. In order for us to switch between these
8903 modes of operation, the text widget has the following function:
8906 void gtk_text_set_editable( GtkText *text,
8910 The <tt/editable/ argument is a TRUE or FALSE value that specifies
8911 whether the user is permitted to edit the contents of the Text
8912 widget. When the text widget is editable, it will display a cursor at
8913 the current insertion point.
8915 You are not, however, restricted to just using the text widget in
8916 these two modes. You can toggle the editable state of the text widget
8917 at any time, and can insert text at any time.
8919 The text widget wraps lines of text that are too long to fit onto a
8920 single line of the display window. Its default behaviour is to break
8921 words across line breaks. This can be changed using the next function:
8924 void gtk_text_set_word_wrap( GtkText *text,
8928 Using this function allows us to specify that the text widget should
8929 wrap long lines on word boundaries. The <tt/word_wrap/ argument is a
8930 TRUE or FALSE value.
8932 <!-- ----------------------------------------------------------------- -->
8933 <sect1>Text Manipulation
8935 The current insertion point of a Text widget can be set using
8937 void gtk_text_set_point( GtkText *text,
8941 where <tt/index/ is the position to set the insertion point.
8943 Analogous to this is the function for getting the current insertion
8947 guint gtk_text_get_point( GtkText *text );
8950 A function that is useful in combination with the above two functions
8954 guint gtk_text_get_length( GtkText *text );
8957 which returns the current length of the Text widget. The length is the
8958 number of characters that are within the text block of the widget,
8959 including characters such as carriage-return, which marks the end of
8962 In order to insert text at the current insertion point of a Text
8963 widget, the function gtk_text_insert is used, which also allows us to
8964 specify background and foreground colors and a font for the text.
8967 void gtk_text_insert( GtkText *text,
8975 Passing a value of <tt/NULL/ in as the value for the foreground color,
8976 background colour or font will result in the values set within the
8977 widget style to be used. Using a value of <tt/-1/ for the length
8978 parameter will result in the whole of the text string given being
8981 The text widget is one of the few within GTK that redraws itself
8982 dynamically, outside of the gtk_main function. This means that all
8983 changes to the contents of the text widget take effect
8984 immediately. This may be undesirable when performing multiple changes
8985 to the text widget. In order to allow us to perform multiple updates
8986 to the text widget without it continuously redrawing, we can freeze
8987 the widget, which temporarily stops it from automatically redrawing
8988 itself every time it is changed. We can then thaw the widget after our
8989 updates are complete.
8991 The following two functions perform this freeze and thaw action:
8994 void gtk_text_freeze( GtkText *text );
8996 void gtk_text_thaw( GtkText *text );
8999 Text is deleted from the text widget relative to the current insertion
9000 point by the following two functions. The return value is a TRUE or
9001 FALSE indicator of whether the operation was successful.
9004 gint gtk_text_backward_delete( GtkText *text,
9007 gint gtk_text_forward_delete ( GtkText *text,
9011 If you want to retrieve the contents of the text widget, then the
9012 macro <tt/GTK_TEXT_INDEX(t, index)/ allows you to retrieve the
9013 character at position <tt/index/ within the text widget <tt/t/.
9015 To retrieve larger blocks of text, we can use the function
9018 gchar *gtk_editable_get_chars( GtkEditable *editable,
9023 This is a function of the parent class of the text widget. A value of
9024 -1 as <tt/end_pos/ signifies the end of the text. The index of the
9027 The function allocates a new chunk of memory for the text block, so
9028 don't forget to free it with a call to g_free when you have finished
9031 <!-- ----------------------------------------------------------------- -->
9032 <sect1>Keyboard Shortcuts
9034 The text widget has a number of pre-installed keyboard shortcuts for
9035 common editing, motion and selection functions. These are accessed
9036 using Control and Alt key combinations.
9038 In addition to these, holding down the Control key whilst using cursor
9039 key movement will move the cursor by words rather than
9040 characters. Holding down Shift whilst using cursor movement will
9041 extend the selection.
9043 <sect2>Motion Shortcuts
9046 <item> Ctrl-A Beginning of line
9047 <item> Ctrl-E End of line
9048 <item> Ctrl-N Next Line
9049 <item> Ctrl-P Previous Line
9050 <item> Ctrl-B Backward one character
9051 <item> Ctrl-F Forward one character
9052 <item> Alt-B Backward one word
9053 <item> Alt-F Forward one word
9056 <sect2>Editing Shortcuts
9059 <item> Ctrl-H Delete Backward Character (Backspace)
9060 <item> Ctrl-D Delete Forward Character (Delete)
9061 <item> Ctrl-W Delete Backward Word
9062 <item> Alt-D Delete Forward Word
9063 <item> Ctrl-K Delete to end of line
9064 <item> Ctrl-U Delete line
9067 <sect2>Selection Shortcuts
9070 <item> Ctrl-X Cut to clipboard
9071 <item> Ctrl-C Copy to clipboard
9072 <item> Ctrl-V Paste from clipboard
9075 <!-- ----------------------------------------------------------------- -->
9076 <sect1>A GtkText Example
9079 /* example-start text text.c */
9084 #include <gtk/gtk.h>
9086 void text_toggle_editable (GtkWidget *checkbutton,
9089 gtk_text_set_editable(GTK_TEXT(text),
9090 GTK_TOGGLE_BUTTON(checkbutton)->active);
9093 void text_toggle_word_wrap (GtkWidget *checkbutton,
9096 gtk_text_set_word_wrap(GTK_TEXT(text),
9097 GTK_TOGGLE_BUTTON(checkbutton)->active);
9100 void close_application( GtkWidget *widget, gpointer data )
9105 int main (int argc, char *argv[])
9113 GtkWidget *separator;
9115 GtkWidget *vscrollbar;
9119 GdkFont *fixed_font;
9123 gtk_init (&argc, &argv);
9125 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
9126 gtk_widget_set_usize (window, 600, 500);
9127 gtk_window_set_policy (GTK_WINDOW(window), TRUE, TRUE, FALSE);
9128 gtk_signal_connect (GTK_OBJECT (window), "destroy",
9129 GTK_SIGNAL_FUNC(close_application),
9131 gtk_window_set_title (GTK_WINDOW (window), "Text Widget Example");
9132 gtk_container_set_border_width (GTK_CONTAINER (window), 0);
9135 box1 = gtk_vbox_new (FALSE, 0);
9136 gtk_container_add (GTK_CONTAINER (window), box1);
9137 gtk_widget_show (box1);
9140 box2 = gtk_vbox_new (FALSE, 10);
9141 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
9142 gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
9143 gtk_widget_show (box2);
9146 table = gtk_table_new (2, 2, FALSE);
9147 gtk_table_set_row_spacing (GTK_TABLE (table), 0, 2);
9148 gtk_table_set_col_spacing (GTK_TABLE (table), 0, 2);
9149 gtk_box_pack_start (GTK_BOX (box2), table, TRUE, TRUE, 0);
9150 gtk_widget_show (table);
9152 /* Create the GtkText widget */
9153 text = gtk_text_new (NULL, NULL);
9154 gtk_text_set_editable (GTK_TEXT (text), TRUE);
9155 gtk_table_attach (GTK_TABLE (table), text, 0, 1, 0, 1,
9156 GTK_EXPAND | GTK_SHRINK | GTK_FILL,
9157 GTK_EXPAND | GTK_SHRINK | GTK_FILL, 0, 0);
9158 gtk_widget_show (text);
9160 /* Add a vertical scrollbar to the GtkText widget */
9161 vscrollbar = gtk_vscrollbar_new (GTK_TEXT (text)->vadj);
9162 gtk_table_attach (GTK_TABLE (table), vscrollbar, 1, 2, 0, 1,
9163 GTK_FILL, GTK_EXPAND | GTK_SHRINK | GTK_FILL, 0, 0);
9164 gtk_widget_show (vscrollbar);
9166 /* Get the system colour map and allocate the colour red */
9167 cmap = gdk_colormap_get_system();
9168 colour.red = 0xffff;
9171 if (!gdk_color_alloc(cmap, &colour)) {
9172 g_error("couldn't allocate colour");
9175 /* Load a fixed font */
9176 fixed_font = gdk_font_load ("-misc-fixed-medium-r-*-*-*-140-*-*-*-*-*-*");
9178 /* Realizing a widget creates a window for it, ready for us to insert some text */
9179 gtk_widget_realize (text);
9181 /* Freeze the text widget, ready for multiple updates */
9182 gtk_text_freeze (GTK_TEXT (text));
9184 /* Insert some coloured text */
9185 gtk_text_insert (GTK_TEXT (text), NULL, &text->style->black, NULL,
9187 gtk_text_insert (GTK_TEXT (text), NULL, &colour, NULL,
9189 gtk_text_insert (GTK_TEXT (text), NULL, &text->style->black, NULL,
9190 "text and different ", -1);
9191 gtk_text_insert (GTK_TEXT (text), fixed_font, &text->style->black, NULL,
9194 /* Load the file text.c into the text window */
9196 infile = fopen("text.c", "r");
9204 nchars = fread(buffer, 1, 1024, infile);
9205 gtk_text_insert (GTK_TEXT (text), fixed_font, NULL,
9206 NULL, buffer, nchars);
9215 /* Thaw the text widget, allowing the updates to become visible */
9216 gtk_text_thaw (GTK_TEXT (text));
9218 hbox = gtk_hbutton_box_new ();
9219 gtk_box_pack_start (GTK_BOX (box2), hbox, FALSE, FALSE, 0);
9220 gtk_widget_show (hbox);
9222 check = gtk_check_button_new_with_label("Editable");
9223 gtk_box_pack_start (GTK_BOX (hbox), check, FALSE, FALSE, 0);
9224 gtk_signal_connect (GTK_OBJECT(check), "toggled",
9225 GTK_SIGNAL_FUNC(text_toggle_editable), text);
9226 gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(check), TRUE);
9227 gtk_widget_show (check);
9228 check = gtk_check_button_new_with_label("Wrap Words");
9229 gtk_box_pack_start (GTK_BOX (hbox), check, FALSE, TRUE, 0);
9230 gtk_signal_connect (GTK_OBJECT(check), "toggled",
9231 GTK_SIGNAL_FUNC(text_toggle_word_wrap), text);
9232 gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(check), FALSE);
9233 gtk_widget_show (check);
9235 separator = gtk_hseparator_new ();
9236 gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 0);
9237 gtk_widget_show (separator);
9239 box2 = gtk_vbox_new (FALSE, 10);
9240 gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
9241 gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, TRUE, 0);
9242 gtk_widget_show (box2);
9244 button = gtk_button_new_with_label ("close");
9245 gtk_signal_connect (GTK_OBJECT (button), "clicked",
9246 GTK_SIGNAL_FUNC(close_application),
9248 gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
9249 GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
9250 gtk_widget_grab_default (button);
9251 gtk_widget_show (button);
9253 gtk_widget_show (window);
9263 <!-- ***************************************************************** -->
9264 <sect> Undocumented Widgets
9265 <!-- ***************************************************************** -->
9267 These all require authors! :) Please consider contributing to our
9270 If you must use one of these widgets that are undocumented, I strongly
9271 suggest you take a look at their respective header files in the GTK
9272 distribution. GTK's function names are very descriptive. Once you
9273 have an understanding of how things work, it's not difficult to figure
9274 out how to use a widget simply by looking at its function
9275 declarations. This, along with a few examples from others' code, and
9276 it should be no problem.
9278 When you do come to understand all the functions of a new undocumented
9279 widget, please consider writing a tutorial on it so others may benefit
9282 <!-- ----------------------------------------------------------------- -->
9285 <!-- ----------------------------------------------------------------- -->
9288 <!-- ----------------------------------------------------------------- -->
9291 <!-- ----------------------------------------------------------------- -->
9294 <!-- ----------------------------------------------------------------- -->
9295 <sect1> Drawing Area
9297 <!-- ----------------------------------------------------------------- -->
9298 <sect1> Font Selection Dialog
9300 <!-- ----------------------------------------------------------------- -->
9303 <!-- ----------------------------------------------------------------- -->
9306 <!-- ----------------------------------------------------------------- -->
9309 <!-- ----------------------------------------------------------------- -->
9312 <!-- ----------------------------------------------------------------- -->
9313 <sect1> Plugs and Sockets
9315 <!-- ----------------------------------------------------------------- -->
9318 <!-- ----------------------------------------------------------------- -->
9324 (This may need to be rewritten to follow the style of the rest of the tutorial)
9328 Previews serve a number of purposes in GIMP/GTK. The most important one is
9329 this. High quality images may take up to tens of megabytes of memory - easy!
9330 Any operation on an image that big is bound to take a long time. If it takes
9331 you 5-10 trial-and-errors (i.e. 10-20 steps, since you have to revert after
9332 you make an error) to choose the desired modification, it make take you
9333 literally hours to make the right one - if you don't run out of memory
9334 first. People who have spent hours in color darkrooms know the feeling.
9335 Previews to the rescue!
9337 But the annoyance of the delay is not the only issue. Oftentimes it is
9338 helpful to compare the Before and After versions side-by-side or at least
9339 back-to-back. If you're working with big images and 10 second delays,
9340 obtaining the Before and After impressions is, to say the least, difficult.
9341 For 30M images (4"x6", 600dpi, 24 bit) the side-by-side comparison is right
9342 out for most people, while back-to-back is more like back-to-1001, 1002,
9343 ..., 1010-back! Previews to the rescue!
9345 But there's more. Previews allow for side-by-side pre-previews. In other
9346 words, you write a plug-in (e.g. the filterpack simulation) which would have
9347 a number of here's-what-it-would-look-like-if-you-were-to-do-this previews.
9348 An approach like this acts as a sort of a preview palette and is very
9349 effective for subtle changes. Let's go previews!
9351 There's more. For certain plug-ins real-time image-specific human
9352 intervention maybe necessary. In the SuperNova plug-in, for example, the
9353 user is asked to enter the coordinates of the center of the future
9354 supernova. The easiest way to do this, really, is to present the user with a
9355 preview and ask him to interactively select the spot. Let's go previews!
9357 Finally, a couple of misc uses. One can use previews even when not working
9358 with big images. For example, they are useful when rendering complicated
9359 patterns. (Just check out the venerable Diffraction plug-in + many other
9360 ones!) As another example, take a look at the colormap rotation plug-in
9361 (work in progress). You can also use previews for little logos inside you
9362 plug-ins and even for an image of yourself, The Author. Let's go previews!
9364 When Not to Use Previews
9366 Don't use previews for graphs, drawing etc. GDK is much faster for that. Use
9367 previews only for rendered images!
9371 You can stick a preview into just about anything. In a vbox, an hbox, a
9372 table, a button, etc. But they look their best in tight frames around them.
9373 Previews by themselves do not have borders and look flat without them. (Of
9374 course, if the flat look is what you want...) Tight frames provide the
9379 Previews in many ways are like any other widgets in GTK (whatever that
9380 means) except they possess an additional feature: they need to be filled with
9381 some sort of an image! First, we will deal exclusively with the GTK aspect
9382 of previews and then we'll discuss how to fill them.
9388 /* Create a preview widget,
9389 set its size, an show it */
9391 preview=gtk_preview_new(GTK_PREVIEW_COLOR)
9393 GTK_PREVIEW_GRAYSCALE);*/
9394 gtk_preview_size (GTK_PREVIEW (preview), WIDTH, HEIGHT);
9395 gtk_widget_show(preview);
9396 my_preview_rendering_function(preview);
9398 Oh yeah, like I said, previews look good inside frames, so how about:
9400 GtkWidget *create_a_preview(int Width,
9407 frame = gtk_frame_new(NULL);
9408 gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
9409 gtk_container_set_border_width (GTK_CONTAINER(frame),0);
9410 gtk_widget_show(frame);
9412 preview=gtk_preview_new (Colorfulness?GTK_PREVIEW_COLOR
9413 :GTK_PREVIEW_GRAYSCALE);
9414 gtk_preview_size (GTK_PREVIEW (preview), Width, Height);
9415 gtk_container_add(GTK_CONTAINER(frame),preview);
9416 gtk_widget_show(preview);
9418 my_preview_rendering_function(preview);
9422 That's my basic preview. This routine returns the "parent" frame so you can
9423 place it somewhere else in your interface. Of course, you can pass the
9424 parent frame to this routine as a parameter. In many situations, however,
9425 the contents of the preview are changed continually by your application. In
9426 this case you may want to pass a pointer to the preview to a
9427 "create_a_preview()" and thus have control of it later.
9429 One more important note that may one day save you a lot of time. Sometimes
9430 it is desirable to label you preview. For example, you may label the preview
9431 containing the original image as "Original" and the one containing the
9432 modified image as "Less Original". It might occur to you to pack the
9433 preview along with the appropriate label into a vbox. The unexpected caveat
9434 is that if the label is wider than the preview (which may happen for a
9435 variety of reasons unforseeable to you, from the dynamic decision on the
9436 size of the preview to the size of the font) the frame expands and no longer
9437 fits tightly over the preview. The same problem can probably arise in other
9442 The solution is to place the preview and the label into a 2x1 table and by
9443 attaching them with the following parameters (this is one possible variations
9444 of course. The key is no GTK_FILL in the second attachment):
9446 gtk_table_attach(GTK_TABLE(table),label,0,1,0,1,
9448 GTK_EXPAND|GTK_FILL,
9450 gtk_table_attach(GTK_TABLE(table),frame,0,1,1,2,
9456 And here's the result:
9462 Making a preview clickable is achieved most easily by placing it in a
9463 button. It also adds a nice border around the preview and you may not even
9464 need to place it in a frame. See the Filter Pack Simulation plug-in for an
9467 This is pretty much it as far as GTK is concerned.
9469 Filling In a Preview
9471 In order to familiarize ourselves with the basics of filling in previews,
9472 let's create the following pattern (contrived by trial and error):
9477 my_preview_rendering_function(GtkWidget *preview)
9480 #define HALF (SIZE/2)
9482 guchar *row=(guchar *) malloc(3*SIZE); /* 3 bits per dot */
9483 gint i, j; /* Coordinates */
9484 double r, alpha, x, y;
9486 if (preview==NULL) return; /* I usually add this when I want */
9487 /* to avoid silly crashes. You */
9488 /* should probably make sure that */
9489 /* everything has been nicely */
9491 for (j=0; j < ABS(cos(2*alpha)) ) { /* Are we inside the shape? */
9492 /* glib.h contains ABS(x). */
9493 row[i*3+0] = sqrt(1-r)*255; /* Define Red */
9494 row[i*3+1] = 128; /* Define Green */
9495 row[i*3+2] = 224; /* Define Blue */
9496 } /* "+0" is for alignment! */
9499 row[i*3+1] = ABS(sin((float)i/SIZE*2*PI))*255;
9500 row[i*3+2] = ABS(sin((float)j/SIZE*2*PI))*255;
9503 gtk_preview_draw_row( GTK_PREVIEW(preview),row,0,j,SIZE);
9504 /* Insert "row" into "preview" starting at the point with */
9505 /* coordinates (0,j) first column, j_th row extending SIZE */
9506 /* pixels to the right */
9509 free(row); /* save some space */
9510 gtk_widget_draw(preview,NULL); /* what does this do? */
9511 gdk_flush(); /* or this? */
9514 Non-GIMP users can have probably seen enough to do a lot of things already.
9515 For the GIMP users I have a few pointers to add.
9519 It is probably wise to keep a reduced version of the image around with just
9520 enough pixels to fill the preview. This is done by selecting every n'th
9521 pixel where n is the ratio of the size of the image to the size of the
9522 preview. All further operations (including filling in the previews) are then
9523 performed on the reduced number of pixels only. The following is my
9524 implementation of reducing the image. (Keep in mind that I've had only basic
9527 (UNTESTED CODE ALERT!!!)
9539 SELECTION_IN_CONTEXT,
9543 ReducedImage *Reduce_The_Image(GDrawable *drawable,
9548 /* This function reduced the image down to the the selected preview size */
9549 /* The preview size is determine by LongerSize, i.e. the greater of the */
9550 /* two dimensions. Works for RGB images only! */
9551 gint RH, RW; /* Reduced height and reduced width */
9552 gint width, height; /* Width and Height of the area being reduced */
9553 gint bytes=drawable->bpp;
9554 ReducedImage *temp=(ReducedImage *)malloc(sizeof(ReducedImage));
9556 guchar *tempRGB, *src_row, *tempmask, *src_mask_row,R,G,B;
9557 gint i, j, whichcol, whichrow, x1, x2, y1, y2;
9558 GPixelRgn srcPR, srcMask;
9559 gint NoSelectionMade=TRUE; /* Assume that we're dealing with the entire */
9562 gimp_drawable_mask_bounds (drawable->id, &x1, &y1, &x2, &y2);
9565 /* If there's a SELECTION, we got its bounds!)
9567 if (width != drawable->width && height != drawable->height)
9568 NoSelectionMade=FALSE;
9569 /* Become aware of whether the user has made an active selection */
9570 /* This will become important later, when creating a reduced mask. */
9572 /* If we want to preview the entire image, overrule the above! */
9573 /* Of course, if no selection has been made, this does nothing! */
9574 if (Selection==ENTIRE_IMAGE) {
9578 y2=drawable->height;
9581 /* If we want to preview a selection with some surrounding area we */
9582 /* have to expand it a little bit. Consider it a bit of a riddle. */
9583 if (Selection==SELECTION_IN_CONTEXT) {
9584 x1=MAX(0, x1-width/2.0);
9585 x2=MIN(drawable->width, x2+width/2.0);
9586 y1=MAX(0, y1-height/2.0);
9587 y2=MIN(drawable->height, y2+height/2.0);
9590 /* How we can determine the width and the height of the area being */
9595 /* The lines below determine which dimension is to be the longer */
9596 /* side. The idea borrowed from the supernova plug-in. I suspect I */
9597 /* could've thought of it myself, but the truth must be told. */
9598 /* Plagiarism stinks! */
9601 RH=(float) height * (float) LongerSize/ (float) width;
9605 RW=(float)width * (float) LongerSize/ (float) height;
9608 /* The entire image is stretched into a string! */
9609 tempRGB = (guchar *) malloc(RW*RH*bytes);
9610 tempmask = (guchar *) malloc(RW*RH);
9612 gimp_pixel_rgn_init (&srcPR, drawable, x1, y1, width, height, FALSE, FALSE);
9613 gimp_pixel_rgn_init (&srcMask, mask, x1, y1, width, height, FALSE, FALSE);
9615 /* Grab enough to save a row of image and a row of mask. */
9616 src_row = (guchar *) malloc (width*bytes);
9617 src_mask_row = (guchar *) malloc (width);
9619 for (i=0; i < RH; i++) {
9620 whichrow=(float)i*(float)height/(float)RH;
9621 gimp_pixel_rgn_get_row (&srcPR, src_row, x1, y1+whichrow, width);
9622 gimp_pixel_rgn_get_row (&srcMask, src_mask_row, x1, y1+whichrow, width);
9624 for (j=0; j < RW; j++) {
9625 whichcol=(float)j*(float)width/(float)RW;
9627 /* No selection made = each point is completely selected! */
9628 if (NoSelectionMade)
9629 tempmask[i*RW+j]=255;
9631 tempmask[i*RW+j]=src_mask_row[whichcol];
9633 /* Add the row to the one long string which now contains the image! */
9634 tempRGB[i*RW*bytes+j*bytes+0]=src_row[whichcol*bytes+0];
9635 tempRGB[i*RW*bytes+j*bytes+1]=src_row[whichcol*bytes+1];
9636 tempRGB[i*RW*bytes+j*bytes+2]=src_row[whichcol*bytes+2];
9638 /* Hold on to the alpha as well */
9640 tempRGB[i*RW*bytes+j*bytes+3]=src_row[whichcol*bytes+3];
9647 temp->mask=tempmask;
9651 The following is a preview function which used the same ReducedImage type!
9652 Note that it uses fakes transparency (if one is present by means of
9653 fake_transparency which is defined as follows:
9655 gint fake_transparency(gint i, gint j)
9657 if ( ((i%20)- 10) * ((j%20)- 10)>0 )
9663 Now here's the preview function:
9666 my_preview_render_function(GtkWidget *preview,
9670 gint Inten, bytes=drawable->bpp;
9673 gint RW=reduced->width;
9674 gint RH=reduced->height;
9675 guchar *row=malloc(bytes*RW);;
9678 for (i=0; i < RH; i++) {
9679 for (j=0; j < RW; j++) {
9681 row[j*3+0] = reduced->rgb[i*RW*bytes + j*bytes + 0];
9682 row[j*3+1] = reduced->rgb[i*RW*bytes + j*bytes + 1];
9683 row[j*3+2] = reduced->rgb[i*RW*bytes + j*bytes + 2];
9686 for (k=0; k<3; k++) {
9687 float transp=reduced->rgb[i*RW*bytes+j*bytes+3]/255.0;
9688 row[3*j+k]=transp*a[3*j+k]+(1-transp)*fake_transparency(i,j);
9691 gtk_preview_draw_row( GTK_PREVIEW(preview),row,0,i,RW);
9695 gtk_widget_draw(preview,NULL);
9701 guint gtk_preview_get_type (void);
9703 void gtk_preview_uninit (void);
9705 GtkWidget* gtk_preview_new (GtkPreviewType type);
9706 /* Described above */
9707 void gtk_preview_size (GtkPreview *preview,
9710 /* Allows you to resize an existing preview. */
9711 /* Apparently there's a bug in GTK which makes */
9712 /* this process messy. A way to clean up a mess */
9713 /* is to manually resize the window containing */
9714 /* the preview after resizing the preview. */
9716 void gtk_preview_put (GtkPreview *preview,
9727 void gtk_preview_put_row (GtkPreview *preview,
9735 void gtk_preview_draw_row (GtkPreview *preview,
9740 /* Described in the text */
9742 void gtk_preview_set_expand (GtkPreview *preview,
9746 /* No clue for any of the below but */
9747 /* should be standard for most widgets */
9748 void gtk_preview_set_gamma (double gamma);
9749 void gtk_preview_set_color_cube (guint nred_shades,
9750 guint ngreen_shades,
9752 guint ngray_shades);
9753 void gtk_preview_set_install_cmap (gint install_cmap);
9754 void gtk_preview_set_reserved (gint nreserved);
9755 GdkVisual* gtk_preview_get_visual (void);
9756 GdkColormap* gtk_preview_get_cmap (void);
9757 GtkPreviewInfo* gtk_preview_get_info (void);
9765 <!-- ***************************************************************** -->
9766 <sect>Setting Widget Attributes<label id="sec_setting_widget_attributes">
9767 <!-- ***************************************************************** -->
9769 This describes the functions used to operate on widgets. These can be
9770 used to set style, padding, size etc.
