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From 04b7954c7f04e7348f139fdf5c38e7702b387ee3 Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Thu, 10 Jan 2019 10:48:02 -0500
Subject: [PATCH 9/9] MetaShapedTexture: save and restore textures on suspend

The proprietary nvidia driver garbles GPU memory on suspend.

In order to workaround that limitation, this commit copies all
textures to host memory on suspend and restores them on resume.

One complication comes from external textures (such as those
given to us by Xwayland for X clients).  We can't just restore
those textures, since they aren't writable.

This commit addresses that complication by keeping a local texture
around for those external textures, and using it instead for parts
of the window that haven't been redrawn since resume.
---
 src/compositor/meta-shaped-texture.c | 494 +++++++++++++++++++++++++--
 src/meta/meta-shaped-texture.h       |   2 +
 2 files changed, 475 insertions(+), 21 deletions(-)

diff --git a/src/compositor/meta-shaped-texture.c b/src/compositor/meta-shaped-texture.c
index d8c250fc9..8de173bf7 100644
--- a/src/compositor/meta-shaped-texture.c
+++ b/src/compositor/meta-shaped-texture.c
@@ -2,166 +2,203 @@
  * Authored By Neil Roberts  <neil@linux.intel.com>
  * and Jasper St. Pierre <jstpierre@mecheye.net>
  *
  * Copyright (C) 2008 Intel Corporation
  * Copyright (C) 2012 Red Hat, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
  *
  * This program 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
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 /**
  * SECTION:meta-shaped-texture
  * @title: MetaShapedTexture
  * @short_description: An actor to draw a masked texture.
  */
 
 #include <config.h>
 
 #include <meta/meta-shaped-texture.h>
 #include "meta-shaped-texture-private.h"
+#include "meta-texture-rectangle.h"
 
 #include <cogl/cogl.h>
 #include <gdk/gdk.h> /* for gdk_rectangle_intersect() */
 
 #include "clutter-utils.h"
 #include "meta-texture-tower.h"
 #include "core/boxes-private.h"
 
 #include "meta-cullable.h"
+#include <meta/meta-backend.h>
 
 static void meta_shaped_texture_dispose  (GObject    *object);
 
 static void meta_shaped_texture_paint (ClutterActor       *actor);
 
 static void meta_shaped_texture_get_preferred_width (ClutterActor *self,
                                                      gfloat        for_height,
                                                      gfloat       *min_width_p,
                                                      gfloat       *natural_width_p);
 
 static void meta_shaped_texture_get_preferred_height (ClutterActor *self,
                                                       gfloat        for_width,
                                                       gfloat       *min_height_p,
                                                       gfloat       *natural_height_p);
 
 static gboolean meta_shaped_texture_get_paint_volume (ClutterActor *self, ClutterPaintVolume *volume);
 
+static void disable_backing_store (MetaShapedTexture *stex);
+
 static void cullable_iface_init (MetaCullableInterface *iface);
 
+static gboolean meta_debug_show_backing_store = FALSE;
+
 G_DEFINE_TYPE_WITH_CODE (MetaShapedTexture, meta_shaped_texture, CLUTTER_TYPE_ACTOR,
                          G_IMPLEMENT_INTERFACE (META_TYPE_CULLABLE, cullable_iface_init));
 
 #define META_SHAPED_TEXTURE_GET_PRIVATE(obj) \
   (G_TYPE_INSTANCE_GET_PRIVATE ((obj), META_TYPE_SHAPED_TEXTURE, \
                                 MetaShapedTexturePrivate))
 
 enum {
   SIZE_CHANGED,
 
   LAST_SIGNAL,
 };
 
 static guint signals[LAST_SIGNAL];
 
+typedef struct
+{
+  CoglTexture *texture;
+  CoglTexture *mask_texture;
+  cairo_surface_t *mask_surface;
+  cairo_region_t *region;
+} MetaTextureBackingStore;
+
 struct _MetaShapedTexturePrivate
 {
   MetaTextureTower *paint_tower;
 
   CoglTexture *texture;
   CoglTexture *mask_texture;
   CoglSnippet *snippet;
 
   CoglPipeline *base_pipeline;
   CoglPipeline *masked_pipeline;
   CoglPipeline *unblended_pipeline;
 
   gboolean is_y_inverted;
 
   /* The region containing only fully opaque pixels */
   cairo_region_t *opaque_region;
 
   /* MetaCullable regions, see that documentation for more details */
   cairo_region_t *clip_region;
   cairo_region_t *unobscured_region;
 
+  /* textures get corrupted on suspend, so save them */
+  cairo_surface_t *saved_base_surface;
+  cairo_surface_t *saved_mask_surface;
+
+  /* We can't just restore external textures, so we need to track
+   * which parts of the external texture are freshly drawn from
+   * the client after corruption, and fill in the rest from our
+   * saved snapshot */
+  MetaTextureBackingStore *backing_store;
+
   guint tex_width, tex_height;
   guint fallback_width, fallback_height;
 
   guint create_mipmaps : 1;
 };
 
 static void
 meta_shaped_texture_class_init (MetaShapedTextureClass *klass)
 {
   GObjectClass *gobject_class = (GObjectClass *) klass;
   ClutterActorClass *actor_class = (ClutterActorClass *) klass;
 
   gobject_class->dispose = meta_shaped_texture_dispose;
 
   actor_class->get_preferred_width = meta_shaped_texture_get_preferred_width;
   actor_class->get_preferred_height = meta_shaped_texture_get_preferred_height;
   actor_class->paint = meta_shaped_texture_paint;
   actor_class->get_paint_volume = meta_shaped_texture_get_paint_volume;
 
   signals[SIZE_CHANGED] = g_signal_new ("size-changed",
                                         G_TYPE_FROM_CLASS (gobject_class),
                                         G_SIGNAL_RUN_LAST,
                                         0,
                                         NULL, NULL, NULL,
                                         G_TYPE_NONE, 0);
 
   g_type_class_add_private (klass, sizeof (MetaShapedTexturePrivate));
+
+  if (g_getenv ("MUTTER_DEBUG_BACKING_STORE"))
+    meta_debug_show_backing_store = TRUE;
 }
 
