cc/resources/pixel_ref_map.h

   1 // Copyright 2015 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_RESOURCES_PIXEL_REF_MAP_H_
   6 #define CC_RESOURCES_PIXEL_REF_MAP_H_
   7
   8 #include <utility>
   9 #include <vector>
  10
  11 #include "base/containers/hash_tables.h"
  12 #include "base/lazy_instance.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "cc/base/cc_export.h"
  15 #include "third_party/skia/include/core/SkPicture.h"
  16 #include "ui/gfx/geometry/rect.h"
  17 #include "ui/gfx/geometry/size.h"
  18
  19 class SkPixelRef;
  20
  21 namespace cc {
  22
  23 class Picture;
  24 class DisplayItemList;
  25
  26 typedef std::pair<int, int> PixelRefMapKey;
  27 typedef std::vector<SkPixelRef*> PixelRefs;
  28 typedef base::hash_map<PixelRefMapKey, PixelRefs> PixelRefHashmap;
  29
  30 // This class is used and owned by cc Picture class. It is used to gather pixel
  31 // refs which would happen after record. It takes in |cell_size| to decide how
  32 // big each grid cell should be.
  33 class CC_EXPORT PixelRefMap {
  34  public:
  35   explicit PixelRefMap(const gfx::Size& cell_size);
  36   ~PixelRefMap();
  37   void GatherPixelRefsFromPicture(SkPicture* picture);
  38
  39   bool empty() const { return data_hash_map_.empty(); }
  40
  41   // This iterator imprecisely returns the set of pixel refs that are needed to
  42   // raster this layer rect from this picture.  Internally, pixel refs are
  43   // clumped into tile grid buckets, so there may be false positives.
  44   class CC_EXPORT Iterator {
  45    public:
  46     // Default iterator constructor that is used as place holder for invalid
  47     // Iterator.
  48     Iterator();
  49     Iterator(const gfx::Rect& layer_rect, const Picture* picture);
  50     Iterator(const gfx::Rect& layer_rect, const DisplayItemList* picture);
  51     ~Iterator();
  52
  53     SkPixelRef* operator->() const {
  54       DCHECK_LT(current_index_, current_pixel_refs_->size());
  55       return (*current_pixel_refs_)[current_index_];
  56     }
  57
  58     SkPixelRef* operator*() const {
  59       DCHECK_LT(current_index_, current_pixel_refs_->size());
  60       return (*current_pixel_refs_)[current_index_];
  61     }
  62
  63     Iterator& operator++();
  64     operator bool() const {
  65       return current_index_ < current_pixel_refs_->size();
  66     }
  67
  68    private:
  69     void PointToFirstPixelRef(const gfx::Rect& query_rect);
  70
  71     static base::LazyInstance<PixelRefs> empty_pixel_refs_;
  72     const PixelRefMap* target_pixel_ref_map_;
  73     const PixelRefs* current_pixel_refs_;
  74     unsigned current_index_;
  75
  76     gfx::Rect map_layer_rect_;
  77
  78     gfx::Point min_point_;
  79     gfx::Point max_point_;
  80     int current_x_;
  81     int current_y_;
  82   };
  83
  84  private:
  85   gfx::Point min_pixel_cell_;
  86   gfx::Point max_pixel_cell_;
  87   gfx::Size cell_size_;
  88
  89   PixelRefHashmap data_hash_map_;
  90 };
  91
  92 }  // namespace cc
  93
  94 #endif  // CC_RESOURCES_PIXEL_REF_MAP_H_