cc/trees/damage_tracker.h

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CC_TREES_DAMAGE_TRACKER_H_
   6 #define CC_TREES_DAMAGE_TRACKER_H_
   7
   8 #include <vector>
   9 #include "base/memory/scoped_ptr.h"
  10 #include "cc/base/cc_export.h"
  11 #include "cc/layers/layer_lists.h"
  12 #include "ui/gfx/geometry/rect.h"
  13
  14 class SkImageFilter;
  15
  16 namespace gfx {
  17 class Rect;
  18 }
  19
  20 namespace cc {
  21
  22 class FilterOperations;
  23 class LayerImpl;
  24 class RenderSurfaceImpl;
  25
  26 // Computes the region where pixels have actually changed on a
  27 // RenderSurfaceImpl. This region is used to scissor what is actually drawn to
  28 // the screen to save GPU computation and bandwidth.
  29 class CC_EXPORT DamageTracker {
  30  public:
  31   static scoped_ptr<DamageTracker> Create();
  32   ~DamageTracker();
  33
  34   void DidDrawDamagedArea() { current_damage_rect_ = gfx::Rect(); }
  35   void AddDamageNextUpdate(const gfx::Rect& dmg) {
  36     current_damage_rect_.Union(dmg);
  37   }
  38   void UpdateDamageTrackingState(
  39       const LayerImplList& layer_list,
  40       int target_surface_layer_id,
  41       bool target_surface_property_changed_only_from_descendant,
  42       const gfx::Rect& target_surface_content_rect,
  43       LayerImpl* target_surface_mask_layer,
  44       const FilterOperations& filters);
  45
  46   gfx::Rect current_damage_rect() { return current_damage_rect_; }
  47
  48  private:
  49   DamageTracker();
  50
  51   gfx::Rect TrackDamageFromActiveLayers(const LayerImplList& layer_list,
  52                                         int target_surface_layer_id);
  53   gfx::Rect TrackDamageFromSurfaceMask(LayerImpl* target_surface_mask_layer);
  54   gfx::Rect TrackDamageFromLeftoverRects();
  55
  56   void PrepareRectHistoryForUpdate();
  57
  58   // These helper functions are used only in TrackDamageFromActiveLayers().
  59   void ExtendDamageForLayer(LayerImpl* layer, gfx::Rect* target_damage_rect);
  60   void ExtendDamageForRenderSurface(LayerImpl* layer,
  61                                     gfx::Rect* target_damage_rect);
  62
  63   struct RectMapData {
  64     RectMapData() : layer_id_(0), mailboxId_(0) {}
  65     explicit RectMapData(int layer_id) : layer_id_(layer_id), mailboxId_(0) {}
  66     void Update(const gfx::Rect& rect, unsigned int mailboxId) {
  67       mailboxId_ = mailboxId;
  68       rect_ = rect;
  69     }
  70
  71     bool operator < (const RectMapData& other) const {
  72       return layer_id_ < other.layer_id_;
  73     }
  74
  75     int layer_id_;
  76     unsigned int mailboxId_;
  77     gfx::Rect rect_;
  78   };
  79   typedef std::vector<RectMapData> SortedRectMap;
  80
  81   RectMapData& RectDataForLayer(int layer_id, bool* layer_is_new);
  82
  83   SortedRectMap rect_history_;
  84
  85   unsigned int mailboxId_;
  86   gfx::Rect current_damage_rect_;
  87
  88   DISALLOW_COPY_AND_ASSIGN(DamageTracker);
  89 };
  90
  91 }  // namespace cc
  92
  93 #endif  // CC_TREES_DAMAGE_TRACKER_H_