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, see <http://www.gnu.org/licenses/>.
19 * Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
20 * file for a list of people on the GTK+ Team. See the ChangeLog
21 * files for a list of changes. These files are distributed with
22 * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
26 #include "gtkadjustment.h"
27 #include "gtkmarshalers.h"
28 #include "gtkprivate.h"
33 * SECTION:gtkadjustment
34 * @Short_description: A representation of an adjustable bounded value
35 * @Title: GtkAdjustment
37 * The #GtkAdjustment object represents a value which has an associated lower
38 * and upper bound, together with step and page increments, and a page size.
39 * It is used within several GTK+ widgets, including
40 * #GtkSpinButton, #GtkViewport, and #GtkRange (which is a base class for
41 * #GtkHScrollbar, #GtkVScrollbar, #GtkHScale, and #GtkVScale).
43 * The #GtkAdjustment object does not update the value itself. Instead
44 * it is left up to the owner of the #GtkAdjustment to control the value.
46 * The owner of the #GtkAdjustment typically calls the
47 * gtk_adjustment_value_changed() and gtk_adjustment_changed() functions
48 * after changing the value and its bounds. This results in the emission of the
49 * #GtkAdjustment::value_changed or #GtkAdjustment::changed signal respectively.
53 struct _GtkAdjustmentPrivate {
57 gdouble step_increment;
58 gdouble page_increment;
81 static void gtk_adjustment_get_property (GObject *object,
85 static void gtk_adjustment_set_property (GObject *object,
89 static void gtk_adjustment_dispatch_properties_changed (GObject *object,
93 static guint adjustment_signals[LAST_SIGNAL] = { 0 };
95 static guint64 adjustment_changed_stamp = 0; /* protected by global gdk lock */
97 G_DEFINE_TYPE (GtkAdjustment, gtk_adjustment, G_TYPE_INITIALLY_UNOWNED)
100 gtk_adjustment_class_init (GtkAdjustmentClass *class)
102 GObjectClass *gobject_class = G_OBJECT_CLASS (class);
104 gobject_class->set_property = gtk_adjustment_set_property;
105 gobject_class->get_property = gtk_adjustment_get_property;
106 gobject_class->dispatch_properties_changed = gtk_adjustment_dispatch_properties_changed;
108 class->changed = NULL;
109 class->value_changed = NULL;
112 * GtkAdjustment:value:
114 * The value of the adjustment.
118 g_object_class_install_property (gobject_class,
120 g_param_spec_double ("value",
122 P_("The value of the adjustment"),
126 GTK_PARAM_READWRITE));
129 * GtkAdjustment:lower:
131 * The minimum value of the adjustment.
135 g_object_class_install_property (gobject_class,
137 g_param_spec_double ("lower",
139 P_("The minimum value of the adjustment"),
143 GTK_PARAM_READWRITE));
146 * GtkAdjustment:upper:
148 * The maximum value of the adjustment.
149 * Note that values will be restricted by
150 * <literal>upper - page-size</literal> if the page-size
151 * property is nonzero.
155 g_object_class_install_property (gobject_class,
157 g_param_spec_double ("upper",
159 P_("The maximum value of the adjustment"),
163 GTK_PARAM_READWRITE));
166 * GtkAdjustment:step-increment:
168 * The step increment of the adjustment.
172 g_object_class_install_property (gobject_class,
174 g_param_spec_double ("step-increment",
175 P_("Step Increment"),
176 P_("The step increment of the adjustment"),
180 GTK_PARAM_READWRITE));
183 * GtkAdjustment:page-increment:
185 * The page increment of the adjustment.
189 g_object_class_install_property (gobject_class,
191 g_param_spec_double ("page-increment",
192 P_("Page Increment"),
193 P_("The page increment of the adjustment"),
197 GTK_PARAM_READWRITE));
200 * GtkAdjustment:page-size:
202 * The page size of the adjustment.
203 * Note that the page-size is irrelevant and should be set to zero
204 * if the adjustment is used for a simple scalar value, e.g. in a
209 g_object_class_install_property (gobject_class,
211 g_param_spec_double ("page-size",
213 P_("The page size of the adjustment"),
217 GTK_PARAM_READWRITE));
220 * GtkAdjustment::changed:
221 * @adjustment: the object which received the signal.
223 * Emitted when one or more of the #GtkAdjustment properties have been
224 * changed, other than the #GtkAdjustment:value property.
226 adjustment_signals[CHANGED] =
227 g_signal_new (I_("changed"),
228 G_OBJECT_CLASS_TYPE (class),
229 G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
230 G_STRUCT_OFFSET (GtkAdjustmentClass, changed),
232 _gtk_marshal_VOID__VOID,
236 * GtkAdjustment::value-changed:
237 * @adjustment: the object which received the signal.
