cc: Add ReverseSpiralDifferenceIterator.

cc/base/tiling_data.h

 // Copyright 2010 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_BASE_TILING_DATA_H_
 #define CC_BASE_TILING_DATA_H_
 
 #include <utility>
 
 #include "base/basictypes.h"
@@ skipping 164 matching lines @@
     enum Direction { UP, LEFT, DOWN, RIGHT };
 
     Direction direction_;
     int delta_x_;
     int delta_y_;
     int current_step_;
     int horizontal_step_count_;
     int vertical_step_count_;
   };
 
+  class CC_EXPORT ReverseSpiralDifferenceIterator : public BaseIterator {
+   public:
+    ReverseSpiralDifferenceIterator();
+    ReverseSpiralDifferenceIterator(const TilingData* tiling_data,
+                                    const gfx::Rect& consider_rect,
+                                    const gfx::Rect& ignore_rect,
+                                    const gfx::Rect& center_rect);
+    ReverseSpiralDifferenceIterator& operator++();
+
+   private:
+    bool in_consider_rect() const {
+      return index_x_ >= consider_left_ && index_x_ <= consider_right_ &&
+             index_y_ >= consider_top_ && index_y_ <= consider_bottom_;
+    }
+    bool in_around_rect() const {
+      return index_x_ >= around_left_ && index_x_ <= around_right_ &&
+             index_y_ >= around_top_ && index_y_ <= around_bottom_;
+    }
+    bool in_ignore_rect() const {
+      return index_x_ >= ignore_left_ && index_x_ <= ignore_right_ &&
+             index_y_ >= ignore_top_ && index_y_ <= ignore_bottom_;
+    }
+    bool valid_column() const {
+      return index_x_ >= consider_left_ && index_x_ <= consider_right_;
+    }
+    bool valid_row() const {
+      return index_y_ >= consider_top_ && index_y_ <= consider_bottom_;
+    }
+
+    int current_step_count() const {
+      return (direction_ == UP || direction_ == DOWN) ? vertical_step_count_
+                                                      : horizontal_step_count_;
+    }
+
+    bool needs_direction_switch() const;
+    void switch_direction();
+
+    int consider_left_;
+    int consider_top_;
+    int consider_right_;
+    int consider_bottom_;
+    int around_left_;
+    int around_top_;
+    int around_right_;
+    int around_bottom_;
+    int ignore_left_;
+    int ignore_top_;
+    int ignore_right_;
+    int ignore_bottom_;
+
+    enum Direction { LEFT, UP, RIGHT, DOWN };
+
+    Direction direction_;
+    int delta_x_;
+    int delta_y_;
+    int current_step_;
+    int horizontal_step_count_;
+    int vertical_step_count_;
+  };
+
  private:
   void AssertTile(int i, int j) const {
     DCHECK_GE(i,  0);
     DCHECK_LT(i, num_tiles_x_);
     DCHECK_GE(j, 0);
     DCHECK_LT(j, num_tiles_y_);
   }
 
   void RecomputeNumTiles();
 
   gfx::Size max_texture_size_;
   gfx::Size tiling_size_;
   int border_texels_;
 
   // These are computed values.
   int num_tiles_x_;
   int num_tiles_y_;
 };
 
 }  // namespace cc
 
 #endif  // CC_BASE_TILING_DATA_H_