gecko-dev/dom/html/HTMLCanvasElement.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#if !defined(mozilla_dom_HTMLCanvasElement_h)
#define mozilla_dom_HTMLCanvasElement_h
#include "mozilla/Attributes.h"
#include "mozilla/WeakPtr.h"
#include "nsIDOMEventListener.h"
#include "nsIDOMHTMLCanvasElement.h"
#include "nsIObserver.h"
#include "nsGenericHTMLElement.h"
#include "nsGkAtoms.h"
#include "nsSize.h"
#include "nsError.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "mozilla/dom/CanvasRenderingContextHelper.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/layers/LayersTypes.h"
class nsICanvasRenderingContextInternal;
class nsITimerCallback;
namespace mozilla {
class WebGLContext;
namespace layers {
class AsyncCanvasRenderer;
class CanvasLayer;
class Image;
class Layer;
class LayerManager;
class SharedSurfaceTextureClient;
} // namespace layers
namespace gfx {
class SourceSurface;
class VRLayerChild;
} // namespace gfx
namespace dom {
class BlobCallback;
class CanvasCaptureMediaStream;
class File;
class HTMLCanvasPrintState;
class OffscreenCanvas;
class PrintCallback;
class RequestedFrameRefreshObserver;
// Listen visibilitychange and memory-pressure event and inform
// context when event is fired.
class HTMLCanvasElementObserver final : public nsIObserver
, public nsIDOMEventListener
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
NS_DECL_NSIDOMEVENTLISTENER
explicit HTMLCanvasElementObserver(HTMLCanvasElement* aElement);
void Destroy();
void RegisterVisibilityChangeEvent();
void UnregisterVisibilityChangeEvent();
void RegisterMemoryPressureEvent();
void UnregisterMemoryPressureEvent();
private:
~HTMLCanvasElementObserver();
HTMLCanvasElement* mElement;
};
/*
* FrameCaptureListener is used by captureStream() as a way of getting video
* frames from the canvas. On a refresh driver tick after something has been
* drawn to the canvas since the last such tick, all registered
* FrameCaptureListeners whose `mFrameCaptureRequested` equals `true`,
* will be given a copy of the just-painted canvas.
* All FrameCaptureListeners get the same copy.
*/
class FrameCaptureListener : public SupportsWeakPtr<FrameCaptureListener>
{
public:
MOZ_DECLARE_WEAKREFERENCE_TYPENAME(FrameCaptureListener)
FrameCaptureListener()
: mFrameCaptureRequested(false) {}
/*
* Called when a frame capture is desired on next paint.
*/
void RequestFrameCapture() { mFrameCaptureRequested = true; }
/*
* Indicates to the canvas whether or not this listener has requested a frame.
*/
bool FrameCaptureRequested() const { return mFrameCaptureRequested; }
/*
* Interface through which new video frames will be provided while
* `mFrameCaptureRequested` is `true`.
*/
virtual void NewFrame(already_AddRefed<layers::Image> aImage,
const TimeStamp& aTime) = 0;
protected:
virtual ~FrameCaptureListener() {}
bool mFrameCaptureRequested;
};
class HTMLCanvasElement final : public nsGenericHTMLElement,
public nsIDOMHTMLCanvasElement,
public CanvasRenderingContextHelper
{
enum {
DEFAULT_CANVAS_WIDTH = 300,
DEFAULT_CANVAS_HEIGHT = 150
};
typedef layers::AsyncCanvasRenderer AsyncCanvasRenderer;
typedef layers::CanvasLayer CanvasLayer;
typedef layers::Layer Layer;
typedef layers::LayerManager LayerManager;
public:
explicit HTMLCanvasElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLCanvasElement, canvas)
// nsISupports
NS_DECL_ISUPPORTS_INHERITED
// nsIDOMHTMLCanvasElement
NS_DECL_NSIDOMHTMLCANVASELEMENT
// CC
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLCanvasElement,
nsGenericHTMLElement)
// WebIDL
uint32_t Height()
{
return GetUnsignedIntAttr(nsGkAtoms::height, DEFAULT_CANVAS_HEIGHT);
}
void SetHeight(uint32_t aHeight, ErrorResult& aRv)
{
if (mOffscreenCanvas) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
SetUnsignedIntAttr(nsGkAtoms::height, aHeight, DEFAULT_CANVAS_HEIGHT, aRv);
}
uint32_t Width()
{
return GetUnsignedIntAttr(nsGkAtoms::width, DEFAULT_CANVAS_WIDTH);
}
void SetWidth(uint32_t aWidth, ErrorResult& aRv)
{
if (mOffscreenCanvas) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
SetUnsignedIntAttr(nsGkAtoms::width, aWidth, DEFAULT_CANVAS_WIDTH, aRv);
}
virtual already_AddRefed<nsISupports>
GetContext(JSContext* aCx, const nsAString& aContextId,
JS::Handle<JS::Value> aContextOptions,
ErrorResult& aRv) override;
