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-rw-r--r--dom/html/HTMLCanvasElement.cpp1367
1 files changed, 1367 insertions, 0 deletions
diff --git a/dom/html/HTMLCanvasElement.cpp b/dom/html/HTMLCanvasElement.cpp
new file mode 100644
index 0000000000..119a6cfcee
--- /dev/null
+++ b/dom/html/HTMLCanvasElement.cpp
@@ -0,0 +1,1367 @@
+/* -*- 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/. */
+
+#include "mozilla/dom/HTMLCanvasElement.h"
+
+#include "ImageEncoder.h"
+#include "jsapi.h"
+#include "jsfriendapi.h"
+#include "MediaTrackGraph.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Base64.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/dom/CanvasCaptureMediaStream.h"
+#include "mozilla/dom/CanvasRenderingContext2D.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/GeneratePlaceholderCanvasData.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/dom/HTMLCanvasElementBinding.h"
+#include "mozilla/dom/VideoStreamTrack.h"
+#include "mozilla/dom/MouseEvent.h"
+#include "mozilla/dom/OffscreenCanvas.h"
+#include "mozilla/dom/OffscreenCanvasDisplayHelper.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/layers/CanvasRenderer.h"
+#include "mozilla/layers/WebRenderCanvasRenderer.h"
+#include "mozilla/layers/WebRenderUserData.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/StaticPrefs_privacy.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/webgpu/CanvasContext.h"
+#include "nsAttrValueInlines.h"
+#include "nsContentUtils.h"
+#include "nsDisplayList.h"
+#include "nsDOMJSUtils.h"
+#include "nsITimer.h"
+#include "nsJSUtils.h"
+#include "nsLayoutUtils.h"
+#include "nsMathUtils.h"
+#include "nsNetUtil.h"
+#include "nsRefreshDriver.h"
+#include "nsStreamUtils.h"
+#include "ActiveLayerTracker.h"
+#include "CanvasUtils.h"
+#include "VRManagerChild.h"
+#include "ClientWebGLContext.h"
+#include "WindowRenderer.h"
+
+using namespace mozilla::layers;
+using namespace mozilla::gfx;
+
+NS_IMPL_NS_NEW_HTML_ELEMENT(Canvas)
+
+namespace mozilla::dom {
+
+class RequestedFrameRefreshObserver : public nsARefreshObserver {
+ NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RequestedFrameRefreshObserver, override)
+
+ public:
+ RequestedFrameRefreshObserver(HTMLCanvasElement* const aOwningElement,
+ nsRefreshDriver* aRefreshDriver,
+ bool aReturnPlaceholderData)
+ : mRegistered(false),
+ mReturnPlaceholderData(aReturnPlaceholderData),
+ mOwningElement(aOwningElement),
+ mRefreshDriver(aRefreshDriver),
+ mWatchManager(this, AbstractThread::MainThread()),
+ mPendingThrottledCapture(false) {
+ MOZ_ASSERT(mOwningElement);
+ }
+
+ static already_AddRefed<DataSourceSurface> CopySurface(
+ const RefPtr<SourceSurface>& aSurface, bool aReturnPlaceholderData) {
+ RefPtr<DataSourceSurface> data = aSurface->GetDataSurface();
+ if (!data) {
+ return nullptr;
+ }
+
+ DataSourceSurface::ScopedMap read(data, DataSourceSurface::READ);
+ if (!read.IsMapped()) {
+ return nullptr;
+ }
+
+ RefPtr<DataSourceSurface> copy = Factory::CreateDataSourceSurfaceWithStride(
+ data->GetSize(), data->GetFormat(), read.GetStride());
+ if (!copy) {
+ return nullptr;
+ }
+
+ DataSourceSurface::ScopedMap write(copy, DataSourceSurface::WRITE);
+ if (!write.IsMapped()) {
+ return nullptr;
+ }
+
+ MOZ_ASSERT(read.GetStride() == write.GetStride());
+ MOZ_ASSERT(data->GetSize() == copy->GetSize());
