gtk2/gtk/gtksizerequest.c

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/* gtksizerequest.c
* Copyright (C) 2007-2010 Openismus GmbH
*
* Authors:
* Mathias Hasselmann <mathias@openismus.com>
* Tristan Van Berkom <tristan.van.berkom@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include "gtksizerequest.h"
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#include "gtkdebug.h"
#include "gtkintl.h"
#include "gtkprivate.h"
#include "gtksizegroup-private.h"
#include "gtksizerequestcacheprivate.h"
#include "gtkwidgetprivate.h"
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#include "gtkcssnodeprivate.h"
#include "gtkcssnumbervalueprivate.h"
#include "gtklayoutmanagerprivate.h"
#ifdef G_ENABLE_CONSISTENCY_CHECKS
static GQuark recursion_check_quark = 0;
static void
push_recursion_check (GtkWidget *widget,
GtkOrientation orientation)
{
gboolean in_measure = FALSE;
if (recursion_check_quark == 0)
recursion_check_quark = g_quark_from_static_string ("gtk-size-request-in-progress");
in_measure = GPOINTER_TO_INT (g_object_get_qdata (G_OBJECT (widget), recursion_check_quark));
if (in_measure)
{
g_warning ("%s %p: widget tried to gtk_widget_measure inside "
" GtkWidget::measure implementation. "
"Should just invoke GTK_WIDGET_GET_CLASS(widget)->measure "
"directly rather than using gtk_widget_measure",
G_OBJECT_TYPE_NAME (widget), widget);
}
g_object_set_qdata (G_OBJECT (widget), recursion_check_quark, GINT_TO_POINTER(TRUE));
}
static void
pop_recursion_check (GtkWidget *widget,
GtkOrientation orientation)
{
g_object_set_qdata (G_OBJECT (widget), recursion_check_quark, NULL);
}
#else
#define push_recursion_check(widget, orientation)
#define pop_recursion_check(widget, orientation)
#endif /* G_ENABLE_CONSISTENCY_CHECKS */
static GtkSizeRequestMode
fetch_request_mode (GtkWidget *widget)
{
GtkLayoutManager *layout_manager = gtk_widget_get_layout_manager (widget);
if (layout_manager != NULL)
return gtk_layout_manager_get_request_mode (layout_manager);
else
return GTK_WIDGET_GET_CLASS (widget)->get_request_mode (widget);
}
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static gint
get_number (GtkCssStyle *style,
guint property)
{
double d = _gtk_css_number_value_get (gtk_css_style_get_value (style, property), 100);
if (d < 1)
return ceil (d);
else
return floor (d);
}
/* Special-case min-width|height to round upwards, to avoid underalloc by 1px */
static int
get_number_ceil (GtkCssStyle *style,
guint property)
{
return ceil (_gtk_css_number_value_get (gtk_css_style_get_value (style, property), 100));
}
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static void
get_box_margin (GtkCssStyle *style,
GtkBorder *margin)
{
margin->top = get_number (style, GTK_CSS_PROPERTY_MARGIN_TOP);
margin->left = get_number (style, GTK_CSS_PROPERTY_MARGIN_LEFT);
margin->bottom = get_number (style, GTK_CSS_PROPERTY_MARGIN_BOTTOM);
margin->right = get_number (style, GTK_CSS_PROPERTY_MARGIN_RIGHT);
}
static void
get_box_border (GtkCssStyle *style,
GtkBorder *border)
{
border->top = get_number (style, GTK_CSS_PROPERTY_BORDER_TOP_WIDTH);
border->left = get_number (style, GTK_CSS_PROPERTY_BORDER_LEFT_WIDTH);
border->bottom = get_number (style, GTK_CSS_PROPERTY_BORDER_BOTTOM_WIDTH);
border->right = get_number (style, GTK_CSS_PROPERTY_BORDER_RIGHT_WIDTH);
}
static void
get_box_padding (GtkCssStyle *style,
GtkBorder *border)
{
border->top = get_number (style, GTK_CSS_PROPERTY_PADDING_TOP);
border->left = get_number (style, GTK_CSS_PROPERTY_PADDING_LEFT);
border->bottom = get_number (style, GTK_CSS_PROPERTY_PADDING_BOTTOM);
border->right = get_number (style, GTK_CSS_PROPERTY_PADDING_RIGHT);
}
static void
gtk_widget_query_size_for_orientation (GtkWidget *widget,
