gtk2/gtk/gtkcenterlayout.c

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/*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gtkcenterlayout.h"
#include "gtkcsspositionvalueprivate.h"
#include "gtkintl.h"
#include "gtklayoutchild.h"
#include "gtkprivate.h"
#include "gtksizerequest.h"
#include "gtkwidgetprivate.h"
#include "gtkcssnodeprivate.h"
/**
* SECTION:gtkcenterlayout
* @Title: GtkCenterLayout
* @Short_description: A centering layout
*
* A #GtkCenterLayout is a layout manager that manages up to three children.
* The start widget is allocated at the start of the layout (left in LRT
* layouts and right in RTL ones), and the end widget at the end.
*
* The center widget is centered regarding the full width of the layout's.
*/
struct _GtkCenterLayout
{
GtkLayoutManager parent_instance;
GtkBaselinePosition baseline_pos;
GtkOrientation orientation;
union {
struct {
GtkWidget *start_widget;
GtkWidget *center_widget;
GtkWidget *end_widget;
};
GtkWidget *children[3];
};
};
G_DEFINE_TYPE (GtkCenterLayout, gtk_center_layout, GTK_TYPE_LAYOUT_MANAGER)
static int
get_spacing (GtkCenterLayout *self,
GtkCssNode *node)
{
GtkCssStyle *style = gtk_css_node_get_style (node);
GtkCssValue *border_spacing;
int css_spacing;
border_spacing = style->size->border_spacing;
if (self->orientation == GTK_ORIENTATION_HORIZONTAL)
css_spacing = _gtk_css_position_value_get_x (border_spacing, 100);
else
css_spacing = _gtk_css_position_value_get_y (border_spacing, 100);
return css_spacing;
}
static GtkSizeRequestMode
gtk_center_layout_get_request_mode (GtkLayoutManager *layout_manager,
GtkWidget *widget)
{
GtkCenterLayout *self = GTK_CENTER_LAYOUT (layout_manager);
int count[3] = { 0, 0, 0 };
if (self->start_widget)
count[gtk_widget_get_request_mode (self->start_widget)]++;
if (self->center_widget)
count[gtk_widget_get_request_mode (self->center_widget)]++;
if (self->end_widget)
count[gtk_widget_get_request_mode (self->end_widget)]++;
if (!count[GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH] &&
!count[GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT])
return GTK_SIZE_REQUEST_CONSTANT_SIZE;
else
return count[GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT] > count[GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH]
? GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT
: GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH;
}
static gboolean
get_expand (GtkWidget *widget,
GtkOrientation orientation)
{
if (orientation == GTK_ORIENTATION_HORIZONTAL)
return gtk_widget_get_hexpand (widget);
else
return gtk_widget_get_vexpand (widget);
}
static void
gtk_center_layout_distribute (GtkCenterLayout *self,
int for_size,
int size,
int spacing,
GtkRequestedSize *sizes)
{
int center_size = 0;
int start_size = 0;
int end_size = 0;
gboolean center_expand = FALSE;
gboolean start_expand = FALSE;
gboolean end_expand = FALSE;
int avail;
int i;
int needed_spacing = 0;
/* Usable space is really less... */
for (i = 0; i < 3; i++)
{
if (self->children[i])
needed_spacing += spacing;
}
needed_spacing -= spacing;
sizes[0].minimum_size = sizes[0].natural_size = 0;
sizes[1].minimum_size = sizes[1].natural_size = 0;
sizes[2].minimum_size = sizes[2].natural_size = 0;
for (i = 0; i < 3; i ++)
{
if (self->children[i])
gtk_widget_measure (self->children[i], self->orientation, for_size,
&sizes[i].minimum_size, &sizes[i].natural_size,
NULL, NULL);
}
if (self->center_widget)
{
