VideoLayerImpl: subtract 1 from visible size when calculating tex stretch.

cc/layers/video_layer_impl.cc

 // Copyright 2011 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 "cc/layers/video_layer_impl.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 167 matching lines @@
   Occlusion occlusion_in_video_space =
       draw_properties()
           .occlusion_in_content_space.GetOcclusionWithGivenDrawTransform(
               transform);
   gfx::Rect visible_quad_rect =
       occlusion_in_video_space.GetUnoccludedContentRect(quad_rect);
   if (visible_quad_rect.IsEmpty())
     return;
 
   // Pixels for macroblocked formats.
-  const float tex_width_scale =
-      static_cast<float>(visible_rect.width()) / coded_size.width();
-  const float tex_height_scale =
-      static_cast<float>(visible_rect.height()) / coded_size.height();
+  float visible_width = static_cast<float>(visible_rect.width());

[enne (OOO), 2016/02/01 21:00:03]

Please leave these as ints and put the static cast down on tex_width_scale.

[wuchengli, 2016/02/02 05:37:27]

Done.

+  float visible_height = static_cast<float>(visible_rect.height());
+  // To prevent sampling outside the visible rect, stretch the video if needed.
+  if (visible_rect.width() < coded_size.width() && visible_rect.width() > 1)
+    visible_width -= 1.f;

[wuchengli, 2016/02/01 03:29:51]

Do we want this for RGB_RESOURCE only or for all frame resource type?

[enne (OOO), 2016/02/01 21:00:03]

If you do this here, it will be for all formats but YUV (just because of how the
code works).  You might want to fix that as well?

If it's the case that textures outside of the visible rect are garbage, then it
probably should be scaled for all formats in this case.

[wuchengli, 2016/02/02 05:37:27]

Done.

+  if (visible_rect.height() < coded_size.height() && visible_rect.height() > 1)
+    visible_height -= 1.f;
+  const float tex_width_scale = visible_width / coded_size.width();
+  const float tex_height_scale = visible_height / coded_size.height();
 
   switch (frame_resource_type_) {
     // TODO(danakj): Remove this, hide it in the hardware path.
     case VideoFrameExternalResources::SOFTWARE_RESOURCE: {
       DCHECK_EQ(frame_resources_.size(), 0u);
       DCHECK_EQ(software_resources_.size(), 1u);
       if (software_resources_.size() < 1u)
         break;
       bool premultiplied_alpha = true;
       gfx::PointF uv_top_left(0.f, 0.f);
@@ skipping 197 matching lines @@
 void VideoLayerImpl::SetNeedsRedraw() {
   SetUpdateRect(gfx::UnionRects(update_rect(), gfx::Rect(bounds())));
   layer_tree_impl()->SetNeedsRedraw();
 }
 
 const char* VideoLayerImpl::LayerTypeAsString() const {
   return "cc::VideoLayerImpl";
 }
 
 }  // namespace cc