cc/playback/discardable_image_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_PLAYBACK_DISCARDABLE_IMAGE_MAP_H_
   6 #define CC_PLAYBACK_DISCARDABLE_IMAGE_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 "skia/ext/discardable_image_utils.h"
  16 #include "third_party/skia/include/core/SkPicture.h"
  17 #include "ui/gfx/geometry/rect.h"
  18 #include "ui/gfx/geometry/size.h"
  19
  20 class SkImage;
  21
  22 namespace cc {
  23
  24 class Picture;
  25 class DisplayItemList;
  26
  27 typedef std::pair<int, int> ImageMapKey;
  28 typedef std::vector<skia::PositionImage> Images;
  29 typedef base::hash_map<ImageMapKey, Images> ImageHashmap;
  30
  31 // This class is used and owned by cc Picture class. It is used to gather images
  32 // which would happen after record. It takes in |cell_size| to decide how
  33 // big each grid cell should be.
  34 class CC_EXPORT DiscardableImageMap {
  35  public:
  36   explicit DiscardableImageMap(const gfx::Size& cell_size);
  37   ~DiscardableImageMap();
  38
  39   void GatherImagesFromPicture(SkPicture* picture, const gfx::Rect& layer_rect);
  40
  41   bool empty() const { return data_hash_map_.empty(); }
  42
  43   // This iterator imprecisely returns the set of images that are needed to
  44   // raster this layer rect from this picture.  Internally, images are
  45   // clumped into tile grid buckets, so there may be false positives.
  46   class CC_EXPORT Iterator {
  47    public:
  48     // Default iterator constructor that is used as place holder for invalid
  49     // Iterator.
  50     Iterator();
  51     Iterator(const gfx::Rect& layer_rect, const Picture* picture);
  52     Iterator(const gfx::Rect& layer_rect, const DisplayItemList* picture);
  53     ~Iterator();
  54
  55     const skia::PositionImage* operator->() const {
  56       DCHECK_LT(current_index_, current_images_->size());
  57       return &(*current_images_)[current_index_];
  58     }
  59
  60     const skia::PositionImage& operator*() const {
  61       DCHECK_LT(current_index_, current_images_->size());
  62       return (*current_images_)[current_index_];
  63     }
  64
  65     Iterator& operator++();
  66     operator bool() const { return current_index_ < current_images_->size(); }
  67
  68    private:
  69     void PointToFirstImage(const gfx::Rect& query_rect);
  70
  71     static base::LazyInstance<Images> empty_images_;
  72     const DiscardableImageMap* target_image_map_;
  73     const Images* current_images_;
  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   ImageHashmap data_hash_map_;
  90 };
  91
  92 }  // namespace cc
  93
  94 #endif  // CC_PLAYBACK_DISCARDABLE_IMAGE_MAP_H_