center_size = CLAMP (size - needed_spacing - (sizes[0].minimum_size + sizes[2].minimum_size), sizes[1].minimum_size, sizes[1].natural_size);
center_expand = get_expand (self->center_widget, self->orientation);
}
if (self->start_widget)
{
avail = MIN ((size - needed_spacing - center_size) / 2, size - needed_spacing - (center_size + sizes[2].minimum_size));
start_size = CLAMP (avail, sizes[0].minimum_size, sizes[0].natural_size);
start_expand = get_expand (self->start_widget, self->orientation);
}
if (self->end_widget)
{
avail = MIN ((size - needed_spacing - center_size) / 2, size - needed_spacing - (center_size + sizes[0].minimum_size));
end_size = CLAMP (avail, sizes[2].minimum_size, sizes[2].natural_size);
end_expand = get_expand (self->end_widget, self->orientation);
}
if (self->center_widget)
{
int center_pos;
center_pos = (size / 2) - (center_size / 2);
/* Push in from start/end */
if (start_size > 0 && start_size + spacing > center_pos)
center_pos = start_size + spacing;
else if (end_size > 0 && size - end_size - spacing < center_pos + center_size)
center_pos = size - center_size - end_size - spacing;
else if (center_expand)
{
center_size = size - 2 * (MAX (start_size, end_size) + spacing);
center_pos = (size / 2) - (center_size / 2) + spacing;
}
if (start_expand)
start_size = center_pos - spacing;
if (end_expand)
end_size = size - (center_pos + center_size) - spacing;
}
else
{
avail = size - needed_spacing - (start_size + end_size);
if (start_expand && end_expand)
{
start_size += avail / 2;
end_size += avail / 2;
}
else if (start_expand)
{
start_size += avail;
}
else if (end_expand)
{
end_size += avail;
}
}
sizes[0].minimum_size = start_size;
sizes[1].minimum_size = center_size;
sizes[2].minimum_size = end_size;
}
static void
gtk_center_layout_measure_orientation (GtkCenterLayout *self,
GtkWidget *widget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
int min[3];
int nat[3];
int n_visible_children = 0;
int spacing;
int i;
spacing = get_spacing (self, gtk_widget_get_css_node (widget));
for (i = 0; i < 3; i ++)
{
GtkWidget *child = self->children[i];
if (child)
{
gtk_widget_measure (child,
orientation,
for_size,
&min[i], &nat[i], NULL, NULL);
if (_gtk_widget_get_visible (child))
n_visible_children ++;
}
else
{
min[i] = 0;
nat[i] = 0;
}
}
*minimum = min[0] + min[1] + min[2];
*natural = nat[1] + 2 * MAX (nat[0], nat[2]);
if (n_visible_children > 0)
{
*minimum += (n_visible_children - 1) * spacing;
*natural += (n_visible_children - 1) * spacing;
}
}
static void
gtk_center_layout_measure_opposite (GtkCenterLayout *self,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
int child_min, child_nat;
int child_min_baseline, child_nat_baseline;
int total_min, above_min, below_min;
int total_nat, above_nat, below_nat;
GtkWidget *child[3];
GtkRequestedSize sizes[3];
int i;
child[0] = self->start_widget;
child[1] = self->center_widget;
child[2] = self->end_widget;
if (for_size >= 0)
gtk_center_layout_distribute (self, -1, for_size, 0, sizes);
above_min = below_min = above_nat = below_nat = -1;
total_min = total_nat = 0;
for (i = 0; i < 3; i++)
{
if (child[i] == NULL)
continue;
gtk_widget_measure (child[i],
orientation,
for_size >= 0 ? sizes[i].minimum_size : -1,
&child_min, &child_nat,
&child_min_baseline, &child_nat_baseline);
if (child_min_baseline >= 0)
{
below_min = MAX (below_min, child_min - child_min_baseline);
above_min = MAX (above_min, child_min_baseline);
below_nat = MAX (below_nat, child_nat - child_nat_baseline);
above_nat = MAX (above_nat, child_nat_baseline);