239 * Emitted when the #GtkAdjustment:value property has been changed.
241 adjustment_signals[VALUE_CHANGED] =
242 g_signal_new (I_("value-changed"),
243 G_OBJECT_CLASS_TYPE (class),
244 G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE,
245 G_STRUCT_OFFSET (GtkAdjustmentClass, value_changed),
247 _gtk_marshal_VOID__VOID,
250 g_type_class_add_private (class, sizeof (GtkAdjustmentPrivate));
254 gtk_adjustment_init (GtkAdjustment *adjustment)
256 adjustment->priv = G_TYPE_INSTANCE_GET_PRIVATE (adjustment,
258 GtkAdjustmentPrivate);
262 gtk_adjustment_get_property (GObject *object,
267 GtkAdjustment *adjustment = GTK_ADJUSTMENT (object);
268 GtkAdjustmentPrivate *priv = adjustment->priv;
273 g_value_set_double (value, priv->value);
276 g_value_set_double (value, priv->lower);
279 g_value_set_double (value, priv->upper);
281 case PROP_STEP_INCREMENT:
282 g_value_set_double (value, priv->step_increment);
284 case PROP_PAGE_INCREMENT:
285 g_value_set_double (value, priv->page_increment);
288 g_value_set_double (value, priv->page_size);
291 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
297 gtk_adjustment_set_property (GObject *object,
302 GtkAdjustment *adjustment = GTK_ADJUSTMENT (object);
303 gdouble double_value = g_value_get_double (value);
304 GtkAdjustmentPrivate *priv = adjustment->priv;
309 gtk_adjustment_set_value (adjustment, double_value);
312 priv->lower = double_value;
315 priv->upper = double_value;
317 case PROP_STEP_INCREMENT:
318 priv->step_increment = double_value;
320 case PROP_PAGE_INCREMENT:
321 priv->page_increment = double_value;
324 priv->page_size = double_value;
327 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
333 gtk_adjustment_dispatch_properties_changed (GObject *object,
337 gboolean changed = FALSE;
340 G_OBJECT_CLASS (gtk_adjustment_parent_class)->dispatch_properties_changed (object, n_pspecs, pspecs);
342 for (i = 0; i < n_pspecs; i++)
343 switch (pspecs[i]->param_id)
347 case PROP_STEP_INCREMENT:
348 case PROP_PAGE_INCREMENT:
358 adjustment_changed_stamp++;
359 gtk_adjustment_changed (GTK_ADJUSTMENT (object));
364 * gtk_adjustment_new:
365 * @value: the initial value.
366 * @lower: the minimum value.
367 * @upper: the maximum value.
368 * @step_increment: the step increment.
369 * @page_increment: the page increment.
370 * @page_size: the page size.
372 * Creates a new #GtkAdjustment.
374 * Returns: a new #GtkAdjustment.
377 gtk_adjustment_new (gdouble value,
380 gdouble step_increment,
381 gdouble page_increment,
384 return g_object_new (GTK_TYPE_ADJUSTMENT,
387 "step-increment", step_increment,
388 "page-increment", page_increment,
389 "page-size", page_size,
395 * gtk_adjustment_get_value:
396 * @adjustment: a #GtkAdjustment
398 * Gets the current value of the adjustment. See
399 * gtk_adjustment_set_value ().
401 * Return value: The current value of the adjustment.
404 gtk_adjustment_get_value (GtkAdjustment *adjustment)
406 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
408 return adjustment->priv->value;
412 * gtk_adjustment_set_value:
413 * @adjustment: a #GtkAdjustment.
414 * @value: the new value.
416 * Sets the #GtkAdjustment value. The value is clamped to lie between
417 * #GtkAdjustment:lower and #GtkAdjustment:upper.
419 * Note that for adjustments which are used in a #GtkScrollbar, the effective
420 * range of allowed values goes from #GtkAdjustment:lower to
421 * #GtkAdjustment:upper - #GtkAdjustment:page_size.
424 gtk_adjustment_set_value (GtkAdjustment *adjustment,
427 GtkAdjustmentPrivate *priv;
429 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
431 priv = adjustment->priv;
433 /* don't use CLAMP() so we don't end up below lower if upper - page_size
434 * is smaller than lower
436 value = MIN (value, priv->upper - priv->page_size);
437 value = MAX (value, priv->lower);
439 if (value != priv->value)
443 gtk_adjustment_value_changed (adjustment);
448 * gtk_adjustment_get_lower:
449 * @adjustment: a #GtkAdjustment
451 * Retrieves the minimum value of the adjustment.
453 * Return value: The current minimum value of the adjustment.
458 gtk_adjustment_get_lower (GtkAdjustment *adjustment)
460 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
462 return adjustment->priv->lower;
466 * gtk_adjustment_set_lower:
467 * @adjustment: a #GtkAdjustment
468 * @lower: the new minimum value
470 * Sets the minimum value of the adjustment.
