gtk2/gtk/gtkoverlay.c

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/*
* gtkoverlay.c
* This file is part of gtk
*
* Copyright (C) 2011 - Ignacio Casal Quinteiro, Mike Krüger
*
* 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
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gtkoverlay.h"
#include "gtkbuildable.h"
#include "gtkscrolledwindow.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"
#include "gtkintl.h"
/**
* SECTION:gtkoverlay
* @short_description: A container which overlays widgets on top of each other
* @title: GtkOverlay
*
* GtkOverlay is a container which contains a single main child, on top
* of which it can place overlay widgets. The
* position of each overlay widget is determined by its #GtkWidget:halign
* and #GtkWidget:valign properties. E.g. a widget with both alignments
* set to %GTK_ALIGN_START will be placed at the top left corner of the
* main widget, whereas an overlay with halign set to %GTK_ALIGN_CENTER
* and valign set to %GTK_ALIGN_END will be placed a the bottom edge of
* the main widget, horizontally centered. The position can be adjusted
* by setting the margin properties of the child to non-zero values.
*
* More complicated placement of overlays is possible by connecting
* to the #GtkOverlay::get-child-position signal.
*
* # GtkOverlay as GtkBuildable
*
* The GtkOverlay implementation of the GtkBuildable interface
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* supports placing a child as an overlay by specifying overlay as
* the type attribute of a `<child>` element.
*/
struct _GtkOverlayPrivate
{
GSList *children;
};
typedef struct _GtkOverlayChild GtkOverlayChild;
struct _GtkOverlayChild
{
GtkWidget *widget;
GdkWindow *window;
};
enum {
GET_CHILD_POSITION,
LAST_SIGNAL
};
static guint signals[LAST_SIGNAL] = { 0 };
static void gtk_overlay_buildable_init (GtkBuildableIface *iface);
G_DEFINE_TYPE_WITH_CODE (GtkOverlay, gtk_overlay, GTK_TYPE_BIN,
G_ADD_PRIVATE (GtkOverlay)
G_IMPLEMENT_INTERFACE (GTK_TYPE_BUILDABLE,
gtk_overlay_buildable_init))
static void
gtk_overlay_compute_child_allocation (GtkOverlay *overlay,
GtkOverlayChild *child,
GtkAllocation *window_allocation,
GtkAllocation *widget_allocation)
{
gint left, right, top, bottom;
GtkAllocation allocation, overlay_allocation;
gboolean result;
g_signal_emit (overlay, signals[GET_CHILD_POSITION],
0, child->widget, &allocation, &result);
gtk_widget_get_allocation (GTK_WIDGET (overlay), &overlay_allocation);
allocation.x += overlay_allocation.x;
allocation.y += overlay_allocation.y;
/* put the margins outside the window; also arrange things
* so that the adjusted child allocation still ends up at 0, 0
*/
left = gtk_widget_get_margin_start (child->widget);
right = gtk_widget_get_margin_end (child->widget);
top = gtk_widget_get_margin_top (child->widget);
bottom = gtk_widget_get_margin_bottom (child->widget);
if (widget_allocation)
{
widget_allocation->x = - left;
widget_allocation->y = - top;
widget_allocation->width = allocation.width;
widget_allocation->height = allocation.height;
}
if (window_allocation)
{
window_allocation->x = allocation.x + left;
window_allocation->y = allocation.y + top;
window_allocation->width = allocation.width - (left + right);
window_allocation->height = allocation.height - (top + bottom);
}
}
static GdkWindow *
gtk_overlay_create_child_window (GtkOverlay *overlay,
GtkOverlayChild *child)
{
GtkWidget *widget = GTK_WIDGET (overlay);
GtkAllocation allocation;
GdkWindow *window;
GdkWindowAttr attributes;
gint attributes_mask;
gtk_overlay_compute_child_allocation (overlay, child, &allocation, NULL);
attributes.window_type = GDK_WINDOW_CHILD;
attributes.wclass = GDK_INPUT_OUTPUT;
attributes.width = allocation.width;
attributes.height = allocation.height;
