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

webkit/glue/media/video_renderer_impl.cc

 // Copyright (c) 2009 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.
 
 #include "media/base/buffers.h"
 #include "media/base/yuv_convert.h"
 #include "webkit/glue/media/video_renderer_impl.h"
 #include "webkit/glue/webmediaplayer_impl.h"
 
 namespace webkit_glue {
@@ skipping 53 matching lines @@
       FastPaint(video_frame, canvas, dest_rect);
     } else {
       SlowPaint(video_frame, canvas, dest_rect);
     }
     video_frame = NULL;
   }
 }
 
 // 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();
 
     // Get the boundary of the device.
     SkIRect device_rect;
     device->getBounds(&device_rect);
 
     // Get the pixel config of the device.
     const SkBitmap::Config config = device->config();
     // Get the total clip rect associated with the canvas.
@@ skipping 178 matching lines @@
     // Transform destination rect to local coordinates.
     SkRect transformed_rect;
     SkRect skia_dest_rect;
     skia_dest_rect.iset(src_rect.x(), src_rect.y(),
                         src_rect.right(), src_rect.bottom());
     matrix.mapRect(&transformed_rect, skia_dest_rect);
     transformed_rect.round(dest_rect);
 }
 
 }  // namespace webkit_glue