gtk2/gtk/gtkoverlay.c
Matthias Clasen 9fa3742c09 Make GtkOverlayLayout public
Keeping the layout manager type private does not
really work when it has layout child properties
that need to be usable in ui files.
2020-05-25 14:22:10 -04:00

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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
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gtkoverlay.h"
#include "gtkoverlaylayout.h"
#include "gtkbuildable.h"
#include "gtkintl.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"
#include "gtkscrolledwindow.h"
#include "gtksnapshot.h"
#include "gtkstylecontext.h"
#include "gtkwidgetprivate.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 GtkOverlay container,
* 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 GtkOverlay,
* 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.
*
* An overlays minimum and natural sizes are those of its main child. The sizes
* of overlay children are not considered when measuring these preferred sizes.
*
* # GtkOverlay as GtkBuildable
*
* The GtkOverlay implementation of the GtkBuildable interface
* supports placing a child as an overlay by specifying “overlay” as
* the “type” attribute of a `<child>` element.
*
* # CSS nodes
*
* GtkOverlay has a single CSS node with the name “overlay”. Overlay children
* whose alignments cause them to be positioned at an edge get the style classes
* “.left”, “.right”, “.top”, and/or “.bottom” according to their position.
*/
enum {
GET_CHILD_POSITION,
LAST_SIGNAL
};
static guint signals[LAST_SIGNAL] = { 0 };
enum {
PROP_CHILD = 1
};
static void gtk_overlay_buildable_init (GtkBuildableIface *iface);
typedef struct _GtkOverlayClass GtkOverlayClass;
struct _GtkOverlay
{
GtkWidget parent_instance;
GtkWidget *child;
};
struct _GtkOverlayClass
{
GtkWidgetClass parent_class;
gboolean (*get_child_position) (GtkOverlay *overlay,
GtkWidget *widget,
GtkAllocation *allocation);
};
G_DEFINE_TYPE_WITH_CODE (GtkOverlay, gtk_overlay, GTK_TYPE_WIDGET,
G_IMPLEMENT_INTERFACE (GTK_TYPE_BUILDABLE,
gtk_overlay_buildable_init))
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;
case GTK_ALIGN_FILL:
case GTK_ALIGN_CENTER:
case GTK_ALIGN_BASELINE:
default:
return align;
}
}
static gboolean
gtk_overlay_get_child_position (GtkOverlay *overlay,
GtkWidget *widget,
GtkAllocation *alloc)
{
GtkRequisition min, req;
GtkAlign halign;
GtkTextDirection direction;
int width, height;
gtk_widget_get_preferred_size (widget, &min, &req);
width = gtk_widget_get_width (GTK_WIDGET (overlay));
height = gtk_widget_get_height (GTK_WIDGET (overlay));
alloc->x = 0;
alloc->width = MAX (min.width, MIN (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, width);
break;
case GTK_ALIGN_CENTER:
alloc->x += width / 2 - alloc->width / 2;
break;
case GTK_ALIGN_END:
alloc->x += width - alloc->width;
break;
case GTK_ALIGN_BASELINE:
default:
g_assert_not_reached ();
break;
}
alloc->y = 0;
alloc->height = MAX (min.height, MIN (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, height);
break;
case GTK_ALIGN_CENTER:
alloc->y += height / 2 - alloc->height / 2;
break;
case GTK_ALIGN_END:
alloc->y += height - alloc->height;
break;
case GTK_ALIGN_BASELINE:
default:
g_assert_not_reached ();
break;
}
return TRUE;
}
static void
gtk_overlay_snapshot_child (GtkWidget *overlay,
GtkWidget *child,
GtkSnapshot *snapshot)
{
graphene_rect_t bounds;
gboolean clip_set;
clip_set = gtk_overlay_get_clip_overlay (GTK_OVERLAY (overlay), child);
if (!clip_set)
{
gtk_widget_snapshot_child (overlay, child, snapshot);
return;
}
graphene_rect_init (&bounds, 0, 0,
gtk_widget_get_width (overlay),
gtk_widget_get_height (overlay));
gtk_snapshot_push_clip (snapshot, &bounds);
gtk_widget_snapshot_child (overlay, child, snapshot);
gtk_snapshot_pop (snapshot);
}
static void
gtk_overlay_snapshot (GtkWidget *widget,
GtkSnapshot *snapshot)
{
GtkWidget *child;
for (child = _gtk_widget_get_first_child (widget);
child != NULL;
child = _gtk_widget_get_next_sibling (child))
{
gtk_overlay_snapshot_child (widget, child, snapshot);
}
}
static void