9772 (Maybe I should make a whole section on accelerators.)
9775 void gtk_widget_install_accelerator( GtkWidget *widget,
9776 GtkAcceleratorTable *table,
9781 void gtk_widget_remove_accelerator ( GtkWidget *widget,
9782 GtkAcceleratorTable *table,
9783 gchar *signal_name);
9785 void gtk_widget_activate( GtkWidget *widget );
9787 void gtk_widget_set_name( GtkWidget *widget,
9790 gchar *gtk_widget_get_name( GtkWidget *widget );
9792 void gtk_widget_set_sensitive( GtkWidget *widget,
9795 void gtk_widget_set_style( GtkWidget *widget,
9798 GtkStyle *gtk_widget_get_style( GtkWidget *widget );
9800 GtkStyle *gtk_widget_get_default_style( void );
9802 void gtk_widget_set_uposition( GtkWidget *widget,
9806 void gtk_widget_set_usize( GtkWidget *widget,
9810 void gtk_widget_grab_focus( GtkWidget *widget );
9812 void gtk_widget_show( GtkWidget *widget );
9814 void gtk_widget_hide( GtkWidget *widget );
9817 <!-- ***************************************************************** -->
9818 <sect>Timeouts, IO and Idle Functions<label id="sec_timeouts">
9819 <!-- ***************************************************************** -->
9821 <!-- ----------------------------------------------------------------- -->
9824 You may be wondering how you make GTK do useful work when in gtk_main.
9825 Well, you have several options. Using the following functions you can
9826 create a timeout function that will be called every "interval"
9830 gint gtk_timeout_add( guint32 interval,
9831 GtkFunction function,
9835 The first argument is the number of milliseconds between calls to your
9836 function. The second argument is the function you wish to have called,
9837 and the third, the data passed to this callback function. The return
9838 value is an integer "tag" which may be used to stop the timeout by
9842 void gtk_timeout_remove( gint tag );
9845 You may also stop the timeout function by returning zero or FALSE from
9846 your callback function. Obviously this means if you want your function
9847 to continue to be called, it should return a non-zero value,
9850 The declaration of your callback should look something like this:
9853 gint timeout_callback( gpointer data );
9856 <!-- ----------------------------------------------------------------- -->
9857 <sect1>Monitoring IO
9859 A nifty feature of GDK (the library that underlies GTK), is the
9860 ability to have it check for data on a file descriptor for you (as
9861 returned by open(2) or socket(2)). This is especially useful for
9862 networking applications. The function:
9865 gint gdk_input_add( gint source,
9866 GdkInputCondition condition,
9867 GdkInputFunction function,
9871 Where the first argument is the file descriptor you wish to have
9872 watched, and the second specifies what you want GDK to look for. This
9876 <item>GDK_INPUT_READ - Call your function when there is data ready for
9877 reading on your file descriptor.
9879 <item>GDK_INPUT_WRITE - Call your function when the file descriptor is
9883 As I'm sure you've figured out already, the third argument is the
9884 function you wish to have called when the above conditions are
9885 satisfied, and the fourth is the data to pass to this function.
9887 The return value is a tag that may be used to stop GDK from monitoring
9888 this file descriptor using the following function.
9891 void gdk_input_remove( gint tag );
9894 The callback function should be declared as:
9897 void input_callback( gpointer data,
9899 GdkInputCondition condition );
9902 Where <tt/source/ and <tt/condition/ are as specified above.
9904 <!-- ----------------------------------------------------------------- -->
9905 <sect1>Idle Functions
9907 <!-- TODO: Need to check on idle priorities - TRG -->
9908 What if you have a function you want called when nothing else is
9912 gint gtk_idle_add( GtkFunction function,
9916 This causes GTK to call the specified function whenever nothing else
9920 void gtk_idle_remove( gint tag );
9923 I won't explain the meaning of the arguments as they follow very much
9924 like the ones above. The function pointed to by the first argument to
9925 gtk_idle_add will be called whenever the opportunity arises. As with
9926 the others, returning FALSE will stop the idle function from being
9929 <!-- ***************************************************************** -->
9930 <sect>Advanced Event and Signal Handling<label id="sec_Adv_Events_and_Signals">
9931 <!-- ***************************************************************** -->
9933 <!-- ----------------------------------------------------------------- -->
9934 <sect1>Signal Functions
9936 <!-- ----------------------------------------------------------------- -->
9937 <sect2>Connecting and Disconnecting Signal Handlers
9941 guint gtk_signal_connect( GtkObject *object,
9944 gpointer func_data );
9946 guint gtk_signal_connect_after( GtkObject *object,
9949 gpointer func_data );
9951 guint gtk_signal_connect_object( GtkObject *object,
9954 GtkObject *slot_object );
9956 guint gtk_signal_connect_object_after( GtkObject *object,
9959 GtkObject *slot_object );
9961 guint gtk_signal_connect_full( GtkObject *object,
9964 GtkCallbackMarshal marshal,
9966 GtkDestroyNotify destroy_func,
9970 guint gtk_signal_connect_interp( GtkObject *object,
9972 GtkCallbackMarshal func,
9974 GtkDestroyNotify destroy_func,
9977 void gtk_signal_connect_object_while_alive( GtkObject *object,
9978 const gchar *signal,
9980 GtkObject *alive_object );
9982 void gtk_signal_connect_while_alive( GtkObject *object,
9983 const gchar *signal,
9986 GtkObject *alive_object );
9988 void gtk_signal_disconnect( GtkObject *object,
9991 void gtk_signal_disconnect_by_func( GtkObject *object,
9996 <!-- ----------------------------------------------------------------- -->
9997 <sect2>Blocking and Unblocking Signal Handlers
10000 void gtk_signal_handler_block( GtkObject *object,
10003 void gtk_signal_handler_block_by_func( GtkObject *object,
10004 GtkSignalFunc func,
10007 void gtk_signal_handler_block_by_data( GtkObject *object,
10010 void gtk_signal_handler_unblock( GtkObject *object,
10011 guint handler_id );
10013 void gtk_signal_handler_unblock_by_func( GtkObject *object,
10014 GtkSignalFunc func,
10017 void gtk_signal_handler_unblock_by_data( GtkObject *object,
10021 <!-- ----------------------------------------------------------------- -->
10022 <sect2>Emitting and Stopping Signals
10025 void gtk_signal_emit( GtkObject *object,
10029 void gtk_signal_emit_by_name( GtkObject *object,
10033 void gtk_signal_emitv( GtkObject *object,
10037 void gtk_signal_emitv_by_name( GtkObject *object,
10041 guint gtk_signal_n_emissions( GtkObject *object,
10044 guint gtk_signal_n_emissions_by_name( GtkObject *object,
10045 const gchar *name );
10047 void gtk_signal_emit_stop( GtkObject *object,
10050 void gtk_signal_emit_stop_by_name( GtkObject *object,
10051 const gchar *name );
10054 <!-- ----------------------------------------------------------------- -->
10055 <sect1>Signal Emission and Propagation
10057 Signal emission is the process wherby GTK runs all handlers for a
10058 specific object and signal.
10060 First, note that the return value from a signal emission is the return
10061 value of the <em>last</em> handler executed. Since event signals are
10062 all of type GTK_RUN_LAST, this will be the default (GTK supplied)
10063 default handler, unless you connect with gtk_signal_connect_after().
10065 The way an event (say GTK_BUTTON_PRESS) is handled, is:
10067 <item>Start with the widget where the event occured.
10069 <item>Emit the generic "event" signal. If that signal handler returns
10070 a value of TRUE, stop all processing.
10072 <item>Otherwise, emit a specific, "button_press_event" signal. If that
10073 returns TRUE, stop all processing.
10075 <item>Otherwise, go to the widget's parent, and repeat the above steps.
10077 <item>Contimue until some signal handler returns TRUE, or until the
10078 top-level widget is reached.
10081 Some consequences of the above are:
10083 <item>Your handler's return value will have no effect if there is a
10084 default handler, unless you connect with gtk_signal_connect_after().
10086 <item>To prevent the default handler from being run, you need to
10087 connect with gtk_signal_connect() and use
10088 gtk_signal_emit_stop_by_name() - the return value only affects whether
10089 the signal is propagated, not the current emission.
10092 <!-- ***************************************************************** -->
10093 <sect>Managing Selections
10094 <!-- ***************************************************************** -->
10096 <!-- ----------------------------------------------------------------- -->
10099 One type of interprocess communication supported by GTK is
10100 <em>selections</em>. A selection identifies a chunk of data, for
10101 instance, a portion of text, selected by the user in some fashion, for
10102 instance, by dragging with the mouse. Only one application on a
10103 display, (the <em>owner</em>) can own a particular selection at one
10104 time, so when a selection is claimed by one application, the previous
10105 owner must indicate to the user that selection has been
10106 relinquished. Other applications can request the contents of a
10107 selection in different forms, called <em>targets</em>. There can be
10108 any number of selections, but most X applications only handle one, the
10109 <em>primary selection</em>.
10111 In most cases, it isn't necessary for a GTK application to deal with
10112 selections itself. The standard widgets, such as the Entry widget,
10113 already have the capability to claim the selection when appropriate
10114 (e.g., when the user drags over text), and to retrieve the contents of
10115 the selection owned by another widget, or another application (e.g.,
10116 when the user clicks the second mouse button). However, there may be
10117 cases in which you want to give other widgets the ability to supply
10118 the selection, or you wish to retrieve targets not supported by
10121 A fundamental concept needed to understand selection handling is that
10122 of the <em>atom</em>. An atom is an integer that uniquely identifies a
10123 string (on a certain display). Certain atoms are predefined by the X
10124 server, and in some cases there are constants in <tt>gtk.h</tt>
10125 corresponding to these atoms. For instance the constant
10126 <tt>GDK_PRIMARY_SELECTION</tt> corresponds to the string "PRIMARY".
10127 In other cases, you should use the functions
10128 <tt>gdk_atom_intern()</tt>, to get the atom corresponding to a string,
10129 and <tt>gdk_atom_name()</tt>, to get the name of an atom. Both
10130 selections and targets are identified by atoms.
10132 <!-- ----------------------------------------------------------------- -->
10133 <sect1> Retrieving the selection
10135 Retrieving the selection is an asynchronous process. To start the
10139 gint gtk_selection_convert( GtkWidget *widget,
10145 This <em>converts</em> the selection into the form specified by
10146 <tt/target/. If at all possible, the time field should be the time
10147 from the event that triggered the selection. This helps make sure that
10148 events occur in the order that the user requested them. However, if it
10149 is not available (for instance, if the conversion was triggered by a
10150 "clicked" signal), then you can use the constant
10151 <tt>GDK_CURRENT_TIME</tt>.
10153 When the selection owner responds to the request, a
10154 "selection_received" signal is sent to your application. The handler
10155 for this signal receives a pointer to a <tt>GtkSelectionData</tt>
10156 structure, which is defined as:
10159 struct _GtkSelectionData
10170 <tt>selection</tt> and <tt>target</tt> are the values you gave in your
10171 <tt>gtk_selection_convert()</tt> call. <tt>type</tt> is an atom that
10172 identifies the type of data returned by the selection owner. Some
10173 possible values are "STRING", a string of latin-1 characters, "ATOM",
10174 a series of atoms, "INTEGER", an integer, etc. Most targets can only
10175 return one type. <tt/format/ gives the length of the units (for
10176 instance characters) in bits. Usually, you don't care about this when
10177 receiving data. <tt>data</tt> is a pointer to the returned data, and
10178 <tt>length</tt> gives the length of the returned data, in bytes. If
10179 <tt>length</tt> is negative, then an error occurred and the selection
10180 could not be retrieved. This might happen if no application owned the
10181 selection, or if you requested a target that the application didn't
10182 support. The buffer is actually guaranteed to be one byte longer than
10183 <tt>length</tt>; the extra byte will always be zero, so it isn't
10184 necessary to make a copy of strings just to null terminate them.
10186 In the following example, we retrieve the special target "TARGETS",
10187 which is a list of all targets into which the selection can be
10191 /* example-start selection gettargets.c */
10193 #include <gtk/gtk.h>
10195 void selection_received (GtkWidget *widget,
10196 GtkSelectionData *selection_data,
10199 /* Signal handler invoked when user clicks on the "Get Targets" button */
10201 get_targets (GtkWidget *widget, gpointer data)
10203 static GdkAtom targets_atom = GDK_NONE;
10205 /* Get the atom corresponding to the string "TARGETS" */
10206 if (targets_atom == GDK_NONE)
10207 targets_atom = gdk_atom_intern ("TARGETS", FALSE);
10209 /* And request the "TARGETS" target for the primary selection */
10210 gtk_selection_convert (widget, GDK_SELECTION_PRIMARY, targets_atom,
10214 /* Signal handler called when the selections owner returns the data */
10216 selection_received (GtkWidget *widget, GtkSelectionData *selection_data,
10223 /* **** IMPORTANT **** Check to see if retrieval succeeded */
10224 if (selection_data->length < 0)
10226 g_print ("Selection retrieval failed\n");
10229 /* Make sure we got the data in the expected form */
10230 if (selection_data->type != GDK_SELECTION_TYPE_ATOM)
10232 g_print ("Selection \"TARGETS\" was not returned as atoms!\n");
10236 /* Print out the atoms we received */
10237 atoms = (GdkAtom *)selection_data->data;
10240 for (i=0; i<selection_data->length/sizeof(GdkAtom); i++)
10243 name = gdk_atom_name (atoms[i]);
10245 g_print ("%s\n",name);
10247 g_print ("(bad atom)\n");
10254 main (int argc, char *argv[])
10259 gtk_init (&argc, &argv);
10261 /* Create the toplevel window */
10263 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
10264 gtk_window_set_title (GTK_WINDOW (window), "Event Box");
10265 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
10267 gtk_signal_connect (GTK_OBJECT (window), "destroy",
10268 GTK_SIGNAL_FUNC (gtk_exit), NULL);
10270 /* Create a button the user can click to get targets */
10272 button = gtk_button_new_with_label ("Get Targets");
10273 gtk_container_add (GTK_CONTAINER (window), button);
10275 gtk_signal_connect (GTK_OBJECT(button), "clicked",
10276 GTK_SIGNAL_FUNC (get_targets), NULL);
10277 gtk_signal_connect (GTK_OBJECT(button), "selection_received",
10278 GTK_SIGNAL_FUNC (selection_received), NULL);
10280 gtk_widget_show (button);
10281 gtk_widget_show (window);
10290 <!-- ----------------------------------------------------------------- -->
10291 <sect1> Supplying the selection
10293 Supplying the selection is a bit more complicated. You must register
10294 handlers that will be called when your selection is requested. For
10295 each selection/target pair you will handle, you make a call to:
10298 void gtk_selection_add_handler( GtkWidget *widget,
10301 GtkSelectionFunction function,
10302 GtkRemoveFunction remove_func,
10306 <tt/widget/, <tt/selection/, and <tt/target/ identify the requests
10307 this handler will manage. <tt/remove_func/, if not
10308 NULL, will be called when the signal handler is removed. This is
10309 useful, for instance, for interpreted languages which need to
10310 keep track of a reference count for <tt/data/.
10312 The callback function has the signature:
10315 typedef void (*GtkSelectionFunction)( GtkWidget *widget,
10316 GtkSelectionData *selection_data,
10321 The GtkSelectionData is the same as above, but this time, we're
10322 responsible for filling in the fields <tt/type/, <tt/format/,
10323 <tt/data/, and <tt/length/. (The <tt/format/ field is actually
10324 important here - the X server uses it to figure out whether the data
10325 needs to be byte-swapped or not. Usually it will be 8 - <em/i.e./ a
10326 character - or 32 - <em/i.e./ a. integer.) This is done by calling the
10330 void gtk_selection_data_set( GtkSelectionData *selection_data,
10337 This function takes care of properly making a copy of the data so that
10338 you don't have to worry about keeping it around. (You should not fill
10339 in the fields of the GtkSelectionData structure by hand.)
10341 When prompted by the user, you claim ownership of the selection by
10345 gint gtk_selection_owner_set( GtkWidget *widget,
10350 If another application claims ownership of the selection, you will
10351 receive a "selection_clear_event".
10353 As an example of supplying the selection, the following program adds
10354 selection functionality to a toggle button. When the toggle button is
10355 depressed, the program claims the primary selection. The only target
10356 supported (aside from certain targets like "TARGETS" supplied by GTK
10357 itself), is the "STRING" target. When this target is requested, a
10358 string representation of the time is returned.
10361 /* example-start selection setselection.c */
10363 #include <gtk/gtk.h>
10366 /* Callback when the user toggles the selection */
10368 selection_toggled (GtkWidget *widget, gint *have_selection)
10370 if (GTK_TOGGLE_BUTTON(widget)->active)
10372 *have_selection = gtk_selection_owner_set (widget,
10373 GDK_SELECTION_PRIMARY,
10375 /* if claiming the selection failed, we return the button to
10377 if (!*have_selection)
10378 gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON(widget), FALSE);
10382 if (*have_selection)
10384 /* Before clearing the selection by setting the owner to NULL,
10385 we check if we are the actual owner */
10386 if (gdk_selection_owner_get (GDK_SELECTION_PRIMARY) == widget->window)
10387 gtk_selection_owner_set (NULL, GDK_SELECTION_PRIMARY,
10389 *have_selection = FALSE;
10394 /* Called when another application claims the selection */
10396 selection_clear (GtkWidget *widget, GdkEventSelection *event,
10397 gint *have_selection)
10399 *have_selection = FALSE;
10400 gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON(widget), FALSE);
10405 /* Supplies the current time as the selection. */
10407 selection_handle (GtkWidget *widget,
10408 GtkSelectionData *selection_data,
10412 time_t current_time;
10414 current_time = time (NULL);
10415 timestr = asctime (localtime(&current_time));
10416 /* When we return a single string, it should not be null terminated.
10417 That will be done for us */
10419 gtk_selection_data_set (selection_data, GDK_SELECTION_TYPE_STRING,
10420 8, timestr, strlen(timestr));
10424 main (int argc, char *argv[])
10428 GtkWidget *selection_button;
10430 static int have_selection = FALSE;
10432 gtk_init (&argc, &argv);
10434 /* Create the toplevel window */
10436 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
10437 gtk_window_set_title (GTK_WINDOW (window), "Event Box");
10438 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
10440 gtk_signal_connect (GTK_OBJECT (window), "destroy",
10441 GTK_SIGNAL_FUNC (gtk_exit), NULL);
10443 /* Create a toggle button to act as the selection */
10445 selection_button = gtk_toggle_button_new_with_label ("Claim Selection");
10446 gtk_container_add (GTK_CONTAINER (window), selection_button);
10447 gtk_widget_show (selection_button);
10449 gtk_signal_connect (GTK_OBJECT(selection_button), "toggled",
10450 GTK_SIGNAL_FUNC (selection_toggled), &have_selection);
10451 gtk_signal_connect (GTK_OBJECT(selection_button), "selection_clear_event",
10452 GTK_SIGNAL_FUNC (selection_clear), &have_selection);
10454 gtk_selection_add_handler (selection_button, GDK_SELECTION_PRIMARY,
10455 GDK_SELECTION_TYPE_STRING,
10456 selection_handle, NULL);
10458 gtk_widget_show (selection_button);
10459 gtk_widget_show (window);
10469 <!-- ***************************************************************** -->
10470 <sect>glib<label id="sec_glib">
10471 <!-- ***************************************************************** -->
10473 glib provides many useful functions and definitions available for use
10474 when creating GDK and GTK applications. I will list them all here with
10475 a brief explanation. Many are duplicates of standard libc functions so
10476 I won't go into detail on those. This is mostly to be used as a reference,
10477 so you know what is available for use.
10479 <!-- ----------------------------------------------------------------- -->
10482 Definitions for the extremes of many of the standard types are:
10497 Also, the following typedefs. The ones left unspecified are dynamically set
10498 depending on the architecture. Remember to avoid counting on the size of a
10499 pointer if you want to be portable! E.g., a pointer on an Alpha is 8 bytes, but 4
10509 unsigned char guchar;
10510 unsigned short gushort;
10511 unsigned long gulong;
10512 unsigned int guint;
10516 long double gldouble;
10528 <!-- ----------------------------------------------------------------- -->
10529 <sect1>Doubly Linked Lists
10531 The following functions are used to create, manage, and destroy doubly
10532 linked lists. I assume you know what linked lists are, as it is beyond the scope
10533 of this document to explain them. Of course, it's not required that you
10534 know these for general use of GTK, but they are nice to know.
10537 GList *g_list_alloc( void );
10539 void g_list_free( GList *list );
10541 void g_list_free_1( GList *list );
10543 GList *g_list_append( GList *list,
10546 GList *g_list_prepend( GList *list,
10549 GList *g_list_insert( GList *list,
10553 GList *g_list_remove( GList *list,
10556 GList *g_list_remove_link( GList *list,
10559 GList *g_list_reverse( GList *list );
10561 GList *g_list_nth( GList *list,
10564 GList *g_list_find( GList *list,
10567 GList *g_list_last( GList *list );
10569 GList *g_list_first( GList *list );
10571 gint g_list_length( GList *list );
10573 void g_list_foreach( GList *list,
10575 gpointer user_data );
10578 <!-- ----------------------------------------------------------------- -->
10579 <sect1>Singly Linked Lists
10581 Many of the above functions for singly linked lists are identical to the
10582 above. Here is a complete list:
10584 GSList *g_slist_alloc( void );
10586 void g_slist_free( GSList *list );
10588 void g_slist_free_1( GSList *list );
10590 GSList *g_slist_append( GSList *list,
10593 GSList *g_slist_prepend( GSList *list,
10596 GSList *g_slist_insert( GSList *list,
10600 GSList *g_slist_remove( GSList *list,
10603 GSList *g_slist_remove_link( GSList *list,
10606 GSList *g_slist_reverse( GSList *list );
10608 GSList *g_slist_nth( GSList *list,
10611 GSList *g_slist_find( GSList *list,
10614 GSList *g_slist_last( GSList *list );
10616 gint g_slist_length( GSList *list );
10618 void g_slist_foreach( GSList *list,
10620 gpointer user_data );
10624 <!-- ----------------------------------------------------------------- -->
10625 <sect1>Memory Management
10628 gpointer g_malloc( gulong size );
10631 This is a replacement for malloc(). You do not need to check the return
10632 value as it is done for you in this function.
10635 gpointer g_malloc0( gulong size );
10638 Same as above, but zeroes the memory before returning a pointer to it.
10641 gpointer g_realloc( gpointer mem,
10645 Relocates "size" bytes of memory starting at "mem". Obviously, the
10646 memory should have been previously allocated.
10649 void g_free( gpointer mem );
10652 Frees memory. Easy one.
10655 void g_mem_profile( void );
10658 Dumps a profile of used memory, but requires that you add #define
10659 MEM_PROFILE to the top of glib/gmem.c and re-make and make install.
10662 void g_mem_check( gpointer mem );
10665 Checks that a memory location is valid. Requires you add #define
10666 MEM_CHECK to the top of gmem.c and re-make and make install.
10668 <!-- ----------------------------------------------------------------- -->
10674 GTimer *g_timer_new( void );
10676 void g_timer_destroy( GTimer *timer );
10678 void g_timer_start( GTimer *timer );
10680 void g_timer_stop( GTimer *timer );
10682 void g_timer_reset( GTimer *timer );
10684 gdouble g_timer_elapsed( GTimer *timer,
10685 gulong *microseconds );
10688 <!-- ----------------------------------------------------------------- -->
10689 <sect1>String Handling
10691 A whole mess of string handling functions. They all look very interesting, and
10692 probably better for many purposes than the standard C string functions, but
10693 require documentation.