}
else
{
total_min = MAX (total_min, child_min);
total_nat = MAX (total_nat, child_nat);
}
}
if (above_min >= 0)
{
int min_baseline = -1;
int nat_baseline = -1;
total_min = MAX (total_min, above_min + below_min);
total_nat = MAX (total_nat, above_nat + below_nat);
switch (self->baseline_pos)
{
case GTK_BASELINE_POSITION_TOP:
min_baseline = above_min;
nat_baseline = above_nat;
break;
case GTK_BASELINE_POSITION_CENTER:
min_baseline = above_min + (total_min - (above_min + below_min)) / 2;
nat_baseline = above_nat + (total_nat - (above_nat + below_nat)) / 2;
break;
case GTK_BASELINE_POSITION_BOTTOM:
min_baseline = total_min - below_min;
nat_baseline = total_nat - below_nat;
break;
default:
break;
}
if (minimum_baseline)
*minimum_baseline = min_baseline;
if (natural_baseline)
*natural_baseline = nat_baseline;
}
*minimum = total_min;
*natural = total_nat;
}
static void
gtk_center_layout_measure (GtkLayoutManager *layout_manager,
GtkWidget *widget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
GtkCenterLayout *self = GTK_CENTER_LAYOUT (layout_manager);
if (self->orientation == orientation)
gtk_center_layout_measure_orientation (self, widget, orientation, for_size,
minimum, natural, minimum_baseline, natural_baseline);
else
gtk_center_layout_measure_opposite (self, orientation, for_size,
minimum, natural, minimum_baseline, natural_baseline);
}
static void
gtk_center_layout_allocate (GtkLayoutManager *layout_manager,
GtkWidget *widget,
int width,
int height,
int baseline)
{
GtkCenterLayout *self = GTK_CENTER_LAYOUT (layout_manager);
GtkWidget *child[3];
int child_size[3];
int child_pos[3];
GtkRequestedSize sizes[3];
int size;
int for_size;
int i;
int spacing;
spacing = get_spacing (self, gtk_widget_get_css_node (widget));
if (self->orientation == GTK_ORIENTATION_HORIZONTAL)
{
size = width;
for_size = height;
}
else
{
size = height;
for_size = width;
baseline = -1;
}
/* Allocate child sizes */
gtk_center_layout_distribute (self, for_size, size, spacing, sizes);
child[1] = self->center_widget;
child_size[1] = sizes[1].minimum_size;
if (self->orientation == GTK_ORIENTATION_HORIZONTAL &&
gtk_widget_get_direction (widget) == GTK_TEXT_DIR_RTL)
{
child[0] = self->end_widget;
child[2] = self->start_widget;
child_size[0] = sizes[2].minimum_size;
child_size[2] = sizes[0].minimum_size;
}
else
{
child[0] = self->start_widget;
child[2] = self->end_widget;
child_size[0] = sizes[0].minimum_size;
child_size[2] = sizes[2].minimum_size;
}
/* Determine baseline */
if (self->orientation == GTK_ORIENTATION_HORIZONTAL &&
baseline == -1)
{
int min_above, nat_above;
int min_below, nat_below;
gboolean have_baseline;
have_baseline = FALSE;
min_above = nat_above = 0;
min_below = nat_below = 0;
for (i = 0; i < 3; i++)
{
if (child[i] && gtk_widget_get_valign (child[i]) == GTK_ALIGN_BASELINE)
{
int child_min_height, child_nat_height;
int child_min_baseline, child_nat_baseline;
child_min_baseline = child_nat_baseline = -1;
gtk_widget_measure (child[i], GTK_ORIENTATION_VERTICAL,
child_size[i],
&child_min_height, &child_nat_height,
&child_min_baseline, &child_nat_baseline);
if (child_min_baseline >= 0)
{
have_baseline = TRUE;
min_below = MAX (min_below, child_min_height - child_min_baseline);
nat_below = MAX (nat_below, child_nat_height - child_nat_baseline);
min_above = MAX (min_above, child_min_baseline);
nat_above = MAX (nat_above, child_nat_baseline);
}
}
}
if (have_baseline)
{
/* TODO: This is purely based on the minimum baseline.
