2 * Copyright (C) 2007-2010 Openismus GmbH
5 * Mathias Hasselmann <mathias@openismus.com>
6 * Tristan Van Berkom <tristan.van.berkom@gmail.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
24 #include "gtksizerequest.h"
28 #include "gtkprivate.h"
29 #include "gtksizegroup-private.h"
30 #include "gtkwidgetprivate.h"
31 #include "deprecated/gtkstyle.h"
34 #ifndef G_DISABLE_CHECKS
35 static GQuark recursion_check_quark = 0;
36 #endif /* G_DISABLE_CHECKS */
39 push_recursion_check (GtkWidget *widget,
40 GtkSizeGroupMode orientation,
43 #ifndef G_DISABLE_CHECKS
44 const char *previous_method;
47 if (recursion_check_quark == 0)
48 recursion_check_quark = g_quark_from_static_string ("gtk-size-request-in-progress");
50 previous_method = g_object_get_qdata (G_OBJECT (widget), recursion_check_quark);
52 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
54 method = for_size < 0 ? "get_width" : "get_width_for_height";
58 method = for_size < 0 ? "get_height" : "get_height_for_width";
61 if (previous_method != NULL)
63 g_warning ("%s %p: widget tried to gtk_widget_%s inside "
64 " GtkWidget ::%s implementation. "
65 "Should just invoke GTK_WIDGET_GET_CLASS(widget)->%s "
66 "directly rather than using gtk_widget_%s",
67 G_OBJECT_TYPE_NAME (widget), widget,
68 method, previous_method,
72 g_object_set_qdata (G_OBJECT (widget), recursion_check_quark, (char*) method);
73 #endif /* G_DISABLE_CHECKS */
77 pop_recursion_check (GtkWidget *widget,
78 GtkSizeGroupMode orientation)
80 #ifndef G_DISABLE_CHECKS
81 g_object_set_qdata (G_OBJECT (widget), recursion_check_quark, NULL);
87 clear_cache (SizeRequestCache *cache,
88 GtkSizeGroupMode orientation)
93 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
95 sizes = cache->widths;
98 cache->cached_widths = 0;
99 cache->last_cached_width = 0;
100 cache->cached_base_width = FALSE;
104 sizes = cache->heights;
106 cache->heights = NULL;
107 cache->cached_heights = 0;
108 cache->last_cached_height = 0;
109 cache->cached_base_height = FALSE;
114 for (i = 0; i < GTK_SIZE_REQUEST_CACHED_SIZES && sizes[i] != NULL; i++)
115 g_slice_free (SizeRequest, sizes[i]);
117 g_slice_free1 (sizeof (SizeRequest *) * GTK_SIZE_REQUEST_CACHED_SIZES, sizes);
122 _gtk_widget_free_cached_sizes (GtkWidget *widget)
124 SizeRequestCache *cache;
126 cache = _gtk_widget_peek_request_cache (widget);
128 clear_cache (cache, GTK_SIZE_GROUP_HORIZONTAL);
129 clear_cache (cache, GTK_SIZE_GROUP_VERTICAL);
132 /* This function checks if 'request_needed' flag is present
133 * and resets the cache state if a request is needed for
134 * a given orientation.
136 static SizeRequestCache *
137 init_cache (GtkWidget *widget)
139 SizeRequestCache *cache;
141 cache = _gtk_widget_peek_request_cache (widget);
143 if (_gtk_widget_get_width_request_needed (widget))
144 clear_cache (cache, GTK_SIZE_GROUP_HORIZONTAL);
146 if (_gtk_widget_get_height_request_needed (widget))
147 clear_cache (cache, GTK_SIZE_GROUP_VERTICAL);
152 /* looks for a cached size request for this for_size. If not
153 * found, returns the oldest entry so it can be overwritten
155 * Note that this caching code was originally derived from
156 * the Clutter toolkit but has evolved for other GTK+ requirements.