 static void
 meta_shaped_texture_init (MetaShapedTexture *self)
 {
   MetaShapedTexturePrivate *priv;
+  MetaBackend *backend = meta_get_backend ();
+  ClutterBackend *clutter_backend = clutter_get_default_backend ();
+  CoglContext *cogl_context =
+    clutter_backend_get_cogl_context (clutter_backend);
 
   priv = self->priv = META_SHAPED_TEXTURE_GET_PRIVATE (self);
 
   priv->paint_tower = meta_texture_tower_new ();
 
   priv->texture = NULL;
   priv->mask_texture = NULL;
   priv->create_mipmaps = TRUE;
   priv->is_y_inverted = TRUE;
+
+  if (cogl_has_feature (cogl_context, COGL_FEATURE_ID_UNSTABLE_TEXTURES))
+    {
+      g_signal_connect_object (backend, "suspending", G_CALLBACK (meta_shaped_texture_save), self, G_CONNECT_SWAPPED);
+      g_signal_connect_object (backend, "resuming", G_CALLBACK (meta_shaped_texture_restore), self, G_CONNECT_SWAPPED);
+    }
 }
 
 static void
 set_unobscured_region (MetaShapedTexture *self,
                        cairo_region_t    *unobscured_region)
 {
   MetaShapedTexturePrivate *priv = self->priv;
 
   g_clear_pointer (&priv->unobscured_region, (GDestroyNotify) cairo_region_destroy);
   if (unobscured_region)
     {
       guint width, height;
 
       if (priv->texture)
         {
           width = priv->tex_width;
           height = priv->tex_height;
         }
       else
         {
           width = priv->fallback_width;
           height = priv->fallback_height;
         }
 
       cairo_rectangle_int_t bounds = { 0, 0, width, height };
       priv->unobscured_region = cairo_region_copy (unobscured_region);
       cairo_region_intersect_rectangle (priv->unobscured_region, &bounds);
     }
 }
 
@@ -183,116 +220,183 @@ meta_shaped_texture_reset_pipelines (MetaShapedTexture *stex)
 
   g_clear_pointer (&priv->base_pipeline, cogl_object_unref);
   g_clear_pointer (&priv->masked_pipeline, cogl_object_unref);
   g_clear_pointer (&priv->unblended_pipeline, cogl_object_unref);
 }
 
 static void
 meta_shaped_texture_dispose (GObject *object)
 {
   MetaShapedTexture *self = (MetaShapedTexture *) object;
   MetaShapedTexturePrivate *priv = self->priv;
 
   if (priv->paint_tower)
     meta_texture_tower_free (priv->paint_tower);
   priv->paint_tower = NULL;
 
   g_clear_pointer (&priv->texture, cogl_object_unref);
   g_clear_pointer (&priv->opaque_region, cairo_region_destroy);
 
   meta_shaped_texture_set_mask_texture (self, NULL);
   set_unobscured_region (self, NULL);
   set_clip_region (self, NULL);
 
   meta_shaped_texture_reset_pipelines (self);
 
   g_clear_pointer (&priv->snippet, cogl_object_unref);
 
   G_OBJECT_CLASS (meta_shaped_texture_parent_class)->dispose (object);
 }
 
+static int
+get_layer_indices (MetaShapedTexture *stex,
+                   int               *main_layer_index,
+                   int               *backing_mask_layer_index,
+                   int               *backing_layer_index,
+                   int               *mask_layer_index)
+{
+  MetaShapedTexturePrivate *priv = stex->priv;
+  int next_layer_index = 0;
+
+  if (main_layer_index)
+    *main_layer_index = next_layer_index;
+
+  next_layer_index++;
+
+  if (priv->backing_store)
+    {
+      if (backing_mask_layer_index)
+        *backing_mask_layer_index = next_layer_index;
+      next_layer_index++;
+      if (backing_layer_index)
+        *backing_layer_index = next_layer_index;
+      next_layer_index++;
+    }
+  else
+    {
+      if (backing_mask_layer_index)
+        *backing_mask_layer_index = -1;
+      if (backing_layer_index)
+        *backing_layer_index = -1;
+    }
+
+  if (mask_layer_index)
+    *mask_layer_index = next_layer_index;
+
+  return next_layer_index;
+}
+
 static CoglPipeline *
 get_base_pipeline (MetaShapedTexture *stex,
                    CoglContext       *ctx)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   CoglPipeline *pipeline;
+  int main_layer_index;
+  int backing_layer_index;
+  int backing_mask_layer_index;
+  int i, number_of_layers;
 
   if (priv->base_pipeline)
     return priv->base_pipeline;
 
   pipeline = cogl_pipeline_new (ctx);
-  cogl_pipeline_set_layer_wrap_mode_s (pipeline, 0,
-                                       COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
-  cogl_pipeline_set_layer_wrap_mode_t (pipeline, 0,
-                                       COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
-  cogl_pipeline_set_layer_wrap_mode_s (pipeline, 1,
-                                       COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
-  cogl_pipeline_set_layer_wrap_mode_t (pipeline, 1,
-                                       COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
+
+  number_of_layers = get_layer_indices (stex,
+                                        &main_layer_index,
+                                        &backing_mask_layer_index,
+                                        &backing_layer_index,
+                                        NULL);
+
+  for (i = 0; i < number_of_layers; i++)
+    {
+      cogl_pipeline_set_layer_wrap_mode_s (pipeline, i,
+                                           COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
+      cogl_pipeline_set_layer_wrap_mode_t (pipeline, i,
+                                           COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE);
+    }
+
   if (!priv->is_y_inverted)
     {
       CoglMatrix matrix;
 
       cogl_matrix_init_identity (&matrix);
       cogl_matrix_scale (&matrix, 1, -1, 1);
       cogl_matrix_translate (&matrix, 0, -1, 0);
-      cogl_pipeline_set_layer_matrix (pipeline, 0, &matrix);
+      cogl_pipeline_set_layer_matrix (pipeline, main_layer_index, &matrix);
+    }
+
+  if (priv->backing_store)
+    {
+      g_autofree char *backing_description = NULL;
+      cogl_pipeline_set_layer_combine (pipeline, backing_mask_layer_index,
+                                       "RGBA = REPLACE(PREVIOUS)",
+                                       NULL);
+      backing_description = g_strdup_printf ("RGBA = INTERPOLATE(PREVIOUS, TEXTURE_%d, TEXTURE_%d[A])",
+                                             backing_layer_index,
+                                             backing_mask_layer_index);
+      cogl_pipeline_set_layer_combine (pipeline,
+                                       backing_layer_index,
+                                       backing_description,
+                                       NULL);
     }
 
