content/renderer/media/video_frame_compositor.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_FRAME_COMPOSITOR_H_
   6 #define CONTENT_RENDERER_MEDIA_VIDEO_FRAME_COMPOSITOR_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "cc/layers/video_frame_provider.h"
  11 #include "content/common/content_export.h"
  12 #include "ui/gfx/size.h"
  13
  14 namespace media {
  15 class VideoFrame;
  16 }
  17
  18 namespace content {
  19
  20 // VideoFrameCompositor handles incoming frames by notifying the compositor and
  21 // dispatching callbacks when detecting changes in video frames.
  22 //
  23 // Typical usage is to deliver ready-to-be-displayed video frames to
  24 // UpdateCurrentFrame() so that VideoFrameCompositor can take care of tracking
  25 // changes in video frames and firing callbacks as needed.
  26 //
  27 // VideoFrameCompositor must live on the same thread as the compositor.
  28 class CONTENT_EXPORT VideoFrameCompositor
  29     : NON_EXPORTED_BASE(public cc::VideoFrameProvider) {
  30  public:
  31   // |natural_size_changed_cb| is run with the new natural size of the video
  32   // frame whenever a change in natural size is detected. It is not called the
  33   // first time UpdateCurrentFrame() is called. Run on the same thread as the
  34   // caller of UpdateCurrentFrame().
  35   //
  36   // |opacity_changed_cb| is run when a change in opacity is detected. It *is*
  37   // called the first time UpdateCurrentFrame() is called. Run on the same
  38   // thread as the caller of UpdateCurrentFrame().
  39   //
  40   // TODO(scherkus): Investigate the inconsistency between the callbacks with
  41   // respect to why we don't call |natural_size_changed_cb| on the first frame.
  42   // I suspect it was for historical reasons that no longer make sense.
  43   VideoFrameCompositor(
  44       const base::Callback<void(gfx::Size)>& natural_size_changed_cb,
  45       const base::Callback<void(bool)>& opacity_changed_cb);
  46   virtual ~VideoFrameCompositor();
  47
  48   // cc::VideoFrameProvider implementation.
  49   virtual void SetVideoFrameProviderClient(
  50       cc::VideoFrameProvider::Client* client) OVERRIDE;
  51   virtual scoped_refptr<media::VideoFrame> GetCurrentFrame() OVERRIDE;
  52   virtual void PutCurrentFrame(
  53       const scoped_refptr<media::VideoFrame>& frame) OVERRIDE;
  54
  55   // Updates the current frame and notifies the compositor.
  56   void UpdateCurrentFrame(const scoped_refptr<media::VideoFrame>& frame);
  57
  58  private:
  59   base::Callback<void(gfx::Size)> natural_size_changed_cb_;
  60   base::Callback<void(bool)> opacity_changed_cb_;
  61
  62   cc::VideoFrameProvider::Client* client_;
  63
  64   scoped_refptr<media::VideoFrame> current_frame_;
  65
  66   DISALLOW_COPY_AND_ASSIGN(VideoFrameCompositor);
  67 };
  68
  69 }  // namespace content
  70
  71 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_FRAME_COMPOSITOR_H_