forked from AuroraMiddleware/gtk
397 lines
13 KiB
C
397 lines
13 KiB
C
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/*
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* Copyright © 2018 Benjamin Otte
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* 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/>.
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*
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* Authors: Benjamin Otte <otte@gnome.org>
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*/
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#include "config.h"
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#include "gdkpaintable.h"
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/**
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* SECTION:paintable
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* @Title: GdkPaintable
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* @Short_description: An interface for a paintable region
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* @See_also: #ClutterContent, #GtkImage, #GdkTexture, #GtkSnapshot
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*
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* #GdkPaintable is a simple interface used by GDK and GDK to represent
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* objects that can be painted anywhere at any size without requiring any
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* sort of layout. The interface is inspired by similar concepts elsewhere,
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* such as #ClutterContent, <ulink
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* linkend="https://www.w3.org/TR/css-images-4/#paint-source">HTML/CSS Paint
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* Sources</ulink> or <ulink linkend="https://www.w3.org/TR/SVG2/pservers.html">
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* SVG Paint Servers</ulink>.
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*
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* A #GdkPaintable can be snapshot at any time and size using
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* gdk_paintable_snapshot(). How the paintable interprets that size and if it
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* scales or centers itself into the given rectangle is implementation defined,
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* though if you are implementing a #GdkPaintable and don't know what to do, it
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* is suggested that you scale your paintable ignoring any potential aspect ratio.
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*
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* The contents that a #GdkPaintable produces may depend on the #GdkSnapshot passed
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* to it. For example, paintables may decide to use more detailed images on higher
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* resolution screens or when OpenGL is available. A #GdkPaintable will however
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* always produce the same output for the same snapshot.
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*
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* A #GdkPaintable may change its contents, meaning that it will now produce a
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* different output with the same snpashot. Once that happens, it will call
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* gdk_paintable_invalidate_contents() which will emit the
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* #GdkPaintable::invalidate-contents signal.
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* If a paintable is known to never change its contents, it will set the
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* %GDK_PAINTABLE_STATIC_CONTENT flag. If a consumer cannot deal with changing
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* contents, it may call gdk_paintable_get_static_image() which will return a
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* static paintable and use that.
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*
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* A paintable can report an intrinsic (or preferred) size or aspect ratio it
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* wishes to be rendered at, though it doesn't have to. Consumers of the interface
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* can use this information to layout thepaintable appropriately.
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* Just like the contents, the size of a paintable can change. A paintable will
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* indicate this by calling gdk_paintable_invalidate_size() which will emit the
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* #GdkPaintable::invalidate-size signal.
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* And just like for contents, if a paintable is known to never change its size,
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* it will set the %GDK_PAINTABLE_STATIC_SIZE flag.
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*/
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G_DEFINE_INTERFACE (GdkPaintable, gdk_paintable, G_TYPE_OBJECT)
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enum {
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INVALIDATE_CONTENTS,
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INVALIDATE_SIZE,
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LAST_SIGNAL
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};
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static guint signals[LAST_SIGNAL] = { 0 };
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static void
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gdk_paintable_default_snapshot (GdkPaintable *paintable,
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GdkSnapshot *snapshot,
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double width,
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double height)
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{
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g_critical ("Paintable of type '%s' does not implement GdkPaintable::snapshot", G_OBJECT_TYPE_NAME (paintable));
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}
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static GdkPaintable *
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gdk_paintable_default_get_current_image (GdkPaintable *paintable)
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{
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g_warning ("FIXME: implement by snapshotting at default size and returning a GskRendererNodePaintable");
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return paintable;
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}
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static GdkPaintableFlags
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gdk_paintable_default_get_flags (GdkPaintable *paintable)
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{
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return 0;
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}
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static int
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gdk_paintable_default_get_intrinsic_width (GdkPaintable *paintable)
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{
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return 0;
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}
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static int
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gdk_paintable_default_get_intrinsic_height (GdkPaintable *paintable)
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{
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return 0;
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}
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static double gdk_paintable_default_get_intrinsic_aspect_ratio (GdkPaintable *paintable)
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{
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int width, height;
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width = gdk_paintable_get_intrinsic_width (paintable);
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height = gdk_paintable_get_intrinsic_height (paintable);
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if (width <= 0 || height <= 0)
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return 0.0;
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return (double) width / height;
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};
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static void
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gdk_paintable_default_init (GdkPaintableInterface *iface)
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{
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iface->snapshot = gdk_paintable_default_snapshot;
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iface->get_current_image = gdk_paintable_default_get_current_image;
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iface->get_flags = gdk_paintable_default_get_flags;
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iface->get_intrinsic_width = gdk_paintable_default_get_intrinsic_width;
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iface->get_intrinsic_height = gdk_paintable_default_get_intrinsic_height;
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iface->get_intrinsic_aspect_ratio = gdk_paintable_default_get_intrinsic_aspect_ratio;
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/**
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* GdkPaintable::invalidate-contents
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* @paintable: a #GdkPaintable
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*
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* Emitted when the contents of the @paintable change.