10696 GString *g_string_new( gchar *init );
10698 void g_string_free( GString *string,
10699 gint free_segment );
10701 GString *g_string_assign( GString *lval,
10704 GString *g_string_truncate( GString *string,
10707 GString *g_string_append( GString *string,
10710 GString *g_string_append_c( GString *string,
10713 GString *g_string_prepend( GString *string,
10716 GString *g_string_prepend_c( GString *string,
10719 void g_string_sprintf( GString *string,
10723 void g_string_sprintfa ( GString *string,
10728 <!-- ----------------------------------------------------------------- -->
10729 <sect1>Utility and Error Functions
10732 gchar *g_strdup( const gchar *str );
10735 Replacement strdup function. Copies the original strings contents to
10736 newly allocated memory, and returns a pointer to it.
10739 gchar *g_strerror( gint errnum );
10742 I recommend using this for all error messages. It's much nicer, and more
10743 portable than perror() or others. The output is usually of the form:
10746 program name:function that failed:file or further description:strerror
10749 Here's an example of one such call used in our hello_world program:
10752 g_print("hello_world:open:%s:%s\n", filename, g_strerror(errno));
10756 void g_error( gchar *format, ... );
10759 Prints an error message. The format is just like printf, but it
10760 prepends "** ERROR **: " to your message, and exits the program.
10761 Use only for fatal errors.
10764 void g_warning( gchar *format, ... );
10767 Same as above, but prepends "** WARNING **: ", and does not exit the
10771 void g_message( gchar *format, ... );
10774 Prints "message: " prepended to the string you pass in.
10777 void g_print( gchar *format, ... );
10780 Replacement for printf().
10782 And our last function:
10785 gchar *g_strsignal( gint signum );
10788 Prints out the name of the Unix system signal given the signal number.
10789 Useful in generic signal handling functions.
10791 All of the above are more or less just stolen from glib.h. If anyone cares
10792 to document any function, just send me an email!
10794 <!-- ***************************************************************** -->
10795 <sect>GTK's rc Files
10796 <!-- ***************************************************************** -->
10798 GTK has its own way of dealing with application defaults, by using rc
10799 files. These can be used to set the colors of just about any widget, and
10800 can also be used to tile pixmaps onto the background of some widgets.
10802 <!-- ----------------------------------------------------------------- -->
10803 <sect1>Functions For rc Files
10805 When your application starts, you should include a call to:
10808 void gtk_rc_parse( char *filename );
10811 Passing in the filename of your rc file. This will cause GTK to parse
10812 this file, and use the style settings for the widget types defined
10815 If you wish to have a special set of widgets that can take on a
10816 different style from others, or any other logical division of widgets,
10820 void gtk_widget_set_name( GtkWidget *widget,
10824 Passing your newly created widget as the first argument, and the name
10825 you wish to give it as the second. This will allow you to change the
10826 attributes of this widget by name through the rc file.
10828 If we use a call something like this:
10831 button = gtk_button_new_with_label ("Special Button");
10832 gtk_widget_set_name (button, "special button");
10835 Then this button is given the name "special button" and may be addressed by
10836 name in the rc file as "special button.GtkButton". [<--- Verify ME!]
10838 The example rc file below, sets the properties of the main window, and lets
10839 all children of that main window inherit the style described by the "main
10840 button" style. The code used in the application is:
10843 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
10844 gtk_widget_set_name (window, "main window");
10847 And then the style is defined in the rc file using:
10850 widget "main window.*GtkButton*" style "main_button"
10853 Which sets all the GtkButton widgets in the "main window" to the
10854 "main_buttons" style as defined in the rc file.
10856 As you can see, this is a fairly powerful and flexible system. Use your
10857 imagination as to how best to take advantage of this.
10859 <!-- ----------------------------------------------------------------- -->
10860 <sect1>GTK's rc File Format
10862 The format of the GTK file is illustrated in the example below. This is
10863 the testgtkrc file from the GTK distribution, but I've added a
10864 few comments and things. You may wish to include this explanation
10865 your application to allow the user to fine tune his application.
10867 There are several directives to change the attributes of a widget.
10870 <item>fg - Sets the foreground color of a widget.
10871 <item>bg - Sets the background color of a widget.
10872 <item>bg_pixmap - Sets the background of a widget to a tiled pixmap.
10873 <item>font - Sets the font to be used with the given widget.
10876 In addition to this, there are several states a widget can be in, and you
10877 can set different colors, pixmaps and fonts for each state. These states are:
10880 <item>NORMAL - The normal state of a widget, without the mouse over top of
10881 it, and not being pressed etc.
10882 <item>PRELIGHT - When the mouse is over top of the widget, colors defined
10883 using this state will be in effect.
10884 <item>ACTIVE - When the widget is pressed or clicked it will be active, and
10885 the attributes assigned by this tag will be in effect.
10886 <item>INSENSITIVE - When a widget is set insensitive, and cannot be
10887 activated, it will take these attributes.
10888 <item>SELECTED - When an object is selected, it takes these attributes.
10891 When using the "fg" and "bg" keywords to set the colors of widgets, the
10895 fg[<STATE>] = { Red, Green, Blue }
10898 Where STATE is one of the above states (PRELIGHT, ACTIVE etc), and the Red,
10899 Green and Blue are values in the range of 0 - 1.0, { 1.0, 1.0, 1.0 } being
10900 white. They must be in float form, or they will register as 0, so a straight
10901 "1" will not work, it must be "1.0". A straight "0" is fine because it
10902 doesn't matter if it's not recognized. Unrecognized values are set to 0.
10904 bg_pixmap is very similar to the above, except the colors are replaced by a
10907 pixmap_path is a list of paths separated by ":"'s. These paths will be
10908 searched for any pixmap you specify.
10910 The font directive is simply:
10912 font = "<font name>"
10915 Where the only hard part is figuring out the font string. Using xfontsel or
10916 similar utility should help.
10918 The "widget_class" sets the style of a class of widgets. These classes are
10919 listed in the widget overview on the class hierarchy.
10921 The "widget" directive sets a specifically named set of widgets to a
10922 given style, overriding any style set for the given widget class.
10923 These widgets are registered inside the application using the
10924 gtk_widget_set_name() call. This allows you to specify the attributes of a
10925 widget on a per widget basis, rather than setting the attributes of an
10926 entire widget class. I urge you to document any of these special widgets so
10927 users may customize them.
10929 When the keyword <tt>parent</> is used as an attribute, the widget will take on
10930 the attributes of its parent in the application.
10932 When defining a style, you may assign the attributes of a previously defined
10933 style to this new one.
10936 style "main_button" = "button"
10938 font = "-adobe-helvetica-medium-r-normal--*-100-*-*-*-*-*-*"
10939 bg[PRELIGHT] = { 0.75, 0, 0 }
10943 This example takes the "button" style, and creates a new "main_button" style
10944 simply by changing the font and prelight background color of the "button"
10947 Of course, many of these attributes don't apply to all widgets. It's a
10948 simple matter of common sense really. Anything that could apply, should.
10950 <!-- ----------------------------------------------------------------- -->
10951 <sect1>Example rc file
10955 # pixmap_path "<dir 1>:<dir 2>:<dir 3>:..."
10957 pixmap_path "/usr/include/X11R6/pixmaps:/home/imain/pixmaps"
10959 # style <name> [= <name>]
10964 # widget <widget_set> style <style_name>
10965 # widget_class <widget_class_set> style <style_name>
10968 # Here is a list of all the possible states. Note that some do not apply to
10971 # NORMAL - The normal state of a widget, without the mouse over top of
10972 # it, and not being pressed etc.
10974 # PRELIGHT - When the mouse is over top of the widget, colors defined
10975 # using this state will be in effect.
10977 # ACTIVE - When the widget is pressed or clicked it will be active, and
10978 # the attributes assigned by this tag will be in effect.
10980 # INSENSITIVE - When a widget is set insensitive, and cannot be
10981 # activated, it will take these attributes.
10983 # SELECTED - When an object is selected, it takes these attributes.
10985 # Given these states, we can set the attributes of the widgets in each of
10986 # these states using the following directives.
10988 # fg - Sets the foreground color of a widget.
10989 # fg - Sets the background color of a widget.
10990 # bg_pixmap - Sets the background of a widget to a tiled pixmap.
10991 # font - Sets the font to be used with the given widget.
10994 # This sets a style called "button". The name is not really important, as
10995 # it is assigned to the actual widgets at the bottom of the file.
10999 #This sets the padding around the window to the pixmap specified.
11000 #bg_pixmap[<STATE>] = "<pixmap filename>"
11001 bg_pixmap[NORMAL] = "warning.xpm"
11006 #Sets the foreground color (font color) to red when in the "NORMAL"
11009 fg[NORMAL] = { 1.0, 0, 0 }
11011 #Sets the background pixmap of this widget to that of its parent.
11012 bg_pixmap[NORMAL] = "<parent>"
11017 # This shows all the possible states for a button. The only one that
11018 # doesn't apply is the SELECTED state.
11020 fg[PRELIGHT] = { 0, 1.0, 1.0 }
11021 bg[PRELIGHT] = { 0, 0, 1.0 }
11022 bg[ACTIVE] = { 1.0, 0, 0 }
11023 fg[ACTIVE] = { 0, 1.0, 0 }
11024 bg[NORMAL] = { 1.0, 1.0, 0 }
11025 fg[NORMAL] = { .99, 0, .99 }
11026 bg[INSENSITIVE] = { 1.0, 1.0, 1.0 }
11027 fg[INSENSITIVE] = { 1.0, 0, 1.0 }
11030 # In this example, we inherit the attributes of the "button" style and then
11031 # override the font and background color when prelit to create a new
11032 # "main_button" style.
11034 style "main_button" = "button"
11036 font = "-adobe-helvetica-medium-r-normal--*-100-*-*-*-*-*-*"
11037 bg[PRELIGHT] = { 0.75, 0, 0 }
11040 style "toggle_button" = "button"
11042 fg[NORMAL] = { 1.0, 0, 0 }
11043 fg[ACTIVE] = { 1.0, 0, 0 }
11045 # This sets the background pixmap of the toggle_button to that of its
11046 # parent widget (as defined in the application).
11047 bg_pixmap[NORMAL] = "<parent>"
11052 bg_pixmap[NORMAL] = "marble.xpm"
11053 fg[NORMAL] = { 1.0, 1.0, 1.0 }
11058 font = "-adobe-helvetica-medium-r-normal--*-80-*-*-*-*-*-*"
11061 # pixmap_path "~/.pixmaps"
11063 # These set the widget types to use the styles defined above.
11064 # The widget types are listed in the class hierarchy, but could probably be
11065 # just listed in this document for the users reference.
11067 widget_class "GtkWindow" style "window"
11068 widget_class "GtkDialog" style "window"
11069 widget_class "GtkFileSelection" style "window"
11070 widget_class "*Gtk*Scale" style "scale"
11071 widget_class "*GtkCheckButton*" style "toggle_button"
11072 widget_class "*GtkRadioButton*" style "toggle_button"
11073 widget_class "*GtkButton*" style "button"
11074 widget_class "*Ruler" style "ruler"
11075 widget_class "*GtkText" style "text"
11077 # This sets all the buttons that are children of the "main window" to
11078 # the main_button style. These must be documented to be taken advantage of.
11079 widget "main window.*GtkButton*" style "main_button"
11082 <!-- ***************************************************************** -->
11083 <sect>Writing Your Own Widgets
11084 <!-- ***************************************************************** -->
11086 <!-- ----------------------------------------------------------------- -->
11089 Although the GTK distribution comes with many types of widgets that
11090 should cover most basic needs, there may come a time when you need to
11091 create your own new widget type. Since GTK uses widget inheritance
11092 extensively, and there is already a widget that is close to what you want,
11093 it is often possible to make a useful new widget type in
11094 just a few lines of code. But before starting work on a new widget, check
11095 around first to make sure that someone has not already written
11096 it. This will prevent duplication of effort and keep the number of
11097 GTK widgets out there to a minimum, which will help keep both the code
11098 and the interface of different applications consistent. As a flip side
11099 to this, once you finish your widget, announce it to the world so
11100 other people can benefit. The best place to do this is probably the
11103 Complete sources for the example widgets are available at the place you
11104 got this tutorial, or from:
11106 <htmlurl url="http://www.gtk.org/~otaylor/gtk/tutorial/"
11107 name="http://www.gtk.org/~otaylor/gtk/tutorial/">
11110 <!-- ----------------------------------------------------------------- -->
11111 <sect1> The Anatomy Of A Widget
11113 In order to create a new widget, it is important to have an
11114 understanding of how GTK objects work. This section is just meant as a
11115 brief overview. See the reference documentation for the details.
11117 GTK widgets are implemented in an object oriented fashion. However,
11118 they are implemented in standard C. This greatly improves portability
11119 and stability over using current generation C++ compilers; however,
11120 it does mean that the widget writer has to pay attention to some of
11121 the implementation details. The information common to all instances of
11122 one class of widgets (e.g., to all Button widgets) is stored in the
11123 <em>class structure</em>. There is only one copy of this in
11124 which is stored information about the class's signals
11125 (which act like virtual functions in C). To support inheritance, the
11126 first field in the class structure must be a copy of the parent's
11127 class structure. The declaration of the class structure of GtkButtton
11131 struct _GtkButtonClass
11133 GtkContainerClass parent_class;
11135 void (* pressed) (GtkButton *button);
11136 void (* released) (GtkButton *button);
11137 void (* clicked) (GtkButton *button);
11138 void (* enter) (GtkButton *button);
11139 void (* leave) (GtkButton *button);
11143 When a button is treated as a container (for instance, when it is
11144 resized), its class structure can be cast to GtkContainerClass, and
11145 the relevant fields used to handle the signals.
11147 There is also a structure for each widget that is created on a
11148 per-instance basis. This structure has fields to store information that
11149 is different for each instance of the widget. We'll call this
11150 structure the <em>object structure</em>. For the Button class, it looks
11156 GtkContainer container;
11160 guint in_button : 1;
11161 guint button_down : 1;
11165 Note that, similar to the class structure, the first field is the
11166 object structure of the parent class, so that this structure can be
11167 cast to the parent class's object structure as needed.
11169 <!-- ----------------------------------------------------------------- -->
11170 <sect1> Creating a Composite widget
11172 <!-- ----------------------------------------------------------------- -->
11173 <sect2> Introduction
11175 One type of widget that you may be interested in creating is a
11176 widget that is merely an aggregate of other GTK widgets. This type of
11177 widget does nothing that couldn't be done without creating new
11178 widgets, but provides a convenient way of packaging user interface
11179 elements for reuse. The FileSelection and ColorSelection widgets in
11180 the standard distribution are examples of this type of widget.
11182 The example widget that we'll create in this section is the Tictactoe
11183 widget, a 3x3 array of toggle buttons which triggers a signal when all
11184 three buttons in a row, column, or on one of the diagonals are
11187 <!-- ----------------------------------------------------------------- -->
11188 <sect2> Choosing a parent class
11190 The parent class for a composite widget is typically the container
11191 class that holds all of the elements of the composite widget. For
11192 example, the parent class of the FileSelection widget is the
11193 Dialog class. Since our buttons will be arranged in a table, it
11194 might seem natural to make our parent class the GtkTable
11195 class. Unfortunately, this turns out not to work. The creation of a
11196 widget is divided among two functions - a <tt/WIDGETNAME_new()/
11197 function that the user calls, and a <tt/WIDGETNAME_init()/ function
11198 which does the basic work of initializing the widget which is
11199 independent of the arguments passed to the <tt/_new()/
11200 function. Descendent widgets only call the <tt/_init/ function of
11201 their parent widget. But this division of labor doesn't work well for
11202 tables, which when created, need to know the number of rows and
11203 columns in the table. Unless we want to duplicate most of the
11204 functionality of <tt/gtk_table_new()/ in our Tictactoe widget, we had
11205 best avoid deriving it from GtkTable. For that reason, we derive it
11206 from GtkVBox instead, and stick our table inside the VBox.
11208 <!-- ----------------------------------------------------------------- -->
11209 <sect2> The header file
11211 Each widget class has a header file which declares the object and
11212 class structures for that widget, along with public functions.
11213 A couple of features are worth pointing out. To prevent duplicate
11214 definitions, we wrap the entire header file in:
11217 #ifndef __TICTACTOE_H__
11218 #define __TICTACTOE_H__
11222 #endif /* __TICTACTOE_H__ */
11225 And to keep C++ programs that include the header file happy, in:
11230 #endif /* __cplusplus */
11236 #endif /* __cplusplus */
11239 Along with the functions and structures, we declare three standard
11240 macros in our header file, <tt/TICTACTOE(obj)/,
11241 <tt/TICTACTOE_CLASS(klass)/, and <tt/IS_TICTACTOE(obj)/, which cast a
11242 pointer into a pointer to the object or class structure, and check
11243 if an object is a Tictactoe widget respectively.
11245 Here is the complete header file:
11250 #ifndef __TICTACTOE_H__
11251 #define __TICTACTOE_H__
11253 #include <gdk/gdk.h>
11254 #include <gtk/gtkvbox.h>
11258 #endif /* __cplusplus */
11260 #define TICTACTOE(obj) GTK_CHECK_CAST (obj, tictactoe_get_type (), Tictactoe)
11261 #define TICTACTOE_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, tictactoe_get_type (), TictactoeClass)
11262 #define IS_TICTACTOE(obj) GTK_CHECK_TYPE (obj, tictactoe_get_type ())
11265 typedef struct _Tictactoe Tictactoe;
11266 typedef struct _TictactoeClass TictactoeClass;
11272 GtkWidget *buttons[3][3];
11275 struct _TictactoeClass
11277 GtkVBoxClass parent_class;
11279 void (* tictactoe) (Tictactoe *ttt);
11282 guint tictactoe_get_type (void);
11283 GtkWidget* tictactoe_new (void);
11284 void tictactoe_clear (Tictactoe *ttt);
11288 #endif /* __cplusplus */
11290 #endif /* __TICTACTOE_H__ */
11294 <!-- ----------------------------------------------------------------- -->
11295 <sect2> The <tt/_get_type()/ function.
11297 We now continue on to the implementation of our widget. A core
11298 function for every widget is the function
11299 <tt/WIDGETNAME_get_type()/. This function, when first called, tells
11300 GTK about the widget class, and gets an ID that uniquely identifies
11301 the widget class. Upon subsequent calls, it just returns the ID.
11305 tictactoe_get_type ()
11307 static guint ttt_type = 0;
11311 GtkTypeInfo ttt_info =
11314 sizeof (Tictactoe),
11315 sizeof (TictactoeClass),
11316 (GtkClassInitFunc) tictactoe_class_init,
11317 (GtkObjectInitFunc) tictactoe_init,
11318 (GtkArgSetFunc) NULL,
11319 (GtkArgGetFunc) NULL
11322 ttt_type = gtk_type_unique (gtk_vbox_get_type (), &ttt_info);
11329 The GtkTypeInfo structure has the following definition:
11332 struct _GtkTypeInfo
11337 GtkClassInitFunc class_init_func;
11338 GtkObjectInitFunc object_init_func;
11339 GtkArgSetFunc arg_set_func;
11340 GtkArgGetFunc arg_get_func;
11344 The fields of this structure are pretty self-explanatory. We'll ignore
11345 the <tt/arg_set_func/ and <tt/arg_get_func/ fields here: they have an important,
11347 unimplemented, role in allowing widget options to be conveniently set
11348 from interpreted languages. Once GTK has a correctly filled in copy of
11349 this structure, it knows how to create objects of a particular widget
11352 <!-- ----------------------------------------------------------------- -->
11353 <sect2> The <tt/_class_init()/ function
11355 The <tt/WIDGETNAME_class_init()/ function initializes the fields of
11356 the widget's class structure, and sets up any signals for the
11357 class. For our Tictactoe widget it looks like:
11366 static gint tictactoe_signals[LAST_SIGNAL] = { 0 };
11369 tictactoe_class_init (TictactoeClass *class)
11371 GtkObjectClass *object_class;
11373 object_class = (GtkObjectClass*) class;
11375 tictactoe_signals[TICTACTOE_SIGNAL] = gtk_signal_new ("tictactoe",
11377 object_class->type,
11378 GTK_SIGNAL_OFFSET (TictactoeClass, tictactoe),
11379 gtk_signal_default_marshaller, GTK_TYPE_NONE, 0);
11382 gtk_object_class_add_signals (object_class, tictactoe_signals, LAST_SIGNAL);
11384 class->tictactoe = NULL;
11388 Our widget has just one signal, the <tt/tictactoe/ signal that is
11389 invoked when a row, column, or diagonal is completely filled in. Not
11390 every composite widget needs signals, so if you are reading this for
11391 the first time, you may want to skip to the next section now, as
11392 things are going to get a bit complicated.
11397 gint gtk_signal_new( const gchar *name,
11398 GtkSignalRunType run_type,
11399 GtkType object_type,
11400 gint function_offset,
11401 GtkSignalMarshaller marshaller,
11402 GtkType return_val,
11407 Creates a new signal. The parameters are:
11410 <item> <tt/name/: The name of the signal.
11411 <item> <tt/run_type/: Whether the default handler runs before or after
11412 user handlers. Usually this will be <tt/GTK_RUN_FIRST/, or <tt/GTK_RUN_LAST/,
11413 although there are other possibilities.
11414 <item> <tt/object_type/: The ID of the object that this signal applies
11415 to. (It will also apply to that objects descendents)
11416 <item> <tt/function_offset/: The offset within the class structure of
11417 a pointer to the default handler.
11418 <item> <tt/marshaller/: A function that is used to invoke the signal
11419 handler. For signal handlers that have no arguments other than the
11420 object that emitted the signal and user data, we can use the
11421 pre-supplied marshaller function <tt/gtk_signal_default_marshaller/.
11422 <item> <tt/return_val/: The type of the return val.
11423 <item> <tt/nparams/: The number of parameters of the signal handler
11424 (other than the two default ones mentioned above)
11425 <item> <tt/.../: The types of the parameters.
11428 When specifying types, the <tt/GtkType/ enumeration is used:
11453 /* it'd be great if the next two could be removed eventually */
11455 GTK_TYPE_C_CALLBACK,
11459 } GtkFundamentalType;
11462 <tt/gtk_signal_new()/ returns a unique integer identifier for the
11463 signal, that we store in the <tt/tictactoe_signals/ array, which we
11464 index using an enumeration. (Conventionally, the enumeration elements
11465 are the signal name, uppercased, but here there would be a conflict
11466 with the <tt/TICTACTOE()/ macro, so we called it <tt/TICTACTOE_SIGNAL/
11469 After creating our signals, we need to tell GTK to associate our
11470 signals with the Tictactoe class. We do that by calling
11471 <tt/gtk_object_class_add_signals()/. We then set the pointer which
11472 points to the default handler for the `tictactoe' signal to NULL,
11473 indicating that there is no default action.
11475 <!-- ----------------------------------------------------------------- -->
11476 <sect2> The <tt/_init()/ function.
11478 Each widget class also needs a function to initialize the object
11479 structure. Usually, this function has the fairly limited role of
11480 setting the fields of the structure to default values. For composite
11481 widgets, however, this function also creates the component widgets.
11485 tictactoe_init (Tictactoe *ttt)
11490 table = gtk_table_new (3, 3, TRUE);
11491 gtk_container_add (GTK_CONTAINER(ttt), table);
11492 gtk_widget_show (table);
11497 ttt->buttons[i][j] = gtk_toggle_button_new ();
11498 gtk_table_attach_defaults (GTK_TABLE(table), ttt->buttons[i][j],
11500 gtk_signal_connect (GTK_OBJECT (ttt->buttons[i][j]), "toggled",
11501 GTK_SIGNAL_FUNC (tictactoe_toggle), ttt);
11502 gtk_widget_set_usize (ttt->buttons[i][j], 20, 20);
11503 gtk_widget_show (ttt->buttons[i][j]);
11508 <!-- ----------------------------------------------------------------- -->
11509 <sect2> And the rest...
11511 There is one more function that every widget (except for base widget
11512 types like GtkBin that cannot be instantiated) needs to have - the
11513 function that the user calls to create an object of that type. This is
11514 conventionally called <tt/WIDGETNAME_new()/. In some
11515 widgets, though not for the Tictactoe widgets, this function takes
11516 arguments, and does some setup based on the arguments. The other two
11517 functions are specific to the Tictactoe widget.
11519 <tt/tictactoe_clear()/ is a public function that resets all the
11520 buttons in the widget to the up position. Note the use of
11521 <tt/gtk_signal_handler_block_by_data()/ to keep our signal handler for
11522 button toggles from being triggered unnecessarily.
11524 <tt/tictactoe_toggle()/ is the signal handler that is invoked when the
11525 user clicks on a button. It checks to see if there are any winning
11526 combinations that involve the toggled button, and if so, emits
11527 the "tictactoe" signal.