* When things fit we should use the natural one
*/
switch (self->baseline_pos)
{
default:
case GTK_BASELINE_POSITION_TOP:
baseline = min_above;
break;
case GTK_BASELINE_POSITION_CENTER:
baseline = min_above + (height - (min_above + min_below)) / 2;
break;
case GTK_BASELINE_POSITION_BOTTOM:
baseline = height - min_below;
break;
}
}
}
/* Allocate child positions */
child_pos[0] = 0;
child_pos[1] = (size / 2) - (child_size[1] / 2);
child_pos[2] = size - child_size[2];
if (child[1])
{
/* Push in from start/end */
if (child_size[0] > 0 && child_size[0] + spacing > child_pos[1])
child_pos[1] = child_size[0] + spacing;
else if (child_size[2] > 0 && size - child_size[2] - spacing < child_pos[1] + child_size[1])
child_pos[1] = size - child_size[1] - child_size[2] - spacing;
}
for (i = 0; i < 3; i++)
{
GtkAllocation child_allocation;
if (child[i] == NULL)
continue;
if (self->orientation == GTK_ORIENTATION_HORIZONTAL)
{
child_allocation.x = child_pos[i];
child_allocation.y = 0;
child_allocation.width = child_size[i];
child_allocation.height = height;
}
else
{
child_allocation.x = 0;
child_allocation.y = child_pos[i];
child_allocation.width = width;
child_allocation.height = child_size[i];
}
gtk_widget_size_allocate (child[i], &child_allocation, baseline);
}
}
static void
gtk_center_layout_class_init (GtkCenterLayoutClass *klass)
{
GtkLayoutManagerClass *layout_class = GTK_LAYOUT_MANAGER_CLASS (klass);
layout_class->get_request_mode = gtk_center_layout_get_request_mode;
layout_class->measure = gtk_center_layout_measure;
layout_class->allocate = gtk_center_layout_allocate;
}
static void
gtk_center_layout_init (GtkCenterLayout *self)
{
self->orientation = GTK_ORIENTATION_HORIZONTAL;
self->baseline_pos = GTK_BASELINE_POSITION_CENTER;
}
/**
* gtk_center_layout_new:
*
* Creates a new #GtkCenterLayout.
*
* Returns: the newly created #GtkCenterLayout
*/
GtkLayoutManager *
gtk_center_layout_new (void)
{
return g_object_new (GTK_TYPE_CENTER_LAYOUT, NULL);
}
/**
* gtk_center_layout_set_orientation:
* @self: a #GtkCenterLayout
* @orientation: the new orientation
*
* Sets the orientation of @self.
*/
void
gtk_center_layout_set_orientation (GtkCenterLayout *self,
GtkOrientation orientation)
{
g_return_if_fail (GTK_IS_CENTER_LAYOUT (self));
if (orientation != self->orientation)
{
self->orientation = orientation;
gtk_layout_manager_layout_changed (GTK_LAYOUT_MANAGER (self));
}
}
/**
* gtk_center_layout_get_orientation:
* @self: a #GtkCenterLayout
*
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* Gets the current orienration of the layout manager.
*
* Returns: The current orientation of @self
*/
GtkOrientation
gtk_center_layout_get_orientation (GtkCenterLayout *self)
{
g_return_val_if_fail (GTK_IS_CENTER_LAYOUT (self), GTK_ORIENTATION_HORIZONTAL);
return self->orientation;
}
/**
* gtk_center_layout_set_baseline_position:
* @self: a #GtkCenterLayout
* @baseline_position: the new baseline position
*
* Sets the new baseline position of @self
*/
void
gtk_center_layout_set_baseline_position (GtkCenterLayout *self,
GtkBaselinePosition baseline_position)
{
g_return_if_fail (GTK_IS_CENTER_LAYOUT (self));
if (baseline_position != self->baseline_pos)
{
self->baseline_pos = baseline_position;
gtk_layout_manager_layout_changed (GTK_LAYOUT_MANAGER (self));
}
}
/**
* gtk_center_layout_get_baseline_position:
* @self: a #GtkCenterLayout
*
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* Returns the baseline position of the layout.