attributes.x = allocation.x;
attributes.y = allocation.y;
attributes.visual = gtk_widget_get_visual (widget);
attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL;
attributes.event_mask = gtk_widget_get_events (widget) | GDK_EXPOSURE_MASK;
window = gdk_window_new (gtk_widget_get_window (widget),
&attributes, attributes_mask);
gtk_widget_register_window (widget, window);
gtk_style_context_set_background (gtk_widget_get_style_context (widget), window);
gtk_widget_set_parent_window (child->widget, window);
return window;
}
static GtkAlign
effective_align (GtkAlign align,
GtkTextDirection direction)
{
switch (align)
{
case GTK_ALIGN_START:
return direction == GTK_TEXT_DIR_RTL ? GTK_ALIGN_END : GTK_ALIGN_START;
case GTK_ALIGN_END:
return direction == GTK_TEXT_DIR_RTL ? GTK_ALIGN_START : GTK_ALIGN_END;
default:
return align;
}
}
static void
gtk_overlay_get_main_widget_allocation (GtkOverlay *overlay,
GtkAllocation *main_alloc_out)
{
GtkWidget *main_widget;
GtkAllocation main_alloc;
main_widget = gtk_bin_get_child (GTK_BIN (overlay));
/* special-case scrolled windows */
if (GTK_IS_SCROLLED_WINDOW (main_widget))
{
GtkWidget *grandchild;
gint x, y;
gboolean res;
grandchild = gtk_bin_get_child (GTK_BIN (main_widget));
res = gtk_widget_translate_coordinates (grandchild, main_widget, 0, 0, &x, &y);
if (res)
{
main_alloc.x = x;
main_alloc.y = y;
}
else
{
main_alloc.x = 0;
main_alloc.y = 0;
}
main_alloc.width = gtk_widget_get_allocated_width (grandchild);
main_alloc.height = gtk_widget_get_allocated_height (grandchild);
}
else if (GTK_IS_WIDGET (main_widget))
{
main_alloc.x = 0;
main_alloc.y = 0;
main_alloc.width = gtk_widget_get_allocated_width (main_widget);
main_alloc.height = gtk_widget_get_allocated_height (main_widget);
}
else
{
main_alloc.x = 0;
main_alloc.y = 0;
main_alloc.width = gtk_widget_get_allocated_width (GTK_WIDGET (overlay));
main_alloc.height = gtk_widget_get_allocated_height (GTK_WIDGET (overlay));
}
if (main_alloc_out)
*main_alloc_out = main_alloc;
}
static void
gtk_overlay_child_update_style_classes (GtkOverlay *overlay,
GtkWidget *child,
GtkAllocation *child_allocation)
{
GtkAllocation overlay_allocation, main_allocation;
GtkAlign valign, halign;
gboolean is_left, is_right, is_top, is_bottom;
gboolean has_left, has_right, has_top, has_bottom;
GtkStyleContext *context;
context = gtk_widget_get_style_context (child);
has_left = gtk_style_context_has_class (context, GTK_STYLE_CLASS_LEFT);
has_right = gtk_style_context_has_class (context, GTK_STYLE_CLASS_RIGHT);
has_top = gtk_style_context_has_class (context, GTK_STYLE_CLASS_TOP);
has_bottom = gtk_style_context_has_class (context, GTK_STYLE_CLASS_BOTTOM);
is_left = is_right = is_top = is_bottom = FALSE;
gtk_overlay_get_main_widget_allocation (overlay, &main_allocation);
gtk_widget_get_allocation (GTK_WIDGET (overlay), &overlay_allocation);
main_allocation.x += overlay_allocation.x;
main_allocation.y += overlay_allocation.y;
halign = effective_align (gtk_widget_get_halign (child),
gtk_widget_get_direction (child));
if (halign == GTK_ALIGN_START)
is_left = (child_allocation->x == main_allocation.x);
else if (halign == GTK_ALIGN_END)
is_right = (child_allocation->x + child_allocation->width ==
main_allocation.x + main_allocation.width);
valign = gtk_widget_get_valign (child);
if (valign == GTK_ALIGN_START)
is_top = (child_allocation->y == main_allocation.y);
else if (valign == GTK_ALIGN_END)
is_bottom = (child_allocation->y + child_allocation->height ==
main_allocation.y + main_allocation.height);
if (has_left && !is_left)
gtk_style_context_remove_class (context, GTK_STYLE_CLASS_LEFT);
else if (!has_left && is_left)
gtk_style_context_add_class (context, GTK_STYLE_CLASS_LEFT);
if (has_right && !is_right)
