1 /* GTK - The GIMP Toolkit
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
21 * Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
22 * file for a list of people on the GTK+ Team. See the ChangeLog
23 * files for a list of changes. These files are distributed with
24 * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
28 #include "gtkadjustment.h"
29 #include "gtkmarshalers.h"
30 #include "gtkprivate.h"
35 * SECTION:gtkadjustment
36 * @Short_description: A representation of an adjustable bounded value
37 * @Title: GtkAdjustment
39 * The #GtkAdjustment object represents a value which has an associated lower
40 * and upper bound, together with step and page increments, and a page size.
41 * It is used within several GTK+ widgets, including
42 * #GtkSpinButton, #GtkViewport, and #GtkRange (which is a base class for
43 * #GtkHScrollbar, #GtkVScrollbar, #GtkHScale, and #GtkVScale).
45 * The #GtkAdjustment object does not update the value itself. Instead
46 * it is left up to the owner of the #GtkAdjustment to control the value.
48 * The owner of the #GtkAdjustment typically calls the
49 * gtk_adjustment_value_changed() and gtk_adjustment_changed() functions
50 * after changing the value and its bounds. This results in the emission of the
51 * #GtkAdjustment::value_changed or #GtkAdjustment::changed signal respectively.
55 struct _GtkAdjustmentPrivate {
59 gdouble step_increment;
60 gdouble page_increment;
83 static void gtk_adjustment_get_property (GObject *object,
87 static void gtk_adjustment_set_property (GObject *object,
91 static void gtk_adjustment_dispatch_properties_changed (GObject *object,
95 static guint adjustment_signals[LAST_SIGNAL] = { 0 };
97 static guint64 adjustment_changed_stamp = 0; /* protected by global gdk lock */
99 G_DEFINE_TYPE (GtkAdjustment, gtk_adjustment, G_TYPE_INITIALLY_UNOWNED)
102 gtk_adjustment_class_init (GtkAdjustmentClass *class)
104 GObjectClass *gobject_class = G_OBJECT_CLASS (class);
106 gobject_class->set_property = gtk_adjustment_set_property;
107 gobject_class->get_property = gtk_adjustment_get_property;
108 gobject_class->dispatch_properties_changed = gtk_adjustment_dispatch_properties_changed;
110 class->changed = NULL;
111 class->value_changed = NULL;
114 * GtkAdjustment:value:
116 * The value of the adjustment.
120 g_object_class_install_property (gobject_class,
122 g_param_spec_double ("value",
124 P_("The value of the adjustment"),
128 GTK_PARAM_READWRITE));
131 * GtkAdjustment:lower:
133 * The minimum value of the adjustment.
137 g_object_class_install_property (gobject_class,
139 g_param_spec_double ("lower",
141 P_("The minimum value of the adjustment"),
145 GTK_PARAM_READWRITE));
148 * GtkAdjustment:upper:
150 * The maximum value of the adjustment.
151 * Note that values will be restricted by
152 * <literal>upper - page-size</literal> if the page-size
153 * property is nonzero.
157 g_object_class_install_property (gobject_class,
159 g_param_spec_double ("upper",
161 P_("The maximum value of the adjustment"),
165 GTK_PARAM_READWRITE));
168 * GtkAdjustment:step-increment:
170 * The step increment of the adjustment.
174 g_object_class_install_property (gobject_class,
176 g_param_spec_double ("step-increment",
177 P_("Step Increment"),
178 P_("The step increment of the adjustment"),
182 GTK_PARAM_READWRITE));
185 * GtkAdjustment:page-increment:
187 * The page increment of the adjustment.
191 g_object_class_install_property (gobject_class,
193 g_param_spec_double ("page-increment",
194 P_("Page Increment"),
195 P_("The page increment of the adjustment"),
199 GTK_PARAM_READWRITE));
202 * GtkAdjustment:page-size:
204 * The page size of the adjustment.
205 * Note that the page-size is irrelevant and should be set to zero
206 * if the adjustment is used for a simple scalar value, e.g. in a
211 g_object_class_install_property (gobject_class,
213 g_param_spec_double ("page-size",
215 P_("The page size of the adjustment"),
219 GTK_PARAM_READWRITE));
222 * GtkAdjustment::changed:
223 * @adjustment: the object which received the signal.
225 * Emitted when one or more of the #GtkAdjustment fields have been changed,
226 * other than the value field.