   if (priv->snippet)
-    cogl_pipeline_add_layer_snippet (pipeline, 0, priv->snippet);
+    cogl_pipeline_add_layer_snippet (pipeline, main_layer_index, priv->snippet);
 
   priv->base_pipeline = pipeline;
 
   return priv->base_pipeline;
 }
 
 static CoglPipeline *
 get_unmasked_pipeline (MetaShapedTexture *stex,
                        CoglContext       *ctx)
 {
   return get_base_pipeline (stex, ctx);
 }
 
 static CoglPipeline *
 get_masked_pipeline (MetaShapedTexture *stex,
                      CoglContext       *ctx)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   CoglPipeline *pipeline;
+  int mask_layer_index;
 
   if (priv->masked_pipeline)
     return priv->masked_pipeline;
 
+  get_layer_indices (stex, NULL, NULL, NULL, &mask_layer_index);
+
   pipeline = cogl_pipeline_copy (get_base_pipeline (stex, ctx));
-  cogl_pipeline_set_layer_combine (pipeline, 1,
+  cogl_pipeline_set_layer_combine (pipeline, mask_layer_index,
                                    "RGBA = MODULATE (PREVIOUS, TEXTURE[A])",
                                    NULL);
 
   priv->masked_pipeline = pipeline;
 
   return pipeline;
 }
 
 static CoglPipeline *
 get_unblended_pipeline (MetaShapedTexture *stex,
                         CoglContext       *ctx)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   CoglPipeline *pipeline;
   CoglColor color;
 
   if (priv->unblended_pipeline)
     return priv->unblended_pipeline;
 
   pipeline = cogl_pipeline_copy (get_base_pipeline (stex, ctx));
   cogl_color_init_from_4ub (&color, 255, 255, 255, 255);
   cogl_pipeline_set_blend (pipeline,
                            "RGBA = ADD (SRC_COLOR, 0)",
                            NULL);
   cogl_pipeline_set_color (pipeline, &color);
 
   priv->unblended_pipeline = pipeline;
 
   return pipeline;
 }
@@ -313,105 +417,111 @@ paint_clipped_rectangle (CoglFramebuffer       *fb,
 
   coords[0] = rect->x / (alloc->x2 - alloc->x1);
   coords[1] = rect->y / (alloc->y2 - alloc->y1);
   coords[2] = (rect->x + rect->width) / (alloc->x2 - alloc->x1);
   coords[3] = (rect->y + rect->height) / (alloc->y2 - alloc->y1);
 
   coords[4] = coords[0];
   coords[5] = coords[1];
   coords[6] = coords[2];
   coords[7] = coords[3];
 
   cogl_framebuffer_draw_multitextured_rectangle (fb, pipeline,
                                                  x1, y1, x2, y2,
                                                  &coords[0], 8);
 }
 
 static void
 set_cogl_texture (MetaShapedTexture *stex,
                   CoglTexture       *cogl_tex)
 {
   MetaShapedTexturePrivate *priv;
   guint width, height;
 
   g_return_if_fail (META_IS_SHAPED_TEXTURE (stex));
 
   priv = stex->priv;
 
   if (priv->texture)
     cogl_object_unref (priv->texture);
 
+  g_clear_pointer (&priv->saved_base_surface, cairo_surface_destroy);
+
   priv->texture = cogl_tex;
 
   if (cogl_tex != NULL)
     {
       cogl_object_ref (cogl_tex);
       width = cogl_texture_get_width (COGL_TEXTURE (cogl_tex));
       height = cogl_texture_get_height (COGL_TEXTURE (cogl_tex));
     }
   else
     {
       width = 0;
       height = 0;
     }
 
   if (priv->tex_width != width ||
       priv->tex_height != height)
     {
       priv->tex_width = width;
       priv->tex_height = height;
       meta_shaped_texture_set_mask_texture (stex, NULL);
       clutter_actor_queue_relayout (CLUTTER_ACTOR (stex));
       g_signal_emit (stex, signals[SIZE_CHANGED], 0);
     }
 
   /* NB: We don't queue a redraw of the actor here because we don't
    * know how much of the buffer has changed with respect to the
    * previous buffer. We only queue a redraw in response to surface
    * damage. */
 
   if (priv->create_mipmaps)
     meta_texture_tower_set_base_texture (priv->paint_tower, cogl_tex);
 }
 
 static void
 do_paint (MetaShapedTexture *stex,
           CoglFramebuffer   *fb,
           CoglTexture       *paint_tex,
           cairo_region_t    *clip_region)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   guint tex_width, tex_height;
   guchar opacity;
   CoglContext *ctx;
   ClutterActorBox alloc;
   CoglPipelineFilter filter;
+  int main_layer_index;
+  int backing_mask_layer_index;
+  int backing_layer_index;
+  int mask_layer_index;
 
   tex_width = priv->tex_width;
   tex_height = priv->tex_height;
 
   if (tex_width == 0 || tex_height == 0) /* no contents yet */
     return;
 
   cairo_rectangle_int_t tex_rect = { 0, 0, tex_width, tex_height };
 
   /* Use nearest-pixel interpolation if the texture is unscaled. This
    * improves performance, especially with software rendering.
    */
 
   filter = COGL_PIPELINE_FILTER_LINEAR;
 
   if (meta_actor_painting_untransformed (fb,
                                          tex_width, tex_height,
                                          NULL, NULL))
     filter = COGL_PIPELINE_FILTER_NEAREST;
 
   ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
 
   opacity = clutter_actor_get_paint_opacity (CLUTTER_ACTOR (stex));
   clutter_actor_get_allocation_box (CLUTTER_ACTOR (stex), &alloc);
 
   cairo_region_t *blended_region;
   gboolean use_opaque_region = (priv->opaque_region != NULL && opacity == 255);
 
   if (use_opaque_region)
     {
@@ -420,123 +530,161 @@ do_paint (MetaShapedTexture *stex,
       else
         blended_region = cairo_region_create_rectangle (&tex_rect);
 
       cairo_region_subtract (blended_region, priv->opaque_region);
     }
   else
     {
       if (priv->clip_region != NULL)
         blended_region = cairo_region_reference (priv->clip_region);
       else
         blended_region = NULL;
     }
 
   /* Limit to how many separate rectangles we'll draw; beyond this just
    * fall back and draw the whole thing */
 #define MAX_RECTS 16
 
   if (blended_region != NULL)
     {
       int n_rects = cairo_region_num_rectangles (blended_region);
       if (n_rects > MAX_RECTS)
         {
           /* Fall back to taking the fully blended path. */
           use_opaque_region = FALSE;
 
           cairo_region_destroy (blended_region);
           blended_region = NULL;
         }
     }
 
+  get_layer_indices (stex,
+                     &main_layer_index,
+                     &backing_mask_layer_index,
+                     &backing_layer_index,
+                     &mask_layer_index);
+
   /* First, paint the unblended parts, which are part of the opaque region. */
   if (use_opaque_region)
     {
       CoglPipeline *opaque_pipeline;
       cairo_region_t *region;
       int n_rects;
       int i;
 
       if (priv->clip_region != NULL)
         {
           region = cairo_region_copy (priv->clip_region);
           cairo_region_intersect (region, priv->opaque_region);
         }
       else
         {
           region = cairo_region_reference (priv->opaque_region);
         }
 
       if (!cairo_region_is_empty (region))
         {
           opaque_pipeline = get_unblended_pipeline (stex, ctx);
-          cogl_pipeline_set_layer_texture (opaque_pipeline, 0, paint_tex);
-          cogl_pipeline_set_layer_filters (opaque_pipeline, 0, filter, filter);
+          cogl_pipeline_set_layer_texture (opaque_pipeline, main_layer_index, paint_tex);
+          cogl_pipeline_set_layer_filters (opaque_pipeline, main_layer_index, filter, filter);
+
+          if (priv->backing_store)
+            {
+              cogl_pipeline_set_layer_texture (opaque_pipeline,
+                                               backing_mask_layer_index,
+                                               priv->backing_store->mask_texture);
+              cogl_pipeline_set_layer_filters (opaque_pipeline,
+                                               backing_mask_layer_index,
+                                               filter, filter);
+              cogl_pipeline_set_layer_texture (opaque_pipeline,
+                                               backing_layer_index,
+                                               priv->backing_store->texture);
+              cogl_pipeline_set_layer_filters (opaque_pipeline,
+                                               backing_layer_index,
+                                               filter, filter);
+            }
 
           n_rects = cairo_region_num_rectangles (region);
           for (i = 0; i < n_rects; i++)
             {
               cairo_rectangle_int_t rect;
               cairo_region_get_rectangle (region, i, &rect);
               paint_clipped_rectangle (fb, opaque_pipeline, &rect, &alloc);
             }
         }
 
       cairo_region_destroy (region);
     }
 
   /* Now, go ahead and paint the blended parts. */
 
   /* We have three cases:
    *   1) blended_region has rectangles - paint the rectangles.
    *   2) blended_region is empty - don't paint anything
    *   3) blended_region is NULL - paint fully-blended.
    *
    *   1) and 3) are the times where we have to paint stuff. This tests
    *   for 1) and 3).
    */
   if (blended_region == NULL || !cairo_region_is_empty (blended_region))
     {
       CoglPipeline *blended_pipeline;
 
       if (priv->mask_texture == NULL)
         {
           blended_pipeline = get_unmasked_pipeline (stex, ctx);
         }
       else
         {
           blended_pipeline = get_masked_pipeline (stex, ctx);
-          cogl_pipeline_set_layer_texture (blended_pipeline, 1, priv->mask_texture);
-          cogl_pipeline_set_layer_filters (blended_pipeline, 1, filter, filter);
+          cogl_pipeline_set_layer_texture (blended_pipeline, mask_layer_index, priv->mask_texture);
+          cogl_pipeline_set_layer_filters (blended_pipeline, mask_layer_index, filter, filter);
         }
 
-      cogl_pipeline_set_layer_texture (blended_pipeline, 0, paint_tex);
-      cogl_pipeline_set_layer_filters (blended_pipeline, 0, filter, filter);
+      cogl_pipeline_set_layer_texture (blended_pipeline, main_layer_index, paint_tex);
+      cogl_pipeline_set_layer_filters (blended_pipeline, main_layer_index, filter, filter);
+
+      if (priv->backing_store)
+        {
+          cogl_pipeline_set_layer_texture (blended_pipeline,
+                                           backing_mask_layer_index,
+                                           priv->backing_store->mask_texture);
+          cogl_pipeline_set_layer_filters (blended_pipeline,
+                                           backing_mask_layer_index,
+                                           filter, filter);
+          cogl_pipeline_set_layer_texture (blended_pipeline,
+                                           backing_layer_index,
+                                           priv->backing_store->texture);
+          cogl_pipeline_set_layer_filters (blended_pipeline,
+                                           backing_layer_index,
+                                           filter, filter);
+        }
 