11533 return GTK_WIDGET ( gtk_type_new (tictactoe_get_type ()));
11537 tictactoe_clear (Tictactoe *ttt)
11544 gtk_signal_handler_block_by_data (GTK_OBJECT(ttt->buttons[i][j]), ttt);
11545 gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (ttt->buttons[i][j]),
11547 gtk_signal_handler_unblock_by_data (GTK_OBJECT(ttt->buttons[i][j]), ttt);
11552 tictactoe_toggle (GtkWidget *widget, Tictactoe *ttt)
11556 static int rwins[8][3] = { { 0, 0, 0 }, { 1, 1, 1 }, { 2, 2, 2 },
11557 { 0, 1, 2 }, { 0, 1, 2 }, { 0, 1, 2 },
11558 { 0, 1, 2 }, { 0, 1, 2 } };
11559 static int cwins[8][3] = { { 0, 1, 2 }, { 0, 1, 2 }, { 0, 1, 2 },
11560 { 0, 0, 0 }, { 1, 1, 1 }, { 2, 2, 2 },
11561 { 0, 1, 2 }, { 2, 1, 0 } };
11563 int success, found;
11565 for (k=0; k<8; k++)
11572 success = success &&
11573 GTK_TOGGLE_BUTTON(ttt->buttons[rwins[k][i]][cwins[k][i]])->active;
11575 ttt->buttons[rwins[k][i]][cwins[k][i]] == widget;
11578 if (success && found)
11580 gtk_signal_emit (GTK_OBJECT (ttt),
11581 tictactoe_signals[TICTACTOE_SIGNAL]);
11588 And finally, an example program using our Tictactoe widget:
11591 #include <gtk/gtk.h>
11592 #include "tictactoe.h"
11594 /* Invoked when a row, column or diagonal is completed */
11596 win (GtkWidget *widget, gpointer data)
11598 g_print ("Yay!\n");
11599 tictactoe_clear (TICTACTOE (widget));
11603 main (int argc, char *argv[])
11608 gtk_init (&argc, &argv);
11610 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
11612 gtk_window_set_title (GTK_WINDOW (window), "Aspect Frame");
11614 gtk_signal_connect (GTK_OBJECT (window), "destroy",
11615 GTK_SIGNAL_FUNC (gtk_exit), NULL);
11617 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
11619 /* Create a new Tictactoe widget */
11620 ttt = tictactoe_new ();
11621 gtk_container_add (GTK_CONTAINER (window), ttt);
11622 gtk_widget_show (ttt);
11624 /* And attach to its "tictactoe" signal */
11625 gtk_signal_connect (GTK_OBJECT (ttt), "tictactoe",
11626 GTK_SIGNAL_FUNC (win), NULL);
11628 gtk_widget_show (window);
11637 <!-- ----------------------------------------------------------------- -->
11638 <sect1> Creating a widget from scratch.
11640 <!-- ----------------------------------------------------------------- -->
11641 <sect2> Introduction
11643 In this section, we'll learn more about how widgets display themselves
11644 on the screen and interact with events. As an example of this, we'll
11645 create an analog dial widget with a pointer that the user can drag to
11648 <!-- ----------------------------------------------------------------- -->
11649 <sect2> Displaying a widget on the screen
11651 There are several steps that are involved in displaying on the screen.
11652 After the widget is created with a call to <tt/WIDGETNAME_new()/,
11653 several more functions are needed:
11656 <item> <tt/WIDGETNAME_realize()/ is responsible for creating an X
11657 window for the widget if it has one.
11658 <item> <tt/WIDGETNAME_map()/ is invoked after the user calls
11659 <tt/gtk_widget_show()/. It is responsible for making sure the widget
11660 is actually drawn on the screen (<em/mapped/). For a container class,
11661 it must also make calls to <tt/map()/> functions of any child widgets.
11662 <item> <tt/WIDGETNAME_draw()/ is invoked when <tt/gtk_widget_draw()/
11663 is called for the widget or one of its ancestors. It makes the actual
11664 calls to the drawing functions to draw the widget on the screen. For
11665 container widgets, this function must make calls to
11666 <tt/gtk_widget_draw()/ for its child widgets.
11667 <item> <tt/WIDGETNAME_expose()/ is a handler for expose events for the
11668 widget. It makes the necessary calls to the drawing functions to draw
11669 the exposed portion on the screen. For container widgets, this
11670 function must generate expose events for its child widgets which don't
11671 have their own windows. (If they have their own windows, then X will
11672 generate the necessary expose events)
11675 You might notice that the last two functions are quite similar - each
11676 is responsible for drawing the widget on the screen. In fact many
11677 types of widgets don't really care about the difference between the
11678 two. The default <tt/draw()/ function in the widget class simply
11679 generates a synthetic expose event for the redrawn area. However, some
11680 types of widgets can save work by distinguishing between the two
11681 functions. For instance, if a widget has multiple X windows, then
11682 since expose events identify the exposed window, it can redraw only
11683 the affected window, which is not possible for calls to <tt/draw()/.
11685 Container widgets, even if they don't care about the difference for
11686 themselves, can't simply use the default <tt/draw()/ function because
11687 their child widgets might care about the difference. However,
11688 it would be wasteful to duplicate the drawing code between the two
11689 functions. The convention is that such widgets have a function called
11690 <tt/WIDGETNAME_paint()/ that does the actual work of drawing the
11691 widget, that is then called by the <tt/draw()/ and <tt/expose()/
11694 In our example approach, since the dial widget is not a container
11695 widget, and only has a single window, we can take the simplest
11696 approach and use the default <tt/draw()/ function and only implement
11697 an <tt/expose()/ function.
11699 <!-- ----------------------------------------------------------------- -->
11700 <sect2> The origins of the Dial Widget
11702 Just as all land animals are just variants on the first amphibian that
11703 crawled up out of the mud, Gtk widgets tend to start off as variants
11704 of some other, previously written widget. Thus, although this section
11705 is entitled `Creating a Widget from Scratch', the Dial widget really
11706 began with the source code for the Range widget. This was picked as a
11707 starting point because it would be nice if our Dial had the same
11708 interface as the Scale widgets which are just specialized descendents
11709 of the Range widget. So, though the source code is presented below in
11710 finished form, it should not be implied that it was written, <em>deus
11711 ex machina</em> in this fashion. Also, if you aren't yet familiar with
11712 how scale widgets work from the application writer's point of view, it
11713 would be a good idea to look them over before continuing.
11715 <!-- ----------------------------------------------------------------- -->
11718 Quite a bit of our widget should look pretty familiar from the
11719 Tictactoe widget. First, we have a header file:
11722 /* GTK - The GIMP Toolkit
11723 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
11725 * This library is free software; you can redistribute it and/or
11726 * modify it under the terms of the GNU Library General Public
11727 * License as published by the Free Software Foundation; either
11728 * version 2 of the License, or (at your option) any later version.
11730 * This library is distributed in the hope that it will be useful,
11731 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11732 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11733 * Library General Public License for more details.
11735 * You should have received a copy of the GNU Library General Public
11736 * License along with this library; if not, write to the Free
11737 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
11740 #ifndef __GTK_DIAL_H__
11741 #define __GTK_DIAL_H__
11743 #include <gdk/gdk.h>
11744 #include <gtk/gtkadjustment.h>
11745 #include <gtk/gtkwidget.h>
11750 #endif /* __cplusplus */
11753 #define GTK_DIAL(obj) GTK_CHECK_CAST (obj, gtk_dial_get_type (), GtkDial)
11754 #define GTK_DIAL_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, gtk_dial_get_type (), GtkDialClass)
11755 #define GTK_IS_DIAL(obj) GTK_CHECK_TYPE (obj, gtk_dial_get_type ())
11758 typedef struct _GtkDial GtkDial;
11759 typedef struct _GtkDialClass GtkDialClass;
11765 /* update policy (GTK_UPDATE_[CONTINUOUS/DELAYED/DISCONTINUOUS]) */
11768 /* Button currently pressed or 0 if none */
11771 /* Dimensions of dial components */
11773 gint pointer_width;
11775 /* ID of update timer, or 0 if none */
11778 /* Current angle */
11781 /* Old values from adjustment stored so we know when something changes */
11786 /* The adjustment object that stores the data for this dial */
11787 GtkAdjustment *adjustment;
11790 struct _GtkDialClass
11792 GtkWidgetClass parent_class;
11796 GtkWidget* gtk_dial_new (GtkAdjustment *adjustment);
11797 guint gtk_dial_get_type (void);
11798 GtkAdjustment* gtk_dial_get_adjustment (GtkDial *dial);
11799 void gtk_dial_set_update_policy (GtkDial *dial,
11800 GtkUpdateType policy);
11802 void gtk_dial_set_adjustment (GtkDial *dial,
11803 GtkAdjustment *adjustment);
11806 #endif /* __cplusplus */
11809 #endif /* __GTK_DIAL_H__ */
11812 Since there is quite a bit more going on in this widget, than the last
11813 one, we have more fields in the data structure, but otherwise things
11814 are pretty similar.
11816 Next, after including header files, and declaring a few constants,
11817 we have some functions to provide information about the widget
11823 #include <gtk/gtkmain.h>
11824 #include <gtk/gtksignal.h>
11826 #include "gtkdial.h"
11828 #define SCROLL_DELAY_LENGTH 300
11829 #define DIAL_DEFAULT_SIZE 100
11831 /* Forward declarations */
11833 [ omitted to save space ]
11837 static GtkWidgetClass *parent_class = NULL;
11840 gtk_dial_get_type ()
11842 static guint dial_type = 0;
11846 GtkTypeInfo dial_info =
11850 sizeof (GtkDialClass),
11851 (GtkClassInitFunc) gtk_dial_class_init,
11852 (GtkObjectInitFunc) gtk_dial_init,
11853 (GtkArgSetFunc) NULL,
11854 (GtkArgGetFunc) NULL,
11857 dial_type = gtk_type_unique (gtk_widget_get_type (), &dial_info);
11864 gtk_dial_class_init (GtkDialClass *class)
11866 GtkObjectClass *object_class;
11867 GtkWidgetClass *widget_class;
11869 object_class = (GtkObjectClass*) class;
11870 widget_class = (GtkWidgetClass*) class;
11872 parent_class = gtk_type_class (gtk_widget_get_type ());
11874 object_class->destroy = gtk_dial_destroy;
11876 widget_class->realize = gtk_dial_realize;
11877 widget_class->expose_event = gtk_dial_expose;
11878 widget_class->size_request = gtk_dial_size_request;
11879 widget_class->size_allocate = gtk_dial_size_allocate;
11880 widget_class->button_press_event = gtk_dial_button_press;
11881 widget_class->button_release_event = gtk_dial_button_release;
11882 widget_class->motion_notify_event = gtk_dial_motion_notify;
11886 gtk_dial_init (GtkDial *dial)
11889 dial->policy = GTK_UPDATE_CONTINUOUS;
11892 dial->pointer_width = 0;
11894 dial->old_value = 0.0;
11895 dial->old_lower = 0.0;
11896 dial->old_upper = 0.0;
11897 dial->adjustment = NULL;
11901 gtk_dial_new (GtkAdjustment *adjustment)
11905 dial = gtk_type_new (gtk_dial_get_type ());
11908 adjustment = (GtkAdjustment*) gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
11910 gtk_dial_set_adjustment (dial, adjustment);
11912 return GTK_WIDGET (dial);
11916 gtk_dial_destroy (GtkObject *object)
11920 g_return_if_fail (object != NULL);
11921 g_return_if_fail (GTK_IS_DIAL (object));
11923 dial = GTK_DIAL (object);
11925 if (dial->adjustment)
11926 gtk_object_unref (GTK_OBJECT (dial->adjustment));
11928 if (GTK_OBJECT_CLASS (parent_class)->destroy)
11929 (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
11933 Note that this <tt/init()/ function does less than for the Tictactoe
11934 widget, since this is not a composite widget, and the <tt/new()/
11935 function does more, since it now has an argument. Also, note that when
11936 we store a pointer to the Adjustment object, we increment its
11937 reference count, (and correspondingly decrement when we no longer use
11938 it) so that GTK can keep track of when it can be safely destroyed.
11941 Also, there are a few function to manipulate the widget's options:
11945 gtk_dial_get_adjustment (GtkDial *dial)
11947 g_return_val_if_fail (dial != NULL, NULL);
11948 g_return_val_if_fail (GTK_IS_DIAL (dial), NULL);
11950 return dial->adjustment;
11954 gtk_dial_set_update_policy (GtkDial *dial,
11955 GtkUpdateType policy)
11957 g_return_if_fail (dial != NULL);
11958 g_return_if_fail (GTK_IS_DIAL (dial));
11960 dial->policy = policy;
11964 gtk_dial_set_adjustment (GtkDial *dial,
11965 GtkAdjustment *adjustment)
11967 g_return_if_fail (dial != NULL);
11968 g_return_if_fail (GTK_IS_DIAL (dial));
11970 if (dial->adjustment)
11972 gtk_signal_disconnect_by_data (GTK_OBJECT (dial->adjustment), (gpointer) dial);
11973 gtk_object_unref (GTK_OBJECT (dial->adjustment));
11976 dial->adjustment = adjustment;
11977 gtk_object_ref (GTK_OBJECT (dial->adjustment));
11979 gtk_signal_connect (GTK_OBJECT (adjustment), "changed",
11980 (GtkSignalFunc) gtk_dial_adjustment_changed,
11982 gtk_signal_connect (GTK_OBJECT (adjustment), "value_changed",
11983 (GtkSignalFunc) gtk_dial_adjustment_value_changed,
11986 dial->old_value = adjustment->value;
11987 dial->old_lower = adjustment->lower;
11988 dial->old_upper = adjustment->upper;
11990 gtk_dial_update (dial);
11994 <sect2> <tt/gtk_dial_realize()/
11997 Now we come to some new types of functions. First, we have a function
11998 that does the work of creating the X window. Notice that a mask is
11999 passed to the function <tt/gdk_window_new()/ which specifies which fields of
12000 the GdkWindowAttr structure actually have data in them (the remaining
12001 fields will be given default values). Also worth noting is the way the
12002 event mask of the widget is created. We call
12003 <tt/gtk_widget_get_events()/ to retrieve the event mask that the user
12004 has specified for this widget (with <tt/gtk_widget_set_events()/, and
12005 add the events that we are interested in ourselves.
12008 After creating the window, we set its style and background, and put a
12009 pointer to the widget in the user data field of the GdkWindow. This
12010 last step allows GTK to dispatch events for this window to the correct
12015 gtk_dial_realize (GtkWidget *widget)
12018 GdkWindowAttr attributes;
12019 gint attributes_mask;
12021 g_return_if_fail (widget != NULL);
12022 g_return_if_fail (GTK_IS_DIAL (widget));
12024 GTK_WIDGET_SET_FLAGS (widget, GTK_REALIZED);
12025 dial = GTK_DIAL (widget);
12027 attributes.x = widget->allocation.x;
12028 attributes.y = widget->allocation.y;
12029 attributes.width = widget->allocation.width;
12030 attributes.height = widget->allocation.height;
12031 attributes.wclass = GDK_INPUT_OUTPUT;
12032 attributes.window_type = GDK_WINDOW_CHILD;
12033 attributes.event_mask = gtk_widget_get_events (widget) |
12034 GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK |
12035 GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK |
12036 GDK_POINTER_MOTION_HINT_MASK;
12037 attributes.visual = gtk_widget_get_visual (widget);
12038 attributes.colormap = gtk_widget_get_colormap (widget);
12040 attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
12041 widget->window = gdk_window_new (widget->parent->window, &attributes, attributes_mask);
12043 widget->style = gtk_style_attach (widget->style, widget->window);
12045 gdk_window_set_user_data (widget->window, widget);
12047 gtk_style_set_background (widget->style, widget->window, GTK_STATE_ACTIVE);
12051 <sect2> Size negotiation
12054 Before the first time that the window containing a widget is
12055 displayed, and whenever the layout of the window changes, GTK asks
12056 each child widget for its desired size. This request is handled by the
12057 function, <tt/gtk_dial_size_request()/. Since our widget isn't a
12058 container widget, and has no real constraints on its size, we just
12059 return a reasonable default value.
12063 gtk_dial_size_request (GtkWidget *widget,
12064 GtkRequisition *requisition)
12066 requisition->width = DIAL_DEFAULT_SIZE;
12067 requisition->height = DIAL_DEFAULT_SIZE;
12072 After all the widgets have requested an ideal size, the layout of the
12073 window is computed and each child widget is notified of its actual
12074 size. Usually, this will at least as large as the requested size, but
12075 if for instance, the user has resized the window, it may occasionally
12076 be smaller than the requested size. The size notification is handled
12077 by the function <tt/gtk_dial_size_allocate()/. Notice that as well as
12078 computing the sizes of some component pieces for future use, this
12079 routine also does the grunt work of moving the widgets X window into
12080 the new position and size.
12084 gtk_dial_size_allocate (GtkWidget *widget,
12085 GtkAllocation *allocation)
12089 g_return_if_fail (widget != NULL);
12090 g_return_if_fail (GTK_IS_DIAL (widget));
12091 g_return_if_fail (allocation != NULL);
12093 widget->allocation = *allocation;
12094 if (GTK_WIDGET_REALIZED (widget))
12096 dial = GTK_DIAL (widget);
12098 gdk_window_move_resize (widget->window,
12099 allocation->x, allocation->y,
12100 allocation->width, allocation->height);
12102 dial->radius = MAX(allocation->width,allocation->height) * 0.45;
12103 dial->pointer_width = dial->radius / 5;
12108 <!-- ----------------------------------------------------------------- -->
12109 <sect2> <tt/gtk_dial_expose()/
12112 As mentioned above, all the drawing of this widget is done in the
12113 handler for expose events. There's not much to remark on here except
12114 the use of the function <tt/gtk_draw_polygon/ to draw the pointer with
12115 three dimensional shading according to the colors stored in the
12120 gtk_dial_expose (GtkWidget *widget,
12121 GdkEventExpose *event)
12124 GdkPoint points[3];
12131 g_return_val_if_fail (widget != NULL, FALSE);
12132 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
12133 g_return_val_if_fail (event != NULL, FALSE);
12135 if (event->count > 0)
12138 dial = GTK_DIAL (widget);
12140 gdk_window_clear_area (widget->window,
12142 widget->allocation.width,
12143 widget->allocation.height);
12145 xc = widget->allocation.width/2;
12146 yc = widget->allocation.height/2;
12150 for (i=0; i<25; i++)
12152 theta = (i*M_PI/18. - M_PI/6.);
12156 tick_length = (i%6 == 0) ? dial->pointer_width : dial->pointer_width/2;
12158 gdk_draw_line (widget->window,
12159 widget->style->fg_gc[widget->state],
12160 xc + c*(dial->radius - tick_length),
12161 yc - s*(dial->radius - tick_length),
12162 xc + c*dial->radius,
12163 yc - s*dial->radius);
12168 s = sin(dial->angle);
12169 c = cos(dial->angle);
12172 points[0].x = xc + s*dial->pointer_width/2;
12173 points[0].y = yc + c*dial->pointer_width/2;
12174 points[1].x = xc + c*dial->radius;
12175 points[1].y = yc - s*dial->radius;
12176 points[2].x = xc - s*dial->pointer_width/2;
12177 points[2].y = yc - c*dial->pointer_width/2;
12179 gtk_draw_polygon (widget->style,
12190 <!-- ----------------------------------------------------------------- -->
12191 <sect2> Event handling
12195 The rest of the widget's code handles various types of events, and
12196 isn't too different from what would be found in many GTK
12197 applications. Two types of events can occur - either the user can
12198 click on the widget with the mouse and drag to move the pointer, or
12199 the value of the Adjustment object can change due to some external
12203 When the user clicks on the widget, we check to see if the click was
12204 appropriately near the pointer, and if so, store then button that the
12205 user clicked with in the <tt/button/ field of the widget
12206 structure, and grab all mouse events with a call to
12207 <tt/gtk_grab_add()/. Subsequent motion of the mouse causes the
12208 value of the control to be recomputed (by the function
12209 <tt/gtk_dial_update_mouse/). Depending on the policy that has been
12210 set, "value_changed" events are either generated instantly
12211 (<tt/GTK_UPDATE_CONTINUOUS/), after a delay in a timer added with
12212 <tt/gtk_timeout_add()/ (<tt/GTK_UPDATE_DELAYED/), or only when the
12213 button is released (<tt/GTK_UPDATE_DISCONTINUOUS/).
12217 gtk_dial_button_press (GtkWidget *widget,
12218 GdkEventButton *event)
12224 double d_perpendicular;
12226 g_return_val_if_fail (widget != NULL, FALSE);
12227 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
12228 g_return_val_if_fail (event != NULL, FALSE);
12230 dial = GTK_DIAL (widget);
12232 /* Determine if button press was within pointer region - we
12233 do this by computing the parallel and perpendicular distance of
12234 the point where the mouse was pressed from the line passing through
12237 dx = event->x - widget->allocation.width / 2;
12238 dy = widget->allocation.height / 2 - event->y;
12240 s = sin(dial->angle);
12241 c = cos(dial->angle);
12243 d_parallel = s*dy + c*dx;
12244 d_perpendicular = fabs(s*dx - c*dy);
12246 if (!dial->button &&
12247 (d_perpendicular < dial->pointer_width/2) &&
12248 (d_parallel > - dial->pointer_width))
12250 gtk_grab_add (widget);
12252 dial->button = event->button;
12254 gtk_dial_update_mouse (dial, event->x, event->y);
12261 gtk_dial_button_release (GtkWidget *widget,
12262 GdkEventButton *event)
12266 g_return_val_if_fail (widget != NULL, FALSE);
12267 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
12268 g_return_val_if_fail (event != NULL, FALSE);
12270 dial = GTK_DIAL (widget);
12272 if (dial->button == event->button)
12274 gtk_grab_remove (widget);
12278 if (dial->policy == GTK_UPDATE_DELAYED)
12279 gtk_timeout_remove (dial->timer);
12281 if ((dial->policy != GTK_UPDATE_CONTINUOUS) &&
12282 (dial->old_value != dial->adjustment->value))
12283 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
12290 gtk_dial_motion_notify (GtkWidget *widget,
12291 GdkEventMotion *event)
12294 GdkModifierType mods;
12297 g_return_val_if_fail (widget != NULL, FALSE);
12298 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
12299 g_return_val_if_fail (event != NULL, FALSE);
12301 dial = GTK_DIAL (widget);
12303 if (dial->button != 0)
12308 if (event->is_hint || (event->window != widget->window))
12309 gdk_window_get_pointer (widget->window, &x, &y, &mods);
12311 switch (dial->button)
12314 mask = GDK_BUTTON1_MASK;
12317 mask = GDK_BUTTON2_MASK;
12320 mask = GDK_BUTTON3_MASK;
12328 gtk_dial_update_mouse (dial, x,y);
12335 gtk_dial_timer (GtkDial *dial)
12337 g_return_val_if_fail (dial != NULL, FALSE);
12338 g_return_val_if_fail (GTK_IS_DIAL (dial), FALSE);
12340 if (dial->policy == GTK_UPDATE_DELAYED)
12341 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
12347 gtk_dial_update_mouse (GtkDial *dial, gint x, gint y)
12352 g_return_if_fail (dial != NULL);
12353 g_return_if_fail (GTK_IS_DIAL (dial));
12355 xc = GTK_WIDGET(dial)->allocation.width / 2;
12356 yc = GTK_WIDGET(dial)->allocation.height / 2;
12358 old_value = dial->adjustment->value;
12359 dial->angle = atan2(yc-y, x-xc);
12361 if (dial->angle < -M_PI/2.)
12362 dial->angle += 2*M_PI;
12364 if (dial->angle < -M_PI/6)
12365 dial->angle = -M_PI/6;
12367 if (dial->angle > 7.*M_PI/6.)
12368 dial->angle = 7.*M_PI/6.;
12370 dial->adjustment->value = dial->adjustment->lower + (7.*M_PI/6 - dial->angle) *
12371 (dial->adjustment->upper - dial->adjustment->lower) / (4.*M_PI/3.);
12373 if (dial->adjustment->value != old_value)
12375 if (dial->policy == GTK_UPDATE_CONTINUOUS)
12377 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
12381 gtk_widget_draw (GTK_WIDGET(dial), NULL);
12383 if (dial->policy == GTK_UPDATE_DELAYED)
12386 gtk_timeout_remove (dial->timer);
12388 dial->timer = gtk_timeout_add (SCROLL_DELAY_LENGTH,
12389 (GtkFunction) gtk_dial_timer,
12398 Changes to the Adjustment by external means are communicated to our
12399 widget by the `changed' and `value_changed' signals. The handlers
12400 for these functions call <tt/gtk_dial_update()/ to validate the
12401 arguments, compute the new pointer angle, and redraw the widget (by
12402 calling <tt/gtk_widget_draw()/).
