Fixing a bug that <video> is not rendered if clipped/mirrored

Since we are not using the YUV->RGB code to perform
fast flipping and mirroring. Use FastPaint to handle
flipping and mirroring was wrong. There's no plan
to support fast flipping and mirroring in the short
future so fall back to SlowPaint for this case.

Review URL: http://codereview.chromium.org/126093

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18403 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 13 insertions, 4 deletions

diff --git a/webkit/glue/media/video_renderer_impl.cc b/webkit/glue/media/video_renderer_impl.cc
index 2b6720f..52a01af1 100644
--- a/webkit/glue/media/video_renderer_impl.cc
+++ b/webkit/glue/media/video_renderer_impl.cc
@@ -71,14 +71,23 @@ void VideoRendererImpl::Paint(skia::PlatformCanvas* canvas,
 
 // CanFastPaint is a helper method to determine the conditions for fast
 // painting. The conditions are:
-//   1. No skew in canvas matrix.
-//   2. Canvas has pixel format ARGB8888.
-//   3. Canvas is opaque.
+// 1. No skew in canvas matrix.
+// 2. No flipping nor mirroring.
+// 3. Canvas has pixel format ARGB8888.
+// 4. Canvas is opaque.
+// TODO(hclam): The fast paint method should support flipping and mirroring.
+// Disable the flipping and mirroring checks once we have it.
 bool VideoRendererImpl::CanFastPaint(skia::PlatformCanvas* canvas,
                                      const gfx::Rect& dest_rect) {
   const SkMatrix& total_matrix = canvas->getTotalMatrix();
+  // Perform the following checks here:
+  // 1. Check for skewing factors of the transformation matrix. They should be
+  //    zero.
+  // 2. Check for mirroring and flipping. Make sure they are greater than zero.
   if (SkScalarNearlyZero(total_matrix.getSkewX()) &&
-      SkScalarNearlyZero(total_matrix.getSkewY())) {
+      SkScalarNearlyZero(total_matrix.getSkewY()) &&
+      total_matrix.getScaleX() > 0 &&
+      total_matrix.getScaleY() > 0) {
     // Get the properties of the SkDevice and the clip rect.
     SkDevice* device = canvas->getDevice();