Extend gfx::canvas to allow DrawBitmapInt(..., alpha). This allows callers to

specify an alpha directly, rather than forcing them to bracket the call with

SaveLayerAlpha(alpha)
DrawBitmapInt()
Restore()

Should be 2x faster or better.
Review URL: https://codereview.chromium.org/11046020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@159948 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 10 insertions, 0 deletions

diff --git a/ui/gfx/canvas.cc b/ui/gfx/canvas.cc
index 1a87c73..c4f98d6 100644
--- a/ui/gfx/canvas.cc
+++ b/ui/gfx/canvas.cc
@@ -287,6 +287,12 @@ void Canvas::DrawImageInt(const gfx::ImageSkia& image, int x, int y) {
   DrawImageInt(image, x, y, paint);
 }
 
+void Canvas::DrawImageInt(const gfx::ImageSkia& image, int x, int y, uint8 a) {
+  SkPaint paint;
+  paint.setAlpha(a);
+  DrawImageInt(image, x, y, paint);
+}
+
 void Canvas::DrawImageInt(const gfx::ImageSkia& image,
                           int x, int y,
                           const SkPaint& paint) {
diff --git a/ui/gfx/canvas.h b/ui/gfx/canvas.h
index 700d7d2..8b039fe 100644
--- a/ui/gfx/canvas.h
+++ b/ui/gfx/canvas.h
@@ -262,6 +262,10 @@ class UI_EXPORT Canvas {
   // Thus, x is 2 pixels if canvas scale = 2 & |x| = 1.
   void DrawImageInt(const gfx::ImageSkia&, int x, int y);
 
+  // Helper for DrawImageInt(..., paint) that constructs a temporary paint and
+  // calls paint.setAlpha(alpha).
+  void DrawImageInt(const gfx::ImageSkia&, int x, int y, uint8 alpha);
+
   // Draws an image with the origin at the specified location, using the
   // specified paint. The upper left corner of the bitmap is rendered at the
   // specified location.