228 adjustment_signals[CHANGED] =
229 g_signal_new (I_("changed"),
230 G_OBJECT_CLASS_TYPE (class),
231 G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
232 G_STRUCT_OFFSET (GtkAdjustmentClass, changed),
234 _gtk_marshal_VOID__VOID,
238 * GtkAdjustment::value-changed:
239 * @adjustment: the object which received the signal.
241 * Emitted when the #GtkAdjustment value field has been changed.
243 adjustment_signals[VALUE_CHANGED] =
244 g_signal_new (I_("value-changed"),
245 G_OBJECT_CLASS_TYPE (class),
246 G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
247 G_STRUCT_OFFSET (GtkAdjustmentClass, value_changed),
249 _gtk_marshal_VOID__VOID,
252 g_type_class_add_private (class, sizeof (GtkAdjustmentPrivate));
256 gtk_adjustment_init (GtkAdjustment *adjustment)
258 adjustment->priv = G_TYPE_INSTANCE_GET_PRIVATE (adjustment,
260 GtkAdjustmentPrivate);
264 gtk_adjustment_get_property (GObject *object,
269 GtkAdjustment *adjustment = GTK_ADJUSTMENT (object);
270 GtkAdjustmentPrivate *priv = adjustment->priv;
275 g_value_set_double (value, priv->value);
278 g_value_set_double (value, priv->lower);
281 g_value_set_double (value, priv->upper);
283 case PROP_STEP_INCREMENT:
284 g_value_set_double (value, priv->step_increment);
286 case PROP_PAGE_INCREMENT:
287 g_value_set_double (value, priv->page_increment);
290 g_value_set_double (value, priv->page_size);
293 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
299 gtk_adjustment_set_property (GObject *object,
304 GtkAdjustment *adjustment = GTK_ADJUSTMENT (object);
305 gdouble double_value = g_value_get_double (value);
306 GtkAdjustmentPrivate *priv = adjustment->priv;
311 gtk_adjustment_set_value (adjustment, double_value);
314 priv->lower = double_value;
317 priv->upper = double_value;
319 case PROP_STEP_INCREMENT:
320 priv->step_increment = double_value;
322 case PROP_PAGE_INCREMENT:
323 priv->page_increment = double_value;
326 priv->page_size = double_value;
329 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
335 gtk_adjustment_dispatch_properties_changed (GObject *object,
339 gboolean changed = FALSE;
342 G_OBJECT_CLASS (gtk_adjustment_parent_class)->dispatch_properties_changed (object, n_pspecs, pspecs);
344 for (i = 0; i < n_pspecs; i++)
345 switch (pspecs[i]->param_id)
349 case PROP_STEP_INCREMENT:
350 case PROP_PAGE_INCREMENT:
360 adjustment_changed_stamp++;
361 gtk_adjustment_changed (GTK_ADJUSTMENT (object));
366 * gtk_adjustment_new:
367 * @value: the initial value.
368 * @lower: the minimum value.
369 * @upper: the maximum value.
370 * @step_increment: the step increment.
371 * @page_increment: the page increment.
372 * @page_size: the page size.
374 * Creates a new #GtkAdjustment.
376 * Returns: a new #GtkAdjustment.
379 gtk_adjustment_new (gdouble value,
382 gdouble step_increment,
383 gdouble page_increment,
386 return g_object_new (GTK_TYPE_ADJUSTMENT,
389 "step-increment", step_increment,
390 "page-increment", page_increment,
391 "page-size", page_size,
397 * gtk_adjustment_get_value:
398 * @adjustment: a #GtkAdjustment
400 * Gets the current value of the adjustment. See
401 * gtk_adjustment_set_value ().
403 * Return value: The current value of the adjustment.
406 gtk_adjustment_get_value (GtkAdjustment *adjustment)
408 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
410 return adjustment->priv->value;
414 * gtk_adjustment_set_value:
415 * @adjustment: a #GtkAdjustment.
416 * @value: the new value.
418 * Sets the #GtkAdjustment value. The value is clamped to lie between
419 * #GtkAdjustment.lower and #GtkAdjustment.upper.
421 * Note that for adjustments which are used in a #GtkScrollbar, the effective
422 * range of allowed values goes from #GtkAdjustment.lower to
423 * #GtkAdjustment.upper - #GtkAdjustment.page_size.