       CoglColor color;
       cogl_color_init_from_4ub (&color, opacity, opacity, opacity, opacity);
       cogl_pipeline_set_color (blended_pipeline, &color);
 
       if (blended_region != NULL)
         {
           /* 1) blended_region is not empty. Paint the rectangles. */
           int i;
           int n_rects = cairo_region_num_rectangles (blended_region);
 
           for (i = 0; i < n_rects; i++)
             {
               cairo_rectangle_int_t rect;
               cairo_region_get_rectangle (blended_region, i, &rect);
 
               if (!gdk_rectangle_intersect (&tex_rect, &rect, &rect))
                 continue;
 
               paint_clipped_rectangle (fb, blended_pipeline, &rect, &alloc);
             }
         }
       else
         {
           /* 3) blended_region is NULL. Do a full paint. */
           cogl_framebuffer_draw_rectangle (fb, blended_pipeline,
                                            0, 0,
                                            alloc.x2 - alloc.x1,
                                            alloc.y2 - alloc.y1);
         }
@@ -698,110 +846,173 @@ meta_shaped_texture_set_create_mipmaps (MetaShapedTexture *stex,
 					gboolean           create_mipmaps)
 {
   MetaShapedTexturePrivate *priv;
 
   g_return_if_fail (META_IS_SHAPED_TEXTURE (stex));
 
   priv = stex->priv;
 
   create_mipmaps = create_mipmaps != FALSE;
 
   if (create_mipmaps != priv->create_mipmaps)
     {
       CoglTexture *base_texture;
       priv->create_mipmaps = create_mipmaps;
       base_texture = create_mipmaps ? priv->texture : NULL;
       meta_texture_tower_set_base_texture (priv->paint_tower, base_texture);
     }
 }
 
 void
 meta_shaped_texture_set_mask_texture (MetaShapedTexture *stex,
                                       CoglTexture       *mask_texture)
 {
   MetaShapedTexturePrivate *priv;
 
   g_return_if_fail (META_IS_SHAPED_TEXTURE (stex));
 
   priv = stex->priv;
 
   g_clear_pointer (&priv->mask_texture, cogl_object_unref);
+  g_clear_pointer (&priv->saved_mask_surface, cairo_surface_destroy);
 
   if (mask_texture != NULL)
     {
       priv->mask_texture = mask_texture;
       cogl_object_ref (priv->mask_texture);
     }
 
   clutter_actor_queue_redraw (CLUTTER_ACTOR (stex));
 }
 
 gboolean
 meta_shaped_texture_is_obscured (MetaShapedTexture *self)
 {
   cairo_region_t *unobscured_region = effective_unobscured_region (self);
 
   if (unobscured_region)
     return cairo_region_is_empty (unobscured_region);
   else
     return FALSE;
 }
 
+static void
+meta_texture_backing_store_redraw_mask (MetaTextureBackingStore *backing_store)
+{
+  CoglError *error = NULL;
+
+  if (!cogl_texture_set_data (backing_store->mask_texture, COGL_PIXEL_FORMAT_A_8,
+                              cairo_image_surface_get_stride (backing_store->mask_surface),
+                              cairo_image_surface_get_data (backing_store->mask_surface), 0,
+                              &error))
+    {
+
+      g_warning ("Failed to update backing mask texture");
+      g_clear_pointer (&error, cogl_error_free);
+    }
+}
+
+static gboolean
+meta_texture_backing_store_shrink (MetaTextureBackingStore     *backing_store,
+                                   const cairo_rectangle_int_t *area)
+{
+  cairo_t *cr;
+
+  cairo_region_subtract_rectangle (backing_store->region, area);
+
+  /* If the client has finally redrawn the entire surface, we can
+   * ditch our snapshot
+   */
+  if (cairo_region_is_empty (backing_store->region))
+    return FALSE;
+
+  cr = cairo_create (backing_store->mask_surface);
+  cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
+  cairo_paint (cr);
+  gdk_cairo_region (cr, backing_store->region);
+  cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
+  cairo_fill (cr);
+  cairo_destroy (cr);
+
+  meta_texture_backing_store_redraw_mask (backing_store);
+
+  return TRUE;
+}
+
+static void
+shrink_backing_region (MetaShapedTexture           *stex,
+                       const cairo_rectangle_int_t *area)
+{
+  MetaShapedTexturePrivate *priv = stex->priv;
+  gboolean still_backing_texture;
+
+  if (!priv->backing_store)
+    return;
+
+  still_backing_texture =
+      meta_texture_backing_store_shrink (priv->backing_store, area);
+
+  if (!still_backing_texture)
+    disable_backing_store (stex);
+}
+
 /**
  * meta_shaped_texture_update_area:
  * @stex: #MetaShapedTexture
  * @x: the x coordinate of the damaged area
  * @y: the y coordinate of the damaged area
  * @width: the width of the damaged area
  * @height: the height of the damaged area
  *
  * Repairs the damaged area indicated by @x, @y, @width and @height
  * and potentially queues a redraw.
  *
  * Return value: Whether a redraw have been queued or not
  */
 gboolean
 meta_shaped_texture_update_area (MetaShapedTexture *stex,
 				 int                x,
 				 int                y,
 				 int                width,
 				 int                height)
 {
   MetaShapedTexturePrivate *priv;
   cairo_region_t *unobscured_region;
   const cairo_rectangle_int_t clip = { x, y, width, height };
 
   priv = stex->priv;
 
   if (priv->texture == NULL)
     return FALSE;
 
+  shrink_backing_region (stex, &clip);
+
   meta_texture_tower_update_area (priv->paint_tower, x, y, width, height);
 
   unobscured_region = effective_unobscured_region (stex);
   if (unobscured_region)
     {
       cairo_region_t *intersection;
 
       if (cairo_region_is_empty (unobscured_region))
         return FALSE;
 
       intersection = cairo_region_copy (unobscured_region);
       cairo_region_intersect_rectangle (intersection, &clip);
 
       if (!cairo_region_is_empty (intersection))
         {
           cairo_rectangle_int_t damage_rect;
           cairo_region_get_extents (intersection, &damage_rect);
           clutter_actor_queue_redraw_with_clip (CLUTTER_ACTOR (stex), &damage_rect);
           cairo_region_destroy (intersection);
           return TRUE;
         }
 
       cairo_region_destroy (intersection);
       return FALSE;
     }
   else
     {
       clutter_actor_queue_redraw_with_clip (CLUTTER_ACTOR (stex), &clip);
       return TRUE;
     }
@@ -892,62 +1103,63 @@ meta_shaped_texture_set_opaque_region (MetaShapedTexture *stex,
   priv = stex->priv;
 
   if (priv->opaque_region)
     cairo_region_destroy (priv->opaque_region);
 
   if (opaque_region)
     priv->opaque_region = cairo_region_reference (opaque_region);
   else
     priv->opaque_region = NULL;
 }
 