gtk_style_context_remove_class (context, GTK_STYLE_CLASS_RIGHT);
else if (!has_right && is_right)
gtk_style_context_add_class (context, GTK_STYLE_CLASS_RIGHT);
if (has_top && !is_top)
gtk_style_context_remove_class (context, GTK_STYLE_CLASS_TOP);
else if (!has_top && is_top)
gtk_style_context_add_class (context, GTK_STYLE_CLASS_TOP);
if (has_bottom && !is_bottom)
gtk_style_context_remove_class (context, GTK_STYLE_CLASS_BOTTOM);
else if (!has_bottom && is_bottom)
gtk_style_context_add_class (context, GTK_STYLE_CLASS_BOTTOM);
}
static void
gtk_overlay_child_allocate (GtkOverlay *overlay,
GtkOverlayChild *child)
{
GtkAllocation window_allocation, child_allocation;
if (gtk_widget_get_mapped (GTK_WIDGET (overlay)))
{
if (gtk_widget_get_visible (child->widget))
gdk_window_show (child->window);
else if (gdk_window_is_visible (child->window))
gdk_window_hide (child->window);
}
if (!gtk_widget_get_visible (child->widget))
return;
gtk_overlay_compute_child_allocation (overlay, child, &window_allocation, &child_allocation);
if (child->window)
gdk_window_move_resize (child->window,
window_allocation.x, window_allocation.y,
window_allocation.width, window_allocation.height);
gtk_overlay_child_update_style_classes (overlay, child->widget, &window_allocation);
gtk_widget_size_allocate (child->widget, &child_allocation);
}
static void
gtk_overlay_size_allocate (GtkWidget *widget,
GtkAllocation *allocation)
{
GtkOverlay *overlay = GTK_OVERLAY (widget);
GtkOverlayPrivate *priv = overlay->priv;
GSList *children;
GtkWidget *main_widget;
GTK_WIDGET_CLASS (gtk_overlay_parent_class)->size_allocate (widget, allocation);
main_widget = gtk_bin_get_child (GTK_BIN (overlay));
if (main_widget && gtk_widget_get_visible (main_widget))
gtk_widget_size_allocate (main_widget, allocation);
for (children = priv->children; children; children = children->next)
gtk_overlay_child_allocate (overlay, children->data);
}
static gboolean
gtk_overlay_get_child_position (GtkOverlay *overlay,
GtkWidget *widget,
GtkAllocation *alloc)
{
GtkAllocation main_alloc;
GtkRequisition min, req;
GtkAlign halign;
GtkTextDirection direction;
gtk_overlay_get_main_widget_allocation (overlay, &main_alloc);
gtk_widget_get_preferred_size (widget, &min, &req);
alloc->x = main_alloc.x;
alloc->width = MAX (min.width, MIN (main_alloc.width, req.width));
direction = gtk_widget_get_direction (widget);
halign = gtk_widget_get_halign (widget);
switch (effective_align (halign, direction))
{
case GTK_ALIGN_START:
/* nothing to do */
break;
case GTK_ALIGN_FILL:
alloc->width = MAX (alloc->width, main_alloc.width);
break;
case GTK_ALIGN_CENTER:
alloc->x += main_alloc.width / 2 - req.width / 2;
break;
case GTK_ALIGN_END:
alloc->x += main_alloc.width - req.width;
break;
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case GTK_ALIGN_BASELINE:
default:
g_assert_not_reached ();
break;
}
alloc->y = main_alloc.y;
alloc->height = MAX (min.height, MIN (main_alloc.height, req.height));
switch (gtk_widget_get_valign (widget))
{
case GTK_ALIGN_START:
/* nothing to do */
break;
case GTK_ALIGN_FILL:
alloc->height = MAX (alloc->height, main_alloc.height);
break;
case GTK_ALIGN_CENTER:
alloc->y += main_alloc.height / 2 - req.height / 2;
break;
case GTK_ALIGN_END:
alloc->y += main_alloc.height - req.height;
break;
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case GTK_ALIGN_BASELINE:
default:
g_assert_not_reached ();
break;
}
return TRUE;
}
static void
gtk_overlay_realize (GtkWidget *widget)
{
GtkOverlay *overlay = GTK_OVERLAY (widget);
GtkOverlayPrivate *priv = overlay->priv;
GtkOverlayChild *child;
GSList *children;
GTK_WIDGET_CLASS (gtk_overlay_parent_class)->realize (widget);
for (children = priv->children; children; children = children->next)
{