+ MOZ_ASSERT(data->GetFormat() == copy->GetFormat());
+
+ if (aReturnPlaceholderData) {
+ auto size = write.GetStride() * copy->GetSize().height;
+ auto* data = write.GetData();
+ GeneratePlaceholderCanvasData(size, data);
+ } else {
+ memcpy(write.GetData(), read.GetData(),
+ write.GetStride() * copy->GetSize().height);
+ }
+
+ return copy.forget();
+ }
+
+ void SetReturnPlaceholderData(bool aReturnPlaceholderData) {
+ mReturnPlaceholderData = aReturnPlaceholderData;
+ }
+
+ void NotifyCaptureStateChange() {
+ if (mPendingThrottledCapture) {
+ return;
+ }
+
+ if (!mOwningElement) {
+ return;
+ }
+
+ Watchable<FrameCaptureState>* captureState =
+ mOwningElement->GetFrameCaptureState();
+ if (!captureState) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: No capture state"_ns);
+ return;
+ }
+
+ if (captureState->Ref() == FrameCaptureState::CLEAN) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: CLEAN"_ns);
+ return;
+ }
+
+ if (!mRefreshDriver) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: no refresh driver"_ns);
+ return;
+ }
+
+ if (!mRefreshDriver->IsThrottled()) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: not throttled"_ns);
+ return;
+ }
+
+ TimeStamp now = TimeStamp::Now();
+ TimeStamp next =
+ mLastCaptureTime.IsNull()
+ ? now
+ : mLastCaptureTime + TimeDuration::FromMilliseconds(
+ nsRefreshDriver::DefaultInterval());
+ if (mLastCaptureTime.IsNull() || next <= now) {
+ AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "CaptureFrame direct while throttled"_ns);
+ CaptureFrame(now);
+ return;
+ }
+
+ nsCString str;
+ if (profiler_thread_is_being_profiled_for_markers()) {
+ str.AppendPrintf("Delaying CaptureFrame by %.2fms",
+ (next - now).ToMilliseconds());
+ }
+ AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {}, str);
+
+ mPendingThrottledCapture = true;
+ AbstractThread::MainThread()->DelayedDispatch(
+ NS_NewRunnableFunction(
+ __func__,
+ [this, self = RefPtr<RequestedFrameRefreshObserver>(this), next] {
+ mPendingThrottledCapture = false;
+ AUTO_PROFILER_MARKER_TEXT(
+ "Canvas CaptureStream", MEDIA_RT, {},
+ "CaptureFrame after delay while throttled"_ns);
+ CaptureFrame(next);
+ }),
+ // next >= now, so this is a guard for (next - now) flooring to 0.
+ std::max<uint32_t>(
+ 1, static_cast<uint32_t>((next - now).ToMilliseconds())));
+ }
+
+ void WillRefresh(TimeStamp aTime) override {
+ AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "CaptureFrame by refresh driver"_ns);
+
+ CaptureFrame(aTime);
+ }
+
+ void CaptureFrame(TimeStamp aTime) {
+ MOZ_ASSERT(NS_IsMainThread());
+
+ if (!mOwningElement) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: no owning element"_ns);
+ return;
+ }
+
+ if (mOwningElement->IsWriteOnly()) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: write only"_ns);
+ return;
+ }
+
+ if (auto* captureStateWatchable = mOwningElement->GetFrameCaptureState();
+ captureStateWatchable &&
+ *captureStateWatchable == FrameCaptureState::CLEAN) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: CLEAN"_ns);
+ return;
+ }
+
+ // Mark the context already now, since if the frame capture state is DIRTY
+ // and we catch an early return below (not marking it CLEAN), the next draw
+ // will not trigger a capture state change from the
+ // Watchable<FrameCaptureState>.
