cc: Add functions for getting absolute tile indices.

cc/base/tiling_data.cc

 // 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.
 
 #include "cc/base/tiling_data.h"
 
 #include <algorithm>
 
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/vector2d.h"
@@ skipping 73 matching lines @@
 int TilingData::TileYIndexFromSrcCoord(int src_position) const {
   if (num_tiles_y_ <= 1)
     return 0;
 
   DCHECK_GT(max_texture_size_.height() - 2 * border_texels_, 0);
   int y = (src_position - border_texels_) /
       (max_texture_size_.height() - 2 * border_texels_);
   return std::min(std::max(y, 0), num_tiles_y_ - 1);
 }
 
+int TilingData::TileAbsoluteXIndexFromSrcCoord(int src_position) const {
+  int inner_tile_width = max_texture_size_.width() - 2 * border_texels_;
+  if (inner_tile_width <= 0)
+    return 0;
+
+  int max_width = inner_tile_width * num_tiles_x_ + 2 * border_texels_;
+  if (src_position >= 0 && src_position < max_width)
+    return TileXIndexFromSrcCoord(src_position);
+
+  if (src_position >= max_width)
+    return num_tiles_x_ + (src_position - max_width) / inner_tile_width;
+
+  return (src_position + 1) / inner_tile_width - 1;
+}
+
+int TilingData::TileAbsoluteYIndexFromSrcCoord(int src_position) const {
+  int inner_tile_height = max_texture_size_.height() - 2 * border_texels_;
+  if (inner_tile_height <= 0)
+    return 0;
+
+  int max_height = inner_tile_height * num_tiles_y_ + 2 * border_texels_;
+  if (src_position >= 0 && src_position < max_height)
+    return TileYIndexFromSrcCoord(src_position);
+
+  if (src_position >= max_height)
+    return num_tiles_y_ + (src_position - max_height) / inner_tile_height;
+
+  return (src_position + 1) / inner_tile_height - 1;
+}
+
 int TilingData::FirstBorderTileXIndexFromSrcCoord(int src_position) const {
   if (num_tiles_x_ <= 1)
     return 0;
 
   DCHECK_GT(max_texture_size_.width() - 2 * border_texels_, 0);
   int inner_tile_size = max_texture_size_.width() - 2 * border_texels_;
   int x = (src_position - 2 * border_texels_) / inner_tile_size;
   return std::min(std::max(x, 0), num_tiles_x_ - 1);
 }
 
@@ skipping 501 matching lines @@
     return *this;
   }
 
   index_x_ = reverse_spiral_iterator_.index_x();
   index_y_ = reverse_spiral_iterator_.index_y();
 
   return *this;
 }
 
 }  // namespace cc