159 get_cached_size (GtkWidget *widget,
160 GtkSizeGroupMode orientation,
164 SizeRequestCache *cache;
165 SizeRequest **cached_sizes;
168 cache = init_cache (widget);
172 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
174 *result = &cache->cached_width;
175 return cache->cached_base_width;
179 *result = &cache->cached_height;
180 return cache->cached_base_height;
184 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
186 cached_sizes = cache->widths;
187 n_sizes = cache->cached_widths;
191 cached_sizes = cache->heights;
192 n_sizes = cache->cached_heights;
195 /* Search for an already cached size */
196 for (i = 0; i < n_sizes; i++)
198 if (cached_sizes[i]->lower_for_size <= for_size &&
199 cached_sizes[i]->upper_for_size >= for_size)
201 *result = &cached_sizes[i]->cached_size;
210 commit_cached_size (GtkWidget *widget,
211 GtkSizeGroupMode orientation,
216 SizeRequestCache *cache;
217 SizeRequest **cached_sizes;
220 cache = _gtk_widget_peek_request_cache (widget);
222 /* First handle caching of the base requests */
225 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
227 cache->cached_width.minimum_size = minimum_size;
228 cache->cached_width.natural_size = natural_size;
229 cache->cached_base_width = TRUE;
233 cache->cached_height.minimum_size = minimum_size;
234 cache->cached_height.natural_size = natural_size;
235 cache->cached_base_height = TRUE;
240 /* Check if the minimum_size and natural_size is already
241 * in the cache and if this result can be used to extend
244 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
246 cached_sizes = cache->widths;
247 n_sizes = cache->cached_widths;
251 cached_sizes = cache->heights;
252 n_sizes = cache->cached_heights;
255 for (i = 0; i < n_sizes; i++)
257 if (cached_sizes[i]->cached_size.minimum_size == minimum_size &&
258 cached_sizes[i]->cached_size.natural_size == natural_size)
260 cached_sizes[i]->lower_for_size = MIN (cached_sizes[i]->lower_for_size, for_size);
261 cached_sizes[i]->upper_for_size = MAX (cached_sizes[i]->upper_for_size, for_size);
266 /* If not found, pull a new size from the cache, the returned size cache
267 * will immediately be used to cache the new computed size so we go ahead
268 * and increment the last_cached_width/height right away */
269 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
271 if (cache->cached_widths < GTK_SIZE_REQUEST_CACHED_SIZES)
273 cache->cached_widths++;
274 cache->last_cached_width = cache->cached_widths - 1;
278 if (++cache->last_cached_width == GTK_SIZE_REQUEST_CACHED_SIZES)
279 cache->last_cached_width = 0;
283 cache->widths = g_slice_alloc0 (sizeof (SizeRequest *) * GTK_SIZE_REQUEST_CACHED_SIZES);
285 if (!cache->widths[cache->last_cached_width])
286 cache->widths[cache->last_cached_width] = g_slice_new (SizeRequest);
288 cache->widths[cache->last_cached_width]->lower_for_size = for_size;
289 cache->widths[cache->last_cached_width]->upper_for_size = for_size;
290 cache->widths[cache->last_cached_width]->cached_size.minimum_size = minimum_size;
291 cache->widths[cache->last_cached_width]->cached_size.natural_size = natural_size;
293 else /* GTK_SIZE_GROUP_VERTICAL */
295 if (cache->cached_heights < GTK_SIZE_REQUEST_CACHED_SIZES)
297 cache->cached_heights++;
298 cache->last_cached_height = cache->cached_heights - 1;
302 if (++cache->last_cached_height == GTK_SIZE_REQUEST_CACHED_SIZES)
303 cache->last_cached_height = 0;
307 cache->heights = g_slice_alloc0 (sizeof (SizeRequest *) * GTK_SIZE_REQUEST_CACHED_SIZES);
309 if (!cache->heights[cache->last_cached_height])
310 cache->heights[cache->last_cached_height] = g_slice_new (SizeRequest);
312 cache->heights[cache->last_cached_height]->lower_for_size = for_size;
313 cache->heights[cache->last_cached_height]->upper_for_size = for_size;
314 cache->heights[cache->last_cached_height]->cached_size.minimum_size = minimum_size;
315 cache->heights[cache->last_cached_height]->cached_size.natural_size = natural_size;
320 get_vfunc_name (GtkSizeGroupMode orientation,
323 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
324 return for_size < 0 ? "get_preferred_width" : "get_preferred_width_for_height";
326 return for_size < 0 ? "get_preferred_height" : "get_preferred_height_for_width";
330 * _gtk_size_group_bump_requisition:
331 * @widget: a #GtkWidget
332 * @mode: either %GTK_SIZE_GROUP_HORIZONTAL or %GTK_SIZE_GROUP_VERTICAL, depending
333 * on the dimension in which to bump the size.