GtkOrientation orientation,
gint for_size,
gint *minimum,
gint *natural,
gint *minimum_baseline,
gint *natural_baseline)
{
const gboolean baselines_requested = (minimum_baseline != NULL || natural_baseline != NULL);
SizeRequestCache *cache;
gint min_size = 0;
gint nat_size = 0;
gint min_baseline = -1;
gint nat_baseline = -1;
gboolean found_in_cache;
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gtk_widget_ensure_resize (widget);
/* We check the request mode first, to determine whether the widget even does
* any wfh/hfw handling. If it doesn't, we reset for_size to -1 and ensure
* that we only cache one size for the widget (i.e. a lot more cache hits). */
cache = _gtk_widget_peek_request_cache (widget);
if (G_UNLIKELY (!cache->request_mode_valid))
{
cache->request_mode = fetch_request_mode (widget);
cache->request_mode_valid = TRUE;
}
if (cache->request_mode == GTK_SIZE_REQUEST_CONSTANT_SIZE)
for_size = -1;
found_in_cache = _gtk_size_request_cache_lookup (cache,
orientation,
for_size,
&min_size,
&nat_size,
&min_baseline,
&nat_baseline);
if (!found_in_cache)
{
GtkWidgetClass *widget_class;
GtkCssStyle *style;
GtkBorder margin, border, padding;
int adjusted_min, adjusted_natural;
int reported_min_size = 0;
int reported_nat_size = 0;
int css_min_size;
int css_min_for_size;
int css_extra_for_size;
int css_extra_size;
style = gtk_css_node_get_style (gtk_widget_get_css_node (widget));
get_box_margin (style, &margin);
get_box_border (style, &border);
get_box_padding (style, &padding);
widget_class = GTK_WIDGET_GET_CLASS (widget);
if (orientation == GTK_ORIENTATION_HORIZONTAL)
{
css_extra_size = margin.left + margin.right + border.left + border.right + padding.left + padding.right;
css_extra_for_size = margin.top + margin.bottom + border.top + border.bottom + padding.top + padding.bottom;
css_min_size = get_number_ceil (style, GTK_CSS_PROPERTY_MIN_WIDTH);
css_min_for_size = get_number_ceil (style, GTK_CSS_PROPERTY_MIN_HEIGHT);
}
else
{
css_extra_size = margin.top + margin.bottom + border.top + border.bottom + padding.top + padding.bottom;
css_extra_for_size = margin.left + margin.right + border.left + border.right + padding.left + padding.right;
css_min_size = get_number_ceil (style, GTK_CSS_PROPERTY_MIN_HEIGHT);
css_min_for_size = get_number_ceil (style, GTK_CSS_PROPERTY_MIN_WIDTH);
}
GtkLayoutManager *layout_manager = gtk_widget_get_layout_manager (widget);
if (layout_manager != NULL)
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{
if (for_size < 0)
{
push_recursion_check (widget, orientation);
gtk_layout_manager_measure (layout_manager, widget,
orientation, -1,
&reported_min_size, &reported_nat_size,
&min_baseline, &nat_baseline);
pop_recursion_check (widget, orientation);
}
else
{
int adjusted_for_size;
int minimum_for_size = 0;
int natural_for_size = 0;
int dummy = 0;
/* Pull the minimum for_size from the cache as it's needed to adjust
* the proposed 'for_size' */
gtk_layout_manager_measure (layout_manager, widget,
OPPOSITE_ORIENTATION (orientation), -1,
&minimum_for_size, &natural_for_size,
NULL, NULL);
if (for_size < MAX (minimum_for_size, css_min_for_size))
for_size = MAX (minimum_for_size, css_min_for_size);
adjusted_for_size = for_size;
gtk_widget_adjust_size_allocation (widget, OPPOSITE_ORIENTATION (orientation),
&for_size, &natural_for_size,
&dummy, &adjusted_for_size);
adjusted_for_size -= css_extra_for_size;
if (adjusted_for_size < 0)
adjusted_for_size = MAX (minimum_for_size, css_min_for_size);
push_recursion_check (widget, orientation);
gtk_layout_manager_measure (layout_manager, widget,
orientation,
adjusted_for_size,
&reported_min_size, &reported_nat_size,