child = children->data;
if (child->window == NULL)
child->window = gtk_overlay_create_child_window (overlay, child);
}
}
static void
gtk_overlay_unrealize (GtkWidget *widget)
{
GtkOverlay *overlay = GTK_OVERLAY (widget);
GtkOverlayPrivate *priv = overlay->priv;
GtkOverlayChild *child;
GSList *children;
for (children = priv->children; children; children = children->next)
{
child = children->data;
gtk_widget_set_parent_window (child->widget, NULL);
gtk_widget_unregister_window (widget, child->window);
gdk_window_destroy (child->window);
child->window = NULL;
}
GTK_WIDGET_CLASS (gtk_overlay_parent_class)->unrealize (widget);
}
static void
gtk_overlay_map (GtkWidget *widget)
{
GtkOverlay *overlay = GTK_OVERLAY (widget);
GtkOverlayPrivate *priv = overlay->priv;
GtkOverlayChild *child;
GSList *children;
GTK_WIDGET_CLASS (gtk_overlay_parent_class)->map (widget);
for (children = priv->children; children; children = children->next)
{
child = children->data;
if (child->window != NULL &&
gtk_widget_get_visible (child->widget) &&
gtk_widget_get_child_visible (child->widget))
gdk_window_show (child->window);
}
}
static void
gtk_overlay_unmap (GtkWidget *widget)
{
GtkOverlay *overlay = GTK_OVERLAY (widget);
GtkOverlayPrivate *priv = overlay->priv;
GtkOverlayChild *child;
GSList *children;
for (children = priv->children; children; children = children->next)
{
child = children->data;
if (child->window != NULL &&
gdk_window_is_visible (child->window))
gdk_window_hide (child->window);
}
GTK_WIDGET_CLASS (gtk_overlay_parent_class)->unmap (widget);
}
static void
gtk_overlay_remove (GtkContainer *container,
GtkWidget *widget)
{
GtkOverlayPrivate *priv = GTK_OVERLAY (container)->priv;
GtkOverlayChild *child;
GSList *children;
for (children = priv->children; children; children = children->next)
{
child = children->data;
if (child->widget == widget)
{
if (child->window != NULL)
{
gtk_widget_unregister_window (GTK_WIDGET (container), child->window);
gdk_window_destroy (child->window);
}
gtk_widget_unparent (widget);
priv->children = g_slist_delete_link (priv->children, children);
g_slice_free (GtkOverlayChild, child);
return;
}
}
GTK_CONTAINER_CLASS (gtk_overlay_parent_class)->remove (container, widget);
}
static void
gtk_overlay_forall (GtkContainer *overlay,
gboolean include_internals,
GtkCallback callback,
gpointer callback_data)
{
GtkOverlayPrivate *priv = GTK_OVERLAY (overlay)->priv;
GtkOverlayChild *child;
GSList *children;
GtkWidget *main_widget;
main_widget = gtk_bin_get_child (GTK_BIN (overlay));
if (main_widget)
(* callback) (main_widget, callback_data);
children = priv->children;
while (children)
{
child = children->data;
children = children->next;
(* callback) (child->widget, callback_data);
}
}
static void
gtk_overlay_class_init (GtkOverlayClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
GtkContainerClass *container_class = GTK_CONTAINER_CLASS (klass);
widget_class->size_allocate = gtk_overlay_size_allocate;
widget_class->realize = gtk_overlay_realize;
widget_class->unrealize = gtk_overlay_unrealize;
widget_class->map = gtk_overlay_map;
widget_class->unmap = gtk_overlay_unmap;
container_class->remove = gtk_overlay_remove;
container_class->forall = gtk_overlay_forall;
klass->get_child_position = gtk_overlay_get_child_position;
/**
* GtkOverlay::get-child-position:
* @overlay: the #GtkOverlay
* @widget: the child widget to position
* @allocation: (type Gdk.Rectangle) (out caller-allocates): return
* location for the allocation
*
* The ::get-child-position signal is emitted to determine
* the position and size of any overlay child widgets. A
* handler for this signal should fill @allocation with
* the desired position and size for @widget, relative to
* the 'main' child of @overlay.