 cairo_region_t *
 meta_shaped_texture_get_opaque_region (MetaShapedTexture *stex)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   return priv->opaque_region;
 }
 
 static gboolean
 should_get_via_offscreen (MetaShapedTexture *stex)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
 
   if (!cogl_texture_is_get_data_supported (priv->texture))
     return TRUE;
 
   return FALSE;
 }
 
 static cairo_surface_t *
-get_image_via_offscreen (MetaShapedTexture     *stex,
-                         cairo_rectangle_int_t *clip)
+get_image_via_offscreen (MetaShapedTexture      *stex,
+                         cairo_rectangle_int_t  *clip,
+                         CoglTexture           **texture)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   ClutterBackend *clutter_backend = clutter_get_default_backend ();
   CoglContext *cogl_context =
     clutter_backend_get_cogl_context (clutter_backend);
   CoglTexture *image_texture;
   GError *error = NULL;
   CoglOffscreen *offscreen;
   CoglFramebuffer *fb;
   CoglMatrix projection_matrix;
   unsigned int fb_width, fb_height;
   cairo_rectangle_int_t fallback_clip;
   CoglColor clear_color;
   cairo_surface_t *surface;
 
   if (cogl_has_feature (cogl_context, COGL_FEATURE_ID_TEXTURE_NPOT))
     {
       fb_width = priv->tex_width;
       fb_height = priv->tex_height;
     }
   else
     {
       fb_width = clutter_util_next_p2 (priv->tex_width);
       fb_height = clutter_util_next_p2 (priv->tex_height);
     }
 
   if (!clip)
     {
       fallback_clip = (cairo_rectangle_int_t) {
         .width = priv->tex_width,
@@ -988,184 +1200,424 @@ get_image_via_offscreen (MetaShapedTexture     *stex,
       g_error_free (error);
       cogl_object_unref (fb);
       return FALSE;
     }
 
   cogl_framebuffer_push_matrix (fb);
   cogl_matrix_init_identity (&projection_matrix);
   cogl_matrix_scale (&projection_matrix,
                      1.0 / (priv->tex_width / 2.0),
                      -1.0 / (priv->tex_height / 2.0), 0);
   cogl_matrix_translate (&projection_matrix,
                          -(priv->tex_width / 2.0),
                          -(priv->tex_height / 2.0), 0);
 
   cogl_framebuffer_set_projection_matrix (fb, &projection_matrix);
 
   cogl_color_init_from_4ub (&clear_color, 0, 0, 0, 0);
   cogl_framebuffer_clear (fb, COGL_BUFFER_BIT_COLOR, &clear_color);
 
   do_paint (stex, fb, priv->texture, NULL);
 
   cogl_framebuffer_pop_matrix (fb);
 
   surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
                                         clip->width, clip->height);
   cogl_framebuffer_read_pixels (fb,
                                 clip->x, clip->y,
                                 clip->width, clip->height,
                                 CLUTTER_CAIRO_FORMAT_ARGB32,
                                 cairo_image_surface_get_data (surface));
+  cairo_surface_mark_dirty (surface);
+
+  if (texture)
+    {
+      *texture = cogl_object_ref (image_texture);
+
+      if (G_UNLIKELY (meta_debug_show_backing_store))
+        {
+          cairo_t *cr;
+
+          cr = cairo_create (surface);
+          cairo_set_source_rgba (cr, 1.0, 0.0, 0.0, 0.75);
+          cairo_paint (cr);
+          cairo_destroy (cr);
+        }
+
+      cogl_texture_set_data (*texture, CLUTTER_CAIRO_FORMAT_ARGB32,
+                             cairo_image_surface_get_stride (surface),
+                             cairo_image_surface_get_data (surface), 0, NULL);
+    }
+
   cogl_object_unref (fb);
 
-  cairo_surface_mark_dirty (surface);
 
   return surface;
 }
 
 /**
  * meta_shaped_texture_get_image:
  * @stex: A #MetaShapedTexture
  * @clip: A clipping rectangle, to help prevent extra processing.
  * In the case that the clipping rectangle is partially or fully
  * outside the bounds of the texture, the rectangle will be clipped.
  *
  * Flattens the two layers of the shaped texture into one ARGB32
  * image by alpha blending the two images, and returns the flattened
  * image.
  *
  * Returns: (transfer full): a new cairo surface to be freed with
  * cairo_surface_destroy().
  */
 cairo_surface_t *
 meta_shaped_texture_get_image (MetaShapedTexture     *stex,
                                cairo_rectangle_int_t *clip)
 {
   MetaShapedTexturePrivate *priv = stex->priv;
   cairo_rectangle_int_t *transformed_clip = NULL;
   CoglTexture *texture, *mask_texture;
   cairo_surface_t *surface;
 
   g_return_val_if_fail (META_IS_SHAPED_TEXTURE (stex), NULL);
 
   texture = COGL_TEXTURE (priv->texture);
 
   if (texture == NULL)
     return NULL;
 
   if (priv->tex_width == 0 || priv->tex_height == 0)
     return NULL;
 
   if (clip != NULL)
     {
       double tex_scale;
       cairo_rectangle_int_t tex_rect;
 
       transformed_clip = alloca (sizeof (cairo_rectangle_int_t));
       *transformed_clip = *clip;
 
       clutter_actor_get_scale (CLUTTER_ACTOR (stex), &tex_scale, NULL);
       meta_rectangle_scale_double (transformed_clip, 1.0 / tex_scale,
                                    META_ROUNDING_STRATEGY_GROW);
 
       tex_rect = (cairo_rectangle_int_t) {
         .width = priv->tex_width,
         .height = priv->tex_height,
       };
 
       if (!meta_rectangle_intersect (&tex_rect, transformed_clip,
                                      transformed_clip))
         return NULL;
     }
 
   if (should_get_via_offscreen (stex))
-    return get_image_via_offscreen (stex, transformed_clip);
+    return get_image_via_offscreen (stex, transformed_clip, NULL);
 
   if (transformed_clip)
     texture = cogl_texture_new_from_sub_texture (texture,
                                                  transformed_clip->x,
                                                  transformed_clip->y,
                                                  transformed_clip->width,
                                                  transformed_clip->height);
 
   surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
                                         cogl_texture_get_width (texture),
                                         cogl_texture_get_height (texture));
 
   cogl_texture_get_data (texture, CLUTTER_CAIRO_FORMAT_ARGB32,
                          cairo_image_surface_get_stride (surface),
                          cairo_image_surface_get_data (surface));
 
   cairo_surface_mark_dirty (surface);
 
   if (transformed_clip)
     cogl_object_unref (texture);
 
   mask_texture = priv->mask_texture;
   if (mask_texture != NULL)
     {
       cairo_t *cr;
       cairo_surface_t *mask_surface;
 
       if (transformed_clip)
         mask_texture =
           cogl_texture_new_from_sub_texture (mask_texture,
                                              transformed_clip->x,
                                              transformed_clip->y,
                                              transformed_clip->width,
                                              transformed_clip->height);
 
       mask_surface = cairo_image_surface_create (CAIRO_FORMAT_A8,
                                                  cogl_texture_get_width (mask_texture),
                                                  cogl_texture_get_height (mask_texture));
 
       cogl_texture_get_data (mask_texture, COGL_PIXEL_FORMAT_A_8,
                              cairo_image_surface_get_stride (mask_surface),
                              cairo_image_surface_get_data (mask_surface));
 
       cairo_surface_mark_dirty (mask_surface);
 
       cr = cairo_create (surface);
       cairo_set_source_surface (cr, mask_surface, 0, 0);
       cairo_set_operator (cr, CAIRO_OPERATOR_DEST_IN);
       cairo_paint (cr);
       cairo_destroy (cr);
 
       cairo_surface_destroy (mask_surface);
 
       if (transformed_clip)
         cogl_object_unref (mask_texture);
     }
 
   return surface;
 }
 
+static void
+meta_texture_backing_store_free (MetaTextureBackingStore *backing_store)
+{
+  g_clear_pointer (&backing_store->texture, cogl_object_unref);
+  g_clear_pointer (&backing_store->mask_texture, cogl_object_unref);
+  g_clear_pointer (&backing_store->mask_surface, cairo_surface_destroy);
+  g_clear_pointer (&backing_store->region, cairo_region_destroy);
+
+  g_slice_free (MetaTextureBackingStore, backing_store);
+}
+
+static MetaTextureBackingStore *
+meta_texture_backing_store_new (CoglTexture *texture)
+{
+  MetaTextureBackingStore *backing_store = NULL;
+  ClutterBackend *backend = clutter_get_default_backend ();
+  CoglContext *context = clutter_backend_get_cogl_context (backend);
+  CoglTexture *mask_texture = NULL;
+  guchar *mask_data;
+  int width, height, stride;
+  cairo_surface_t *surface;
+  cairo_region_t *region;
+  cairo_rectangle_int_t backing_rectangle;
+
+  width = cogl_texture_get_width (texture);
+  height = cogl_texture_get_height (texture);
+  stride = cairo_format_stride_for_width (CAIRO_FORMAT_A8, width);
+
+  /* we start off by only letting the backing texture through, and none of the real texture */
+  backing_rectangle.x = 0;
+  backing_rectangle.y = 0;
+  backing_rectangle.width = width;
+  backing_rectangle.height = height;
+
+  region = cairo_region_create_rectangle (&backing_rectangle);
+
+  /* initialize mask to transparent, so the entire backing store shows through
+   * up front
+   */
+  mask_data = g_malloc0 (stride * height);
+  surface = cairo_image_surface_create_for_data (mask_data,
+                                                 CAIRO_FORMAT_A8,
+                                                 width,
+                                                 height,
+                                                 stride);
+
+  if (meta_texture_rectangle_check (texture))
+    {
+      mask_texture = COGL_TEXTURE (cogl_texture_rectangle_new_with_size (context,
+                                                                         width,
+                                                                         height));
+      cogl_texture_set_components (mask_texture, COGL_TEXTURE_COMPONENTS_A);
+      cogl_texture_set_region (mask_texture,
+                               0, 0,
+                               0, 0,
+                               width, height,
+                               width, height,
+                               COGL_PIXEL_FORMAT_A_8,
+                               stride, mask_data);
+    }
+  else
+    {
+      CoglError *error = NULL;
+
+      mask_texture = COGL_TEXTURE (cogl_texture_2d_new_from_data (context, width, height,
+                                                                  COGL_PIXEL_FORMAT_A_8,
+                                                                  stride, mask_data, &error));
+
+      if (error)
+        {
+          g_warning ("Failed to allocate mask texture: %s", error->message);
+          cogl_error_free (error);
+        }
+    }
+
+  if (mask_texture)
+    {
+      backing_store = g_slice_new0 (MetaTextureBackingStore);
+      backing_store->texture = cogl_object_ref (texture);
+      backing_store->mask_texture = mask_texture;
+      backing_store->mask_surface = surface;
+      backing_store->region = region;
+    }
+
+  return backing_store;
+}
+
+static void
+enable_backing_store (MetaShapedTexture *stex,
+                      CoglTexture       *texture)
+{
+  MetaShapedTexturePrivate *priv = stex->priv;
+
+  g_clear_pointer (&priv->backing_store, meta_texture_backing_store_free);
+
+  priv->backing_store = meta_texture_backing_store_new (texture);
+
+  meta_shaped_texture_reset_pipelines (stex);
+}
+
+static void
+disable_backing_store (MetaShapedTexture *stex)
+{
+  MetaShapedTexturePrivate *priv = stex->priv;
+
+  g_clear_pointer (&priv->backing_store, meta_texture_backing_store_free);
+
+  meta_shaped_texture_reset_pipelines (stex);
+}
+
+void
+meta_shaped_texture_save (MetaShapedTexture *stex)
+{
+
+  CoglTexture *texture, *mask_texture;
+  MetaShapedTexturePrivate *priv = stex->priv;
+  cairo_surface_t *surface;
+
+  g_return_if_fail (META_IS_SHAPED_TEXTURE (stex));
+
+  texture = COGL_TEXTURE (priv->texture);
+
+  if (texture == NULL)
+    return;
+
+  g_clear_pointer (&priv->saved_base_surface, cairo_surface_destroy);
+  g_clear_pointer (&priv->saved_mask_surface, cairo_surface_destroy);
+  g_clear_pointer (&priv->backing_store, meta_texture_backing_store_free);
+
+  if (should_get_via_offscreen (stex))
+    {
+      CoglTexture *backing_texture;
+
+      meta_shaped_texture_reset_pipelines (stex);
+
+      surface = get_image_via_offscreen (stex, NULL, &backing_texture);
+
+      enable_backing_store (stex, backing_texture);
+      cogl_object_unref (backing_texture);
+    }
+  else
+    {
+      surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+                                            cogl_texture_get_width (texture),
+                                            cogl_texture_get_height (texture));
+
+      cogl_texture_get_data (texture, CLUTTER_CAIRO_FORMAT_ARGB32,
+                             cairo_image_surface_get_stride (surface),
+                             cairo_image_surface_get_data (surface));
+    }
+
+  priv->saved_base_surface = surface;
+
+  mask_texture = stex->priv->mask_texture;
+  if (mask_texture != NULL)
+    {
+      cairo_surface_t *mask_surface;
+
+      mask_surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+                                                 cogl_texture_get_width (mask_texture),
+                                                 cogl_texture_get_height (mask_texture));
+
+      cogl_texture_get_data (mask_texture, CLUTTER_CAIRO_FORMAT_ARGB32,
+                             cairo_image_surface_get_stride (mask_surface),
+                             cairo_image_surface_get_data (mask_surface));
+
+      cairo_surface_mark_dirty (mask_surface);
+
+      priv->saved_mask_surface = mask_surface;
+    }
+}
+
+void
+meta_shaped_texture_restore (MetaShapedTexture *stex)
+{
+  MetaShapedTexturePrivate *priv = stex->priv;
+  CoglTexture *texture;
+  CoglError *error = NULL;
+
+  texture = meta_shaped_texture_get_texture (stex);
+
+  if (texture == NULL)
+    return;
+
+  if (priv->mask_texture)
+    {
+      if (!cogl_texture_set_data (priv->mask_texture, CLUTTER_CAIRO_FORMAT_ARGB32,
+                                  cairo_image_surface_get_stride (priv->saved_mask_surface),
+                                  cairo_image_surface_get_data (priv->saved_mask_surface), 0,
+                                  &error))
+        {
+          g_warning ("Failed to restore mask texture");
+          g_clear_pointer (&error, cogl_error_free);
+        }
+      g_clear_pointer (&priv->saved_mask_surface, cairo_surface_destroy);
+    }
+
+  /* if the main texture doesn't support direct writes, then
+   * write to the local backing texture instead, and blend old
+   * versus new at paint time.
+   */
+  if (priv->backing_store)
+    {
+      meta_texture_backing_store_redraw_mask (priv->backing_store);
+      texture = priv->backing_store->texture;
+    }
+
+  if (!cogl_texture_set_data (texture, CLUTTER_CAIRO_FORMAT_ARGB32,
+                              cairo_image_surface_get_stride (priv->saved_base_surface),
+                              cairo_image_surface_get_data (priv->saved_base_surface), 0,
+                              &error))
+    {
+      g_warning ("Failed to restore texture");
+      g_clear_pointer (&error, cogl_error_free);
+    }
+  g_clear_pointer (&priv->saved_base_surface, cairo_surface_destroy);
+
+  clutter_actor_queue_redraw (CLUTTER_ACTOR (stex));
+}
+
 void
 meta_shaped_texture_set_fallback_size (MetaShapedTexture *self,
                                        guint              fallback_width,
                                        guint              fallback_height)
 {
   MetaShapedTexturePrivate *priv = self->priv;
 