&min_baseline, &nat_baseline);
pop_recursion_check (widget, orientation);
}
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}
else
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{
if (for_size < 0)
{
push_recursion_check (widget, orientation);
widget_class->measure (widget, orientation, -1,
&reported_min_size, &reported_nat_size,
&min_baseline, &nat_baseline);
pop_recursion_check (widget, orientation);
}
else
{
int adjusted_for_size;
int minimum_for_size = 0;
int natural_for_size = 0;
int dummy = 0;
/* Pull the minimum for_size from the cache as it's needed to adjust
* the proposed 'for_size' */
gtk_widget_measure (widget, OPPOSITE_ORIENTATION (orientation), -1,
&minimum_for_size, &natural_for_size, NULL, NULL);
/* TODO: Warn if the given for_size is too small? */
if (for_size < MAX (minimum_for_size, css_min_for_size))
for_size = MAX (minimum_for_size, css_min_for_size);
adjusted_for_size = for_size;
gtk_widget_adjust_size_allocation (widget, OPPOSITE_ORIENTATION (orientation),
&for_size, &natural_for_size,
&dummy, &adjusted_for_size);
adjusted_for_size -= css_extra_for_size;
push_recursion_check (widget, orientation);
widget_class->measure (widget,
orientation,
adjusted_for_size,
&reported_min_size, &reported_nat_size,
&min_baseline, &nat_baseline);
pop_recursion_check (widget, orientation);
}
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}
min_size = MAX (0, MAX (reported_min_size, css_min_size)) + css_extra_size;
nat_size = MAX (0, MAX (reported_nat_size, css_min_size)) + css_extra_size;
if (G_UNLIKELY (min_size > nat_size))
{
if (orientation == GTK_ORIENTATION_HORIZONTAL)
{
g_warning ("%s %p (%s) reported min width %d and natural width %d in measure() with for_size=%d; natural size must be >= min size",
G_OBJECT_TYPE_NAME (widget), widget,
gtk_css_node_get_name (gtk_widget_get_css_node (widget)),
min_size, nat_size, for_size);
}
else
{
g_warning ("%s %p (%s) reported min height %d and natural height %d in measure() with for_size=%d; natural size must be >= min size",
G_OBJECT_TYPE_NAME (widget), widget,
gtk_css_node_get_name (gtk_widget_get_css_node (widget)),
min_size, nat_size, for_size);
}
nat_size = min_size;
}
else if (G_UNLIKELY (min_size < 0))
{
g_warning ("%s %p (%s) reported min %s %d, but sizes must be >= 0",
G_OBJECT_TYPE_NAME (widget), widget,
gtk_css_node_get_name (gtk_widget_get_css_node (widget)),
orientation == GTK_ORIENTATION_HORIZONTAL ? "width" : "height",
min_size);
min_size = 0;
nat_size = MAX (0, min_size);
}
adjusted_min = min_size;
adjusted_natural = nat_size;
gtk_widget_adjust_size_request (widget, orientation,
&adjusted_min, &adjusted_natural);
if (adjusted_min < min_size ||
adjusted_natural < nat_size)
{
g_warning ("%s %p adjusted size %s min %d natural %d must not decrease below min %d natural %d",
G_OBJECT_TYPE_NAME (widget), widget,
orientation == GTK_ORIENTATION_VERTICAL ? "vertical" : "horizontal",
adjusted_min, adjusted_natural,
min_size, nat_size);
/* don't use the adjustment */
}
else if (adjusted_min > adjusted_natural)
{
g_warning ("%s %p adjusted size %s min %d natural %d original min %d natural %d has min greater than natural",
G_OBJECT_TYPE_NAME (widget), widget,
orientation == GTK_ORIENTATION_VERTICAL ? "vertical" : "horizontal",
adjusted_min, adjusted_natural,
min_size, nat_size);
/* don't use the adjustment */
}
else
{
/* adjustment looks good */
min_size = adjusted_min;
nat_size = adjusted_natural;
}
if (baselines_requested && (min_baseline != -1 || nat_baseline != -1))
{
if (orientation == GTK_ORIENTATION_HORIZONTAL)
{
g_warning ("%s %p reported a horizontal baseline",
G_OBJECT_TYPE_NAME (widget), widget);
min_baseline = -1;
nat_baseline = -1;
}
