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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 "StreamTracks.h"
class nsIPrincipal;
namespace mozilla {
class DOMMediaStream;
class MediaStreamListener;
class SourceMediaStream;
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()
* v
* ___________________
* | StreamListener |
* ---------------------------------------| (All image access |----------------
* === MediaStreamGraph Thread === | Mutex Guarded) |
* |___________________|
* ^ |
* NotifyPull() | | AppendToTrack()
* | v
* ___________________________
* | |
* | MSG / SourceMediaStream |
* |___________________________|
* ----------------------------------------------------------------------------
*/
/*
* 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(SourceMediaStream* aSourceStream,
const TrackID& aTrackId,
const PrincipalHandle& aPrincipalHandle);
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(OutputStreamDriver);
/*
* Sub classes can SetImage() to update the image being appended to the
* output stream. It will be appended on the next NotifyPull from MSG.
*/
void SetImage(const RefPtr<layers::Image>& aImage);
/*
* Makes sure any internal resources this driver is holding that may create
* reference cycles are released.
*/
virtual void Forget() {}
protected:
virtual ~OutputStreamDriver();
class StreamListener;
private:
RefPtr<SourceMediaStream> mSourceStream;
RefPtr<StreamListener> mStreamListener;
};
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, const TrackID& aTrackId,
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();
/**
* Create a CanvasCaptureMediaStream whose underlying stream is a SourceMediaStream.
*/
static already_AddRefed<CanvasCaptureMediaStream>
CreateSourceStream(nsPIDOMWindowInner* aWindow,
HTMLCanvasElement* aCanvas);
protected:
~CanvasCaptureMediaStream();
private:
RefPtr<HTMLCanvasElement> mCanvas;
RefPtr<OutputStreamDriver> mOutputStreamDriver;
};
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_CanvasCaptureMediaStream_h_ */
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