Implementation of principal-component color reduction.

ui/gfx/color_utils.h

Index: ui/gfx/color_utils.h
diff --git a/ui/gfx/color_utils.h b/ui/gfx/color_utils.h
index 1beb7c6b12a672261d3cb1ace5ba6ef214c7b684..2bac747996108ce8bc618985d45bb7f8fd2dc40e 100644
--- a/ui/gfx/color_utils.h
+++ b/ui/gfx/color_utils.h
@@ -8,6 +8,8 @@
 #include "base/basictypes.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/ui_export.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/vector3d_f.h"
 
 class SkBitmap;
 
@@ -77,6 +79,26 @@ UI_EXPORT SkColor InvertColor(SkColor color);
 // Gets a Windows system color as a SkColor
 UI_EXPORT SkColor GetSysSkColor(int which);
 
+// Apply a color reduction transform defined by |color_transform| vector to
+// |source_bitmap|. The result is put into |target_bitmap|, which is expected
+// to be initialized to the required size and type (SkBitmap::kA8_Config).
+// If |fit_to_range|, result is transfored linearly to fit 0-0xFF range.
+// Otherwise, data is clipped.
+// Returns true if the target has been computed.
+UI_EXPORT bool ApplyColorReduction(const SkBitmap& source_bitmap,
+                                   const gfx::Vector3dF& color_transform,
+                                   bool fit_to_range,
+                                   SkBitmap* target_bitmap);
+
+// Compute a monochrome image representing the principal color component of
+// the |source_bitmap|. The result is stored in |target_bitmap|, which must be
+// initialized to the required size and type (SkBitmap::kA8_Config).
+// Returns true if the conversion succeeded. Note that there might be legitimate
+// reasons for the process to fail even if all input was correct. This is a
+// condition the caller must be able to handle.
+UI_EXPORT bool ComputePrincipalComponentImage(const SkBitmap& source_bitmap,
+                                              SkBitmap* target_bitmap);
+
 }  // namespace color_utils
 
 #endif  // UI_GFX_COLOR_UTILS_H_