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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_dom_CanvasCaptureMediaStream_h_
#define mozilla_dom_CanvasCaptureMediaStream_h_
#include "DOMMediaStream.h"
#include "mozilla/dom/HTMLCanvasElement.h"
#include "PrincipalHandle.h"
class nsIPrincipal;
namespace mozilla {
class DOMMediaStream;
class SourceMediaTrack;
namespace layers {
class Image;
} // namespace layers
namespace dom {
class CanvasCaptureMediaStream;
class HTMLCanvasElement;
class OutputStreamFrameListener;
/*
* The CanvasCaptureMediaStream is a MediaStream subclass that provides a video
* track containing frames from a canvas. See an architectural overview below.
*
* ----------------------------------------------------------------------------
* === Main Thread === __________________________
* | |
* | CanvasCaptureMediaStream |
* |__________________________|
* |
* | RequestFrame()
* v
* ________________________
* ________ FrameCaptureRequested? | |
* | | ------------------------> | OutputStreamDriver |
* | Canvas | SetFrameCapture() | (FrameCaptureListener) |
* |________| ------------------------> |________________________|
* |
* | SetImage() -
* | AppendToTrack()
* |
* v
* __________________________
* | |
* | MTG / SourceMediaTrack |
* |__________________________|
* ----------------------------------------------------------------------------
*/
/*
* Base class for drivers of the output stream.
* It is up to each sub class to implement the NewFrame() callback of
* FrameCaptureListener.
*/
class OutputStreamDriver : public FrameCaptureListener {
public:
OutputStreamDriver(SourceMediaTrack* aSourceStream,
const PrincipalHandle& aPrincipalHandle);
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(OutputStreamDriver);
/*
* Called from js' requestFrame() when it wants the next painted frame to be
* explicitly captured.
*/
virtual void RequestFrameCapture() = 0;
/*
* Sub classes can SetImage() to update the image being appended to the
* output stream. It will be appended on the next NotifyPull from MTG.
*/
void SetImage(RefPtr<layers::Image>&& aImage, const TimeStamp& aTime);
/*
* Ends the track in mSourceStream when we know there won't be any more images
* requested for it.
*/
void EndTrack();
const RefPtr<SourceMediaTrack> mSourceStream;
const PrincipalHandle mPrincipalHandle;
protected:
virtual ~OutputStreamDriver();
};
class CanvasCaptureMediaStream : public DOMMediaStream {
public:
CanvasCaptureMediaStream(nsPIDOMWindowInner* aWindow,
HTMLCanvasElement* aCanvas);
NS_DECL_ISUPPORTS_INHERITED
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CanvasCaptureMediaStream,
DOMMediaStream)
nsresult Init(const dom::Optional<double>& aFPS, nsIPrincipal* aPrincipal);
JSObject* WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) override;
// WebIDL
HTMLCanvasElement* Canvas() const { return mCanvas; }
void RequestFrame();
dom::FrameCaptureListener* FrameCaptureListener();
/**
* Stops capturing for this stream at mCanvas.
*/
void StopCapture();
SourceMediaTrack* GetSourceStream() const;
protected:
~CanvasCaptureMediaStream();
private:
RefPtr<HTMLCanvasElement> mCanvas;
RefPtr<OutputStreamDriver> mOutputStreamDriver;
};
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_CanvasCaptureMediaStream_h_ */
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