12406 gtk_dial_update (GtkDial *dial)
12410 g_return_if_fail (dial != NULL);
12411 g_return_if_fail (GTK_IS_DIAL (dial));
12413 new_value = dial->adjustment->value;
12415 if (new_value < dial->adjustment->lower)
12416 new_value = dial->adjustment->lower;
12418 if (new_value > dial->adjustment->upper)
12419 new_value = dial->adjustment->upper;
12421 if (new_value != dial->adjustment->value)
12423 dial->adjustment->value = new_value;
12424 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
12427 dial->angle = 7.*M_PI/6. - (new_value - dial->adjustment->lower) * 4.*M_PI/3. /
12428 (dial->adjustment->upper - dial->adjustment->lower);
12430 gtk_widget_draw (GTK_WIDGET(dial), NULL);
12434 gtk_dial_adjustment_changed (GtkAdjustment *adjustment,
12439 g_return_if_fail (adjustment != NULL);
12440 g_return_if_fail (data != NULL);
12442 dial = GTK_DIAL (data);
12444 if ((dial->old_value != adjustment->value) ||
12445 (dial->old_lower != adjustment->lower) ||
12446 (dial->old_upper != adjustment->upper))
12448 gtk_dial_update (dial);
12450 dial->old_value = adjustment->value;
12451 dial->old_lower = adjustment->lower;
12452 dial->old_upper = adjustment->upper;
12457 gtk_dial_adjustment_value_changed (GtkAdjustment *adjustment,
12462 g_return_if_fail (adjustment != NULL);
12463 g_return_if_fail (data != NULL);
12465 dial = GTK_DIAL (data);
12467 if (dial->old_value != adjustment->value)
12469 gtk_dial_update (dial);
12471 dial->old_value = adjustment->value;
12476 <!-- ----------------------------------------------------------------- -->
12477 <sect2> Possible Enhancements
12480 The Dial widget as we've described it so far runs about 670 lines of
12481 code. Although that might sound like a fair bit, we've really
12482 accomplished quite a bit with that much code, especially since much of
12483 that length is headers and boilerplate. However, there are quite a few
12484 more enhancements that could be made to this widget:
12487 <item> If you try this widget out, you'll find that there is some
12488 flashing as the pointer is dragged around. This is because the entire
12489 widget is erased every time the pointer is moved before being
12490 redrawn. Often, the best way to handle this problem is to draw to an
12491 offscreen pixmap, then copy the final results onto the screen in one
12492 step. (The ProgressBar widget draws itself in this fashion.)
12494 <item> The user should be able to use the up and down arrow keys to
12495 increase and decrease the value.
12497 <item> It would be nice if the widget had buttons to increase and
12498 decrease the value in small or large steps. Although it would be
12499 possible to use embedded Button widgets for this, we would also like
12500 the buttons to auto-repeat when held down, as the arrows on a
12501 scrollbar do. Most of the code to implement this type of behavior can
12502 be found in the GtkRange widget.
12504 <item> The Dial widget could be made into a container widget with a
12505 single child widget positioned at the bottom between the buttons
12506 mentioned above. The user could then add their choice of a label or
12507 entry widget to display the current value of the dial.
12511 <!-- ----------------------------------------------------------------- -->
12512 <sect1> Learning More
12515 Only a small part of the many details involved in creating widgets
12516 could be described above. If you want to write your own widgets, the
12517 best source of examples is the GTK source itself. Ask yourself some
12518 questions about the widget you want to write: is it a Container
12519 widget? does it have its own window? is it a modification of an
12520 existing widget? Then find a similar widget, and start making changes.
12523 <!-- ***************************************************************** -->
12524 <sect>Scribble, A Simple Example Drawing Program
12525 <!-- ***************************************************************** -->
12527 <!-- ----------------------------------------------------------------- -->
12531 In this section, we will build a simple drawing program. In the
12532 process, we will examine how to handle mouse events, how to draw in a
12533 window, and how to do drawing better by using a backing pixmap. After
12534 creating the simple drawing program, we will extend it by adding
12535 support for XInput devices, such as drawing tablets. GTK provides
12536 support routines which makes getting extended information, such as
12537 pressure and tilt, from such devices quite easy.
12539 <!-- ----------------------------------------------------------------- -->
12540 <sect1> Event Handling
12543 The GTK signals we have already discussed are for high-level actions,
12544 such as a menu item being selected. However, sometimes it is useful to
12545 learn about lower-level occurrences, such as the mouse being moved, or
12546 a key being pressed. There are also GTK signals corresponding to these
12547 low-level <em>events</em>. The handlers for these signals have an
12548 extra parameter which is a pointer to a structure containing
12549 information about the event. For instance, motion events handlers are
12550 passed a pointer to a GdkEventMotion structure which looks (in part)
12554 struct _GdkEventMotion
12567 <tt/type/ will be set to the event type, in this case
12568 <tt/GDK_MOTION_NOTIFY/, window is the window in which the event
12569 occurred. <tt/x/ and <tt/y/ give the coordinates of the event,
12570 and <tt/state/ specifies the modifier state when the event
12571 occurred (that is, it specifies which modifier keys and mouse buttons
12572 were pressed.) It is the bitwise OR of some of the following:
12591 As for other signals, to determine what happens when an event occurs
12592 we call <tt>gtk_signal_connect()</tt>. But we also need let GTK
12593 know which events we want to be notified about. To do this, we call
12597 void gtk_widget_set_events (GtkWidget *widget,
12601 The second field specifies the events we are interested in. It
12602 is the bitwise OR of constants that specify different types
12603 of events. For future reference the event types are:
12607 GDK_POINTER_MOTION_MASK
12608 GDK_POINTER_MOTION_HINT_MASK
12609 GDK_BUTTON_MOTION_MASK
12610 GDK_BUTTON1_MOTION_MASK
12611 GDK_BUTTON2_MOTION_MASK
12612 GDK_BUTTON3_MOTION_MASK
12613 GDK_BUTTON_PRESS_MASK
12614 GDK_BUTTON_RELEASE_MASK
12616 GDK_KEY_RELEASE_MASK
12617 GDK_ENTER_NOTIFY_MASK
12618 GDK_LEAVE_NOTIFY_MASK
12619 GDK_FOCUS_CHANGE_MASK
12621 GDK_PROPERTY_CHANGE_MASK
12622 GDK_PROXIMITY_IN_MASK
12623 GDK_PROXIMITY_OUT_MASK
12626 There are a few subtle points that have to be observed when calling
12627 <tt/gtk_widget_set_events()/. First, it must be called before the X window
12628 for a GTK widget is created. In practical terms, this means you
12629 should call it immediately after creating the widget. Second, the
12630 widget must have an associated X window. For efficiency, many widget
12631 types do not have their own window, but draw in their parent's window.
12654 To capture events for these widgets, you need to use an EventBox
12655 widget. See the section on the <ref id="sec_EventBox"
12656 name="EventBox"> widget for details.
12659 For our drawing program, we want to know when the mouse button is
12660 pressed and when the mouse is moved, so we specify
12661 <tt/GDK_POINTER_MOTION_MASK/ and <tt/GDK_BUTTON_PRESS_MASK/. We also
12662 want to know when we need to redraw our window, so we specify
12663 <tt/GDK_EXPOSURE_MASK/. Although we want to be notified via a
12664 Configure event when our window size changes, we don't have to specify
12665 the corresponding <tt/GDK_STRUCTURE_MASK/ flag, because it is
12666 automatically specified for all windows.
12669 It turns out, however, that there is a problem with just specifying
12670 <tt/GDK_POINTER_MOTION_MASK/. This will cause the server to add a new
12671 motion event to the event queue every time the user moves the mouse.
12672 Imagine that it takes us 0.1 seconds to handle a motion event, but the
12673 X server queues a new motion event every 0.05 seconds. We will soon
12674 get way behind the users drawing. If the user draws for 5 seconds,
12675 it will take us another 5 seconds to catch up after they release
12676 the mouse button! What we would like is to only get one motion
12677 event for each event we process. The way to do this is to
12678 specify <tt/GDK_POINTER_MOTION_HINT_MASK/.
12681 When we specify <tt/GDK_POINTER_MOTION_HINT_MASK/, the server sends
12682 us a motion event the first time the pointer moves after entering
12683 our window, or after a button press or release event. Subsequent
12684 motion events will be suppressed until we explicitly ask for
12685 the position of the pointer using the function:
12688 GdkWindow* gdk_window_get_pointer (GdkWindow *window,
12691 GdkModifierType *mask);
12694 (There is another function, <tt>gtk_widget_get_pointer()</tt> which
12695 has a simpler interface, but turns out not to be very useful, since
12696 it only retrieves the position of the mouse, not whether the buttons
12700 The code to set the events for our window then looks like:
12703 gtk_signal_connect (GTK_OBJECT (drawing_area), "expose_event",
12704 (GtkSignalFunc) expose_event, NULL);
12705 gtk_signal_connect (GTK_OBJECT(drawing_area),"configure_event",
12706 (GtkSignalFunc) configure_event, NULL);
12707 gtk_signal_connect (GTK_OBJECT (drawing_area), "motion_notify_event",
12708 (GtkSignalFunc) motion_notify_event, NULL);
12709 gtk_signal_connect (GTK_OBJECT (drawing_area), "button_press_event",
12710 (GtkSignalFunc) button_press_event, NULL);
12712 gtk_widget_set_events (drawing_area, GDK_EXPOSURE_MASK
12713 | GDK_LEAVE_NOTIFY_MASK
12714 | GDK_BUTTON_PRESS_MASK
12715 | GDK_POINTER_MOTION_MASK
12716 | GDK_POINTER_MOTION_HINT_MASK);
12719 We'll save the "expose_event" and "configure_event" handlers for
12720 later. The "motion_notify_event" and "button_press_event" handlers
12725 button_press_event (GtkWidget *widget, GdkEventButton *event)
12727 if (event->button == 1 && pixmap != NULL)
12728 draw_brush (widget, event->x, event->y);
12734 motion_notify_event (GtkWidget *widget, GdkEventMotion *event)
12737 GdkModifierType state;
12739 if (event->is_hint)
12740 gdk_window_get_pointer (event->window, &x, &y, &state);
12745 state = event->state;
12748 if (state & GDK_BUTTON1_MASK && pixmap != NULL)
12749 draw_brush (widget, x, y);
12755 <!-- ----------------------------------------------------------------- -->
12756 <sect1> The DrawingArea Widget, And Drawing
12759 We know turn to the process of drawing on the screen. The
12760 widget we use for this is the DrawingArea widget. A drawing area
12761 widget is essentially an X window and nothing more. It is a blank
12762 canvas in which we can draw whatever we like. A drawing area
12763 is created using the call:
12766 GtkWidget* gtk_drawing_area_new (void);
12769 A default size for the widget can be specified by calling:
12772 void gtk_drawing_area_size (GtkDrawingArea *darea,
12777 This default size can be overridden, as is true for all widgets,
12778 by calling <tt>gtk_widget_set_usize()</tt>, and that, in turn, can
12779 be overridden if the user manually resizes the the window containing
12783 It should be noted that when we create a DrawingArea widget, we are,
12784 <em>completely</em> responsible for drawing the contents. If our
12785 window is obscured then uncovered, we get an exposure event and must
12786 redraw what was previously hidden.
12789 Having to remember everything that was drawn on the screen so we
12790 can properly redraw it can, to say the least, be a nuisance. In
12791 addition, it can be visually distracting if portions of the
12792 window are cleared, then redrawn step by step. The solution to
12793 this problem is to use an offscreen <em>backing pixmap</em>.
12794 Instead of drawing directly to the screen, we draw to an image
12795 stored in server memory but not displayed, then when the image
12796 changes or new portions of the image are displayed, we copy the
12797 relevant portions onto the screen.
12800 To create an offscreen pixmap, we call the function:
12803 GdkPixmap* gdk_pixmap_new (GdkWindow *window,
12809 The <tt>window</tt> parameter specifies a GDK window that this pixmap
12810 takes some of its properties from. <tt>width</tt> and <tt>height</tt>
12811 specify the size of the pixmap. <tt>depth</tt> specifies the <em>color
12812 depth</em>, that is the number of bits per pixel, for the new window.
12813 If the depth is specified as <tt>-1</tt>, it will match the depth
12814 of <tt>window</tt>.
12817 We create the pixmap in our "configure_event" handler. This event
12818 is generated whenever the window changes size, including when it
12819 is originally created.
12822 /* Backing pixmap for drawing area */
12823 static GdkPixmap *pixmap = NULL;
12825 /* Create a new backing pixmap of the appropriate size */
12827 configure_event (GtkWidget *widget, GdkEventConfigure *event)
12830 gdk_pixmap_unref(pixmap);
12832 pixmap = gdk_pixmap_new(widget->window,
12833 widget->allocation.width,
12834 widget->allocation.height,
12836 gdk_draw_rectangle (pixmap,
12837 widget->style->white_gc,
12840 widget->allocation.width,
12841 widget->allocation.height);
12847 The call to <tt>gdk_draw_rectangle()</tt> clears the pixmap
12848 initially to white. We'll say more about that in a moment.
12851 Our exposure event handler then simply copies the relevant portion
12852 of the pixmap onto the screen (we determine the area we need
12853 to redraw by using the event->area field of the exposure event):
12856 /* Redraw the screen from the backing pixmap */
12858 expose_event (GtkWidget *widget, GdkEventExpose *event)
12860 gdk_draw_pixmap(widget->window,
12861 widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
12863 event->area.x, event->area.y,
12864 event->area.x, event->area.y,
12865 event->area.width, event->area.height);
12871 We've now seen how to keep the screen up to date with our pixmap, but
12872 how do we actually draw interesting stuff on our pixmap? There are a
12873 large number of calls in GTK's GDK library for drawing on
12874 <em>drawables</em>. A drawable is simply something that can be drawn
12875 upon. It can be a window, a pixmap, or a bitmap (a black and white
12876 image). We've already seen two such calls above,
12877 <tt>gdk_draw_rectangle()</tt> and <tt>gdk_draw_pixmap()</tt>. The
12882 gdk_draw_rectangle ()
12884 gdk_draw_polygon ()
12891 gdk_draw_segments ()
12894 See the reference documentation or the header file
12895 <tt><gdk/gdk.h></tt> for further details on these functions.
12896 These functions all share the same first two arguments. The first
12897 argument is the drawable to draw upon, the second argument is a
12898 <em>graphics context</em> (GC).
12901 A graphics context encapsulates information about things such as
12902 foreground and background color and line width. GDK has a full set of
12903 functions for creating and modifying graphics contexts, but to keep
12904 things simple we'll just use predefined graphics contexts. Each widget
12905 has an associated style. (Which can be modified in a gtkrc file, see
12906 the section GTK's rc file.) This, among other things, stores a number
12907 of graphics contexts. Some examples of accessing these graphics
12911 widget->style->white_gc
12912 widget->style->black_gc
12913 widget->style->fg_gc[GTK_STATE_NORMAL]
12914 widget->style->bg_gc[GTK_WIDGET_STATE(widget)]
12917 The fields <tt>fg_gc</tt>, <tt>bg_gc</tt>, <tt>dark_gc</tt>, and
12918 <tt>light_gc</tt> are indexed by a parameter of type
12919 <tt>GtkStateType</tt> which can take on the values:
12924 GTK_STATE_PRELIGHT,
12925 GTK_STATE_SELECTED,
12926 GTK_STATE_INSENSITIVE
12929 For instance, the for <tt/GTK_STATE_SELECTED/ the default foreground
12930 color is white and the default background color, dark blue.
12933 Our function <tt>draw_brush()</tt>, which does the actual drawing
12934 on the screen, is then:
12937 /* Draw a rectangle on the screen */
12939 draw_brush (GtkWidget *widget, gdouble x, gdouble y)
12941 GdkRectangle update_rect;
12943 update_rect.x = x - 5;
12944 update_rect.y = y - 5;
12945 update_rect.width = 10;
12946 update_rect.height = 10;
12947 gdk_draw_rectangle (pixmap,
12948 widget->style->black_gc,
12950 update_rect.x, update_rect.y,
12951 update_rect.width, update_rect.height);
12952 gtk_widget_draw (widget, &update_rect);
12956 After we draw the rectangle representing the brush onto the pixmap,
12957 we call the function:
12960 void gtk_widget_draw (GtkWidget *widget,
12961 GdkRectangle *area);
12964 which notifies X that the area given by the <tt>area</tt> parameter
12965 needs to be updated. X will eventually generate an expose event
12966 (possibly combining the areas passed in several calls to
12967 <tt>gtk_widget_draw()</tt>) which will cause our expose event handler
12968 to copy the relevant portions to the screen.
12971 We have now covered the entire drawing program except for a few
12972 mundane details like creating the main window. The complete
12973 source code is available from the location from which you got
12974 this tutorial, or from:
12976 <htmlurl url="http://www.gtk.org/~otaylor/gtk/tutorial/"
12977 name="http://www.gtk.org/~otaylor/gtk/tutorial/">
12980 <!-- ----------------------------------------------------------------- -->
12981 <sect1> Adding XInput support
12985 It is now possible to buy quite inexpensive input devices such
12986 as drawing tablets, which allow drawing with a much greater
12987 ease of artistic expression than does a mouse. The simplest way
12988 to use such devices is simply as a replacement for the mouse,
12989 but that misses out many of the advantages of these devices,
12993 <item> Pressure sensitivity
12994 <item> Tilt reporting
12995 <item> Sub-pixel positioning
12996 <item> Multiple inputs (for example, a stylus with a point and eraser)
12999 For information about the XInput extension, see the <htmlurl
13000 url="http://www.msc.cornell.edu/~otaylor/xinput/XInput-HOWTO.html"
13001 name="XInput-HOWTO">.
13004 If we examine the full definition of, for example, the GdkEventMotion
13005 structure, we see that it has fields to support extended device
13009 struct _GdkEventMotion
13021 GdkInputSource source;
13026 <tt/pressure/ gives the pressure as a floating point number between
13027 0 and 1. <tt/xtilt/ and <tt/ytilt/ can take on values between
13028 -1 and 1, corresponding to the degree of tilt in each direction.
13029 <tt/source/ and <tt/deviceid/ specify the device for which the
13030 event occurred in two different ways. <tt/source/ gives some simple
13031 information about the type of device. It can take the enumeration
13041 <tt/deviceid/ specifies a unique numeric ID for the device. This can
13042 be used to find out further information about the device using the
13043 <tt/gdk_input_list_devices()/ call (see below). The special value
13044 <tt/GDK_CORE_POINTER/ is used for the core pointer device. (Usually
13047 <sect2> Enabling extended device information
13050 To let GTK know about our interest in the extended device information,
13051 we merely have to add a single line to our program:
13054 gtk_widget_set_extension_events (drawing_area, GDK_EXTENSION_EVENTS_CURSOR);
13057 By giving the value <tt/GDK_EXTENSION_EVENTS_CURSOR/ we say that
13058 we are interested in extension events, but only if we don't have
13059 to draw our own cursor. See the section <ref
13060 id="sec_Further_Sophistications" name="Further Sophistications"> below
13061 for more information about drawing the cursor. We could also
13062 give the values <tt/GDK_EXTENSION_EVENTS_ALL/ if we were willing
13063 to draw our own cursor, or <tt/GDK_EXTENSION_EVENTS_NONE/ to revert
13064 back to the default condition.
13067 This is not completely the end of the story however. By default,
13068 no extension devices are enabled. We need a mechanism to allow
13069 users to enable and configure their extension devices. GTK provides
13070 the InputDialog widget to automate this process. The following
13071 procedure manages an InputDialog widget. It creates the dialog if
13072 it isn't present, and raises it to the top otherwise.
13076 input_dialog_destroy (GtkWidget *w, gpointer data)
13078 *((GtkWidget **)data) = NULL;
13082 create_input_dialog ()
13084 static GtkWidget *inputd = NULL;
13088 inputd = gtk_input_dialog_new();
13090 gtk_signal_connect (GTK_OBJECT(inputd), "destroy",
13091 (GtkSignalFunc)input_dialog_destroy, &inputd);
13092 gtk_signal_connect_object (GTK_OBJECT(GTK_INPUT_DIALOG(inputd)->close_button),
13094 (GtkSignalFunc)gtk_widget_hide,
13095 GTK_OBJECT(inputd));
13096 gtk_widget_hide ( GTK_INPUT_DIALOG(inputd)->save_button);
13098 gtk_widget_show (inputd);
13102 if (!GTK_WIDGET_MAPPED(inputd))
13103 gtk_widget_show(inputd);
13105 gdk_window_raise(inputd->window);
13110 (You might want to take note of the way we handle this dialog. By
13111 connecting to the "destroy" signal, we make sure that we don't keep a
13112 pointer to dialog around after it is destroyed - that could lead to a
13116 The InputDialog has two buttons "Close" and "Save", which by default
13117 have no actions assigned to them. In the above function we make
13118 "Close" hide the dialog, hide the "Save" button, since we don't
13119 implement saving of XInput options in this program.
13121 <sect2> Using extended device information
13124 Once we've enabled the device, we can just use the extended
13125 device information in the extra fields of the event structures.
13126 In fact, it is always safe to use this information since these
13127 fields will have reasonable default values even when extended
13128 events are not enabled.
13131 Once change we do have to make is to call
13132 <tt/gdk_input_window_get_pointer()/ instead of
13133 <tt/gdk_window_get_pointer/. This is necessary because
13134 <tt/gdk_window_get_pointer/ doesn't return the extended device
13138 void gdk_input_window_get_pointer (GdkWindow *window,
13145 GdkModifierType *mask);
13148 When calling this function, we need to specify the device ID as
13149 well as the window. Usually, we'll get the device ID from the
13150 <tt/deviceid/ field of an event structure. Again, this function
13151 will return reasonable values when extension events are not
13152 enabled. (In this case, <tt/event->deviceid/ will have the value
13153 <tt/GDK_CORE_POINTER/).
13155 So the basic structure of our button-press and motion event handlers,
13156 doesn't change much - we just need to add code to deal with the
13157 extended information.
13161 button_press_event (GtkWidget *widget, GdkEventButton *event)
13163 print_button_press (event->deviceid);
13165 if (event->button == 1 && pixmap != NULL)
13166 draw_brush (widget, event->source, event->x, event->y, event->pressure);
13172 motion_notify_event (GtkWidget *widget, GdkEventMotion *event)
13176 GdkModifierType state;
13178 if (event->is_hint)
13179 gdk_input_window_get_pointer (event->window, event->deviceid,
13180 &x, &y, &pressure, NULL, NULL, &state);
13185 pressure = event->pressure;
13186 state = event->state;
13189 if (state & GDK_BUTTON1_MASK && pixmap != NULL)
13190 draw_brush (widget, event->source, x, y, pressure);
13196 We also need to do something with the new information. Our new
13197 <tt/draw_brush()/ function draws with a different color for
13198 each <tt/event->source/ and changes the brush size depending
13202 /* Draw a rectangle on the screen, size depending on pressure,
13203 and color on the type of device */
13205 draw_brush (GtkWidget *widget, GdkInputSource source,
13206 gdouble x, gdouble y, gdouble pressure)
13209 GdkRectangle update_rect;
13213 case GDK_SOURCE_MOUSE:
13214 gc = widget->style->dark_gc[GTK_WIDGET_STATE (widget)];
13216 case GDK_SOURCE_PEN:
13217 gc = widget->style->black_gc;
13219 case GDK_SOURCE_ERASER:
13220 gc = widget->style->white_gc;
13223 gc = widget->style->light_gc[GTK_WIDGET_STATE (widget)];
13226 update_rect.x = x - 10 * pressure;
13227 update_rect.y = y - 10 * pressure;
13228 update_rect.width = 20 * pressure;
13229 update_rect.height = 20 * pressure;
13230 gdk_draw_rectangle (pixmap, gc, TRUE,
13231 update_rect.x, update_rect.y,
13232 update_rect.width, update_rect.height);
13233 gtk_widget_draw (widget, &update_rect);
13237 <sect2> Finding out more about a device
13240 As an example of how to find out more about a device, our program
13241 will print the name of the device that generates each button
13242 press. To find out the name of a device, we call the function:
13245 GList *gdk_input_list_devices (void);
13248 which returns a GList (a linked list type from the glib library)
13249 of GdkDeviceInfo structures. The GdkDeviceInfo structure is defined
13253 struct _GdkDeviceInfo
13257 GdkInputSource source;
13263 GdkDeviceKey *keys;
13267 Most of these fields are configuration information that you
13268 can ignore unless you are implemented XInput configuration
13269 saving. The we are interested in here is <tt/name/ which is
13270 simply the name that X assigns to the device. The other field
13271 that isn't configuration information is <tt/has_cursor/. If
13272 <tt/has_cursor/ is false, then we we need to draw our own
13273 cursor. But since we've specified <tt/GDK_EXTENSION_EVENTS_CURSOR/,
13274 we don't have to worry about this.
13277 Our <tt/print_button_press()/ function simply iterates through
13278 the returned list until it finds a match, then prints out
13279 the name of the device.