334 * @for_size: Size to request minimum and natural size for
335 * @minimum: a pointer to the widget's minimum size
336 * @natural: a pointer to the widget's natural size
338 * Refreshes the sizegroup while returning the groups requested
339 * value in the dimension @mode.
341 * This function is used both to update sizegroup minimum and natural size
342 * information and widget minimum and natural sizes in multiple passes from
343 * the size request apis.
346 gtk_size_group_bump_requisition (GtkWidget *widget,
347 GtkSizeGroupMode mode,
355 gint min_result = 0, nat_result = 0;
357 if (!_gtk_widget_get_sizegroups (widget))
360 widgets = _gtk_size_group_get_widget_peers (widget, mode);
362 g_hash_table_foreach (widgets, (GHFunc) g_object_ref, NULL);
364 g_hash_table_iter_init (&iter, widgets);
365 while (g_hash_table_iter_next (&iter, &key, NULL))
367 GtkWidget *tmp_widget = key;
368 gint min_dimension, nat_dimension;
370 if (tmp_widget == widget)
372 min_dimension = *minimum;
373 nat_dimension = *natural;
377 _gtk_widget_compute_size_for_orientation (tmp_widget, mode, TRUE, for_size, &min_dimension, &nat_dimension);
380 min_result = MAX (min_result, min_dimension);
381 nat_result = MAX (nat_result, nat_dimension);
384 g_hash_table_foreach (widgets, (GHFunc) g_object_unref, NULL);
386 g_hash_table_destroy (widgets);
388 *minimum = min_result;
389 *natural = nat_result;
392 /* This is the main function that checks for a cached size and
393 * possibly queries the widget class to compute the size if it's
394 * not cached. If the for_size here is -1, then get_preferred_width()
395 * or get_preferred_height() will be used.
398 _gtk_widget_compute_size_for_orientation (GtkWidget *widget,
399 GtkSizeGroupMode orientation,
400 gboolean ignore_size_groups,
405 CachedSize *cached_size;
406 gboolean found_in_cache = FALSE;
410 found_in_cache = get_cached_size (widget, orientation, for_size, &cached_size);
414 gint adjusted_min, adjusted_natural, adjusted_for_size = for_size;
416 gtk_widget_ensure_style (widget);
418 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
420 if (for_size < 0 || gtk_widget_get_request_mode (widget) == GTK_SIZE_REQUEST_CONSTANT_SIZE)
422 push_recursion_check (widget, orientation, for_size);
423 GTK_WIDGET_GET_CLASS (widget)->get_preferred_width (widget, &min_size, &nat_size);
424 pop_recursion_check (widget, orientation);
428 gint ignored_position = 0;
432 /* Pull the base natural height from the cache as it's needed to adjust
433 * the proposed 'for_size' */
434 gtk_widget_get_preferred_height (widget, &minimum_height, &natural_height);
436 /* convert for_size to unadjusted height (for_size is a proposed allocation) */
437 GTK_WIDGET_GET_CLASS (widget)->adjust_size_allocation (widget,
438 GTK_ORIENTATION_VERTICAL,
444 push_recursion_check (widget, orientation, for_size);
445 GTK_WIDGET_GET_CLASS (widget)->get_preferred_width_for_height (widget,
446 MAX (adjusted_for_size, minimum_height),
447 &min_size, &nat_size);
448 pop_recursion_check (widget, orientation);
453 if (for_size < 0 || gtk_widget_get_request_mode (widget) == GTK_SIZE_REQUEST_CONSTANT_SIZE)
455 push_recursion_check (widget, orientation, for_size);
456 GTK_WIDGET_GET_CLASS (widget)->get_preferred_height (widget, &min_size, &nat_size);
457 pop_recursion_check (widget, orientation);
461 gint ignored_position = 0;
465 /* Pull the base natural width from the cache as it's needed to adjust
466 * the proposed 'for_size' */
467 gtk_widget_get_preferred_width (widget, &minimum_width, &natural_width);
469 /* convert for_size to unadjusted width (for_size is a proposed allocation) */
470 GTK_WIDGET_GET_CLASS (widget)->adjust_size_allocation (widget,
471 GTK_ORIENTATION_HORIZONTAL,
477 push_recursion_check (widget, orientation, for_size);
478 GTK_WIDGET_GET_CLASS (widget)->get_preferred_height_for_width (widget,
479 MAX (adjusted_for_size, minimum_width),
480 &min_size, &nat_size);
481 pop_recursion_check (widget, orientation);
485 if (min_size > nat_size)
487 g_warning ("%s %p reported min size %d and natural size %d in %s(); natural size must be >= min size",
488 G_OBJECT_TYPE_NAME (widget), widget, min_size, nat_size, get_vfunc_name (orientation, for_size));
491 if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
492 _gtk_widget_set_width_request_needed (widget, FALSE);
494 _gtk_widget_set_height_request_needed (widget, FALSE);
496 adjusted_min = min_size;
497 adjusted_natural = nat_size;
498 GTK_WIDGET_GET_CLASS (widget)->adjust_size_request (widget,
499 orientation == GTK_SIZE_GROUP_HORIZONTAL ?
