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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
NON_EXPORTED_BASE(public cc::VideoFrameProvider)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_
72