13283 print_button_press (guint32 deviceid)
13287 /* gdk_input_list_devices returns an internal list, so we shouldn't
13288 free it afterwards */
13289 tmp_list = gdk_input_list_devices();
13293 GdkDeviceInfo *info = (GdkDeviceInfo *)tmp_list->data;
13295 if (info->deviceid == deviceid)
13297 printf("Button press on device '%s'\n", info->name);
13301 tmp_list = tmp_list->next;
13306 That completes the changes to `XInputize' our program. As with
13307 the first version, the complete source is available at the location
13308 from which you got this tutorial, or from:
13310 <htmlurl url="http://www.gtk.org/~otaylor/gtk/tutorial/"
13311 name="http://www.gtk.org/~otaylor/gtk/tutorial/">
13314 <sect2> Further sophistications <label id="sec_Further_Sophistications">
13317 Although our program now supports XInput quite well, it lacks some
13318 features we would want in a full-featured application. First, the user
13319 probably doesn't want to have to configure their device each time they
13320 run the program, so we should allow them to save the device
13321 configuration. This is done by iterating through the return of
13322 <tt/gdk_input_list_devices()/ and writing out the configuration to a
13326 To restore the state next time the program is run, GDK provides
13327 functions to change device configuration:
13330 gdk_input_set_extension_events()
13331 gdk_input_set_source()
13332 gdk_input_set_mode()
13333 gdk_input_set_axes()
13334 gdk_input_set_key()
13337 (The list returned from <tt/gdk_input_list_devices()/ should not be
13338 modified directly.) An example of doing this can be found in the
13339 drawing program gsumi. (Available from <htmlurl
13340 url="http://www.msc.cornell.edu/~otaylor/gsumi/"
13341 name="http://www.msc.cornell.edu/~otaylor/gsumi/">) Eventually, it
13342 would be nice to have a standard way of doing this for all
13343 applications. This probably belongs at a slightly higher level than
13344 GTK, perhaps in the GNOME library.
13347 Another major omission that we have mentioned above is the lack of
13348 cursor drawing. Platforms other than XFree86 currently do not allow
13349 simultaneously using a device as both the core pointer and directly by
13350 an application. See the <url
13351 url="http://www.msc.cornell.edu/~otaylor/xinput/XInput-HOWTO.html"
13352 name="XInput-HOWTO"> for more information about this. This means that
13353 applications that want to support the widest audience need to draw
13357 An application that draws its own cursor needs to do two things:
13358 determine if the current device needs a cursor drawn or not, and
13359 determine if the current device is in proximity. (If the current
13360 device is a drawing tablet, it's a nice touch to make the cursor
13361 disappear when the stylus is lifted from the tablet. When the
13362 device is touching the stylus, that is called "in proximity.")
13363 The first is done by searching the device list, as we did
13364 to find out the device name. The second is achieved by selecting
13365 "proximity_out" events. An example of drawing one's own cursor is
13366 found in the 'testinput' program found in the GTK distribution.
13368 <!-- ***************************************************************** -->
13369 <sect>Tips For Writing GTK Applications
13370 <!-- ***************************************************************** -->
13373 This section is simply a gathering of wisdom, general style guidelines
13374 and hints to creating good GTK applications. It is totally useless
13375 right now cause its only a topic sentence :)
13377 Use GNU autoconf and automake! They are your friends :) I am planning
13378 to make a quick intro on them here.
13380 <!-- ***************************************************************** -->
13381 <sect>Contributing <label id="sec_Contributing">
13382 <!-- ***************************************************************** -->
13385 This document, like so much other great software out there, was
13386 created for free by volunteers. If you are at all knowledgeable about
13387 any aspect of GTK that does not already have documentation, please
13388 consider contributing to this document.
13390 If you do decide to contribute, please mail your text to Tony Gale,
13391 <tt><htmlurl url="mailto:gale@gtk.org"
13392 name="gale@gtk.org"></tt>. Also, be aware that the entirety of this
13393 document is free, and any addition by you provide must also be
13394 free. That is, people may use any portion of your examples in their
13395 programs, and copies of this document may be distributed at will etc.
13399 <!-- ***************************************************************** -->
13401 <!-- ***************************************************************** -->
13403 I would like to thank the following for their contributions to this text.
13406 <item>Bawer Dagdeviren, <tt><htmlurl url="mailto:chamele0n@geocities.com"
13407 name="chamele0n@geocities.com"></tt> for the menus tutorial.
13409 <item>Raph Levien, <tt><htmlurl url="mailto:raph@acm.org"
13410 name="raph@acm.org"></tt>
13411 for hello world ala GTK, widget packing, and general all around wisdom.
13412 He's also generously donated a home for this tutorial.
13414 <item>Peter Mattis, <tt><htmlurl url="mailto:petm@xcf.berkeley.edu"
13415 name="petm@xcf.berkeley.edu"></tt> for the simplest GTK program..
13416 and the ability to make it :)
13418 <item>Werner Koch <tt><htmlurl url="mailto:werner.koch@guug.de"
13419 name="werner.koch@guug.de"></tt> for converting the original plain text to
13420 SGML, and the widget class hierarchy.
13422 <item>Mark Crichton <tt><htmlurl
13423 url="mailto:crichton@expert.cc.purdue.edu"
13424 name="crichton@expert.cc.purdue.edu"></tt> for the menu factory code,
13425 and the table packing tutorial.
13427 <item>Owen Taylor <tt><htmlurl url="mailto:owt1@cornell.edu"
13428 name="owt1@cornell.edu"></tt> for the EventBox widget section (and the
13429 patch to the distro). He's also responsible for the selections code
13430 and tutorial, as well as the sections on writing your own GTK widgets,
13431 and the example application. Thanks a lot Owen for all you help!
13433 <item>Mark VanderBoom <tt><htmlurl url="mailto:mvboom42@calvin.edu"
13434 name="mvboom42@calvin.edu"></tt> for his wonderful work on the
13435 Notebook, Progress Bar, Dialogs, and File selection widgets. Thanks a
13436 lot Mark! You've been a great help.
13438 <item>Tim Janik <tt><htmlurl url="mailto:timj@gtk.org"
13439 name="timj@psynet.net"></tt> for his great job on the Lists
13440 Widget. His excellent work on automatically extracting the widget tree
13441 and signal information from GTK. Thanks Tim :)
13443 <item>Rajat Datta <tt><htmlurl url="mailto:rajat@ix.netcom.com"
13444 name="rajat@ix.netcom.com"</tt> for the excellent job on the Pixmap
13447 <item>Michael K. Johnson <tt><htmlurl url="mailto:johnsonm@redhat.com"
13448 name="johnsonm@redhat.com"></tt> for info and code for popup menus.
13450 <item>David Huggins-Daines <tt><htmlurl
13451 url="mailto:bn711@freenet.carleton.ca"
13452 name="bn711@freenet.carleton.ca"></tt> for the Range Widgets and Tree
13455 <item>Stefan Mars <tt><htmlurl url="mailto:mars@lysator.liu.se"
13456 name="mars@lysator.liu.se"></tt> for the GtkCList section
13459 And to all of you who commented and helped refine this document.
13463 <!-- ***************************************************************** -->
13464 <sect> Tutorial Copyright and Permissions Notice
13465 <!-- ***************************************************************** -->
13468 The GTK Tutorial is Copyright (C) 1997 Ian Main.
13470 Copyright (C) 1998-1999 Tony Gale.
13472 Permission is granted to make and distribute verbatim copies of this
13473 manual provided the copyright notice and this permission notice are
13474 preserved on all copies.
13476 Permission is granted to copy and distribute modified versions of
13477 this document under the conditions for verbatim copying, provided that
13478 this copyright notice is included exactly as in the original,
13479 and that the entire resulting derived work is distributed under
13480 the terms of a permission notice identical to this one.
13481 <P>Permission is granted to copy and distribute translations of this
13482 document into another language, under the above conditions for modified
13485 If you are intending to incorporate this document into a published
13486 work, please contact the maintainer, and we will make an effort
13487 to ensure that you have the most up to date information available.
13489 There is no guarantee that this document lives up to its intended
13490 purpose. This is simply provided as a free resource. As such,
13491 the authors and maintainers of the information provided within can
13492 not make any guarantee that the information is even accurate.
13494 <!-- ***************************************************************** -->
13496 <!-- ***************************************************************** -->
13498 <!-- ***************************************************************** -->
13499 <sect> GTK Signals <label id="sec_GTK_Signals">
13500 <!-- ***************************************************************** -->
13502 As GTK is an object oriented widget set, it has a hierarchy of
13503 inheritance. This inheritance mechanism applies for
13504 signals. Therefore, you should refer to the widget hierarchy tree when
13505 using the signals listed in this section.
13507 <!-- ----------------------------------------------------------------- -->
13509 <!-- ----------------------------------------------------------------- -->
13512 void GtkObject::destroy (GtkObject *,
13516 <!-- ----------------------------------------------------------------- -->
13518 <!-- ----------------------------------------------------------------- -->
13522 void GtkWidget::show (GtkWidget *,
13524 void GtkWidget::hide (GtkWidget *,
13526 void GtkWidget::map (GtkWidget *,
13528 void GtkWidget::unmap (GtkWidget *,
13530 void GtkWidget::realize (GtkWidget *,
13532 void GtkWidget::unrealize (GtkWidget *,
13534 void GtkWidget::draw (GtkWidget *,
13537 void GtkWidget::draw-focus (GtkWidget *,
13539 void GtkWidget::draw-default (GtkWidget *,
13541 void GtkWidget::size-request (GtkWidget *,
13544 void GtkWidget::size-allocate (GtkWidget *,
13547 void GtkWidget::state-changed (GtkWidget *,
13550 void GtkWidget::parent-set (GtkWidget *,
13553 void GtkWidget::style-set (GtkWidget *,
13556 void GtkWidget::add-accelerator (GtkWidget *,
13563 void GtkWidget::remove-accelerator (GtkWidget *,
13568 gboolean GtkWidget::event (GtkWidget *,
13571 gboolean GtkWidget::button-press-event (GtkWidget *,
13574 gboolean GtkWidget::button-release-event (GtkWidget *,
13577 gboolean GtkWidget::motion-notify-event (GtkWidget *,
13580 gboolean GtkWidget::delete-event (GtkWidget *,
13583 gboolean GtkWidget::destroy-event (GtkWidget *,
13586 gboolean GtkWidget::expose-event (GtkWidget *,
13589 gboolean GtkWidget::key-press-event (GtkWidget *,
13592 gboolean GtkWidget::key-release-event (GtkWidget *,
13595 gboolean GtkWidget::enter-notify-event (GtkWidget *,
13598 gboolean GtkWidget::leave-notify-event (GtkWidget *,
13601 gboolean GtkWidget::configure-event (GtkWidget *,
13604 gboolean GtkWidget::focus-in-event (GtkWidget *,
13607 gboolean GtkWidget::focus-out-event (GtkWidget *,
13610 gboolean GtkWidget::map-event (GtkWidget *,
13613 gboolean GtkWidget::unmap-event (GtkWidget *,
13616 gboolean GtkWidget::property-notify-event (GtkWidget *,
13619 gboolean GtkWidget::selection-clear-event (GtkWidget *,
13622 gboolean GtkWidget::selection-request-event (GtkWidget *,
13625 gboolean GtkWidget::selection-notify-event (GtkWidget *,
13628 void GtkWidget::selection-get (GtkWidget *,
13629 GtkSelectionData *,
13632 void GtkWidget::selection-received (GtkWidget *,
13633 GtkSelectionData *,
13636 gboolean GtkWidget::proximity-in-event (GtkWidget *,
13639 gboolean GtkWidget::proximity-out-event (GtkWidget *,
13642 void GtkWidget::drag-begin (GtkWidget *,
13645 void GtkWidget::drag-end (GtkWidget *,
13648 void GtkWidget::drag-data-delete (GtkWidget *,
13651 void GtkWidget::drag-leave (GtkWidget *,
13655 gboolean GtkWidget::drag-motion (GtkWidget *,
13661 gboolean GtkWidget::drag-drop (GtkWidget *,
13667 void GtkWidget::drag-data-get (GtkWidget *,
13669 GtkSelectionData *,
13673 void GtkWidget::drag-data-received (GtkWidget *,
13677 GtkSelectionData *,
13681 gboolean GtkWidget::client-event (GtkWidget *,
13684 gboolean GtkWidget::no-expose-event (GtkWidget *,
13687 gboolean GtkWidget::visibility-notify-event (GtkWidget *,
13690 void GtkWidget::debug-msg (GtkWidget *,
13695 <!-- ----------------------------------------------------------------- -->
13697 <!-- ----------------------------------------------------------------- -->
13700 void GtkData::disconnect (GtkData *,
13704 <!-- ----------------------------------------------------------------- -->
13705 <sect1>GtkContainer
13706 <!-- ----------------------------------------------------------------- -->
13709 void GtkContainer::add (GtkContainer *,
13712 void GtkContainer::remove (GtkContainer *,
13715 void GtkContainer::check-resize (GtkContainer *,
13717 GtkDirectionType GtkContainer::focus (GtkContainer *,
13720 void GtkContainer::set-focus-child (GtkContainer *,
13725 <!-- ----------------------------------------------------------------- -->
13727 <!-- ----------------------------------------------------------------- -->
13730 void GtkCalendar::month-changed (GtkCalendar *,
13732 void GtkCalendar::day-selected (GtkCalendar *,
13734 void GtkCalendar::day-selected-double-click (GtkCalendar *,
13736 void GtkCalendar::prev-month (GtkCalendar *,
13738 void GtkCalendar::next-month (GtkCalendar *,
13740 void GtkCalendar::prev-year (GtkCalendar *,
13742 void GtkCalendar::next-year (GtkCalendar *,
13746 <!-- ----------------------------------------------------------------- -->
13748 <!-- ----------------------------------------------------------------- -->
13751 void GtkEditable::changed (GtkEditable *,
13753 void GtkEditable::insert-text (GtkEditable *,
13758 void GtkEditable::delete-text (GtkEditable *,
13762 void GtkEditable::activate (GtkEditable *,
13764 void GtkEditable::set-editable (GtkEditable *,
13767 void GtkEditable::move-cursor (GtkEditable *,
13771 void GtkEditable::move-word (GtkEditable *,
13774 void GtkEditable::move-page (GtkEditable *,
13778 void GtkEditable::move-to-row (GtkEditable *,
13781 void GtkEditable::move-to-column (GtkEditable *,
13784 void GtkEditable::kill-char (GtkEditable *,
13787 void GtkEditable::kill-word (GtkEditable *,
13790 void GtkEditable::kill-line (GtkEditable *,
13793 void GtkEditable::cut-clipboard (GtkEditable *,
13795 void GtkEditable::copy-clipboard (GtkEditable *,
13797 void GtkEditable::paste-clipboard (GtkEditable *,
13801 <!-- ----------------------------------------------------------------- -->
13802 <sect1>GtkTipsQuery
13803 <!-- ----------------------------------------------------------------- -->
13806 void GtkTipsQuery::start-query (GtkTipsQuery *,
13808 void GtkTipsQuery::stop-query (GtkTipsQuery *,
13810 void GtkTipsQuery::widget-entered (GtkTipsQuery *,
13815 gboolean GtkTipsQuery::widget-selected (GtkTipsQuery *,
13823 <!-- ----------------------------------------------------------------- -->
13825 <!-- ----------------------------------------------------------------- -->
13828 void GtkCList::select-row (GtkCList *,
13833 void GtkCList::unselect-row (GtkCList *,
13838 void GtkCList::row-move (GtkCList *,
13842 void GtkCList::click-column (GtkCList *,
13845 void GtkCList::resize-column (GtkCList *,
13849 void GtkCList::toggle-focus-row (GtkCList *,
13851 void GtkCList::select-all (GtkCList *,
13853 void GtkCList::unselect-all (GtkCList *,
13855 void GtkCList::undo-selection (GtkCList *,
13857 void GtkCList::start-selection (GtkCList *,
13859 void GtkCList::end-selection (GtkCList *,
13861 void GtkCList::toggle-add-mode (GtkCList *,
13863 void GtkCList::extend-selection (GtkCList *,
13868 void GtkCList::scroll-vertical (GtkCList *,
13872 void GtkCList::scroll-horizontal (GtkCList *,
13876 void GtkCList::abort-column-resize (GtkCList *,
13880 <!-- ----------------------------------------------------------------- -->
13882 <!-- ----------------------------------------------------------------- -->
13885 void GtkNotebook::switch-page (GtkNotebook *,
13892 <!-- ----------------------------------------------------------------- -->
13894 <!-- ----------------------------------------------------------------- -->
13897 void GtkList::selection-changed (GtkList *,
13899 void GtkList::select-child (GtkList *,
13902 void GtkList::unselect-child (GtkList *,
13907 <!-- ----------------------------------------------------------------- -->
13908 <sect1>GtkMenuShell
13909 <!-- ----------------------------------------------------------------- -->
13912 void GtkMenuShell::deactivate (GtkMenuShell *,
13914 void GtkMenuShell::selection-done (GtkMenuShell *,
13916 void GtkMenuShell::move-current (GtkMenuShell *,
13917 GtkMenuDirectionType,
13919 void GtkMenuShell::activate-current (GtkMenuShell *,
13922 void GtkMenuShell::cancel (GtkMenuShell *,
13926 <!-- ----------------------------------------------------------------- -->
13928 <!-- ----------------------------------------------------------------- -->
13931 void GtkToolbar::orientation-changed (GtkToolbar *,
13934 void GtkToolbar::style-changed (GtkToolbar *,
13939 <!-- ----------------------------------------------------------------- -->
13941 <!-- ----------------------------------------------------------------- -->
13944 void GtkTree::selection-changed (GtkTree *,
13946 void GtkTree::select-child (GtkTree *,
13949 void GtkTree::unselect-child (GtkTree *,
13954 <!-- ----------------------------------------------------------------- -->
13956 <!-- ----------------------------------------------------------------- -->
13959 void GtkButton::pressed (GtkButton *,
13961 void GtkButton::released (GtkButton *,
13963 void GtkButton::clicked (GtkButton *,
13965 void GtkButton::enter (GtkButton *,
13967 void GtkButton::leave (GtkButton *,
13971 <!-- ----------------------------------------------------------------- -->
13973 <!-- ----------------------------------------------------------------- -->
13976 void GtkItem::select (GtkItem *,
13978 void GtkItem::deselect (GtkItem *,
13980 void GtkItem::toggle (GtkItem *,
13984 <!-- ----------------------------------------------------------------- -->
13986 <!-- ----------------------------------------------------------------- -->
13989 void GtkWindow::set-focus (GtkWindow *,
13994 <!-- ----------------------------------------------------------------- -->
13995 <sect1>GtkHandleBox
13996 <!-- ----------------------------------------------------------------- -->
13999 void GtkHandleBox::child-attached (GtkHandleBox *,
14002 void GtkHandleBox::child-detached (GtkHandleBox *,
14007 <!-- ----------------------------------------------------------------- -->
14008 <sect1>GtkToggleButton
14009 <!-- ----------------------------------------------------------------- -->
14012 void GtkToggleButton::toggled (GtkToggleButton *,
14017 <!-- ----------------------------------------------------------------- -->
14019 <!-- ----------------------------------------------------------------- -->
14022 void GtkMenuItem::activate (GtkMenuItem *,
14024 void GtkMenuItem::activate-item (GtkMenuItem *,
14028 <!-- ----------------------------------------------------------------- -->
14030 <!-- ----------------------------------------------------------------- -->
14033 void GtkListItem::toggle-focus-row (GtkListItem *,
14035 void GtkListItem::select-all (GtkListItem *,
14037 void GtkListItem::unselect-all (GtkListItem *,
14039 void GtkListItem::undo-selection (GtkListItem *,
14041 void GtkListItem::start-selection (GtkListItem *,
14043 void GtkListItem::end-selection (GtkListItem *,
14045 void GtkListItem::toggle-add-mode (GtkListItem *,
14047 void GtkListItem::extend-selection (GtkListItem *,
14052 void GtkListItem::scroll-vertical (GtkListItem *,
14056 void GtkListItem::scroll-horizontal (GtkListItem *,
14062 <!-- ----------------------------------------------------------------- -->
14064 <!-- ----------------------------------------------------------------- -->
14067 void GtkTreeItem::collapse (GtkTreeItem *,
14069 void GtkTreeItem::expand (GtkTreeItem *,
14073 <!-- ----------------------------------------------------------------- -->
14074 <sect1>GtkCheckMenuItem
14075 <!-- ----------------------------------------------------------------- -->
14078 void GtkCheckMenuItem::toggled (GtkCheckMenuItem *,
14082 <!-- ----------------------------------------------------------------- -->
14083 <sect1>GtkInputDialog
14084 <!-- ----------------------------------------------------------------- -->
14087 void GtkInputDialog::enable-device (GtkInputDialog *,
14090 void GtkInputDialog::disable-device (GtkInputDialog *,
14095 <!-- ----------------------------------------------------------------- -->
14096 <sect1>GtkColorSelection
14097 <!-- ----------------------------------------------------------------- -->
14100 void GtkColorSelection::color-changed (GtkColorSelection *,
14104 <!-- ----------------------------------------------------------------- -->
14105 <sect1>GtkStatusBar
14106 <!-- ----------------------------------------------------------------- -->
14109 void GtkStatusbar::text-pushed (GtkStatusbar *,
14113 void GtkStatusbar::text-popped (GtkStatusbar *,
14119 <!-- ----------------------------------------------------------------- -->
14121 <!-- ----------------------------------------------------------------- -->
14124 void GtkCTree::tree-select-row (GtkCTree *,
14128 void GtkCTree::tree-unselect-row (GtkCTree *,
14132 void GtkCTree::tree-expand (GtkCTree *,
14135 void GtkCTree::tree-collapse (GtkCTree *,
14138 void GtkCTree::tree-move (GtkCTree *,
14143 void GtkCTree::change-focus-row-expansion (GtkCTree *,
14144 GtkCTreeExpansionType,
14148 <!-- ----------------------------------------------------------------- -->
14150 <!-- ----------------------------------------------------------------- -->
14153 void GtkCurve::curve-type-changed (GtkCurve *,
14157 <!-- ----------------------------------------------------------------- -->
14158 <sect1>GtkAdjustment
14159 <!-- ----------------------------------------------------------------- -->
14162 void GtkAdjustment::changed (GtkAdjustment *,
14164 void GtkAdjustment::value-changed (GtkAdjustment *,
14168 <!-- ***************************************************************** -->
14169 <sect> GDK Event Types<label id="sec_GDK_Event_Types">
14170 <!-- ***************************************************************** -->
14172 The follwing data types are passed into event handlers by GTK+. For
14173 each data type listed, the signals that use this data type are listed.
14178 <item>drag_end_event
14181 <item> GdkEventType
14186 <item>destroy_event
14189 <item>no_expose_event
14192 <item> GdkEventExpose
14197 <item> GdkEventNoExpose
14199 <item> GdkEventVisibility
14201 <item> GdkEventMotion
14203 <item>motion_notify_event
14206 <item> GdkEventButton
14208 <item>button_press_event
14209 <item>button_release_event
14214 <item>key_press_event
14215 <item>key_release_event
14218 <item> GdkEventCrossing
14220 <item>enter_notify_event
14221 <item>leave_notify_event
14224 <item> GdkEventFocus
14226 <item>focus_in_event
14227 <item>focus_out_event
14230 <item> GdkEventConfigure
14232 <item>configure_event
14235 <item> GdkEventProperty
14237 <item>property_notify_event
14240 <item> GdkEventSelection
14242 <item>selection_clear_event
14243 <item>selection_request_event
14244 <item>selection_notify_event
14247 <item> GdkEventProximity
14249 <item>proximity_in_event
14250 <item>proximity_out_event
14253 <item> GdkEventDragBegin
14255 <item>drag_begin_event
14258 <item> GdkEventDragRequest
14260 <item>drag_request_event
14263 <item> GdkEventDropEnter
14265 <item>drop_enter_event
14268 <item> GdkEventDropLeave
14270 <item>drop_leave_event
14273 <item> GdkEventDropDataAvailable
14275 <item>drop_data_available_event
14278 <item> GdkEventClient
14283 <item> GdkEventOther
14289 The data type <tt/GdkEventType/ is a special data type that is used by
14290 all the other data types as an indicator of the data type being passed
14291 to the signal handler. As you will see below, each of the event data
14292 structures has a member of this type. It is defined as an enumeration
14302 GDK_MOTION_NOTIFY = 3,
14303 GDK_BUTTON_PRESS = 4,
14304 GDK_2BUTTON_PRESS = 5,
14305 GDK_3BUTTON_PRESS = 6,
14306 GDK_BUTTON_RELEASE = 7,
14308 GDK_KEY_RELEASE = 9,
14309 GDK_ENTER_NOTIFY = 10,
14310 GDK_LEAVE_NOTIFY = 11,
14311 GDK_FOCUS_CHANGE = 12,
14312 GDK_CONFIGURE = 13,
14315 GDK_PROPERTY_NOTIFY = 16,
14316 GDK_SELECTION_CLEAR = 17,
14317 GDK_SELECTION_REQUEST = 18,
14318 GDK_SELECTION_NOTIFY = 19,
14319 GDK_PROXIMITY_IN = 20,
14320 GDK_PROXIMITY_OUT = 21,
14321 GDK_DRAG_BEGIN = 22,
14322 GDK_DRAG_REQUEST = 23,
14323 GDK_DROP_ENTER = 24,
14324 GDK_DROP_LEAVE = 25,
14325 GDK_DROP_DATA_AVAIL = 26,
14326 GDK_CLIENT_EVENT = 27,
14327 GDK_VISIBILITY_NOTIFY = 28,
14328 GDK_NO_EXPOSE = 29,
14329 GDK_OTHER_EVENT = 9999 /* Deprecated, use filters instead */
14333 The other event type that is different from the others is
14334 <tt/GdkEvent/ itself. This is a union of all the other
14335 data types, which allows it to be cast to a specific
14336 event data type within a signal handler.