500 GTK_ORIENTATION_HORIZONTAL :
501 GTK_ORIENTATION_VERTICAL,
505 if (adjusted_min < min_size ||
506 adjusted_natural < nat_size)
508 g_warning ("%s %p adjusted size %s min %d natural %d must not decrease below min %d natural %d",
509 G_OBJECT_TYPE_NAME (widget), widget,
510 orientation == GTK_SIZE_GROUP_VERTICAL ? "vertical" : "horizontal",
511 adjusted_min, adjusted_natural,
513 /* don't use the adjustment */
515 else if (adjusted_min > adjusted_natural)
517 g_warning ("%s %p adjusted size %s min %d natural %d original min %d natural %d has min greater than natural",
518 G_OBJECT_TYPE_NAME (widget), widget,
519 orientation == GTK_SIZE_GROUP_VERTICAL ? "vertical" : "horizontal",
520 adjusted_min, adjusted_natural,
522 /* don't use the adjustment */
526 /* adjustment looks good */
527 min_size = adjusted_min;
528 nat_size = adjusted_natural;
531 commit_cached_size (widget, orientation, for_size, min_size, nat_size);
535 min_size = cached_size->minimum_size;
536 nat_size = cached_size->natural_size;
539 if (!ignore_size_groups)
540 gtk_size_group_bump_requisition (widget,
547 *minimum_size = min_size;
550 *natural_size = nat_size;
552 g_assert (min_size <= nat_size);
554 GTK_NOTE (SIZE_REQUEST,
555 g_print ("[%p] %s\t%s: %d is minimum %d and natural: %d (hit cache: %s, ignore size groups: %s)\n",
556 widget, G_OBJECT_TYPE_NAME (widget),
557 orientation == GTK_SIZE_GROUP_HORIZONTAL ?
558 "width for height" : "height for width" ,
559 for_size, min_size, nat_size,
560 found_in_cache ? "yes" : "no",
561 ignore_size_groups ? "yes" : "no"));
566 * gtk_widget_get_request_mode:
567 * @widget: a #GtkWidget instance
569 * Gets whether the widget prefers a height-for-width layout
570 * or a width-for-height layout.
572 * <note><para>#GtkBin widgets generally propagate the preference of
573 * their child, container widgets need to request something either in
574 * context of their children or in context of their allocation
575 * capabilities.</para></note>
577 * Returns: The #GtkSizeRequestMode preferred by @widget.
582 gtk_widget_get_request_mode (GtkWidget *widget)
584 g_return_val_if_fail (GTK_IS_WIDGET (widget), GTK_SIZE_REQUEST_CONSTANT_SIZE);
586 return GTK_WIDGET_GET_CLASS (widget)->get_request_mode (widget);
590 * gtk_widget_get_preferred_width:
591 * @widget: a #GtkWidget instance
592 * @minimum_width: (out) (allow-none): location to store the minimum width, or %NULL
593 * @natural_width: (out) (allow-none): location to store the natural width, or %NULL
595 * Retrieves a widget's initial minimum and natural width.
597 * <note><para>This call is specific to height-for-width
598 * requests.</para></note>
600 * The returned request will be modified by the
601 * GtkWidgetClass::adjust_size_request virtual method and by any
602 * #GtkSizeGroup<!-- -->s that have been applied. That is, the returned request
603 * is the one that should be used for layout, not necessarily the one
604 * returned by the widget itself.