void ToDataURL(JSContext* aCx, const nsAString& aType,
JS::Handle<JS::Value> aParams,
nsAString& aDataURL, CallerType aCallerType,
ErrorResult& aRv);
void ToBlob(JSContext* aCx,
BlobCallback& aCallback,
const nsAString& aType,
JS::Handle<JS::Value> aParams,
CallerType aCallerType,
ErrorResult& aRv);
OffscreenCanvas* TransferControlToOffscreen(ErrorResult& aRv);
bool MozOpaque() const
{
return GetBoolAttr(nsGkAtoms::moz_opaque);
}
void SetMozOpaque(bool aValue, ErrorResult& aRv)
{
if (mOffscreenCanvas) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
SetHTMLBoolAttr(nsGkAtoms::moz_opaque, aValue, aRv);
}
already_AddRefed<File> MozGetAsFile(const nsAString& aName,
const nsAString& aType,
CallerType aCallerType,
ErrorResult& aRv);
already_AddRefed<nsISupports> MozGetIPCContext(const nsAString& aContextId,
ErrorResult& aRv);
PrintCallback* GetMozPrintCallback() const;
void SetMozPrintCallback(PrintCallback* aCallback);
already_AddRefed<CanvasCaptureMediaStream>
CaptureStream(const Optional<double>& aFrameRate, ErrorResult& aRv);
/**
* Get the size in pixels of this canvas element
*/
nsIntSize GetSize();
/**
* Determine whether the canvas is write-only.
*/
bool IsWriteOnly();
/**
* Force the canvas to be write-only.
*/
void SetWriteOnly();
/**
* Notify that some canvas content has changed and the window may
* need to be updated. aDamageRect is in canvas coordinates.
*/
void InvalidateCanvasContent(const mozilla::gfx::Rect* aDamageRect);
/*
* Notify that we need to repaint the entire canvas, including updating of
* the layer tree.
*/
void InvalidateCanvas();
/*
* Get the number of contexts in this canvas, and request a context at
* an index.
*/
int32_t CountContexts ();
nsICanvasRenderingContextInternal *GetContextAtIndex (int32_t index);
/*
* Returns true if the canvas context content is guaranteed to be opaque
* across its entire area.
*/
bool GetIsOpaque();
virtual bool GetOpaqueAttr() override;
virtual already_AddRefed<gfx::SourceSurface> GetSurfaceSnapshot(bool* aPremultAlpha = nullptr);
/*
* Register a FrameCaptureListener with this canvas.
* The canvas hooks into the RefreshDriver while there are
* FrameCaptureListeners registered.
* The registered FrameCaptureListeners are stored as WeakPtrs, thus it's the
* caller's responsibility to keep them alive. Once a registered
* FrameCaptureListener is destroyed it will be automatically deregistered.
*/
nsresult RegisterFrameCaptureListener(FrameCaptureListener* aListener);
/*
* Returns true when there is at least one registered FrameCaptureListener
* that has requested a frame capture.
*/
bool IsFrameCaptureRequested() const;
/*
* Processes destroyed FrameCaptureListeners and removes them if necessary.
* Should there be none left, the FrameRefreshObserver will be unregistered.
*/
void ProcessDestroyedFrameListeners();
/*
* Called by the RefreshDriver hook when a frame has been captured.
* Makes a copy of the provided surface and hands it to all
* FrameCaptureListeners having requested frame capture.
*/
void SetFrameCapture(already_AddRefed<gfx::SourceSurface> aSurface,
const TimeStamp& aTime);
virtual bool ParseAttribute(int32_t aNamespaceID,
nsIAtom* aAttribute,
const nsAString& aValue,
nsAttrValue& aResult) override;
nsChangeHint GetAttributeChangeHint(const nsIAtom* aAttribute, int32_t aModType) const override;
// SetAttr override. C++ is stupid, so have to override both
// overloaded methods.
nsresult SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
const nsAString& aValue, bool aNotify)
{
return SetAttr(aNameSpaceID, aName, nullptr, aValue, aNotify);
}
virtual nsresult SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
nsIAtom* aPrefix, const nsAString& aValue,
bool aNotify) override;
virtual nsresult UnsetAttr(int32_t aNameSpaceID, nsIAtom* aName,
bool aNotify) override;
virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const override;
nsresult CopyInnerTo(mozilla::dom::Element* aDest);
virtual nsresult GetEventTargetParent(
mozilla::EventChainPreVisitor& aVisitor) override;
/*
* Helpers called by various users of Canvas
*/
already_AddRefed<Layer> GetCanvasLayer(nsDisplayListBuilder* aBuilder,
Layer *aOldLayer,
LayerManager *aManager);
// Should return true if the canvas layer should always be marked inactive.
