Draw Transform of Render Surface From Property Trees

cc/trees/draw_property_utils.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/draw_property_utils.h"
 
 #include <vector>
 
 #include "cc/base/math_util.h"
 #include "cc/layers/layer.h"
@@ skipping 569 matching lines @@
 gfx::Transform DrawTransformFromPropertyTrees(const Layer* layer,
                                               const TransformTree& tree) {
   return DrawTransformFromPropertyTreesInternal(layer, tree);
 }
 
 gfx::Transform DrawTransformFromPropertyTrees(const LayerImpl* layer,
                                               const TransformTree& tree) {
   return DrawTransformFromPropertyTreesInternal(layer, tree);
 }
 
+gfx::Transform DrawTransformOfRenderSurfaceFromPropertyTrees(
+    const RenderSurfaceImpl* render_surface,
+    const TransformTree& tree) {
+  const TransformNode* node = tree.Node(render_surface->TransformTreeIndex());
+  gfx::Transform render_surface_transform;
+  // The draw transform of root render surface is identity tranform.
+  if (node->id == 1)
+    return render_surface_transform;
+  const TransformNode* target_node = tree.Node(node->data.target_id);
+  if (target_node->id == 1)
+    target_node = tree.Node(0);
+  tree.ComputeTransformWithDestinationSublayerScale(node->id, target_node->id,
+                                                    &render_surface_transform);
+  render_surface_transform.Scale(1.0 / node->data.sublayer_scale.x(),
+                                 1.0 / node->data.sublayer_scale.y());
+  return render_surface_transform;
+}
+
 template <typename LayerType>
 gfx::Transform ScreenSpaceTransformFromPropertyTreesInternal(
     LayerType* layer,
     const TransformTree& tree) {
   gfx::Transform xform(1, 0, 0, 1, layer->offset_to_transform_parent().x(),
                        layer->offset_to_transform_parent().y());
   if (layer->transform_tree_index() >= 0) {
     gfx::Transform ssxform =
         tree.Node(layer->transform_tree_index())->data.to_screen;
     xform.ConcatTransform(ssxform);
@@ skipping 69 matching lines @@
   if (static_cast<int>(layer->offset_to_transform_parent().x()) !=
       layer->offset_to_transform_parent().x())
     return false;
   if (static_cast<int>(layer->offset_to_transform_parent().y()) !=
       layer->offset_to_transform_parent().y())
     return false;
   return true;
 }
 
 }  // namespace cc