609 gtk_widget_get_preferred_width (GtkWidget *widget,
613 g_return_if_fail (GTK_IS_WIDGET (widget));
614 g_return_if_fail (minimum_width != NULL || natural_width != NULL);
616 _gtk_widget_compute_size_for_orientation (widget,
617 GTK_SIZE_GROUP_HORIZONTAL,
626 * gtk_widget_get_preferred_height:
627 * @widget: a #GtkWidget instance
628 * @minimum_height: (out) (allow-none): location to store the minimum height, or %NULL
629 * @natural_height: (out) (allow-none): location to store the natural height, or %NULL
631 * Retrieves a widget's initial minimum and natural height.
633 * <note><para>This call is specific to width-for-height requests.</para></note>
635 * The returned request will be modified by the
636 * GtkWidgetClass::adjust_size_request virtual method and by any
637 * #GtkSizeGroup<!-- -->s that have been applied. That is, the returned request
638 * is the one that should be used for layout, not necessarily the one
639 * returned by the widget itself.
644 gtk_widget_get_preferred_height (GtkWidget *widget,
645 gint *minimum_height,
646 gint *natural_height)
648 g_return_if_fail (GTK_IS_WIDGET (widget));
649 g_return_if_fail (minimum_height != NULL || natural_height != NULL);
651 _gtk_widget_compute_size_for_orientation (widget,
652 GTK_SIZE_GROUP_VERTICAL,
662 * gtk_widget_get_preferred_width_for_height:
663 * @widget: a #GtkWidget instance
664 * @height: the height which is available for allocation
665 * @minimum_width: (out) (allow-none): location for storing the minimum width, or %NULL
666 * @natural_width: (out) (allow-none): location for storing the natural width, or %NULL
668 * Retrieves a widget's minimum and natural width if it would be given
669 * the specified @height.
671 * The returned request will be modified by the
672 * GtkWidgetClass::adjust_size_request virtual method and by any
673 * #GtkSizeGroup<!-- -->s that have been applied. That is, the returned request
674 * is the one that should be used for layout, not necessarily the one
675 * returned by the widget itself.
680 gtk_widget_get_preferred_width_for_height (GtkWidget *widget,
685 g_return_if_fail (GTK_IS_WIDGET (widget));
686 g_return_if_fail (minimum_width != NULL || natural_width != NULL);
687 g_return_if_fail (height >= 0);
689 _gtk_widget_compute_size_for_orientation (widget,
690 GTK_SIZE_GROUP_HORIZONTAL,
698 * gtk_widget_get_preferred_height_for_width:
699 * @widget: a #GtkWidget instance
700 * @width: the width which is available for allocation
701 * @minimum_height: (out) (allow-none): location for storing the minimum height, or %NULL
702 * @natural_height: (out) (allow-none): location for storing the natural height, or %NULL
704 * Retrieves a widget's minimum and natural height if it would be given
705 * the specified @width.
707 * The returned request will be modified by the
708 * GtkWidgetClass::adjust_size_request virtual method and by any
709 * #GtkSizeGroup<!-- -->s that have been applied. That is, the returned request
710 * is the one that should be used for layout, not necessarily the one
711 * returned by the widget itself.
716 gtk_widget_get_preferred_height_for_width (GtkWidget *widget,
718 gint *minimum_height,
719 gint *natural_height)
721 g_return_if_fail (GTK_IS_WIDGET (widget));
722 g_return_if_fail (minimum_height != NULL || natural_height != NULL);
723 g_return_if_fail (width >= 0);
725 _gtk_widget_compute_size_for_orientation (widget,
726 GTK_SIZE_GROUP_VERTICAL,
734 * gtk_widget_get_preferred_size:
735 * @widget: a #GtkWidget instance
736 * @minimum_size: (out) (allow-none): location for storing the minimum size, or %NULL
737 * @natural_size: (out) (allow-none): location for storing the natural size, or %NULL
739 * Retrieves the minimum and natural size of a widget, taking
740 * into account the widget's preference for height-for-width management.
742 * This is used to retrieve a suitable size by container widgets which do
743 * not impose any restrictions on the child placement. It can be used
744 * to deduce toplevel window and menu sizes as well as child widgets in
745 * free-form containers such as GtkLayout.