gtk_overlay_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GtkOverlay *overlay = GTK_OVERLAY (object);
switch (prop_id)
{
case PROP_CHILD:
g_value_set_object (value, gtk_overlay_get_child (overlay));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gtk_overlay_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GtkOverlay *overlay = GTK_OVERLAY (object);
switch (prop_id)
{
case PROP_CHILD:
gtk_overlay_set_child (overlay, g_value_get_object (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gtk_overlay_dispose (GObject *object)
{
GtkOverlay *overlay = GTK_OVERLAY (object);
GtkWidget *child;
g_clear_pointer (&overlay->child, gtk_widget_unparent);
while ((child = gtk_widget_get_first_child (GTK_WIDGET (overlay))))
gtk_widget_unparent (child);
G_OBJECT_CLASS (gtk_overlay_parent_class)->dispose (object);
}
static void
gtk_overlay_compute_expand (GtkWidget *widget,
gboolean *hexpand,
gboolean *vexpand)
{
GtkOverlay *overlay = GTK_OVERLAY (widget);
if (overlay->child)
{
*hexpand = gtk_widget_compute_expand (overlay->child, GTK_ORIENTATION_HORIZONTAL);
*vexpand = gtk_widget_compute_expand (overlay->child, GTK_ORIENTATION_VERTICAL);
}
else
{
*hexpand = FALSE;
*vexpand = FALSE;
}
}
static void
gtk_overlay_class_init (GtkOverlayClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
object_class->dispose = gtk_overlay_dispose;
object_class->get_property = gtk_overlay_get_property;
object_class->set_property = gtk_overlay_set_property;
widget_class->snapshot = gtk_overlay_snapshot;
widget_class->compute_expand = gtk_overlay_compute_expand;
klass->get_child_position = gtk_overlay_get_child_position;
g_object_class_install_property (object_class,
PROP_CHILD,
g_param_spec_object ("child",
P_("Child"),
P_("The child widget"),
GTK_TYPE_WIDGET,
GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY));
/**
* 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);
g_signal_set_va_marshaller (signals[GET_CHILD_POSITION],
G_TYPE_FROM_CLASS (object_class),
_gtk_marshal_BOOLEAN__OBJECT_BOXEDv);
gtk_widget_class_set_css_name (widget_class, I_("overlay"));
gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_OVERLAY_LAYOUT);
}
static void
gtk_overlay_init (GtkOverlay *overlay)
{
}
static GtkBuildableIface *parent_buildable_iface;
static void
gtk_overlay_buildable_add_child (GtkBuildable *buildable,
GtkBuilder *builder,
GObject *child,
const gchar *type)
{
if (GTK_IS_WIDGET (child))
{
if (type && strcmp (type, "overlay") == 0)
gtk_overlay_add_overlay (GTK_OVERLAY (buildable), GTK_WIDGET (child));
else if (!type)
gtk_overlay_set_child (GTK_OVERLAY (buildable), GTK_WIDGET (child));
else
GTK_BUILDER_WARN_INVALID_CHILD_TYPE (buildable, type);
}
else
{
parent_buildable_iface->add_child (buildable, builder, child, type);
}
}
static void
gtk_overlay_buildable_init (GtkBuildableIface *iface)
{
parent_buildable_iface = g_type_interface_peek_parent (iface);
iface->add_child = gtk_overlay_buildable_add_child;
}
/**
* gtk_overlay_new:
*
* Creates a new #GtkOverlay.
*
* Returns: a new #GtkOverlay object.
*/
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.
*/
void
gtk_overlay_add_overlay (GtkOverlay *overlay,
GtkWidget *widget)
{
g_return_if_fail (GTK_IS_OVERLAY (overlay));
g_return_if_fail (GTK_IS_WIDGET (widget));
g_return_if_fail (widget != overlay->child);
gtk_widget_insert_before (widget, GTK_WIDGET (overlay), NULL);
}
/**
* gtk_overlay_remove_overlay:
* @overlay: a #GtkOverlay
* @widget: a #GtkWidget to be removed
*
* Removes an overlay that was added with gtk_overlay_add_overlay().
*/
void
gtk_overlay_remove_overlay (GtkOverlay *overlay,
GtkWidget *widget)
{
g_return_if_fail (GTK_IS_OVERLAY (overlay));
g_return_if_fail (GTK_IS_WIDGET (widget));
g_return_if_fail (gtk_widget_get_parent (widget) == GTK_WIDGET (overlay));
g_return_if_fail (widget != overlay->child);
gtk_widget_unparent (widget);
}
/**
* gtk_overlay_set_measure_overlay:
* @overlay: a #GtkOverlay
* @widget: an overlay child of #GtkOverlay
* @measure: whether the child should be measured
*
* Sets whether @widget is included in the measured size of @overlay.
