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// Copyright (c) 2012 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.
#ifndef CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_FRAME_SUBSCRIBER_H_
#define CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_FRAME_SUBSCRIBER_H_
#include "base/callback.h"
#include "base/time/time.h"
namespace gfx {
class Rect;
class Size;
} // namespace gfx
namespace media {
class VideoFrame;
} // namespace media
namespace content {
// Defines an interface for listening to events of frame presentation and to
// instruct the platform layer (i.e. RenderWidgetHostView) to copy a frame.
//
// Further processing is possible (e.g. scale and color space conversion)
// through this interface. See ShouldCaptureFrame() for details.
//
// It is platform dependent which thread this object lives on, but it is
// guaranteed to be used on a single thread.
class RenderWidgetHostViewFrameSubscriber {
public:
virtual ~RenderWidgetHostViewFrameSubscriber() {}
// Called when a captured frame is available or the frame is no longer
// needed by the platform layer.
//
// If |frame_captured| is true then frame provided contains valid content and
// |timestamp| is the time when the frame was painted.
//
// If |frame_captured| is false then the content in frame provided is
// invalid. There was an error during the process of frame capture or the
// platform layer is shutting down. |timestamp| is also invalid in this case.
typedef base::Callback<void(base::TimeTicks /* timestamp */,
bool /* frame_captured */)> DeliverFrameCallback;
// Called when a new frame is going to be presented at time
// |present_time| with |damage_rect| being the region of the frame that has
// changed since the last frame. The implementation decides whether the
// current frame should be captured or not.
//
// Return true if the current frame should be captured. If so, |storage|
// will be set to hold an appropriately sized and allocated buffer into which
// to copy the frame. The platform presenter will perform scaling and color
// space conversion to fit into the output frame.
//
// Destination format is determined by |storage|, currently only
// media::VideoFrame::YV12 is supported. Platform layer will perform color
// space conversion if needed.
//
// When the frame is available |callback| will be called. It is up to the
// platform layer to decide when to deliver a captured frame.
//
// Return false if the current frame should not be captured.
virtual bool ShouldCaptureFrame(const gfx::Rect& damage_rect,
base::TimeTicks present_time,
scoped_refptr<media::VideoFrame>* storage,
DeliverFrameCallback* callback) = 0;
};
} // namespace content
#endif // CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_FRAME_SUBSCRIBER_H_