*
* Returns: The current baseline position of @self.
*/
GtkBaselinePosition
gtk_center_layout_get_baseline_position (GtkCenterLayout *self)
{
g_return_val_if_fail (GTK_IS_CENTER_LAYOUT (self), GTK_BASELINE_POSITION_TOP);
return self->baseline_pos;
}
/**
* gtk_center_layout_set_start_widget:
* @self: a #GtkCenterLayout
* @widget: (nullable): the new start widget
*
* Sets the new start widget of @self.
*
* To remove the existing start widget, pass %NULL.
*/
void
gtk_center_layout_set_start_widget (GtkCenterLayout *self,
GtkWidget *widget)
{
g_return_if_fail (GTK_IS_CENTER_LAYOUT (self));
g_return_if_fail (widget == NULL || GTK_IS_WIDGET (widget));
if (self->start_widget == widget)
return;
self->start_widget = widget;
gtk_layout_manager_layout_changed (GTK_LAYOUT_MANAGER (self));
}
/**
* gtk_center_layout_get_start_widget:
* @self: a #GtkCenterLayout
*
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* Returns the start widget fo the layout.
*
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* Returns: (nullable) (transfer none): The current start widget of @self
*/
GtkWidget *
gtk_center_layout_get_start_widget (GtkCenterLayout *self)
{
g_return_val_if_fail (GTK_IS_CENTER_LAYOUT (self), NULL);
return self->start_widget;
}
/**
* gtk_center_layout_set_center_widget:
* @self: a #GtkCenterLayout
* @widget: (nullable): the new center widget
*
* Sets the new center widget of @self.
*
* To remove the existing center widget, pass %NULL.
*/
void
gtk_center_layout_set_center_widget (GtkCenterLayout *self,
GtkWidget *widget)
{
g_return_if_fail (GTK_IS_CENTER_LAYOUT (self));
g_return_if_fail (widget == NULL || GTK_IS_WIDGET (widget));
if (self->center_widget == widget)
return;
self->center_widget = widget;
gtk_layout_manager_layout_changed (GTK_LAYOUT_MANAGER (self));
}
/**
* gtk_center_layout_get_center_widget:
* @self: a #GtkCenterLayout
*
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* Returns the center widget of the layout.
*
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* Returns: (nullable) (transfer none): the current center widget of @self
*/
GtkWidget *
gtk_center_layout_get_center_widget (GtkCenterLayout *self)
{
g_return_val_if_fail (GTK_IS_CENTER_LAYOUT (self), NULL);
return self->center_widget;
}
/**
* gtk_center_layout_set_end_widget:
* @self: a #GtkCenterLayout
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* @widget: (nullable) (transfer none): the new end widget
*
* Sets the new end widget of @self.
*
* To remove the existing center widget, pass %NULL.
*/
void
gtk_center_layout_set_end_widget (GtkCenterLayout *self,
GtkWidget *widget)
{
g_return_if_fail (GTK_IS_CENTER_LAYOUT (self));
g_return_if_fail (widget == NULL || GTK_IS_WIDGET (widget));
if (self->end_widget == widget)
return;
self->end_widget = widget;
gtk_layout_manager_layout_changed (GTK_LAYOUT_MANAGER (self));
}
/**
* gtk_center_layout_get_end_widget:
* @self: a #GtkCenterLayout
*
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* Returns the end widget of the layout.
*
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* Returns: (nullable) (transfer none): the current end widget of @self
*/
GtkWidget *
gtk_center_layout_get_end_widget (GtkCenterLayout *self)
{
g_return_val_if_fail (GTK_IS_CENTER_LAYOUT (self), NULL);
return self->end_widget;
}