*
* The overlay will request the size of the largest child that has
* this property set to %TRUE. Children who are not included may
* be drawn outside of @overlay's allocation if they are too large.
*/
void
gtk_overlay_set_measure_overlay (GtkOverlay *overlay,
GtkWidget *widget,
gboolean measure)
{
GtkLayoutManager *layout;
GtkOverlayLayoutChild *child;
g_return_if_fail (GTK_IS_OVERLAY (overlay));
g_return_if_fail (GTK_IS_WIDGET (widget));
layout = gtk_widget_get_layout_manager (GTK_WIDGET (overlay));
child = GTK_OVERLAY_LAYOUT_CHILD (gtk_layout_manager_get_layout_child (layout, widget));
gtk_overlay_layout_child_set_measure (child, measure);
}
/**
* gtk_overlay_get_measure_overlay:
* @overlay: a #GtkOverlay
* @widget: an overlay child of #GtkOverlay
*
* Gets whether @widget's size is included in the measurement of
* @overlay.
*
* Returns: whether the widget is measured
*/
gboolean
gtk_overlay_get_measure_overlay (GtkOverlay *overlay,
GtkWidget *widget)
{
GtkLayoutManager *layout;
GtkOverlayLayoutChild *child;
g_return_val_if_fail (GTK_IS_OVERLAY (overlay), FALSE);
g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
layout = gtk_widget_get_layout_manager (GTK_WIDGET (overlay));
child = GTK_OVERLAY_LAYOUT_CHILD (gtk_layout_manager_get_layout_child (layout, widget));
return gtk_overlay_layout_child_get_measure (child);
}
/**
* gtk_overlay_set_clip_overlay:
* @overlay: a #GtkOverlay
* @widget: an overlay child of #GtkOverlay
* @clip_overlay: whether the child should be clipped
*
* Sets whether @widget should be clipped within the parent.
*/
void
gtk_overlay_set_clip_overlay (GtkOverlay *overlay,
GtkWidget *widget,
gboolean clip_overlay)
{
GtkLayoutManager *layout;
GtkOverlayLayoutChild *child;
g_return_if_fail (GTK_IS_OVERLAY (overlay));
g_return_if_fail (GTK_IS_WIDGET (widget));
layout = gtk_widget_get_layout_manager (GTK_WIDGET (overlay));
child = GTK_OVERLAY_LAYOUT_CHILD (gtk_layout_manager_get_layout_child (layout, widget));
gtk_overlay_layout_child_set_clip_overlay (child, clip_overlay);
}
/**
* gtk_overlay_get_clip_overlay:
* @overlay: a #GtkOverlay
* @widget: an overlay child of #GtkOverlay
*
* Gets whether @widget should be clipped within the parent.
*
* Returns: whether the widget is clipped within the parent.
*/
gboolean
gtk_overlay_get_clip_overlay (GtkOverlay *overlay,
GtkWidget *widget)
{
GtkLayoutManager *layout;
GtkOverlayLayoutChild *child;
g_return_val_if_fail (GTK_IS_OVERLAY (overlay), FALSE);
g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
layout = gtk_widget_get_layout_manager (GTK_WIDGET (overlay));
child = GTK_OVERLAY_LAYOUT_CHILD (gtk_layout_manager_get_layout_child (layout, widget));
return gtk_overlay_layout_child_get_clip_overlay (child);
}
/**
* gtk_overlay_set_child:
* @overlay: a #GtkOverlay
* @child: (allow-none): the child widget
*
* Sets the child widget of @overlay.
*/
void
gtk_overlay_set_child (GtkOverlay *overlay,
GtkWidget *child)
{
g_return_if_fail (GTK_IS_OVERLAY (overlay));
g_return_if_fail (child == NULL || GTK_IS_WIDGET (child));
g_clear_pointer (&overlay->child, gtk_widget_unparent);
overlay->child = child;
if (child)
{
/* Make sure the main-child node is the first one */
gtk_widget_insert_after (child, GTK_WIDGET (overlay), NULL);
}
g_object_notify (G_OBJECT (overlay), "child");
}
/**
* gtk_overlay_get_child:
* @overlay: a #GtkOverlay
*
* Gets the child widget of @overlay.
*
* Returns: (nullable) (transfer none): the child widget of @overlay
*/
GtkWidget *
gtk_overlay_get_child (GtkOverlay *overlay)
{
g_return_val_if_fail (GTK_IS_OVERLAY (overlay), NULL);
return overlay->child;
}