Optimize to copy from rotated video to canvas.

media/filters/skcanvas_video_renderer.cc

Index: media/filters/skcanvas_video_renderer.cc
diff --git a/media/filters/skcanvas_video_renderer.cc b/media/filters/skcanvas_video_renderer.cc
index 9bdd393e56c31c368b926de08be9e4e42a993382..d3b7876096bad8ad9da24c8438ca283da3779e4e 100644
--- a/media/filters/skcanvas_video_renderer.cc
+++ b/media/filters/skcanvas_video_renderer.cc
@@ -328,41 +328,39 @@ void SkCanvasVideoRenderer::Paint(const scoped_refptr<VideoFrame>& video_frame,
       NOTREACHED();
     }
 
-    // TODO(rileya): Perform this rotation on the canvas, rather than allocating
-    // a new bitmap and copying.
-    switch (video_rotation) {
-      case VIDEO_ROTATION_0:
-        break;
-      case VIDEO_ROTATION_90:
-        last_frame_ = SkBitmapOperations::Rotate(
-            last_frame_, SkBitmapOperations::ROTATION_90_CW);
-        break;
-      case VIDEO_ROTATION_180:
-        last_frame_ = SkBitmapOperations::Rotate(
-            last_frame_, SkBitmapOperations::ROTATION_180_CW);
-        break;
-      case VIDEO_ROTATION_270:
-        last_frame_ = SkBitmapOperations::Rotate(
-            last_frame_, SkBitmapOperations::ROTATION_270_CW);
-        break;
-    }
-
-    // We copied the frame into a new bitmap and threw out the old one, so we
-    // no longer have a |generator_| around. This should be removed when the
-    // above TODO is addressed.
-    if (video_rotation != VIDEO_ROTATION_0)
-      generator_ = NULL;
-
     last_frame_timestamp_ = video_frame->timestamp();
   } else if (generator_) {
     generator_->set_frame(video_frame);
   }
 
   paint.setXfermodeMode(mode);
-
-  // Paint using |last_frame_|.
   paint.setFilterLevel(SkPaint::kLow_FilterLevel);
-  canvas->drawBitmapRect(last_frame_, NULL, dest, &paint);
+
+  SkScalar angle = SkFloatToScalar(0.0f);
+  switch (video_rotation) {
+    case VIDEO_ROTATION_0:
+      break;
+    case VIDEO_ROTATION_90:
+      angle = SkFloatToScalar(90.0f);
+      break;
+    case VIDEO_ROTATION_180:
+      angle = SkFloatToScalar(180.0f);
+      break;
+    case VIDEO_ROTATION_270:
+      angle = SkFloatToScalar(270.0f);
+      break;
+  }
+  if (video_rotation != VIDEO_ROTATION_0) {
+    canvas->save();
+    canvas->translate(SkFloatToScalar(dest_rect.width() * 0.5f),
+                     SkFloatToScalar(dest_rect.height() * 0.5f));
+    canvas->rotate(angle);
+    canvas->translate(-SkFloatToScalar(dest_rect.width() * 0.5f),
+                     -SkFloatToScalar(dest_rect.height() * 0.5f));
+  }
+  canvas->drawBitmap(last_frame_, 0, 0, &paint);
+  if (video_rotation != VIDEO_ROTATION_0)
+    canvas->restore();

[dshwang, 2014/10/02 19:17:30]

This code is almost copy&paste from
https://code.google.com/p/chromium/codesearch#chromium/src/ui/gfx/skbitmap_op...

   canvas->flush();
 }