*
* The default handler for this signal uses the @widget's
* halign and valign properties to determine the position
* and gives the widget its natural size (except that an
* alignment of %GTK_ALIGN_FILL will cause the overlay to
* be full-width/height). If the main child is a
* #GtkScrolledWindow, the overlays are placed relative
* to its contents.
*
* Returns: %TRUE if the @allocation has been filled
*/
signals[GET_CHILD_POSITION] =
g_signal_new (I_("get-child-position"),
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkOverlayClass, get_child_position),
_gtk_boolean_handled_accumulator, NULL,
_gtk_marshal_BOOLEAN__OBJECT_BOXED,
G_TYPE_BOOLEAN, 2,
GTK_TYPE_WIDGET,
GDK_TYPE_RECTANGLE | G_SIGNAL_TYPE_STATIC_SCOPE);
}
static void
gtk_overlay_init (GtkOverlay *overlay)
{
overlay->priv = gtk_overlay_get_instance_private (overlay);
gtk_widget_set_has_window (GTK_WIDGET (overlay), FALSE);
}
static void
gtk_overlay_buildable_add_child (GtkBuildable *buildable,
GtkBuilder *builder,
GObject *child,
const gchar *type)
{
if (type && strcmp (type, "overlay") == 0)
gtk_overlay_add_overlay (GTK_OVERLAY (buildable), GTK_WIDGET (child));
else if (!type)
gtk_container_add (GTK_CONTAINER (buildable), GTK_WIDGET (child));
else
GTK_BUILDER_WARN_INVALID_CHILD_TYPE (buildable, type);
}
static void
gtk_overlay_buildable_init (GtkBuildableIface *iface)
{
iface->add_child = gtk_overlay_buildable_add_child;
}
/**
* gtk_overlay_new:
*
* Creates a new #GtkOverlay.
*
* Returns: a new #GtkOverlay object.
*
* Since: 3.2
*/
GtkWidget *
gtk_overlay_new (void)
{
return g_object_new (GTK_TYPE_OVERLAY, NULL);
}
/**
* gtk_overlay_add_overlay:
* @overlay: a #GtkOverlay
* @widget: a #GtkWidget to be added to the container
*
* Adds @widget to @overlay.
*
* The widget will be stacked on top of the main widget
* added with gtk_container_add().
*
* The position at which @widget is placed is determined
* from its #GtkWidget:halign and #GtkWidget:valign properties.
*
* Since: 3.2
*/
void
gtk_overlay_add_overlay (GtkOverlay *overlay,
GtkWidget *widget)
{
GtkOverlayPrivate *priv = overlay->priv;
GtkOverlayChild *child;
g_return_if_fail (GTK_IS_OVERLAY (overlay));
g_return_if_fail (GTK_IS_WIDGET (widget));
child = g_slice_new0 (GtkOverlayChild);
child->widget = widget;
priv->children = g_slist_append (priv->children, child);
if (gtk_widget_get_realized (GTK_WIDGET (overlay)))
{
child->window = gtk_overlay_create_child_window (overlay, child);
gtk_widget_set_parent (widget, GTK_WIDGET (overlay));
}
else
gtk_widget_set_parent (widget, GTK_WIDGET (overlay));
}