472 * When setting multiple adjustment properties via their individual
473 * setters, multiple #GtkAdjustment::changed signals will be emitted. However, since
474 * the emission of the #GtkAdjustment::changed signal is tied to the emission of the
475 * #GObject::notify signals of the changed properties, it's possible
476 * to compress the #GtkAdjustment::changed signals into one by calling
477 * g_object_freeze_notify() and g_object_thaw_notify() around the
478 * calls to the individual setters.
480 * Alternatively, using a single g_object_set() for all the properties
481 * to change, or using gtk_adjustment_configure() has the same effect
482 * of compressing #GtkAdjustment::changed emissions.
487 gtk_adjustment_set_lower (GtkAdjustment *adjustment,
490 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
492 if (lower != adjustment->priv->lower)
493 g_object_set (adjustment, "lower", lower, NULL);
497 * gtk_adjustment_get_upper:
498 * @adjustment: a #GtkAdjustment
500 * Retrieves the maximum value of the adjustment.
502 * Return value: The current maximum value of the adjustment.
507 gtk_adjustment_get_upper (GtkAdjustment *adjustment)
509 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
511 return adjustment->priv->upper;
515 * gtk_adjustment_set_upper:
516 * @adjustment: a #GtkAdjustment
517 * @upper: the new maximum value
519 * Sets the maximum value of the adjustment.
521 * Note that values will be restricted by
522 * <literal>upper - page-size</literal> if the page-size
523 * property is nonzero.
525 * See gtk_adjustment_set_lower() about how to compress multiple
526 * emissions of the #GtkAdjustment::changed signal when setting multiple adjustment
532 gtk_adjustment_set_upper (GtkAdjustment *adjustment,
535 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
537 if (upper != adjustment->priv->upper)
538 g_object_set (adjustment, "upper", upper, NULL);
542 * gtk_adjustment_get_step_increment:
543 * @adjustment: a #GtkAdjustment
545 * Retrieves the step increment of the adjustment.
547 * Return value: The current step increment of the adjustment.
552 gtk_adjustment_get_step_increment (GtkAdjustment *adjustment)
554 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
556 return adjustment->priv->step_increment;
560 * gtk_adjustment_set_step_increment:
561 * @adjustment: a #GtkAdjustment
562 * @step_increment: the new step increment
564 * Sets the step increment of the adjustment.
566 * See gtk_adjustment_set_lower() about how to compress multiple
567 * emissions of the #GtkAdjustment::changed signal when setting multiple adjustment
573 gtk_adjustment_set_step_increment (GtkAdjustment *adjustment,
574 gdouble step_increment)
576 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
578 if (step_increment != adjustment->priv->step_increment)
579 g_object_set (adjustment, "step-increment", step_increment, NULL);
583 * gtk_adjustment_get_page_increment:
584 * @adjustment: a #GtkAdjustment
586 * Retrieves the page increment of the adjustment.
588 * Return value: The current page increment of the adjustment.
593 gtk_adjustment_get_page_increment (GtkAdjustment *adjustment)
595 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
597 return adjustment->priv->page_increment;
601 * gtk_adjustment_set_page_increment:
602 * @adjustment: a #GtkAdjustment
603 * @page_increment: the new page increment
605 * Sets the page increment of the adjustment.
607 * See gtk_adjustment_set_lower() about how to compress multiple
608 * emissions of the #GtkAdjustment::changed signal when setting multiple adjustment
614 gtk_adjustment_set_page_increment (GtkAdjustment *adjustment,
615 gdouble page_increment)
617 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
619 if (page_increment != adjustment->priv->page_increment)
620 g_object_set (adjustment, "page-increment", page_increment, NULL);
624 * gtk_adjustment_get_page_size:
625 * @adjustment: a #GtkAdjustment
627 * Retrieves the page size of the adjustment.
629 * Return value: The current page size of the adjustment.
634 gtk_adjustment_get_page_size (GtkAdjustment *adjustment)
636 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0.0);
638 return adjustment->priv->page_size;
642 * gtk_adjustment_set_page_size:
643 * @adjustment: a #GtkAdjustment
644 * @page_size: the new page size
646 * Sets the page size of the adjustment.
648 * See gtk_adjustment_set_lower() about how to compress multiple
649 * emissions of the GtkAdjustment::changed signal when setting multiple adjustment
655 gtk_adjustment_set_page_size (GtkAdjustment *adjustment,
658 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
660 if (page_size != adjustment->priv->page_size)
661 g_object_set (adjustment, "page-size", page_size, NULL);
665 * gtk_adjustment_configure:
666 * @adjustment: a #GtkAdjustment
667 * @value: the new value
668 * @lower: the new minimum value
669 * @upper: the new maximum value
670 * @step_increment: the new step increment
671 * @page_increment: the new page increment
672 * @page_size: the new page size
674 * Sets all properties of the adjustment at once.