else if (min_baseline == -1 || nat_baseline == -1)
{
g_warning ("%s %p reported baseline for only one of min/natural (min: %d, natural: %d)",
G_OBJECT_TYPE_NAME (widget), widget,
min_baseline, nat_baseline);
min_baseline = -1;
nat_baseline = -1;
}
else if (min_baseline > reported_min_size ||
nat_baseline > reported_nat_size ||
min_baseline < 0 ||
nat_baseline < 0)
{
g_warning ("%s %p reported baselines of minimum %d and natural %d, but sizes of "
"minimum %d and natural %d. Baselines must be inside the widget size.",
G_OBJECT_TYPE_NAME (widget), widget, min_baseline, nat_baseline,
reported_min_size, reported_nat_size);
min_baseline = -1;
nat_baseline = -1;
}
else
{
if (css_min_size > reported_min_size)
{
min_baseline += (css_min_size - reported_min_size) / 2;
nat_baseline += (css_min_size - reported_min_size) / 2;
}
min_baseline += margin.top + border.top + padding.top;
nat_baseline += margin.top + border.top + padding.top;
gtk_widget_adjust_baseline_request (widget, &min_baseline, &nat_baseline);
}
}
_gtk_size_request_cache_commit (cache,
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orientation,
for_size,
min_size,
nat_size,
min_baseline,
nat_baseline);
}
if (minimum)
*minimum = min_size;
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if (natural)
*natural = nat_size;
if (minimum_baseline)
*minimum_baseline = min_baseline;
if (natural_baseline)
*natural_baseline = nat_baseline;
g_assert (min_size <= nat_size);
GTK_DISPLAY_NOTE (_gtk_widget_get_display (widget), SIZE_REQUEST, {
GString *s;
s = g_string_new ("");
g_string_append_printf (s, "[%p] %s\t%s: %d is minimum %d and natural: %d",
widget, G_OBJECT_TYPE_NAME (widget),
orientation == GTK_ORIENTATION_HORIZONTAL
? "width for height"
: "height for width",
for_size, min_size, nat_size);
if (min_baseline != -1 || nat_baseline != -1)
{
g_string_append_printf (s, ", baseline %d/%d",
min_baseline, nat_baseline);
}
g_string_append_printf (s, " (hit cache: %s)\n",
found_in_cache ? "yes" : "no");
g_message ("%s", s->str);
g_string_free (s, TRUE);
});
}
/**
* gtk_widget_measure:
* @widget: A #GtkWidget instance
* @orientation: the orientation to measure
* @for_size: Size for the opposite of @orientation, i.e.
* if @orientation is %GTK_ORIENTATION_HORIZONTAL, this is
* the height the widget should be measured with. The %GTK_ORIENTATION_VERTICAL
* case is analogous. This way, both height-for-width and width-for-height
* requests can be implemented. If no size is known, -1 can be passed.
* @minimum: (out) (optional): location to store the minimum size, or %NULL
* @natural: (out) (optional): location to store the natural size, or %NULL
* @minimum_baseline: (out) (optional): location to store the baseline
* position for the minimum size, or %NULL
* @natural_baseline: (out) (optional): location to store the baseline
* position for the natural size, or %NULL
*
* Measures @widget in the orientation @orientation and for the given @for_size.
* As an example, if @orientation is %GTK_ORIENTATION_HORIZONTAL and @for_size is 300,
* this functions will compute the minimum and natural width of @widget if
* it is allocated at a height of 300 pixels.
*
* See [GtkWidgets geometry management section][geometry-management] for
* a more details on implementing #GtkWidgetClass.measure().
*/
void
gtk_widget_measure (GtkWidget *widget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
g_return_if_fail (GTK_IS_WIDGET (widget));
g_return_if_fail (for_size >= -1);
g_return_if_fail (orientation == GTK_ORIENTATION_HORIZONTAL ||
orientation == GTK_ORIENTATION_VERTICAL);
/* This is the main function that checks for a cached size and
* possibly queries the widget class to compute the size if it's
* not cached.
