Implement remaining SkBitmapOperations as ImageSkiaOperations

ui/gfx/image/image_skia_operations.h

 // Copyright (c) 2012 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 UI_GFX_IMAGESKIA_OPERATIONS_H_
 #define UI_GFX_IMAGESKIA_OPERATIONS_H_
 
 #include "base/gtest_prod_util.h"
 #include "ui/base/ui_export.h"
-#include "ui/gfx/size.h"
+#include "ui/gfx/color_utils.h"
 
 namespace gfx {
 class ImageSkia;
+class Rect;
+class Size;
 
 class UI_EXPORT ImageSkiaOperations {
  public:
   // Create an image that is a blend of two others. The alpha argument
   // specifies the opacity of the second imag. The provided image must
   // use the kARGB_8888_Config config and be of equal dimensions.
   static ImageSkia CreateBlendedImage(const ImageSkia& first,
                                       const ImageSkia& second,
                                       double alpha);
 
   // Create an image that is the original image masked out by the mask defined
   // in the alpha image. The images must use the kARGB_8888_Config config and
   // be of equal dimensions.
   static ImageSkia CreateMaskedImage(const ImageSkia& first,
                                      const ImageSkia& alpha);
 
   // Create an image that is cropped from another image. This is special
   // because it tiles the original image, so your coordinates can extend
   // outside the bounds of the original image.
   static ImageSkia CreateTiledImage(const ImageSkia& image,
                                     int src_x, int src_y,
                                     int dst_w, int dst_h);
 
+  // We create a button background image by compositing the color and image

[sky, 2012/07/16 21:23:40]

We create -> Creates

+  // together, then applying the mask. This is a highly specialized composite
+  // operation that is the equivalent of drawing a background in |color|,
+  // tiling |image| over the top, and then masking the result out with |mask|.
+  // The images must use kARGB_8888_Config config.
+  static ImageSkia CreateButtonBackground(SkColor color,
+                                          const gfx::ImageSkia& image,
+                                          const gfx::ImageSkia& mask);
+
+  // Returns an image which is a subset of |image| with bounds |subset_bounds|.
+  // |image| cannot have image reps of |kA1_Config| config.

[sky, 2012/07/16 21:23:40]

What does this second line mean?
kAll_Config?

[pkotwicz, 2012/07/17 01:15:41]

The config of the bitmaps contained by the ImageSkia on which ExtractSubset
operates on cannot be kA1_Config. 
kA1_Config is a config simillar to kARGB_8888_Config. SkBitmap::extractSubset is
not supported for kA1_Config.

[sky, 2012/07/20 23:21:25]

Make the comment clearer than. Right now it is confusing.

+  static ImageSkia ExtractSubset(const gfx::ImageSkia& image,
+                                 const gfx::Rect& subset_bounds);
+
   // Creates an image that resizes |source| to given |target_size_in_dip|.
   // The resize operation occurs synchronously at the time that the desired
   // scale factor is known (either GetRepresentation is called or the image
   // is painted).
   // As |source| is cached for the lifetime of this object and the resize
   // operation will most likely be performed on the UI thread, the maximum
   // supported DIP size of |source| and |target_size_in_dip| is 64x64 DIP.
   // Resizing larger bitmaps should be done more explicitly using
   // ImageOperations::Resize.
   static ImageSkia CreateResizedImage(const ImageSkia& source,
                                       const Size& target_size_in_dip);
 
  private:
   ImageSkiaOperations();  // Class for scoping only.
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_IMAGESKIA_OPERATIONS_H_