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*
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* Examples for such an event would be videos changing to the next frame or
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* the icon theme for an icon changing.
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*
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* Since: 4.0
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*/
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signals[INVALIDATE_CONTENTS] =
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g_signal_new ("invalidate-contents",
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GDK_TYPE_PAINTABLE,
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G_SIGNAL_RUN_LAST,
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0,
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NULL, NULL,
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g_cclosure_marshal_VOID__VOID,
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G_TYPE_NONE, 0);
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/**
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* GdkPaintable::invalidate-size
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* @paintable: a #GdkPaintable
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*
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* Emitted when the intrinsic size of the @paintable changes. This means the values
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* reported by at least one of gdk_paintable_get_intrinsic_width(),
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* gdk_paintable_get_intrinsic_height() or gdk_paintable_get_intrinsic_aspect_ratio()
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* has changed.
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*
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* Examples for such an event would be a paintable displaying the contents of a toplevel
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* window being resized.
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*
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* Since: 4.0
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*/
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signals[INVALIDATE_SIZE] =
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g_signal_new ("invalidate-size",
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GDK_TYPE_PAINTABLE,
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G_SIGNAL_RUN_LAST,
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0,
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NULL, NULL,
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g_cclosure_marshal_VOID__VOID,
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G_TYPE_NONE, 0);
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}
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/**
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* gdk_paintable_snapshot:
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* @paintable: a #GdkPaintable
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* @snapshot: a #GdkSnapshot to snapshot to
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* @width: width to snapshot in
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* @height: height to snapshot in
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*
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* Snapshots the given paintable with the given @width and @height at the
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* current (0,0) offset of the @snapshot. If @width and @height are not larger
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* than zero, this function will do nothing.
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*
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* Since: 4.0
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**/
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void
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gdk_paintable_snapshot (GdkPaintable *paintable,
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GdkSnapshot *snapshot,
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double width,
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double height)
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{
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GdkPaintableInterface *iface;
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g_return_if_fail (GDK_IS_PAINTABLE (paintable));
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g_return_if_fail (snapshot != NULL);
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if (width <= 0.0 || height <= 0.0)
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return;
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iface = GDK_PAINTABLE_GET_IFACE (paintable);
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iface->snapshot (paintable, snapshot, width, height);
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}
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#define GDK_PAINTABLE_IMMUTABLE (GDK_PAINTABLE_STATIC_SIZE | GDK_PAINTABLE_STATIC_CONTENTS)
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static inline gboolean
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gdk_paintable_is_immutable (GdkPaintable *paintable)
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{
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return (gdk_paintable_get_flags (paintable) & GDK_PAINTABLE_IMMUTABLE) == GDK_PAINTABLE_IMMUTABLE;
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}
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/**
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* gdk_paintable_get_current_image:
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* @paintable: a #GdkPaintable
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*
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* Gets an immutable paintable for the current contents displayed by @paintable.
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*
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* This is useful when you want to retain the current state of an animation, for
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* example to take a screenshot of a running animation.
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*
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* If the @paintable is already immutable, it will return itself.
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*
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* Returns: (transfer full): An immutable paintable for the current
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* contents of @paintable.
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**/
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GdkPaintable *
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gdk_paintable_get_current_image (GdkPaintable *paintable)
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{
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GdkPaintableInterface *iface;
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g_return_val_if_fail (GDK_IS_PAINTABLE (paintable), NULL);
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if (gdk_paintable_is_immutable (paintable))
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return g_object_ref (paintable);
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iface = GDK_PAINTABLE_GET_IFACE (paintable);
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return iface->get_current_image (paintable);
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}
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/**
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* gdk_paintable_get_flags:
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* @paintable: a #GdkPaintable
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*
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* Get flags for the paintable. This is oftentimes useful for optimizations.
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*
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* See #GdkPaintableFlags for the flags and what they mean.
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*
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* Returns: The #GdkPaintableFlags for this paintable.
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**/
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GdkPaintableFlags
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gdk_paintable_get_flags (GdkPaintable *paintable)
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{
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GdkPaintableInterface *iface;
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g_return_val_if_fail (GDK_IS_PAINTABLE (paintable), 0);
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iface = GDK_PAINTABLE_GET_IFACE (paintable);
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return iface->get_flags (paintable);
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}
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/**
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* gdk_paintable_get_intrinsic_width:
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* @paintable: a #GdkPaintable
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*
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* Gets the preferred width the @paintable would like to be displayed at.