*/
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if (!_gtk_widget_get_visible (widget) && !GTK_IS_ROOT (widget))
{
if (minimum)
*minimum = 0;
if (natural)
*natural = 0;
if (minimum_baseline)
*minimum_baseline = -1;
if (natural_baseline)
*natural_baseline = -1;
return;
}
if (G_LIKELY (!_gtk_widget_get_sizegroups (widget)))
{
gtk_widget_query_size_for_orientation (widget, orientation, for_size, minimum, natural,
minimum_baseline, natural_baseline);
}
else
{
GHashTable *widgets;
GHashTableIter iter;
gpointer key;
int min_result = 0, nat_result = 0;
widgets = _gtk_size_group_get_widget_peers (widget, orientation);
g_hash_table_iter_init (&iter, widgets);
while (g_hash_table_iter_next (&iter, &key, NULL))
{
GtkWidget *tmp_widget = key;
int min_dimension, nat_dimension;
gtk_widget_query_size_for_orientation (tmp_widget, orientation, for_size,
&min_dimension, &nat_dimension, NULL, NULL);
min_result = MAX (min_result, min_dimension);
nat_result = MAX (nat_result, nat_dimension);
}
g_hash_table_destroy (widgets);
/* Baselines make no sense with sizegroups really */
if (minimum_baseline)
*minimum_baseline = -1;
if (natural_baseline)
*natural_baseline = -1;
if (minimum)
*minimum = min_result;
if (natural)
*natural = nat_result;
}
}
/**
* gtk_widget_get_request_mode:
* @widget: a #GtkWidget instance
*
* Gets whether the widget prefers a height-for-width layout
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* or a width-for-height layout.
*
* #GtkBin widgets generally propagate the preference of
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* their child, container widgets need to request something either in
* context of their children or in context of their allocation
* capabilities.
*
* Returns: The #GtkSizeRequestMode preferred by @widget.
*/
GtkSizeRequestMode
gtk_widget_get_request_mode (GtkWidget *widget)
{
SizeRequestCache *cache;
cache = _gtk_widget_peek_request_cache (widget);
if (G_UNLIKELY (!cache->request_mode_valid))
{
cache->request_mode = fetch_request_mode (widget);
cache->request_mode_valid = TRUE;
}
return cache->request_mode;
}
/*
* _gtk_widget_get_preferred_size_and_baseline:
* @widget: a #GtkWidget instance
* @minimum_size: (out) (allow-none): location for storing the minimum size, or %NULL
* @natural_size: (out) (allow-none): location for storing the natural size, or %NULL
*
* Retrieves the minimum and natural size and the corresponding baselines of a widget, taking
* into account the widgets preference for height-for-width management. The baselines may
* be -1 which means that no baseline is requested for this widget.
*
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* This is used to retrieve a suitable size by container widgets which do
* not impose any restrictions on the child placement. It can be used
* to deduce toplevel window and menu sizes as well as child widgets in
* free-form containers such as GtkLayout.
*
* Handle with care. Note that the natural height of a height-for-width
* widget will generally be a smaller size than the minimum height, since the required
* height for the natural width is generally smaller than the required height for
* the minimum width.
*/
void
_gtk_widget_get_preferred_size_and_baseline (GtkWidget *widget,
GtkRequisition *minimum_size,
GtkRequisition *natural_size,
gint *minimum_baseline,
gint *natural_baseline)
{
gint min_width, nat_width;
gint min_height, nat_height;
g_return_if_fail (GTK_IS_WIDGET (widget));
if (gtk_widget_get_request_mode (widget) == GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH)
{
gtk_widget_measure (widget, GTK_ORIENTATION_HORIZONTAL, -1,
&min_width, &nat_width, NULL, NULL);
if (minimum_size)
{
minimum_size->width = min_width;
gtk_widget_measure (widget,
GTK_ORIENTATION_VERTICAL, min_width,
&minimum_size->height, NULL, minimum_baseline, NULL);
}
if (natural_size)
{
natural_size->width = nat_width;
gtk_widget_measure (widget,
GTK_ORIENTATION_VERTICAL, nat_width,
NULL, &natural_size->height, NULL, natural_baseline);
}
}
else /* GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT or CONSTANT_SIZE */
{
gtk_widget_measure (widget, GTK_ORIENTATION_VERTICAL,
-1, &min_height, &nat_height, minimum_baseline, natural_baseline);
if (minimum_size)
{
minimum_size->height = min_height;
gtk_widget_measure (widget, GTK_ORIENTATION_HORIZONTAL, min_height,
&minimum_size->width, NULL, NULL, NULL);
}
if (natural_size)
{
natural_size->height = nat_height;
gtk_widget_measure (widget, GTK_ORIENTATION_HORIZONTAL, nat_height,
NULL, &natural_size->width, NULL, NULL);
}
}
}
/**
* gtk_widget_get_preferred_size:
* @widget: a #GtkWidget instance
* @minimum_size: (out) (allow-none): location for storing the minimum size, or %NULL
* @natural_size: (out) (allow-none): location for storing the natural size, or %NULL
*
* Retrieves the minimum and natural size of a widget, taking
* into account the widgets preference for height-for-width management.