+ mOwningElement->MarkContextCleanForFrameCapture();
+
+ mOwningElement->ProcessDestroyedFrameListeners();
+
+ if (!mOwningElement->IsFrameCaptureRequested(aTime)) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: no capture requested"_ns);
+ return;
+ }
+
+ RefPtr<SourceSurface> snapshot;
+ {
+ AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "GetSnapshot"_ns);
+ snapshot = mOwningElement->GetSurfaceSnapshot(nullptr);
+ if (!snapshot) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: snapshot failed"_ns);
+ return;
+ }
+ }
+
+ RefPtr<DataSourceSurface> copy;
+ {
+ AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "CopySurface"_ns);
+ copy = CopySurface(snapshot, mReturnPlaceholderData);
+ if (!copy) {
+ PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
+ "Abort: copy failed"_ns);
+ return;
+ }
+ }
+
+ nsCString str;
+ if (profiler_thread_is_being_profiled_for_markers()) {
+ TimeDuration sinceLast =
+ aTime - (mLastCaptureTime.IsNull() ? aTime : mLastCaptureTime);
+ str.AppendPrintf("Forwarding captured frame %.2fms after last",
+ sinceLast.ToMilliseconds());
+ }
+ AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {}, str);
+
+ if (!mLastCaptureTime.IsNull() && aTime <= mLastCaptureTime) {
+ aTime = mLastCaptureTime + TimeDuration::FromMilliseconds(1);
+ }
+ mLastCaptureTime = aTime;
+
+ mOwningElement->SetFrameCapture(copy.forget(), aTime);
+ }
+
+ void DetachFromRefreshDriver() {
+ MOZ_ASSERT(mOwningElement);
+ MOZ_ASSERT(mRefreshDriver);
+
+ Unregister();
+ mRefreshDriver = nullptr;
+ mWatchManager.Shutdown();
+ }
+
+ void Register() {
+ if (mRegistered) {
+ return;
+ }
+
+ MOZ_ASSERT(mRefreshDriver);
+ if (mRefreshDriver) {
+ mRefreshDriver->AddRefreshObserver(this, FlushType::Display,
+ "Canvas frame capture listeners");
+ mRegistered = true;
+ }
+
+ if (!mOwningElement) {
+ return;
+ }
+
+ if (Watchable<FrameCaptureState>* captureState =
+ mOwningElement->GetFrameCaptureState()) {
+ mWatchManager.Watch(
+ *captureState,
+ &RequestedFrameRefreshObserver::NotifyCaptureStateChange);
+ }
+ }
+
+ void Unregister() {
+ if (!mRegistered) {
+ return;
+ }
+
+ MOZ_ASSERT(mRefreshDriver);
+ if (mRefreshDriver) {
+ mRefreshDriver->RemoveRefreshObserver(this, FlushType::Display);
+ mRegistered = false;
+ }
+
+ if (!mOwningElement) {
+ return;
+ }
+
+ if (Watchable<FrameCaptureState>* captureState =
+ mOwningElement->GetFrameCaptureState()) {
+ mWatchManager.Unwatch(
+ *captureState,
+ &RequestedFrameRefreshObserver::NotifyCaptureStateChange);
+ }
+ }
+
+ private:
+ virtual ~RequestedFrameRefreshObserver() {
+ MOZ_ASSERT(!mRefreshDriver);
+ MOZ_ASSERT(!mRegistered);
+ }
+
+ bool mRegistered;
+ bool mReturnPlaceholderData;
+ const WeakPtr<HTMLCanvasElement> mOwningElement;
+ RefPtr<nsRefreshDriver> mRefreshDriver;
+ WatchManager<RequestedFrameRefreshObserver> mWatchManager;
+ TimeStamp mLastCaptureTime;
+ bool mPendingThrottledCapture;
+};
+
+// ---------------------------------------------------------------------------
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLCanvasPrintState, mCanvas, mContext,
+ mCallback)
+
+HTMLCanvasPrintState::HTMLCanvasPrintState(
+ HTMLCanvasElement* aCanvas, nsICanvasRenderingContextInternal* aContext,
+ nsITimerCallback* aCallback)
+ : mIsDone(false),
+ mPendingNotify(false),
+ mCanvas(aCanvas),
+ mContext(aContext),
+ mCallback(aCallback) {}
+
+HTMLCanvasPrintState::~HTMLCanvasPrintState() = default;
+
+/* virtual */
+JSObject* HTMLCanvasPrintState::WrapObject(JSContext* aCx,
+ JS::Handle<JSObject*> aGivenProto) {
+ return MozCanvasPrintState_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+nsISupports* HTMLCanvasPrintState::Context() const { return mContext; }
+
+void HTMLCanvasPrintState::Done() {
+ if (!mPendingNotify && !mIsDone) {
+ // The canvas needs to be invalidated for printing reftests on linux to
+ // work.