// We should return true here if we can't do accelerated compositing with
// a non-BasicCanvasLayer.
bool ShouldForceInactiveLayer(LayerManager *aManager);
// Call this whenever we need future changes to the canvas
// to trigger fresh invalidation requests. This needs to be called
// whenever we render the canvas contents to the screen, or whenever we
// take a snapshot of the canvas that needs to be "live" (e.g. -moz-element).
void MarkContextClean();
// Call this after capturing a frame, so we can avoid unnecessary surface
// copies for future frames when no drawing has occurred.
void MarkContextCleanForFrameCapture();
// Starts returning false when something is drawn.
bool IsContextCleanForFrameCapture();
nsresult GetContext(const nsAString& aContextId, nsISupports** aContext);
layers::LayersBackend GetCompositorBackendType() const;
void OnVisibilityChange();
void OnMemoryPressure();
static void SetAttrFromAsyncCanvasRenderer(AsyncCanvasRenderer *aRenderer);
static void InvalidateFromAsyncCanvasRenderer(AsyncCanvasRenderer *aRenderer);
void StartVRPresentation();
void StopVRPresentation();
already_AddRefed<layers::SharedSurfaceTextureClient> GetVRFrame();
protected:
virtual ~HTMLCanvasElement();
virtual JSObject* WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
virtual nsIntSize GetWidthHeight() override;
virtual already_AddRefed<nsICanvasRenderingContextInternal>
CreateContext(CanvasContextType aContextType) override;
nsresult ExtractData(nsAString& aType,
const nsAString& aOptions,
nsIInputStream** aStream);
nsresult ToDataURLImpl(JSContext* aCx,
const nsAString& aMimeType,
const JS::Value& aEncoderOptions,
nsAString& aDataURL);
nsresult MozGetAsFileImpl(const nsAString& aName,
const nsAString& aType,
File** aResult);
void CallPrintCallback();
AsyncCanvasRenderer* GetAsyncCanvasRenderer();
bool mResetLayer;
RefPtr<HTMLCanvasElement> mOriginalCanvas;
RefPtr<PrintCallback> mPrintCallback;
RefPtr<HTMLCanvasPrintState> mPrintState;
nsTArray<WeakPtr<FrameCaptureListener>> mRequestedFrameListeners;
RefPtr<RequestedFrameRefreshObserver> mRequestedFrameRefreshObserver;
RefPtr<AsyncCanvasRenderer> mAsyncCanvasRenderer;
RefPtr<OffscreenCanvas> mOffscreenCanvas;
RefPtr<HTMLCanvasElementObserver> mContextObserver;
bool mVRPresentationActive;
public:
// Record whether this canvas should be write-only or not.
// We set this when script paints an image from a different origin.
// We also transitively set it when script paints a canvas which
// is itself write-only.
bool mWriteOnly;
bool IsPrintCallbackDone();
void HandlePrintCallback(nsPresContext::nsPresContextType aType);
nsresult DispatchPrintCallback(nsITimerCallback* aCallback);
void ResetPrintCallback();
HTMLCanvasElement* GetOriginalCanvas();
CanvasContextType GetCurrentContextType() {
return mCurrentContextType;
}
};
class HTMLCanvasPrintState final : public nsWrapperCache
{
public:
HTMLCanvasPrintState(HTMLCanvasElement* aCanvas,
nsICanvasRenderingContextInternal* aContext,
nsITimerCallback* aCallback);
nsISupports* Context() const;
void Done();
void NotifyDone();
bool mIsDone;
NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(HTMLCanvasPrintState)
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(HTMLCanvasPrintState)
virtual JSObject* WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto) override;
HTMLCanvasElement* GetParentObject()
{
return mCanvas;
}
private:
~HTMLCanvasPrintState();
bool mPendingNotify;
protected:
RefPtr<HTMLCanvasElement> mCanvas;
nsCOMPtr<nsICanvasRenderingContextInternal> mContext;
nsCOMPtr<nsITimerCallback> mCallback;
};
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_HTMLCanvasElement_h */