747 * <note><para>Handle with care. Note that the natural height of a height-for-width
748 * widget will generally be a smaller size than the minimum height, since the required
749 * height for the natural width is generally smaller than the required height for
750 * the minimum width.</para></note>
755 gtk_widget_get_preferred_size (GtkWidget *widget,
756 GtkRequisition *minimum_size,
757 GtkRequisition *natural_size)
759 gint min_width, nat_width;
760 gint min_height, nat_height;
762 g_return_if_fail (GTK_IS_WIDGET (widget));
764 if (gtk_widget_get_request_mode (widget) == GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH)
766 gtk_widget_get_preferred_width (widget, &min_width, &nat_width);
770 minimum_size->width = min_width;
771 gtk_widget_get_preferred_height_for_width (widget, min_width,
772 &minimum_size->height, NULL);
777 natural_size->width = nat_width;
778 gtk_widget_get_preferred_height_for_width (widget, nat_width,
779 NULL, &natural_size->height);
782 else /* GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT or CONSTANT_SIZE */
784 gtk_widget_get_preferred_height (widget, &min_height, &nat_height);
788 minimum_size->height = min_height;
789 gtk_widget_get_preferred_width_for_height (widget, min_height,
790 &minimum_size->width, NULL);
795 natural_size->height = nat_height;
796 gtk_widget_get_preferred_width_for_height (widget, nat_height,
797 NULL, &natural_size->width);
804 compare_gap (gconstpointer p1,
808 GtkRequestedSize *sizes = data;
809 const guint *c1 = p1;
810 const guint *c2 = p2;
812 const gint d1 = MAX (sizes[*c1].natural_size -
813 sizes[*c1].minimum_size,
815 const gint d2 = MAX (sizes[*c2].natural_size -
816 sizes[*c2].minimum_size,
819 gint delta = (d2 - d1);
828 * gtk_distribute_natural_allocation:
829 * @extra_space: Extra space to redistribute among children after subtracting
830 * minimum sizes and any child padding from the overall allocation
831 * @n_requested_sizes: Number of requests to fit into the allocation
832 * @sizes: An array of structs with a client pointer and a minimum/natural size
833 * in the orientation of the allocation.
835 * Distributes @extra_space to child @sizes by bringing smaller
836 * children up to natural size first.
838 * The remaining space will be added to the @minimum_size member of the
839 * GtkRequestedSize struct. If all sizes reach their natural size then
840 * the remaining space is returned.
842 * Returns: The remainder of @extra_space after redistributing space
846 gtk_distribute_natural_allocation (gint extra_space,
847 guint n_requested_sizes,
848 GtkRequestedSize *sizes)
853 g_return_val_if_fail (extra_space >= 0, 0);
855 spreading = g_newa (guint, n_requested_sizes);
857 for (i = 0; i < n_requested_sizes; i++)
860 /* Distribute the container's extra space c_gap. We want to assign
861 * this space such that the sum of extra space assigned to children
862 * (c^i_gap) is equal to c_cap. The case that there's not enough
863 * space for all children to take their natural size needs some
864 * attention. The goals we want to achieve are:
866 * a) Maximize number of children taking their natural size.
867 * b) The allocated size of children should be a continuous
868 * function of c_gap. That is, increasing the container size by
869 * one pixel should never make drastic changes in the distribution.
870 * c) If child i takes its natural size and child j doesn't,
871 * child j should have received at least as much gap as child i.
873 * The following code distributes the additional space by following
877 /* Sort descending by gap and position. */
878 g_qsort_with_data (spreading,
879 n_requested_sizes, sizeof (guint),
882 /* Distribute available space.
883 * This master piece of a loop was conceived by Behdad Esfahbod.
885 for (i = n_requested_sizes - 1; extra_space > 0 && i >= 0; --i)
887 /* Divide remaining space by number of remaining children.
888 * Sort order and reducing remaining space by assigned space
889 * ensures that space is distributed equally.
891 gint glue = (extra_space + i) / (i + 1);
892 gint gap = sizes[(spreading[i])].natural_size
893 - sizes[(spreading[i])].minimum_size;
895 gint extra = MIN (glue, gap);
897 sizes[spreading[i]].minimum_size += extra;
899 extra_space -= extra;