   priv->fallback_width = fallback_width;
   priv->fallback_height = fallback_height;
 }
 
 static void
 meta_shaped_texture_cull_out (MetaCullable   *cullable,
                               cairo_region_t *unobscured_region,
                               cairo_region_t *clip_region)
 {
   MetaShapedTexture *self = META_SHAPED_TEXTURE (cullable);
   MetaShapedTexturePrivate *priv = self->priv;
 
   set_unobscured_region (self, unobscured_region);
   set_clip_region (self, clip_region);
 
   if (clutter_actor_get_paint_opacity (CLUTTER_ACTOR (self)) == 0xff)
     {
       if (priv->opaque_region)
         {
           if (unobscured_region)
             cairo_region_subtract (unobscured_region, priv->opaque_region);
           if (clip_region)
             cairo_region_subtract (clip_region, priv->opaque_region);
diff --git a/src/meta/meta-shaped-texture.h b/src/meta/meta-shaped-texture.h
index 80b23f2ea..fc0567c9f 100644
--- a/src/meta/meta-shaped-texture.h
+++ b/src/meta/meta-shaped-texture.h
@@ -54,33 +54,35 @@ struct _MetaShapedTextureClass
  */
 struct _MetaShapedTexture
 {
   /*< private >*/
   ClutterActor parent;
 
   MetaShapedTexturePrivate *priv;
 };
 
 GType meta_shaped_texture_get_type (void) G_GNUC_CONST;
 
 void meta_shaped_texture_set_create_mipmaps (MetaShapedTexture *stex,
 					     gboolean           create_mipmaps);
 
 gboolean meta_shaped_texture_update_area (MetaShapedTexture *stex,
                                           int                x,
                                           int                y,
                                           int                width,
                                           int                height);
 
 CoglTexture * meta_shaped_texture_get_texture (MetaShapedTexture *stex);
 
 void meta_shaped_texture_set_mask_texture (MetaShapedTexture *stex,
                                            CoglTexture       *mask_texture);
 void meta_shaped_texture_set_opaque_region (MetaShapedTexture *stex,
                                             cairo_region_t    *opaque_region);
 
 cairo_surface_t * meta_shaped_texture_get_image (MetaShapedTexture     *stex,
                                                  cairo_rectangle_int_t *clip);
 
+void meta_shaped_texture_save (MetaShapedTexture *self);
+void meta_shaped_texture_restore (MetaShapedTexture *self);
 G_END_DECLS
 
 #endif /* __META_SHAPED_TEXTURE_H__ */
-- 
2.18.1