676 * Use this function to avoid multiple emissions of the #GtkAdjustment::changed
677 * signal. See gtk_adjustment_set_lower() for an alternative way
678 * of compressing multiple emissions of #GtkAdjustment::changed into one.
683 gtk_adjustment_configure (GtkAdjustment *adjustment,
687 gdouble step_increment,
688 gdouble page_increment,
691 GtkAdjustmentPrivate *priv;
692 gboolean value_changed = FALSE;
693 guint64 old_stamp = adjustment_changed_stamp;
695 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
697 priv = adjustment->priv;
699 g_object_freeze_notify (G_OBJECT (adjustment));
701 g_object_set (adjustment,
704 "step-increment", step_increment,
705 "page-increment", page_increment,
706 "page-size", page_size,
709 /* don't use CLAMP() so we don't end up below lower if upper - page_size
710 * is smaller than lower
712 value = MIN (value, upper - page_size);
713 value = MAX (value, lower);
715 if (value != priv->value)
717 /* set value manually to make sure "changed" is emitted with the
718 * new value in place and is emitted before "value-changed"
721 value_changed = TRUE;
724 g_object_thaw_notify (G_OBJECT (adjustment));
726 if (old_stamp == adjustment_changed_stamp)
727 gtk_adjustment_changed (adjustment); /* force emission before ::value-changed */
730 gtk_adjustment_value_changed (adjustment);
734 * gtk_adjustment_changed:
735 * @adjustment: a #GtkAdjustment
737 * Emits a #GtkAdjustment::changed signal from the #GtkAdjustment.
738 * This is typically called by the owner of the #GtkAdjustment after it has
739 * changed any of the #GtkAdjustment properties other than the value.
742 gtk_adjustment_changed (GtkAdjustment *adjustment)
744 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
746 g_signal_emit (adjustment, adjustment_signals[CHANGED], 0);
750 * gtk_adjustment_value_changed:
751 * @adjustment: a #GtkAdjustment
753 * Emits a #GtkAdjustment::value_changed signal from the #GtkAdjustment.
754 * This is typically called by the owner of the #GtkAdjustment after it has
755 * changed the #GtkAdjustment:value property.
758 gtk_adjustment_value_changed (GtkAdjustment *adjustment)
760 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
762 g_signal_emit (adjustment, adjustment_signals[VALUE_CHANGED], 0);
763 g_object_notify (G_OBJECT (adjustment), "value");
767 * gtk_adjustment_clamp_page:
768 * @adjustment: a #GtkAdjustment.
769 * @lower: the lower value.
770 * @upper: the upper value.
772 * Updates the #GtkAdjustment:value property to ensure that the range
773 * between @lower and @upper is in the current page (i.e. between
774 * #GtkAdjustment:value and #GtkAdjustment:value + #GtkAdjustment:page_size).
775 * If the range is larger than the page size, then only the start of it will
776 * be in the current page.
777 * A #GtkAdjustment::changed signal will be emitted if the value is changed.
780 gtk_adjustment_clamp_page (GtkAdjustment *adjustment,
784 GtkAdjustmentPrivate *priv;
785 gboolean need_emission;
787 g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
789 priv = adjustment->priv;
791 lower = CLAMP (lower, priv->lower, priv->upper);
792 upper = CLAMP (upper, priv->lower, priv->upper);
794 need_emission = FALSE;
796 if (priv->value + priv->page_size < upper)
798 priv->value = upper - priv->page_size;
799 need_emission = TRUE;
801 if (priv->value > lower)
804 need_emission = TRUE;
808 gtk_adjustment_value_changed (adjustment);
812 * gtk_adjustment_get_minimum_increment:
813 * @adjustment: a #GtkAdjustment
815 * Gets the smaller of step increment and page increment.
817 * Returns: the minimum increment of @adjustment
822 gtk_adjustment_get_minimum_increment (GtkAdjustment *adjustment)
824 GtkAdjustmentPrivate *priv;
825 gdouble minimum_increment;
827 g_return_val_if_fail (GTK_IS_ADJUSTMENT (adjustment), 0);
829 priv = adjustment->priv;
831 if (priv->step_increment != 0 && priv->page_increment != 0)
833 if (ABS (priv->step_increment) < ABS (priv->page_increment))
834 minimum_increment = priv->step_increment;
836 minimum_increment = priv->page_increment;
838 else if (priv->step_increment == 0 && priv->page_increment == 0)
840 minimum_increment = 0;
842 else if (priv->step_increment == 0)
844 minimum_increment = priv->page_increment;
848 minimum_increment = priv->step_increment;
851 return minimum_increment;