*
* This is used to retrieve a suitable size by container widgets which do
* not impose any restrictions on the child placement. It can be used
* to deduce toplevel window and menu sizes as well as child widgets in
* free-form containers such as GtkLayout.
*
* Handle with care. Note that the natural height of a height-for-width
* widget will generally be a smaller size than the minimum height, since the required
* height for the natural width is generally smaller than the required height for
* the minimum width.
*
* Use gtk_widget_measure() if you want to support
* baseline alignment.
*/
void
gtk_widget_get_preferred_size (GtkWidget *widget,
GtkRequisition *minimum_size,
GtkRequisition *natural_size)
{
_gtk_widget_get_preferred_size_and_baseline (widget, minimum_size, natural_size,
NULL, NULL);
}
static gint
compare_gap (gconstpointer p1,
gconstpointer p2,
gpointer data)
{
GtkRequestedSize *sizes = data;
const guint *c1 = p1;
const guint *c2 = p2;
const gint d1 = MAX (sizes[*c1].natural_size -
sizes[*c1].minimum_size,
0);
const gint d2 = MAX (sizes[*c2].natural_size -
sizes[*c2].minimum_size,
0);
gint delta = (d2 - d1);
if (0 == delta)
delta = (*c2 - *c1);
return delta;
}
/**
* gtk_distribute_natural_allocation:
* @extra_space: Extra space to redistribute among children after subtracting
* minimum sizes and any child padding from the overall allocation
* @n_requested_sizes: Number of requests to fit into the allocation
* @sizes: An array of structs with a client pointer and a minimum/natural size
* in the orientation of the allocation.
*
* Distributes @extra_space to child @sizes by bringing smaller
* children up to natural size first.
*
* The remaining space will be added to the @minimum_size member of the
* GtkRequestedSize struct. If all sizes reach their natural size then
* the remaining space is returned.
*
* Returns: The remainder of @extra_space after redistributing space
* to @sizes.
*/
gint
gtk_distribute_natural_allocation (gint extra_space,
guint n_requested_sizes,
GtkRequestedSize *sizes)
{
guint *spreading;
gint i;
g_return_val_if_fail (extra_space >= 0, 0);
spreading = g_newa (guint, n_requested_sizes);
for (i = 0; i < n_requested_sizes; i++)
spreading[i] = i;
/* Distribute the container's extra space c_gap. We want to assign
* this space such that the sum of extra space assigned to children
* (c^i_gap) is equal to c_cap. The case that there's not enough
* space for all children to take their natural size needs some
* attention. The goals we want to achieve are:
*
* a) Maximize number of children taking their natural size.
* b) The allocated size of children should be a continuous
* function of c_gap. That is, increasing the container size by
* one pixel should never make drastic changes in the distribution.
* c) If child i takes its natural size and child j doesn't,
* child j should have received at least as much gap as child i.
*
* The following code distributes the additional space by following
* these rules.
*/
/* Sort descending by gap and position. */
g_qsort_with_data (spreading,
n_requested_sizes, sizeof (guint),
compare_gap, sizes);
/* Distribute available space.
* This master piece of a loop was conceived by Behdad Esfahbod.
*/
for (i = n_requested_sizes - 1; extra_space > 0 && i >= 0; --i)
{
/* Divide remaining space by number of remaining children.
* Sort order and reducing remaining space by assigned space
* ensures that space is distributed equally.
*/
gint glue = (extra_space + i) / (i + 1);
gint gap = sizes[(spreading[i])].natural_size
- sizes[(spreading[i])].minimum_size;
gint extra = MIN (glue, gap);
sizes[spreading[i]].minimum_size += extra;
extra_space -= extra;
}
return extra_space;
}