14338 <!-- Just a big list for now, needs expanding upon - TRG -->
14339 So, the event data types are defined as follows:
14342 struct _GdkEventAny
14349 struct _GdkEventExpose
14355 gint count; /* If non-zero, how many more events follow. */
14358 struct _GdkEventNoExpose
14363 /* XXX: does anyone need the X major_code or minor_code fields? */
14366 struct _GdkEventVisibility
14371 GdkVisibilityState state;
14374 struct _GdkEventMotion
14387 GdkInputSource source;
14389 gdouble x_root, y_root;
14392 struct _GdkEventButton
14405 GdkInputSource source;
14407 gdouble x_root, y_root;
14410 struct _GdkEventKey
14422 struct _GdkEventCrossing
14427 GdkWindow *subwindow;
14428 GdkNotifyType detail;
14431 struct _GdkEventFocus
14439 struct _GdkEventConfigure
14449 struct _GdkEventProperty
14459 struct _GdkEventSelection
14471 /* This event type will be used pretty rarely. It only is important
14472 for XInput aware programs that are drawing their own cursor */
14474 struct _GdkEventProximity
14480 GdkInputSource source;
14484 struct _GdkEventDragRequest
14492 guint protocol_version:4;
14494 guint willaccept:1;
14495 guint delete_data:1; /* Do *not* delete if link is sent, only
14502 guint8 isdrop; /* This gdk event can be generated by a couple of
14503 X events - this lets the app know whether the
14504 drop really occurred or we just set the data */
14506 GdkPoint drop_coords;
14511 struct _GdkEventDragBegin
14518 guint protocol_version:4;
14525 struct _GdkEventDropEnter
14533 guint protocol_version:4;
14535 guint extended_typelist:1;
14542 struct _GdkEventDropLeave
14550 guint protocol_version:4;
14557 struct _GdkEventDropDataAvailable
14565 guint protocol_version:4;
14571 gchar *data_type; /* MIME type */
14572 gulong data_numbytes;
14578 struct _GdkEventClient
14583 GdkAtom message_type;
14584 gushort data_format;
14592 struct _GdkEventOther
14601 <!-- ***************************************************************** -->
14602 <sect> Code Examples
14603 <!-- ***************************************************************** -->
14605 Below are the code examples that are used in the above text
14606 which are not included in complete form elsewhere.
14608 <!-- ----------------------------------------------------------------- -->
14610 <!-- ----------------------------------------------------------------- -->
14614 /* example-start tictactoe tictactoe.h */
14616 /* GTK - The GIMP Toolkit
14617 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
14619 * This library is free software; you can redistribute it and/or
14620 * modify it under the terms of the GNU Library General Public
14621 * License as published by the Free Software Foundation; either
14622 * version 2 of the License, or (at your option) any later version.
14624 * This library is distributed in the hope that it will be useful,
14625 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14626 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14627 * Library General Public License for more details.
14629 * You should have received a copy of the GNU Library General Public
14630 * License along with this library; if not, write to the
14631 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
14632 * Boston, MA 02111-1307, USA.
14634 #ifndef __TICTACTOE_H__
14635 #define __TICTACTOE_H__
14638 #include <gdk/gdk.h>
14639 #include <gtk/gtkvbox.h>
14644 #endif /* __cplusplus */
14646 #define TICTACTOE(obj) GTK_CHECK_CAST (obj, tictactoe_get_type (), Tictactoe)
14647 #define TICTACTOE_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, tictactoe_get_type (), TictactoeClass)
14648 #define IS_TICTACTOE(obj) GTK_CHECK_TYPE (obj, tictactoe_get_type ())
14651 typedef struct _Tictactoe Tictactoe;
14652 typedef struct _TictactoeClass TictactoeClass;
14658 GtkWidget *buttons[3][3];
14661 struct _TictactoeClass
14663 GtkVBoxClass parent_class;
14665 void (* tictactoe) (Tictactoe *ttt);
14668 guint tictactoe_get_type (void);
14669 GtkWidget* tictactoe_new (void);
14670 void tictactoe_clear (Tictactoe *ttt);
14674 #endif /* __cplusplus */
14676 #endif /* __TICTACTOE_H__ */
14681 <!-- ----------------------------------------------------------------- -->
14685 /* example-start tictactoe tictactoe.c */
14687 /* GTK - The GIMP Toolkit
14688 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
14690 * This library is free software; you can redistribute it and/or
14691 * modify it under the terms of the GNU Library General Public
14692 * License as published by the Free Software Foundation; either
14693 * version 2 of the License, or (at your option) any later version.
14695 * This library is distributed in the hope that it will be useful,
14696 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14697 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14698 * Library General Public License for more details.
14700 * You should have received a copy of the GNU Library General Public
14701 * License along with this library; if not, write to the
14702 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
14703 * Boston, MA 02111-1307, USA.
14705 #include "gtk/gtksignal.h"
14706 #include "gtk/gtktable.h"
14707 #include "gtk/gtktogglebutton.h"
14708 #include "tictactoe.h"
14715 static void tictactoe_class_init (TictactoeClass *klass);
14716 static void tictactoe_init (Tictactoe *ttt);
14717 static void tictactoe_toggle (GtkWidget *widget, Tictactoe *ttt);
14719 static gint tictactoe_signals[LAST_SIGNAL] = { 0 };
14722 tictactoe_get_type ()
14724 static guint ttt_type = 0;
14728 GtkTypeInfo ttt_info =
14731 sizeof (Tictactoe),
14732 sizeof (TictactoeClass),
14733 (GtkClassInitFunc) tictactoe_class_init,
14734 (GtkObjectInitFunc) tictactoe_init,
14735 (GtkArgSetFunc) NULL,
14736 (GtkArgGetFunc) NULL
14739 ttt_type = gtk_type_unique (gtk_vbox_get_type (), &ttt_info);
14746 tictactoe_class_init (TictactoeClass *class)
14748 GtkObjectClass *object_class;
14750 object_class = (GtkObjectClass*) class;
14752 tictactoe_signals[TICTACTOE_SIGNAL] = gtk_signal_new ("tictactoe",
14754 object_class->type,
14755 GTK_SIGNAL_OFFSET (TictactoeClass, tictactoe),
14756 gtk_signal_default_marshaller, GTK_TYPE_NONE, 0);
14759 gtk_object_class_add_signals (object_class, tictactoe_signals, LAST_SIGNAL);
14761 class->tictactoe = NULL;
14765 tictactoe_init (Tictactoe *ttt)
14770 table = gtk_table_new (3, 3, TRUE);
14771 gtk_container_add (GTK_CONTAINER(ttt), table);
14772 gtk_widget_show (table);
14777 ttt->buttons[i][j] = gtk_toggle_button_new ();
14778 gtk_table_attach_defaults (GTK_TABLE(table), ttt->buttons[i][j],
14780 gtk_signal_connect (GTK_OBJECT (ttt->buttons[i][j]), "toggled",
14781 GTK_SIGNAL_FUNC (tictactoe_toggle), ttt);
14782 gtk_widget_set_usize (ttt->buttons[i][j], 20, 20);
14783 gtk_widget_show (ttt->buttons[i][j]);
14790 return GTK_WIDGET ( gtk_type_new (tictactoe_get_type ()));
14794 tictactoe_clear (Tictactoe *ttt)
14801 gtk_signal_handler_block_by_data (GTK_OBJECT(ttt->buttons[i][j]), ttt);
14802 gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (ttt->buttons[i][j]),
14804 gtk_signal_handler_unblock_by_data (GTK_OBJECT(ttt->buttons[i][j]), ttt);
14809 tictactoe_toggle (GtkWidget *widget, Tictactoe *ttt)
14813 static int rwins[8][3] = { { 0, 0, 0 }, { 1, 1, 1 }, { 2, 2, 2 },
14814 { 0, 1, 2 }, { 0, 1, 2 }, { 0, 1, 2 },
14815 { 0, 1, 2 }, { 0, 1, 2 } };
14816 static int cwins[8][3] = { { 0, 1, 2 }, { 0, 1, 2 }, { 0, 1, 2 },
14817 { 0, 0, 0 }, { 1, 1, 1 }, { 2, 2, 2 },
14818 { 0, 1, 2 }, { 2, 1, 0 } };
14820 int success, found;
14822 for (k=0; k<8; k++)
14829 success = success &&
14830 GTK_TOGGLE_BUTTON(ttt->buttons[rwins[k][i]][cwins[k][i]])->active;
14832 ttt->buttons[rwins[k][i]][cwins[k][i]] == widget;
14835 if (success && found)
14837 gtk_signal_emit (GTK_OBJECT (ttt),
14838 tictactoe_signals[TICTACTOE_SIGNAL]);
14847 <!-- ----------------------------------------------------------------- -->
14851 /* example-start tictactoe ttt_test.c */
14853 #include <gtk/gtk.h>
14854 #include "tictactoe.h"
14857 win (GtkWidget *widget, gpointer data)
14859 g_print ("Yay!\n");
14860 tictactoe_clear (TICTACTOE (widget));
14864 main (int argc, char *argv[])
14869 gtk_init (&argc, &argv);
14871 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
14873 gtk_window_set_title (GTK_WINDOW (window), "Aspect Frame");
14875 gtk_signal_connect (GTK_OBJECT (window), "destroy",
14876 GTK_SIGNAL_FUNC (gtk_exit), NULL);
14878 gtk_container_set_border_width (GTK_CONTAINER (window), 10);
14880 ttt = tictactoe_new ();
14882 gtk_container_add (GTK_CONTAINER (window), ttt);
14883 gtk_widget_show (ttt);
14885 gtk_signal_connect (GTK_OBJECT (ttt), "tictactoe",
14886 GTK_SIGNAL_FUNC (win), NULL);
14888 gtk_widget_show (window);
14898 <!-- ----------------------------------------------------------------- -->
14901 <!-- ----------------------------------------------------------------- -->
14905 /* example-start gtkdial gtkdial.h */
14907 /* GTK - The GIMP Toolkit
14908 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
14910 * This library is free software; you can redistribute it and/or
14911 * modify it under the terms of the GNU Library General Public
14912 * License as published by the Free Software Foundation; either
14913 * version 2 of the License, or (at your option) any later version.
14915 * This library is distributed in the hope that it will be useful,
14916 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14917 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14918 * Library General Public License for more details.
14920 * You should have received a copy of the GNU Library General Public
14921 * License along with this library; if not, write to the
14922 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
14923 * Boston, MA 02111-1307, USA.
14925 #ifndef __GTK_DIAL_H__
14926 #define __GTK_DIAL_H__
14929 #include <gdk/gdk.h>
14930 #include <gtk/gtkadjustment.h>
14931 #include <gtk/gtkwidget.h>
14936 #endif /* __cplusplus */
14939 #define GTK_DIAL(obj) GTK_CHECK_CAST (obj, gtk_dial_get_type (), GtkDial)
14940 #define GTK_DIAL_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, gtk_dial_get_type (), GtkDialClass)
14941 #define GTK_IS_DIAL(obj) GTK_CHECK_TYPE (obj, gtk_dial_get_type ())
14944 typedef struct _GtkDial GtkDial;
14945 typedef struct _GtkDialClass GtkDialClass;
14951 /* update policy (GTK_UPDATE_[CONTINUOUS/DELAYED/DISCONTINUOUS]) */
14954 /* Button currently pressed or 0 if none */
14957 /* Dimensions of dial components */
14959 gint pointer_width;
14961 /* ID of update timer, or 0 if none */
14964 /* Current angle */
14967 /* Old values from adjustment stored so we know when something changes */
14972 /* The adjustment object that stores the data for this dial */
14973 GtkAdjustment *adjustment;
14976 struct _GtkDialClass
14978 GtkWidgetClass parent_class;
14982 GtkWidget* gtk_dial_new (GtkAdjustment *adjustment);
14983 guint gtk_dial_get_type (void);
14984 GtkAdjustment* gtk_dial_get_adjustment (GtkDial *dial);
14985 void gtk_dial_set_update_policy (GtkDial *dial,
14986 GtkUpdateType policy);
14988 void gtk_dial_set_adjustment (GtkDial *dial,
14989 GtkAdjustment *adjustment);
14992 #endif /* __cplusplus */
14995 #endif /* __GTK_DIAL_H__ */
14999 <!-- ----------------------------------------------------------------- -->
15003 /* example-start gtkdial gtkdial.c */
15005 /* GTK - The GIMP Toolkit
15006 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
15008 * This library is free software; you can redistribute it and/or
15009 * modify it under the terms of the GNU Library General Public
15010 * License as published by the Free Software Foundation; either
15011 * version 2 of the License, or (at your option) any later version.
15013 * This library is distributed in the hope that it will be useful,
15014 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15016 * Library General Public License for more details.
15018 * You should have received a copy of the GNU Library General Public
15019 * License along with this library; if not, write to the
15020 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
15021 * Boston, MA 02111-1307, USA.
15025 #include <gtk/gtkmain.h>
15026 #include <gtk/gtksignal.h>
15028 #include "gtkdial.h"
15030 #define SCROLL_DELAY_LENGTH 300
15031 #define DIAL_DEFAULT_SIZE 100
15033 /* Forward declarations */
15035 static void gtk_dial_class_init (GtkDialClass *klass);
15036 static void gtk_dial_init (GtkDial *dial);
15037 static void gtk_dial_destroy (GtkObject *object);
15038 static void gtk_dial_realize (GtkWidget *widget);
15039 static void gtk_dial_size_request (GtkWidget *widget,
15040 GtkRequisition *requisition);
15041 static void gtk_dial_size_allocate (GtkWidget *widget,
15042 GtkAllocation *allocation);
15043 static gint gtk_dial_expose (GtkWidget *widget,
15044 GdkEventExpose *event);
15045 static gint gtk_dial_button_press (GtkWidget *widget,
15046 GdkEventButton *event);
15047 static gint gtk_dial_button_release (GtkWidget *widget,
15048 GdkEventButton *event);
15049 static gint gtk_dial_motion_notify (GtkWidget *widget,
15050 GdkEventMotion *event);
15051 static gint gtk_dial_timer (GtkDial *dial);
15053 static void gtk_dial_update_mouse (GtkDial *dial, gint x, gint y);
15054 static void gtk_dial_update (GtkDial *dial);
15055 static void gtk_dial_adjustment_changed (GtkAdjustment *adjustment,
15057 static void gtk_dial_adjustment_value_changed (GtkAdjustment *adjustment,
15062 static GtkWidgetClass *parent_class = NULL;
15065 gtk_dial_get_type ()
15067 static guint dial_type = 0;
15071 GtkTypeInfo dial_info =
15075 sizeof (GtkDialClass),
15076 (GtkClassInitFunc) gtk_dial_class_init,
15077 (GtkObjectInitFunc) gtk_dial_init,
15078 (GtkArgSetFunc) NULL,
15079 (GtkArgGetFunc) NULL,
15082 dial_type = gtk_type_unique (gtk_widget_get_type (), &dial_info);
15089 gtk_dial_class_init (GtkDialClass *class)
15091 GtkObjectClass *object_class;
15092 GtkWidgetClass *widget_class;
15094 object_class = (GtkObjectClass*) class;
15095 widget_class = (GtkWidgetClass*) class;
15097 parent_class = gtk_type_class (gtk_widget_get_type ());
15099 object_class->destroy = gtk_dial_destroy;
15101 widget_class->realize = gtk_dial_realize;
15102 widget_class->expose_event = gtk_dial_expose;
15103 widget_class->size_request = gtk_dial_size_request;
15104 widget_class->size_allocate = gtk_dial_size_allocate;
15105 widget_class->button_press_event = gtk_dial_button_press;
15106 widget_class->button_release_event = gtk_dial_button_release;
15107 widget_class->motion_notify_event = gtk_dial_motion_notify;
15111 gtk_dial_init (GtkDial *dial)
15114 dial->policy = GTK_UPDATE_CONTINUOUS;
15117 dial->pointer_width = 0;
15119 dial->old_value = 0.0;
15120 dial->old_lower = 0.0;
15121 dial->old_upper = 0.0;
15122 dial->adjustment = NULL;
15126 gtk_dial_new (GtkAdjustment *adjustment)
15130 dial = gtk_type_new (gtk_dial_get_type ());
15133 adjustment = (GtkAdjustment*) gtk_adjustment_new (0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
15135 gtk_dial_set_adjustment (dial, adjustment);
15137 return GTK_WIDGET (dial);
15141 gtk_dial_destroy (GtkObject *object)
15145 g_return_if_fail (object != NULL);
15146 g_return_if_fail (GTK_IS_DIAL (object));
15148 dial = GTK_DIAL (object);
15150 if (dial->adjustment)
15151 gtk_object_unref (GTK_OBJECT (dial->adjustment));
15153 if (GTK_OBJECT_CLASS (parent_class)->destroy)
15154 (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
15158 gtk_dial_get_adjustment (GtkDial *dial)
15160 g_return_val_if_fail (dial != NULL, NULL);
15161 g_return_val_if_fail (GTK_IS_DIAL (dial), NULL);
15163 return dial->adjustment;
15167 gtk_dial_set_update_policy (GtkDial *dial,
15168 GtkUpdateType policy)
15170 g_return_if_fail (dial != NULL);
15171 g_return_if_fail (GTK_IS_DIAL (dial));
15173 dial->policy = policy;
15177 gtk_dial_set_adjustment (GtkDial *dial,
15178 GtkAdjustment *adjustment)
15180 g_return_if_fail (dial != NULL);
15181 g_return_if_fail (GTK_IS_DIAL (dial));
15183 if (dial->adjustment)
15185 gtk_signal_disconnect_by_data (GTK_OBJECT (dial->adjustment), (gpointer) dial);
15186 gtk_object_unref (GTK_OBJECT (dial->adjustment));
15189 dial->adjustment = adjustment;
15190 gtk_object_ref (GTK_OBJECT (dial->adjustment));
15192 gtk_signal_connect (GTK_OBJECT (adjustment), "changed",
15193 (GtkSignalFunc) gtk_dial_adjustment_changed,
15195 gtk_signal_connect (GTK_OBJECT (adjustment), "value_changed",
15196 (GtkSignalFunc) gtk_dial_adjustment_value_changed,
15199 dial->old_value = adjustment->value;
15200 dial->old_lower = adjustment->lower;
15201 dial->old_upper = adjustment->upper;
15203 gtk_dial_update (dial);
15207 gtk_dial_realize (GtkWidget *widget)
15210 GdkWindowAttr attributes;
15211 gint attributes_mask;
15213 g_return_if_fail (widget != NULL);
15214 g_return_if_fail (GTK_IS_DIAL (widget));
15216 GTK_WIDGET_SET_FLAGS (widget, GTK_REALIZED);
15217 dial = GTK_DIAL (widget);
15219 attributes.x = widget->allocation.x;
15220 attributes.y = widget->allocation.y;
15221 attributes.width = widget->allocation.width;
15222 attributes.height = widget->allocation.height;
15223 attributes.wclass = GDK_INPUT_OUTPUT;
15224 attributes.window_type = GDK_WINDOW_CHILD;
15225 attributes.event_mask = gtk_widget_get_events (widget) |
15226 GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK |
15227 GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK |
15228 GDK_POINTER_MOTION_HINT_MASK;
15229 attributes.visual = gtk_widget_get_visual (widget);
15230 attributes.colormap = gtk_widget_get_colormap (widget);
15232 attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
15233 widget->window = gdk_window_new (widget->parent->window, &attributes, attributes_mask);
15235 widget->style = gtk_style_attach (widget->style, widget->window);
15237 gdk_window_set_user_data (widget->window, widget);
15239 gtk_style_set_background (widget->style, widget->window, GTK_STATE_ACTIVE);
15243 gtk_dial_size_request (GtkWidget *widget,
15244 GtkRequisition *requisition)
15246 requisition->width = DIAL_DEFAULT_SIZE;
15247 requisition->height = DIAL_DEFAULT_SIZE;
15251 gtk_dial_size_allocate (GtkWidget *widget,
15252 GtkAllocation *allocation)
15256 g_return_if_fail (widget != NULL);
15257 g_return_if_fail (GTK_IS_DIAL (widget));
15258 g_return_if_fail (allocation != NULL);
15260 widget->allocation = *allocation;
15261 dial = GTK_DIAL (widget);
15263 if (GTK_WIDGET_REALIZED (widget))
15266 gdk_window_move_resize (widget->window,
15267 allocation->x, allocation->y,
15268 allocation->width, allocation->height);
15271 dial->radius = MIN(allocation->width,allocation->height) * 0.45;
15272 dial->pointer_width = dial->radius / 5;
15276 gtk_dial_expose (GtkWidget *widget,
15277 GdkEventExpose *event)
15280 GdkPoint points[3];
15287 g_return_val_if_fail (widget != NULL, FALSE);
15288 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
15289 g_return_val_if_fail (event != NULL, FALSE);
15291 if (event->count > 0)
15294 dial = GTK_DIAL (widget);
15296 gdk_window_clear_area (widget->window,
15298 widget->allocation.width,
15299 widget->allocation.height);
15301 xc = widget->allocation.width/2;
15302 yc = widget->allocation.height/2;
15306 for (i=0; i<25; i++)
15308 theta = (i*M_PI/18. - M_PI/6.);
15312 tick_length = (i%6 == 0) ? dial->pointer_width : dial->pointer_width/2;
15314 gdk_draw_line (widget->window,
15315 widget->style->fg_gc[widget->state],
15316 xc + c*(dial->radius - tick_length),
15317 yc - s*(dial->radius - tick_length),
15318 xc + c*dial->radius,
15319 yc - s*dial->radius);
15324 s = sin(dial->angle);
15325 c = cos(dial->angle);
15328 points[0].x = xc + s*dial->pointer_width/2;
15329 points[0].y = yc + c*dial->pointer_width/2;
15330 points[1].x = xc + c*dial->radius;
15331 points[1].y = yc - s*dial->radius;
15332 points[2].x = xc - s*dial->pointer_width/2;
15333 points[2].y = yc - c*dial->pointer_width/2;
15335 gtk_draw_polygon (widget->style,
15346 gtk_dial_button_press (GtkWidget *widget,
15347 GdkEventButton *event)
15353 double d_perpendicular;
15355 g_return_val_if_fail (widget != NULL, FALSE);
15356 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
15357 g_return_val_if_fail (event != NULL, FALSE);
15359 dial = GTK_DIAL (widget);
15361 /* Determine if button press was within pointer region - we
15362 do this by computing the parallel and perpendicular distance of
15363 the point where the mouse was pressed from the line passing through
15366 dx = event->x - widget->allocation.width / 2;
15367 dy = widget->allocation.height / 2 - event->y;
15369 s = sin(dial->angle);
15370 c = cos(dial->angle);
15372 d_parallel = s*dy + c*dx;
15373 d_perpendicular = fabs(s*dx - c*dy);
15375 if (!dial->button &&
15376 (d_perpendicular < dial->pointer_width/2) &&
15377 (d_parallel > - dial->pointer_width))
15379 gtk_grab_add (widget);
15381 dial->button = event->button;
15383 gtk_dial_update_mouse (dial, event->x, event->y);
15390 gtk_dial_button_release (GtkWidget *widget,
15391 GdkEventButton *event)
15395 g_return_val_if_fail (widget != NULL, FALSE);
15396 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
15397 g_return_val_if_fail (event != NULL, FALSE);
15399 dial = GTK_DIAL (widget);
15401 if (dial->button == event->button)
15403 gtk_grab_remove (widget);
15407 if (dial->policy == GTK_UPDATE_DELAYED)
15408 gtk_timeout_remove (dial->timer);
15410 if ((dial->policy != GTK_UPDATE_CONTINUOUS) &&
15411 (dial->old_value != dial->adjustment->value))
15412 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
15419 gtk_dial_motion_notify (GtkWidget *widget,
15420 GdkEventMotion *event)
15423 GdkModifierType mods;
15426 g_return_val_if_fail (widget != NULL, FALSE);
15427 g_return_val_if_fail (GTK_IS_DIAL (widget), FALSE);
15428 g_return_val_if_fail (event != NULL, FALSE);
15430 dial = GTK_DIAL (widget);
15432 if (dial->button != 0)
15437 if (event->is_hint || (event->window != widget->window))
15438 gdk_window_get_pointer (widget->window, &x, &y, &mods);
15440 switch (dial->button)
15443 mask = GDK_BUTTON1_MASK;
15446 mask = GDK_BUTTON2_MASK;
15449 mask = GDK_BUTTON3_MASK;
15456 if (mods & mask)
15457 gtk_dial_update_mouse (dial, x,y);
15464 gtk_dial_timer (GtkDial *dial)
15466 g_return_val_if_fail (dial != NULL, FALSE);
15467 g_return_val_if_fail (GTK_IS_DIAL (dial), FALSE);
15469 if (dial->policy == GTK_UPDATE_DELAYED)
15470 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
15476 gtk_dial_update_mouse (GtkDial *dial, gint x, gint y)
15481 g_return_if_fail (dial != NULL);
15482 g_return_if_fail (GTK_IS_DIAL (dial));
15484 xc = GTK_WIDGET(dial)->allocation.width / 2;
15485 yc = GTK_WIDGET(dial)->allocation.height / 2;
15487 old_value = dial->adjustment->value;
15488 dial->angle = atan2(yc-y, x-xc);
15490 if (dial->angle < -M_PI/2.)
