Add library support for subpixel rendering of images during Resize().

BUG=34809
TEST=No test since inactive by default. For a very manual test, modify Resize()
to only call the subpixel variant. Then go to your favorite web page (with some
image) and choose Zoom > Smaller

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@40292 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 15 insertions, 1 deletions

diff --git a/skia/ext/image_operations.h b/skia/ext/image_operations.h
index e9f448b..0d92d83 100644
--- a/skia/ext/image_operations.h
+++ b/skia/ext/image_operations.h
@@ -23,6 +23,10 @@ class ImageOperations {
     // 3-cycle Lanczos filter. This is tall in the middle, goes negative on
     // each side, then oscillates 2 more times. It gives nice sharp edges.
     RESIZE_LANCZOS3,
+
+    // Lanczos filter + subpixel interpolation. If subpixel rendering is not
+    // appropriate we automatically fall back to Lanczos.
+    RESIZE_SUBPIXEL,
   };
 
   // Resizes the given source bitmap using the specified resize method, so that
@@ -46,9 +50,19 @@ class ImageOperations {
 
  private:
   ImageOperations();  // Class for scoping only.
+
+  // Supports all methods except RESIZE_SUBPIXEL.
+  static SkBitmap ResizeBasic(const SkBitmap& source,
+                              ResizeMethod method,
+                              int dest_width, int dest_height,
+                              const SkIRect& dest_subset);
+
+  // Subpixel renderer.
+  static SkBitmap ResizeSubpixel(const SkBitmap& source,
+                                 int dest_width, int dest_height,
+                                 const SkIRect& dest_subset);
 };
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_IMAGE_OPERATIONS_H_
-