cc: Compute draw transforms dynamically.

cc/trees/property_tree.h

 // 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.
 
 #ifndef CC_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <stddef.h>
 
+#include <map>
 #include <memory>
 #include <unordered_map>
 #include <vector>
 
 #include "cc/animation/element_id.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/synced_property.h"
 #include "cc/output/filter_operations.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/scroll_offset.h"
@@ skipping 115 matching lines @@
   TransformTree& operator=(const TransformTree&);
 
   bool operator==(const TransformTree& other) const;
 
   static const int kContentsRootNodeId = 1;
 
   int Insert(const TransformNode& tree_node, int parent_id);
 
   void clear();
 
-  // Computes the change of basis transform from node |source_id| to |dest_id|.
-  // The function returns false iff the inverse of a singular transform was
-  // used (and the result should, therefore, not be trusted). Transforms may
-  // be computed between any pair of nodes that have an ancestor/descendant
-  // relationship. Transforms between other pairs of nodes may only be computed
-  // if the following condition holds: let id1 the larger id and let id2 be the
-  // other id; then the nearest ancestor of node id1 whose id is smaller than
-  // id2 is the lowest common ancestor of the pair of nodes, and the transform
-  // from this lowest common ancestor to node id2 is only a 2d translation.
-  bool ComputeTransform(int source_id,
-                        int dest_id,
-                        gfx::Transform* transform) const;
-
   void OnTransformAnimated(const gfx::Transform& transform,
                            int id,
                            LayerTreeImpl* layer_tree_impl);
   // Computes the change of basis transform from node |source_id| to |dest_id|.
   // This is used by scroll children to compute transform from their scroll
   // parent space (source) to their parent space (destination) and it can atmost
   // be a translation. This function assumes that the path from source to
   // destination has only translations. So, it should not be called when there
   // can be intermediate 3d transforms but the end result is a translation.
   bool ComputeTranslation(int source_id,
@@ skipping 57 matching lines @@
   const std::vector<int>& nodes_affected_by_inner_viewport_bounds_delta()
       const {
     return nodes_affected_by_inner_viewport_bounds_delta_;
   }
   const std::vector<int>& nodes_affected_by_outer_viewport_bounds_delta()
       const {
     return nodes_affected_by_outer_viewport_bounds_delta_;
   }
 
   const gfx::Transform& FromTarget(int node_id, int effect) const;
-  void SetFromTarget(int node_id, const gfx::Transform& transform);
-
-  // TODO(sunxd): Remove target space transforms in cached data when we
-  // completely implement computing draw transforms on demand.
   const gfx::Transform& ToTarget(int node_id, int effect_id) const;
-  void SetToTarget(int node_id, const gfx::Transform& transform);
 
   const gfx::Transform& FromScreen(int node_id) const;
   void SetFromScreen(int node_id, const gfx::Transform& transform);
 
   const gfx::Transform& ToScreen(int node_id) const;
   void SetToScreen(int node_id, const gfx::Transform& transform);
 
   int TargetId(int node_id) const;
   void SetTargetId(int node_id, int target_id);
 
   int ContentTargetId(int node_id) const;
   void SetContentTargetId(int node_id, int content_target_id);
 
   const std::vector<TransformCachedNodeData>& cached_data() const {
     return cached_data_;
   }
 
   void ToProtobuf(proto::PropertyTree* proto) const;
   void FromProtobuf(const proto::PropertyTree& proto,
                     std::unordered_map<int, int>* node_id_to_index_map);
 
-  // Computes the combined transform between |source_id| and |dest_id|. These
-  // two nodes must be on the same ancestor chain.
-  void CombineTransformsBetween(int source_id,
-                                int dest_id,
-                                gfx::Transform* transform) const;
-
-  // Computes the combined inverse transform between |source_id| and |dest_id|
-  // and returns false if the inverse of a singular transform was used. These
-  // two nodes must be on the same ancestor chain.
-  bool CombineInversesBetween(int source_id,
-                              int dest_id,
-                              gfx::Transform* transform) const;
-
  private:
   // Returns true iff the node at |desc_id| is a descendant of the node at
   // |anc_id|.
   bool IsDescendant(int desc_id, int anc_id) const;
 
   void UpdateLocalTransform(TransformNode* node);
   void UpdateScreenSpaceTransform(TransformNode* node,
                                   TransformNode* parent_node,
                                   TransformNode* target_node);
   void UpdateSurfaceContentsScale(TransformNode* node);
@@ skipping 229 matching lines @@
 
   // TODO(sunxd): Move screen space transforms here if it can improve
   // performance.
   DrawTransformData()
       : update_number(-1), transforms(gfx::Transform(), gfx::Transform()) {}
 };
 
 struct PropertyTreesCachedData {
   int property_tree_update_number;
   std::vector<AnimationScaleData> animation_scales;
-  mutable std::vector<std::unordered_map<int, DrawTransformData>>
-      draw_transforms;
+  mutable std::vector<std::map<int, DrawTransformData>> draw_transforms;

[ajuma, 2016/09/07 14:51:23]

As discussed offline, please compare the performance of using unordered_map vs
map here on the telemetry cluster.

[sunxd, 2016/09/07 15:20:02]

Acknowledged.

 
   PropertyTreesCachedData();
   ~PropertyTreesCachedData();
 };
 
 class CC_EXPORT PropertyTrees final {
  public:
   PropertyTrees();
   PropertyTrees(const PropertyTrees& other) = delete;
   ~PropertyTrees();
@@ skipping 24 matching lines @@
   bool changed;
   // We cache a global bool for full tree damages to avoid walking the entire
   // tree.
   // TODO(jaydasika): Changes to transform and effects that damage the entire
   // tree should be tracked by this bool. Currently, they are tracked by the
   // individual nodes.
   bool full_tree_damaged;
   int sequence_number;
   bool is_main_thread;
   bool is_active;
-  bool verify_transform_tree_calculations;
 
   void clear();
 
   void SetInnerViewportContainerBoundsDelta(gfx::Vector2dF bounds_delta);
   void SetOuterViewportContainerBoundsDelta(gfx::Vector2dF bounds_delta);
   void SetInnerViewportScrollBoundsDelta(gfx::Vector2dF bounds_delta);
   void PushOpacityIfNeeded(PropertyTrees* target_tree);
   void RemoveIdFromIdToIndexMaps(int id);
   bool IsInIdToIndexMap(TreeType tree_type, int id);
   void UpdateChangeTracking();
@@ skipping 41 matching lines @@
   gfx::Vector2dF inner_viewport_container_bounds_delta_;
   gfx::Vector2dF outer_viewport_container_bounds_delta_;
   gfx::Vector2dF inner_viewport_scroll_bounds_delta_;
 
   PropertyTreesCachedData cached_data_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_