426 gtk_adjustment_set_value (GtkAdjustment *adjustment,
429 GtkAdjustmentPrivate *priv;
431 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
433 priv = adjustment->priv;
435 /* don't use CLAMP() so we don't end up below lower if upper - page_size
436 * is smaller than lower
438 value = MIN (value, priv->upper - priv->page_size);
439 value = MAX (value, priv->lower);
441 if (value != priv->value)
445 gtk_adjustment_value_changed (adjustment);
450 * gtk_adjustment_get_lower:
451 * @adjustment: a #GtkAdjustment
453 * Retrieves the minimum value of the adjustment.
455 * Return value: The current minimum value of the adjustment.
460 gtk_adjustment_get_lower (GtkAdjustment *adjustment)
462 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
464 return adjustment->priv->lower;
468 * gtk_adjustment_set_lower:
469 * @adjustment: a #GtkAdjustment
470 * @lower: the new minimum value
472 * Sets the minimum value of the adjustment.
474 * When setting multiple adjustment properties via their individual
475 * setters, multiple "changed" signals will be emitted. However, since
476 * the emission of the "changed" signal is tied to the emission of the
477 * "GObject::notify" signals of the changed properties, it's possible
478 * to compress the "changed" signals into one by calling
479 * g_object_freeze_notify() and g_object_thaw_notify() around the
480 * calls to the individual setters.
482 * Alternatively, using a single g_object_set() for all the properties
483 * to change, or using gtk_adjustment_configure() has the same effect
484 * of compressing "changed" emissions.
489 gtk_adjustment_set_lower (GtkAdjustment *adjustment,
492 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
494 if (lower != adjustment->priv->lower)
495 g_object_set (adjustment, "lower", lower, NULL);
499 * gtk_adjustment_get_upper:
500 * @adjustment: a #GtkAdjustment
502 * Retrieves the maximum value of the adjustment.
504 * Return value: The current maximum value of the adjustment.
509 gtk_adjustment_get_upper (GtkAdjustment *adjustment)
511 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
513 return adjustment->priv->upper;
517 * gtk_adjustment_set_upper:
518 * @adjustment: a #GtkAdjustment
519 * @upper: the new maximum value
521 * Sets the maximum value of the adjustment.
523 * Note that values will be restricted by
524 * <literal>upper - page-size</literal> if the page-size
525 * property is nonzero.
527 * See gtk_adjustment_set_lower() about how to compress multiple
528 * emissions of the "changed" signal when setting multiple adjustment
534 gtk_adjustment_set_upper (GtkAdjustment *adjustment,
537 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
539 if (upper != adjustment->priv->upper)
540 g_object_set (adjustment, "upper", upper, NULL);
544 * gtk_adjustment_get_step_increment:
545 * @adjustment: a #GtkAdjustment
547 * Retrieves the step increment of the adjustment.
549 * Return value: The current step increment of the adjustment.
554 gtk_adjustment_get_step_increment (GtkAdjustment *adjustment)
556 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
558 return adjustment->priv->step_increment;
562 * gtk_adjustment_set_step_increment:
563 * @adjustment: a #GtkAdjustment
564 * @step_increment: the new step increment
566 * Sets the step increment of the adjustment.
568 * See gtk_adjustment_set_lower() about how to compress multiple
569 * emissions of the "changed" signal when setting multiple adjustment
575 gtk_adjustment_set_step_increment (GtkAdjustment *adjustment,
576 gdouble step_increment)
578 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
580 if (step_increment != adjustment->priv->step_increment)
581 g_object_set (adjustment, "step-increment", step_increment, NULL);
585 * gtk_adjustment_get_page_increment:
586 * @adjustment: a #GtkAdjustment
588 * Retrieves the page increment of the adjustment.
590 * Return value: The current page increment of the adjustment.
595 gtk_adjustment_get_page_increment (GtkAdjustment *adjustment)
597 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
599 return adjustment->priv->page_increment;
603 * gtk_adjustment_set_page_increment:
604 * @adjustment: a #GtkAdjustment
605 * @page_increment: the new page increment
607 * Sets the page increment of the adjustment.
609 * See gtk_adjustment_set_lower() about how to compress multiple
610 * emissions of the "changed" signal when setting multiple adjustment
616 gtk_adjustment_set_page_increment (GtkAdjustment *adjustment,
617 gdouble page_increment)
619 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
621 if (page_increment != adjustment->priv->page_increment)
622 g_object_set (adjustment, "page-increment", page_increment, NULL);
626 * gtk_adjustment_get_page_size:
627 * @adjustment: a #GtkAdjustment
629 * Retrieves the page size of the adjustment.
631 * Return value: The current page size of the adjustment.