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* Consumers of this interface can use this to reserve enough space to draw
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* the paintable.
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*
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* This is a purely informational value and does not in any way limit the values
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* that may be passed to gdk_paintable_snapshot().
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*
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* If the @paintable does not have a preferred width, it returns 0. Negative
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* values are never returned.
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*
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* Returns: the intrinsic width of @paintable or 0 if none.
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**/
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int
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gdk_paintable_get_intrinsic_width (GdkPaintable *paintable)
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{
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GdkPaintableInterface *iface;
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g_return_val_if_fail (GDK_IS_PAINTABLE (paintable), 0);
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iface = GDK_PAINTABLE_GET_IFACE (paintable);
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return iface->get_intrinsic_width (paintable);
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}
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/**
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* gdk_paintable_get_intrinsic_height:
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* @paintable: a #GdkPaintable
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*
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* Gets the preferred height the @paintable would like to be displayed at.
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* Consumers of this interface can use this to reserve enough space to draw
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* the paintable.
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*
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* This is a purely informational value and does not in any way limit the values
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* that may be passed to gdk_paintable_snapshot().
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*
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* If the @paintable does not have a preferred height, it returns 0. Negative
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* values are never returned.
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*
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* Returns: the intrinsic height of @paintable or 0 if none.
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**/
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int
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gdk_paintable_get_intrinsic_height (GdkPaintable *paintable)
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{
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GdkPaintableInterface *iface;
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g_return_val_if_fail (GDK_IS_PAINTABLE (paintable), 0);
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iface = GDK_PAINTABLE_GET_IFACE (paintable);
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return iface->get_intrinsic_height (paintable);
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}
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/**
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* gdk_paintable_get_intrinsic_aspect_ratio:
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* @paintable: a #GdkPaintable
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*
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* Gets the preferred aspect ratio the @paintable would like to be displayed at.
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* The aspect ration is the width divided by the height, so a value of 0.5 means
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* that the @paintable prefers to be displayed twice as high as it is wide.
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* Consumers of this interface can use this to preserve aspect ratio when displaying
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* this paintable.
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*
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* This is a purely informational value and does not in any way limit the values
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* that may be passed to gdk_paintable_snapshot().
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*
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* Usually when a @paintable returns non-0 values from
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* gdk_paintable_get_intrinsic_width() and gdk_paintable_get_intrinsic_height()
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* the aspect ratio should conform to those values, though that is not required.
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*
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* If the @paintable does not have a preferred aspect ratio, it returns 0.0.
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* Negative values are never returned.
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*
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* Returns: the intrinsic aspect ratio of @paintable or 0.0 if none.
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**/
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double
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gdk_paintable_get_intrinsic_aspect_ratio (GdkPaintable *paintable)
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{
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GdkPaintableInterface *iface;
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g_return_val_if_fail (GDK_IS_PAINTABLE (paintable), 0);
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iface = GDK_PAINTABLE_GET_IFACE (paintable);
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return iface->get_intrinsic_aspect_ratio (paintable);
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}
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/**
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* gdk_paintable_invalidate_contents:
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* @paintable: a #GdkPaintable
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*
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* Called by implementations of #GdkPaintable to invalidate their contents.
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* Unless the contents are invalidated, implementations must guarantee that
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* multiple calls to GdkPaintable::snapshot produce the same output.
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*
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* This function will emit the GdkPaintable::invalidate-contents signal.
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*
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* If a @paintable reports the %GDK_PAINTABLE_STATIC_CONTENTS flag,
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* it must not call this function.
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**/
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void
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gdk_paintable_invalidate_contents (GdkPaintable *paintable)
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{
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g_return_if_fail (GDK_IS_PAINTABLE (paintable));
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g_return_if_fail (!(gdk_paintable_get_flags (paintable) & GDK_PAINTABLE_STATIC_CONTENTS));
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g_signal_emit (paintable, signals[INVALIDATE_CONTENTS], 0);
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}
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/**
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* gdk_paintable_invalidate_size:
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* @paintable: a #GdkPaintable
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*
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* Called by implementations of #GdkPaintable to invalidate their size.
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* As long as the size is not invalidated, @paintable must return the same values
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* for its width, height and intrinsic height.
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*
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* This function will emit the GdkPaintable::invalidate-size signal.
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*
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* If a @paintable reports the %GDK_PAINTABLE_STATIC_SIZE flag,
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* it must not call this function.
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**/
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void
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gdk_paintable_invalidate_size (GdkPaintable *paintable)
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{
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g_return_if_fail (GDK_IS_PAINTABLE (paintable));
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g_return_if_fail (!(gdk_paintable_get_flags (paintable) & GDK_PAINTABLE_STATIC_SIZE));
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g_signal_emit (paintable, signals[INVALIDATE_SIZE], 0);
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}
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