cc: Implement tile iteration order based on pyramid sequence. [old]

cc/base/tiling_data.h

Index: cc/base/tiling_data.h
diff --git a/cc/base/tiling_data.h b/cc/base/tiling_data.h
index 2e392ce3e74da10b5778cfced59f3a50e60ce95d..9a05463e6bfeedb29ddc081a7a35c473f91437a7 100644
--- a/cc/base/tiling_data.h
+++ b/cc/base/tiling_data.h
@@ -5,10 +5,14 @@
 #ifndef CC_BASE_TILING_DATA_H_
 #define CC_BASE_TILING_DATA_H_
 
+#include <list>
 #include <utility>
+#include <vector>
 
 #include "base/logging.h"
+#include "base/memory/ptr_util.h"
 #include "cc/base/cc_export.h"
+#include "cc/base/pyramid_sequence.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -140,6 +144,38 @@ class CC_EXPORT TilingData {
     DifferenceIterator& operator++();
   };
 
+  struct LevelDistance {
+    int level;
+    int distance;
+  };
+
+  class LDSequence {

[vmpstr, 2016/06/16 18:28:58]

I prefer to not abberviate here

[vmpstr, 2016/06/16 18:28:58]

Needs a comment

+   public:
+    typedef std::list<LDSequence> List;
+
+    LDSequence(PyramidSequence traversal_seq,

[vmpstr, 2016/06/16 18:28:58]

don't abbreviate seq

+               PyramidSequence level_seq,
+               bool swapped,
+               int distance);
+    LDSequence(const LDSequence& other);
+    ~LDSequence();
+
+    bool IsValid() const { return !level_distances_.empty(); }
+    int GetIndexX() const;
+    int GetIndexY() const;
+    int GetTopDistance();
+    bool Advance();
+
+   private:
+    void Reset();
+
+    PyramidSequence traversal_seq_;
+    bool swapped_;
+    int current_seq_index_;
+    int current_level_index_;
+    std::vector<LevelDistance> level_distances_;
+  };
+
   // Iterate through all indices whose bounds + border intersect with
   // |consider| but which also do not intersect with |ignore|. The iterator
   // order is a counterclockwise spiral around the given center.
@@ -150,32 +186,22 @@ class CC_EXPORT TilingData {
                              const gfx::Rect& consider_rect,
                              const gfx::Rect& ignore_rect,
                              const gfx::Rect& center_rect);
+    ~SpiralDifferenceIterator();
     SpiralDifferenceIterator& operator++();
 
-   private:
-    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 valid_column(int column) const {
+      return column >= 0 && column <= num_tiles_x_;
     }
 
-    bool needs_direction_switch() const;
-    void switch_direction();
+    bool valid_row(int row) const { return row >= 0 && row <= num_tiles_y_; }
 
-    enum Direction { UP, LEFT, DOWN, RIGHT };
+   private:
+    LDSequence::List::iterator GetNextLDSequence();
 
-    Direction direction_;
-    int delta_x_;
-    int delta_y_;
-    int current_step_;
-    int horizontal_step_count_;
-    int vertical_step_count_;
+    int num_tiles_x_;
+    int num_tiles_y_;
+    LDSequence::List ld_sequences_;
+    LDSequence::List::iterator current_ld_seq;
   };
 
   class CC_EXPORT ReverseSpiralDifferenceIterator