636 gtk_adjustment_get_page_size (GtkAdjustment *adjustment)
638 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
640 return adjustment->priv->page_size;
644 * gtk_adjustment_set_page_size:
645 * @adjustment: a #GtkAdjustment
646 * @page_size: the new page size
648 * Sets the page size of the adjustment.
650 * See gtk_adjustment_set_lower() about how to compress multiple
651 * emissions of the "changed" signal when setting multiple adjustment
657 gtk_adjustment_set_page_size (GtkAdjustment *adjustment,
660 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
662 if (page_size != adjustment->priv->page_size)
663 g_object_set (adjustment, "page-size", page_size, NULL);
667 * gtk_adjustment_configure:
668 * @adjustment: a #GtkAdjustment
669 * @value: the new value
670 * @lower: the new minimum value
671 * @upper: the new maximum value
672 * @step_increment: the new step increment
673 * @page_increment: the new page increment
674 * @page_size: the new page size
676 * Sets all properties of the adjustment at once.
678 * Use this function to avoid multiple emissions of the "changed"
679 * signal. See gtk_adjustment_set_lower() for an alternative way
680 * of compressing multiple emissions of "changed" into one.
685 gtk_adjustment_configure (GtkAdjustment *adjustment,
689 gdouble step_increment,
690 gdouble page_increment,
693 GtkAdjustmentPrivate *priv;
694 gboolean value_changed = FALSE;
695 guint64 old_stamp = adjustment_changed_stamp;
697 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
699 priv = adjustment->priv;
701 g_object_freeze_notify (G_OBJECT (adjustment));
703 g_object_set (adjustment,
706 "step-increment", step_increment,
707 "page-increment", page_increment,
708 "page-size", page_size,
711 /* don't use CLAMP() so we don't end up below lower if upper - page_size
712 * is smaller than lower
714 value = MIN (value, upper - page_size);
715 value = MAX (value, lower);
717 if (value != priv->value)
719 /* set value manually to make sure "changed" is emitted with the
720 * new value in place and is emitted before "value-changed"
723 value_changed = TRUE;
726 g_object_thaw_notify (G_OBJECT (adjustment));
728 if (old_stamp == adjustment_changed_stamp)
729 gtk_adjustment_changed (adjustment); /* force emission before ::value-changed */
732 gtk_adjustment_value_changed (adjustment);
736 * gtk_adjustment_changed:
737 * @adjustment: a #GtkAdjustment
739 * Emits a #GtkAdjustment::changed signal from the #GtkAdjustment.
740 * This is typically called by the owner of the #GtkAdjustment after it has
741 * changed any of the #GtkAdjustment fields other than the value.
744 gtk_adjustment_changed (GtkAdjustment *adjustment)
746 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
748 g_signal_emit (adjustment, adjustment_signals[CHANGED], 0);
752 * gtk_adjustment_value_changed:
753 * @adjustment: a #GtkAdjustment
755 * Emits a #GtkAdjustment::value_changed signal from the #GtkAdjustment.
756 * This is typically called by the owner of the #GtkAdjustment after it has
757 * changed the #GtkAdjustment value field.
760 gtk_adjustment_value_changed (GtkAdjustment *adjustment)
762 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
764 g_signal_emit (adjustment, adjustment_signals[VALUE_CHANGED], 0);
765 g_object_notify (G_OBJECT (adjustment), "value");
769 * gtk_adjustment_clamp_page:
770 * @adjustment: a #GtkAdjustment.
771 * @lower: the lower value.
772 * @upper: the upper value.
774 * Updates the #GtkAdjustment #GtkAdjustment.value to ensure that the range
775 * between @lower and @upper is in the current page (i.e. between
776 * #GtkAdjustment.value and #GtkAdjustment.value + #GtkAdjustment.page_size).
777 * If the range is larger than the page size, then only the start of it will
778 * be in the current page.
779 * A #GtkAdjustment::changed signal will be emitted if the value is changed.
782 gtk_adjustment_clamp_page (GtkAdjustment *adjustment,
786 GtkAdjustmentPrivate *priv;
787 gboolean need_emission;
789 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
791 priv = adjustment->priv;
793 lower = CLAMP (lower, priv->lower, priv->upper);
794 upper = CLAMP (upper, priv->lower, priv->upper);
796 need_emission = FALSE;
798 if (priv->value + priv->page_size < upper)
800 priv->value = upper - priv->page_size;
801 need_emission = TRUE;
803 if (priv->value > lower)
806 need_emission = TRUE;
810 gtk_adjustment_value_changed (adjustment);