15491 dial->angle += 2*M_PI;
15493 if (dial->angle < -M_PI/6)
15494 dial->angle = -M_PI/6;
15496 if (dial->angle > 7.*M_PI/6.)
15497 dial->angle = 7.*M_PI/6.;
15499 dial->adjustment->value = dial->adjustment->lower + (7.*M_PI/6 - dial->angle) *
15500 (dial->adjustment->upper - dial->adjustment->lower) / (4.*M_PI/3.);
15502 if (dial->adjustment->value != old_value)
15504 if (dial->policy == GTK_UPDATE_CONTINUOUS)
15506 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
15510 gtk_widget_draw (GTK_WIDGET(dial), NULL);
15512 if (dial->policy == GTK_UPDATE_DELAYED)
15515 gtk_timeout_remove (dial->timer);
15517 dial->timer = gtk_timeout_add (SCROLL_DELAY_LENGTH,
15518 (GtkFunction) gtk_dial_timer,
15526 gtk_dial_update (GtkDial *dial)
15530 g_return_if_fail (dial != NULL);
15531 g_return_if_fail (GTK_IS_DIAL (dial));
15533 new_value = dial->adjustment->value;
15535 if (new_value < dial->adjustment->lower)
15536 new_value = dial->adjustment->lower;
15538 if (new_value > dial->adjustment->upper)
15539 new_value = dial->adjustment->upper;
15541 if (new_value != dial->adjustment->value)
15543 dial->adjustment->value = new_value;
15544 gtk_signal_emit_by_name (GTK_OBJECT (dial->adjustment), "value_changed");
15547 dial->angle = 7.*M_PI/6. - (new_value - dial->adjustment->lower) * 4.*M_PI/3. /
15548 (dial->adjustment->upper - dial->adjustment->lower);
15550 gtk_widget_draw (GTK_WIDGET(dial), NULL);
15554 gtk_dial_adjustment_changed (GtkAdjustment *adjustment,
15559 g_return_if_fail (adjustment != NULL);
15560 g_return_if_fail (data != NULL);
15562 dial = GTK_DIAL (data);
15564 if ((dial->old_value != adjustment->value) ||
15565 (dial->old_lower != adjustment->lower) ||
15566 (dial->old_upper != adjustment->upper))
15568 gtk_dial_update (dial);
15570 dial->old_value = adjustment->value;
15571 dial->old_lower = adjustment->lower;
15572 dial->old_upper = adjustment->upper;
15577 gtk_dial_adjustment_value_changed (GtkAdjustment *adjustment,
15582 g_return_if_fail (adjustment != NULL);
15583 g_return_if_fail (data != NULL);
15585 dial = GTK_DIAL (data);
15587 if (dial->old_value != adjustment->value)
15589 gtk_dial_update (dial);
15591 dial->old_value = adjustment->value;
15597 <!-- ----------------------------------------------------------------- -->
15601 /* example-start scribble-simple scribble-simple.c */
15603 /* GTK - The GIMP Toolkit
15604 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
15606 * This library is free software; you can redistribute it and/or
15607 * modify it under the terms of the GNU Library General Public
15608 * License as published by the Free Software Foundation; either
15609 * version 2 of the License, or (at your option) any later version.
15611 * This library is distributed in the hope that it will be useful,
15612 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15613 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15614 * Library General Public License for more details.
15616 * You should have received a copy of the GNU Library General Public
15617 * License along with this library; if not, write to the
15618 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
15619 * Boston, MA 02111-1307, USA.
15622 #include <gtk/gtk.h>
15624 /* Backing pixmap for drawing area */
15625 static GdkPixmap *pixmap = NULL;
15627 /* Create a new backing pixmap of the appropriate size */
15629 configure_event (GtkWidget *widget, GdkEventConfigure *event)
15632 gdk_pixmap_unref(pixmap);
15634 pixmap = gdk_pixmap_new(widget->window,
15635 widget->allocation.width,
15636 widget->allocation.height,
15638 gdk_draw_rectangle (pixmap,
15639 widget->style->white_gc,
15642 widget->allocation.width,
15643 widget->allocation.height);
15648 /* Redraw the screen from the backing pixmap */
15650 expose_event (GtkWidget *widget, GdkEventExpose *event)
15652 gdk_draw_pixmap(widget->window,
15653 widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
15655 event->area.x, event->area.y,
15656 event->area.x, event->area.y,
15657 event->area.width, event->area.height);
15662 /* Draw a rectangle on the screen */
15664 draw_brush (GtkWidget *widget, gdouble x, gdouble y)
15666 GdkRectangle update_rect;
15668 update_rect.x = x - 5;
15669 update_rect.y = y - 5;
15670 update_rect.width = 10;
15671 update_rect.height = 10;
15672 gdk_draw_rectangle (pixmap,
15673 widget->style->black_gc,
15675 update_rect.x, update_rect.y,
15676 update_rect.width, update_rect.height);
15677 gtk_widget_draw (widget, &update_rect);
15681 button_press_event (GtkWidget *widget, GdkEventButton *event)
15683 if (event->button == 1 && pixmap != NULL)
15684 draw_brush (widget, event->x, event->y);
15690 motion_notify_event (GtkWidget *widget, GdkEventMotion *event)
15693 GdkModifierType state;
15695 if (event->is_hint)
15696 gdk_window_get_pointer (event->window, &x, &y, &state);
15701 state = event->state;
15704 if (state & GDK_BUTTON1_MASK && pixmap != NULL)
15705 draw_brush (widget, x, y);
15717 main (int argc, char *argv[])
15720 GtkWidget *drawing_area;
15725 gtk_init (&argc, &argv);
15727 window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
15728 gtk_widget_set_name (window, "Test Input");
15730 vbox = gtk_vbox_new (FALSE, 0);
15731 gtk_container_add (GTK_CONTAINER (window), vbox);
15732 gtk_widget_show (vbox);
15734 gtk_signal_connect (GTK_OBJECT (window), "destroy",
15735 GTK_SIGNAL_FUNC (quit), NULL);
15737 /* Create the drawing area */
15739 drawing_area = gtk_drawing_area_new ();
15740 gtk_drawing_area_size (GTK_DRAWING_AREA (drawing_area), 200, 200);
15741 gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);
15743 gtk_widget_show (drawing_area);
15745 /* Signals used to handle backing pixmap */
15747 gtk_signal_connect (GTK_OBJECT (drawing_area), "expose_event",
15748 (GtkSignalFunc) expose_event, NULL);
15749 gtk_signal_connect (GTK_OBJECT(drawing_area),"configure_event",
15750 (GtkSignalFunc) configure_event, NULL);
15752 /* Event signals */
15754 gtk_signal_connect (GTK_OBJECT (drawing_area), "motion_notify_event",
15755 (GtkSignalFunc) motion_notify_event, NULL);
15756 gtk_signal_connect (GTK_OBJECT (drawing_area), "button_press_event",
15757 (GtkSignalFunc) button_press_event, NULL);
15759 gtk_widget_set_events (drawing_area, GDK_EXPOSURE_MASK
15760 | GDK_LEAVE_NOTIFY_MASK
15761 | GDK_BUTTON_PRESS_MASK
15762 | GDK_POINTER_MOTION_MASK
15763 | GDK_POINTER_MOTION_HINT_MASK);
15765 /* .. And a quit button */
15766 button = gtk_button_new_with_label ("Quit");
15767 gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
15769 gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
15770 GTK_SIGNAL_FUNC (gtk_widget_destroy),
15771 GTK_OBJECT (window));
15772 gtk_widget_show (button);
15774 gtk_widget_show (window);
15783 <!-- ***************************************************************** -->
15785 <!-- ***************************************************************** -->
15787 NOTE: The GtkList widget has been superseded by the GtkCList
15788 widget. It is detailed here just for completeness.
15790 The GtkList widget is designed to act as a vertical container for
15791 widgets that should be of the type GtkListItem.
15793 A GtkList widget has its own window to receive events and its own
15794 background color which is usually white. As it is directly derived
15795 from a GtkContainer it can be treated as such by using the
15796 GTK_CONTAINER(List) macro, see the GtkContainer widget for more on
15797 this. One should already be familiar with the usage of a GList and
15798 its related functions g_list_*() to be able to use the GtkList widget
15801 There is one field inside the structure definition of the GtkList
15802 widget that will be of greater interest to us, this is:
15809 guint selection_mode;
15814 The selection field of a GtkList points to a linked list of all items
15815 that are currently selected, or NULL if the selection is empty. So to
15816 learn about the current selection we read the GTK_LIST()->selection
15817 field, but do not modify it since the internal fields are maintained
15818 by the gtk_list_*() functions.
15820 The selection_mode of the GtkList determines the selection facilities
15821 of a GtkList and therefore the contents of the GTK_LIST()->selection
15822 field. The selection_mode may be one of the following:
15825 <item> GTK_SELECTION_SINGLE - The selection is either NULL
15826 or contains a GList pointer
15827 for a single selected item.
15829 <item> GTK_SELECTION_BROWSE - The selection is NULL if the list
15830 contains no widgets or insensitive
15831 ones only, otherwise it contains
15832 a GList pointer for one GList
15833 structure, and therefore exactly
15836 <item> GTK_SELECTION_MULTIPLE - The selection is NULL if no list
15837 items are selected or a GList pointer
15838 for the first selected item. That
15839 in turn points to a GList structure
15840 for the second selected item and so
15843 <item> GTK_SELECTION_EXTENDED - The selection is always NULL.
15846 The default is GTK_SELECTION_MULTIPLE.
15848 <!-- ----------------------------------------------------------------- -->
15852 void selection_changed( GtkList *list );
15855 This signal will be invoked whenever the selection field of a GtkList
15856 has changed. This happens when a child of the GtkList got selected or
15860 void select_child( GtkList *list,
15864 This signal is invoked when a child of the GtkList is about to get
15865 selected. This happens mainly on calls to gtk_list_select_item(),
15866 gtk_list_select_child(), button presses and sometimes indirectly
15867 triggered on some else occasions where children get added to or
15868 removed from the GtkList.
15871 void unselect_child( GtkList *list,
15872 GtkWidget *child );
15875 This signal is invoked when a child of the GtkList is about to get
15876 deselected. This happens mainly on calls to gtk_list_unselect_item(),
15877 gtk_list_unselect_child(), button presses and sometimes indirectly
15878 triggered on some else occasions where children get added to or
15879 removed from the GtkList.
15881 <!-- ----------------------------------------------------------------- -->
15885 guint gtk_list_get_type( void );
15888 Returns the `GtkList' type identifier.
15891 GtkWidget *gtk_list_new( void );
15894 Create a new GtkList object. The new widget is returned as a pointer
15895 to a GtkWidget object. NULL is returned on failure.
15898 void gtk_list_insert_items( GtkList *list,
15903 Insert list items into the list, starting at <tt/position/.
15904 <tt/items/ is a doubly linked list where each nodes data pointer is
15905 expected to point to a newly created GtkListItem. The GList nodes of
15906 <tt/items/ are taken over by the list.
15909 void gtk_list_append_items( GtkList *list,
15913 Insert list items just like gtk_list_insert_items() at the end of the
15914 list. The GList nodes of <tt/items/ are taken over by the list.
15917 void gtk_list_prepend_items( GtkList *list,
15921 Insert list items just like gtk_list_insert_items() at the very
15922 beginning of the list. The GList nodes of <tt/items/ are taken over by
15926 void gtk_list_remove_items( GtkList *list,
15930 Remove list items from the list. <tt/items/ is a doubly linked list
15931 where each nodes data pointer is expected to point to a direct child
15932 of list. It is the callers responsibility to make a call to
15933 g_list_free(items) afterwards. Also the caller has to destroy the list
15937 void gtk_list_clear_items( GtkList *list,
15942 Remove and destroy list items from the list. A widget is affected if
15943 its current position within the list is in the range specified by
15944 <tt/start/ and <tt/end/.
15947 void gtk_list_select_item( GtkList *list,
15951 Invoke the select_child signal for a list item specified through its
15952 current position within the list.
15955 void gtk_list_unselect_item( GtkList *list,
15959 Invoke the unselect_child signal for a list item specified through its
15960 current position within the list.
15963 void gtk_list_select_child( GtkList *list,
15967 Invoke the select_child signal for the specified child.
15970 void gtk_list_unselect_child( GtkList *list,
15974 Invoke the unselect_child signal for the specified child.
15977 gint gtk_list_child_position( GtkList *list,
15981 Return the position of <tt/child/ within the list. "-1" is returned on
15985 void gtk_list_set_selection_mode( GtkList *list,
15986 GtkSelectionMode mode );
15989 Set the selection mode MODE which can be of GTK_SELECTION_SINGLE,
15990 GTK_SELECTION_BROWSE, GTK_SELECTION_MULTIPLE or
15991 GTK_SELECTION_EXTENDED.
15994 GtkList *GTK_LIST( gpointer obj );
15997 Cast a generic pointer to `GtkList *'. *Note Standard Macros::, for
16001 GtkListClass *GTK_LIST_CLASS( gpointer class);
16004 Cast a generic pointer to `GtkListClass*'. *Note Standard Macros::,
16008 gint GTK_IS_LIST( gpointer obj);
16011 Determine if a generic pointer refers to a `GtkList' object. *Note
16012 Standard Macros::, for more info.
16014 <!-- ----------------------------------------------------------------- -->
16017 Following is an example program that will print out the changes of the
16018 selection of a GtkList, and lets you "arrest" list items into a prison
16019 by selecting them with the rightmost mouse button.
16022 /* example-start list list.c */
16024 /* Include the gtk+ header files
16025 * Include stdio.h, we need that for the printf() function
16027 #include <gtk/gtk.h>
16030 /* This is our data identification string to store
16031 * data in list items
16033 const gchar *list_item_data_key="list_item_data";
16036 /* prototypes for signal handler that we are going to connect
16037 * to the GtkList widget
16039 static void sigh_print_selection( GtkWidget *gtklist,
16040 gpointer func_data);
16042 static void sigh_button_event( GtkWidget *gtklist,
16043 GdkEventButton *event,
16044 GtkWidget *frame );
16047 /* Main function to set up the user interface */
16049 gint main (int argc,
16052 GtkWidget *separator;
16055 GtkWidget *scrolled_window;
16057 GtkWidget *gtklist;
16059 GtkWidget *list_item;
16065 /* Initialize gtk+ (and subsequently gdk) */
16067 gtk_init(&argc, &argv);
16070 /* Create a window to put all the widgets in
16071 * connect gtk_main_quit() to the "destroy" event of
16072 * the window to handle window manager close-window-events
16074 window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
16075 gtk_window_set_title(GTK_WINDOW(window), "GtkList Example");
16076 gtk_signal_connect(GTK_OBJECT(window),
16078 GTK_SIGNAL_FUNC(gtk_main_quit),
16082 /* Inside the window we need a box to arrange the widgets
16084 vbox=gtk_vbox_new(FALSE, 5);
16085 gtk_container_set_border_width(GTK_CONTAINER(vbox), 5);
16086 gtk_container_add(GTK_CONTAINER(window), vbox);
16087 gtk_widget_show(vbox);
16089 /* This is the scrolled window to put the GtkList widget inside */
16090 scrolled_window=gtk_scrolled_window_new(NULL, NULL);
16091 gtk_widget_set_usize(scrolled_window, 250, 150);
16092 gtk_container_add(GTK_CONTAINER(vbox), scrolled_window);
16093 gtk_widget_show(scrolled_window);
16095 /* Create the GtkList widget.
16096 * Connect the sigh_print_selection() signal handler
16097 * function to the "selection_changed" signal of the GtkList
16098 * to print out the selected items each time the selection
16100 gtklist=gtk_list_new();
16101 gtk_scrolled_window_add_with_viewport( GTK_SCROLLED_WINDOW(scrolled_window),
16103 gtk_widget_show(gtklist);
16104 gtk_signal_connect(GTK_OBJECT(gtklist),
16105 "selection_changed",
16106 GTK_SIGNAL_FUNC(sigh_print_selection),
16109 /* We create a "Prison" to put a list item in ;) */
16110 frame=gtk_frame_new("Prison");
16111 gtk_widget_set_usize(frame, 200, 50);
16112 gtk_container_set_border_width(GTK_CONTAINER(frame), 5);
16113 gtk_frame_set_shadow_type(GTK_FRAME(frame), GTK_SHADOW_OUT);
16114 gtk_container_add(GTK_CONTAINER(vbox), frame);
16115 gtk_widget_show(frame);
16117 /* Connect the sigh_button_event() signal handler to the GtkList
16118 * which will handle the "arresting" of list items
16120 gtk_signal_connect(GTK_OBJECT(gtklist),
16121 "button_release_event",
16122 GTK_SIGNAL_FUNC(sigh_button_event),
16125 /* Create a separator */
16126 separator=gtk_hseparator_new();
16127 gtk_container_add(GTK_CONTAINER(vbox), separator);
16128 gtk_widget_show(separator);
16130 /* Finally create a button and connect it's "clicked" signal
16131 * to the destruction of the window */
16132 button=gtk_button_new_with_label("Close");
16133 gtk_container_add(GTK_CONTAINER(vbox), button);
16134 gtk_widget_show(button);
16135 gtk_signal_connect_object(GTK_OBJECT(button),
16137 GTK_SIGNAL_FUNC(gtk_widget_destroy),
16138 GTK_OBJECT(window));
16141 /* Now we create 5 list items, each having it's own
16142 * label and add them to the GtkList using gtk_container_add()
16143 * Also we query the text string from the label and
16144 * associate it with the list_item_data_key for each list item
16146 for (i=0; i<5; i++) {
16150 sprintf(buffer, "ListItemContainer with Label #%d", i);
16151 label=gtk_label_new(buffer);
16152 list_item=gtk_list_item_new();
16153 gtk_container_add(GTK_CONTAINER(list_item), label);
16154 gtk_widget_show(label);
16155 gtk_container_add(GTK_CONTAINER(gtklist), list_item);
16156 gtk_widget_show(list_item);
16157 gtk_label_get(GTK_LABEL(label), &string);
16158 gtk_object_set_data(GTK_OBJECT(list_item),
16159 list_item_data_key,
16162 /* Here, we are creating another 5 labels, this time
16163 * we use gtk_list_item_new_with_label() for the creation
16164 * we can't query the text string from the label because
16165 * we don't have the labels pointer and therefore
16166 * we just associate the list_item_data_key of each
16167 * list item with the same text string.
16168 * For adding of the list items we put them all into a doubly
16169 * linked list (GList), and then add them by a single call to
16170 * gtk_list_append_items().
16171 * Because we use g_list_prepend() to put the items into the
16172 * doubly linked list, their order will be descending (instead
16173 * of ascending when using g_list_append())
16176 for (; i<10; i++) {
16177 sprintf(buffer, "List Item with Label %d", i);
16178 list_item=gtk_list_item_new_with_label(buffer);
16179 dlist=g_list_prepend(dlist, list_item);
16180 gtk_widget_show(list_item);
16181 gtk_object_set_data(GTK_OBJECT(list_item),
16182 list_item_data_key,
16183 "ListItem with integrated Label");
16185 gtk_list_append_items(GTK_LIST(gtklist), dlist);
16187 /* Finally we want to see the window, don't we? ;) */
16188 gtk_widget_show(window);
16190 /* Fire up the main event loop of gtk */
16193 /* We get here after gtk_main_quit() has been called which
16194 * happens if the main window gets destroyed
16199 /* This is the signal handler that got connected to button
16200 * press/release events of the GtkList
16202 void sigh_button_event( GtkWidget *gtklist,
16203 GdkEventButton *event,
16206 /* We only do something if the third (rightmost mouse button
16209 if (event->type==GDK_BUTTON_RELEASE &&
16210 event->button==3) {
16211 GList *dlist, *free_list;
16212 GtkWidget *new_prisoner;
16214 /* Fetch the currently selected list item which
16215 * will be our next prisoner ;)
16217 dlist=GTK_LIST(gtklist)->selection;
16219 new_prisoner=GTK_WIDGET(dlist->data);
16223 /* Look for already imprisoned list items, we
16224 * will put them back into the list.
16225 * Remember to free the doubly linked list that
16226 * gtk_container_children() returns
16228 dlist=gtk_container_children(GTK_CONTAINER(frame));
16231 GtkWidget *list_item;
16233 list_item=dlist->data;
16235 gtk_widget_reparent(list_item, gtklist);
16239 g_list_free(free_list);
16241 /* If we have a new prisoner, remove him from the
16242 * GtkList and put him into the frame "Prison".
16243 * We need to unselect the item first.
16245 if (new_prisoner) {
16246 GList static_dlist;
16248 static_dlist.data=new_prisoner;
16249 static_dlist.next=NULL;
16250 static_dlist.prev=NULL;
16252 gtk_list_unselect_child(GTK_LIST(gtklist),
16254 gtk_widget_reparent(new_prisoner, frame);
16259 /* This is the signal handler that gets called if GtkList
16260 * emits the "selection_changed" signal
16262 void sigh_print_selection( GtkWidget *gtklist,
16263 gpointer func_data)
16267 /* Fetch the doubly linked list of selected items
16268 * of the GtkList, remember to treat this as read-only!
16270 dlist=GTK_LIST(gtklist)->selection;
16272 /* If there are no selected items there is nothing more
16273 * to do than just telling the user so
16276 g_print("Selection cleared\n");
16279 /* Ok, we got a selection and so we print it
16281 g_print("The selection is a ");
16283 /* Get the list item from the doubly linked list
16284 * and then query the data associated with list_item_data_key.
16285 * We then just print it */
16287 GtkObject *list_item;
16288 gchar *item_data_string;
16290 list_item=GTK_OBJECT(dlist->data);
16291 item_data_string=gtk_object_get_data(list_item,
16292 list_item_data_key);
16293 g_print("%s ", item_data_string);
16302 <!-- ----------------------------------------------------------------- -->
16303 <sect1> List Item Widget
16305 The GtkListItem widget is designed to act as a container holding up to
16306 one child, providing functions for selection/deselection just like the
16307 GtkList widget requires them for its children.
16309 A GtkListItem has its own window to receive events and has its own
16310 background color which is usually white.
16312 As it is directly derived from a GtkItem it can be treated as such by
16313 using the GTK_ITEM(ListItem) macro, see the GtkItem widget for more on
16314 this. Usually a GtkListItem just holds a label to identify e.g. a
16315 filename within a GtkList -- therefore the convenience function
16316 gtk_list_item_new_with_label() is provided. The same effect can be
16317 achieved by creating a GtkLabel on its own, setting its alignment to
16318 xalign=0 and yalign=0.5 with a subsequent container addition to the
16321 As one is not forced to add a GtkLabel to a GtkListItem, you could
16322 also add a GtkVBox or a GtkArrow etc. to the GtkListItem.
16324 <!-- ----------------------------------------------------------------- -->
16327 A GtkListItem does not create new signals on its own, but inherits
16328 the signals of a GtkItem. *Note GtkItem::, for more info.
16330 <!-- ----------------------------------------------------------------- -->
16334 guint gtk_list_item_get_type( void );
16337 Returns the `GtkListItem' type identifier.
16340 GtkWidget *gtk_list_item_new( void );
16343 Create a new GtkListItem object. The new widget is returned as a
16344 pointer to a GtkWidget object. NULL is returned on failure.
16347 GtkWidget *gtk_list_item_new_with_label( gchar *label );
16350 Create a new GtkListItem object, having a single GtkLabel as the sole
16351 child. The new widget is returned as a pointer to a GtkWidget
16352 object. NULL is returned on failure.
16355 void gtk_list_item_select( GtkListItem *list_item );
16358 This function is basically a wrapper around a call to gtk_item_select
16359 (GTK_ITEM (list_item)) which will emit the select signal. *Note
16360 GtkItem::, for more info.
16363 void gtk_list_item_deselect( GtkListItem *list_item );
16366 This function is basically a wrapper around a call to
16367 gtk_item_deselect (GTK_ITEM (list_item)) which will emit the deselect
16368 signal. *Note GtkItem::, for more info.
16371 GtkListItem *GTK_LIST_ITEM( gpointer obj );
16374 Cast a generic pointer to `GtkListItem*'. *Note Standard Macros::, for
16378 GtkListItemClass *GTK_LIST_ITEM_CLASS( gpointer class );
16381 Cast a generic pointer to GtkListItemClass*. *Note Standard Macros::,
16385 gint GTK_IS_LIST_ITEM( gpointer obj );
16388 Determine if a generic pointer refers to a `GtkListItem' object.
16389 *Note Standard Macros::, for more info.
16391 <!-- ----------------------------------------------------------------- -->
16394 Please see the GtkList example on this, which covers the usage of a
16395 GtkListItem as well.