+ if (mCanvas) {
+ mCanvas->InvalidateCanvas();
+ }
+ RefPtr<nsRunnableMethod<HTMLCanvasPrintState>> doneEvent =
+ NewRunnableMethod("dom::HTMLCanvasPrintState::NotifyDone", this,
+ &HTMLCanvasPrintState::NotifyDone);
+ if (NS_SUCCEEDED(NS_DispatchToCurrentThread(doneEvent))) {
+ mPendingNotify = true;
+ }
+ }
+}
+
+void HTMLCanvasPrintState::NotifyDone() {
+ mIsDone = true;
+ mPendingNotify = false;
+ if (mCallback) {
+ mCallback->Notify(nullptr);
+ }
+}
+
+// ---------------------------------------------------------------------------
+
+HTMLCanvasElementObserver::HTMLCanvasElementObserver(
+ HTMLCanvasElement* aElement)
+ : mElement(aElement) {
+ RegisterObserverEvents();
+}
+
+HTMLCanvasElementObserver::~HTMLCanvasElementObserver() { Destroy(); }
+
+void HTMLCanvasElementObserver::Destroy() {
+ UnregisterObserverEvents();
+ mElement = nullptr;
+}
+
+void HTMLCanvasElementObserver::RegisterObserverEvents() {
+ if (!mElement) {
+ return;
+ }
+
+ nsCOMPtr<nsIObserverService> observerService =
+ mozilla::services::GetObserverService();
+
+ MOZ_ASSERT(observerService);
+
+ if (observerService) {
+ observerService->AddObserver(this, "memory-pressure", false);
+ observerService->AddObserver(this, "canvas-device-reset", false);
+ }
+}
+
+void HTMLCanvasElementObserver::UnregisterObserverEvents() {
+ if (!mElement) {
+ return;
+ }
+
+ nsCOMPtr<nsIObserverService> observerService =
+ mozilla::services::GetObserverService();
+
+ // Do not assert on observerService here. This might be triggered by
+ // the cycle collector at a late enough time, that XPCOM services are
+ // no longer available. See bug 1029504.
+ if (observerService) {
+ observerService->RemoveObserver(this, "memory-pressure");
+ observerService->RemoveObserver(this, "canvas-device-reset");
+ }
+}
+
+NS_IMETHODIMP
+HTMLCanvasElementObserver::Observe(nsISupports*, const char* aTopic,
+ const char16_t*) {
+ if (!mElement) {
+ return NS_OK;
+ }
+
+ if (strcmp(aTopic, "memory-pressure") == 0) {
+ mElement->OnMemoryPressure();
+ } else if (strcmp(aTopic, "canvas-device-reset") == 0) {
+ mElement->OnDeviceReset();
+ }
+
+ return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(HTMLCanvasElementObserver, nsIObserver)
+
+// ---------------------------------------------------------------------------
+
+HTMLCanvasElement::HTMLCanvasElement(
+ already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
+ : nsGenericHTMLElement(std::move(aNodeInfo)),
+ mResetLayer(true),
+ mMaybeModified(false),
+ mWriteOnly(false) {}
+
+HTMLCanvasElement::~HTMLCanvasElement() { Destroy(); }
+
+void HTMLCanvasElement::Destroy() {
+ if (mOffscreenDisplay) {
+ mOffscreenDisplay->DestroyElement();
+ mOffscreenDisplay = nullptr;
+ mImageContainer = nullptr;
+ }
+
+ if (mContextObserver) {
+ mContextObserver->Destroy();
+ mContextObserver = nullptr;
+ }
+
+ ResetPrintCallback();
+ if (mRequestedFrameRefreshObserver) {
+ mRequestedFrameRefreshObserver->DetachFromRefreshDriver();
+ mRequestedFrameRefreshObserver = nullptr;
+ }
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLCanvasElement)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(HTMLCanvasElement,
+ nsGenericHTMLElement)
+ tmp->Destroy();
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(mCurrentContext, mPrintCallback, mPrintState,
+ mOriginalCanvas, mOffscreenCanvas)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(HTMLCanvasElement,
+ nsGenericHTMLElement)
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCurrentContext, mPrintCallback,
+ mPrintState, mOriginalCanvas,
+ mOffscreenCanvas)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(HTMLCanvasElement,
+ nsGenericHTMLElement)
+
+NS_IMPL_ELEMENT_CLONE(HTMLCanvasElement)
+
+/* virtual */
+JSObject* HTMLCanvasElement::WrapNode(JSContext* aCx,
+ JS::Handle<JSObject*> aGivenProto) {
+ return HTMLCanvasElement_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+already_AddRefed<nsICanvasRenderingContextInternal>
+HTMLCanvasElement::CreateContext(CanvasContextType aContextType) {
+ // Note that the compositor backend will be LAYERS_NONE if there is no widget.
+ RefPtr<nsICanvasRenderingContextInternal> ret =
+ CreateContextHelper(aContextType, GetCompositorBackendType());
+
+ // Add Observer for webgl canvas.
+ if (aContextType == CanvasContextType::WebGL1 ||
+ aContextType == CanvasContextType::WebGL2 ||
+ aContextType == CanvasContextType::Canvas2D) {
+ if (!mContextObserver) {
+ mContextObserver = new HTMLCanvasElementObserver(this);
+ }
+ }
+
+ ret->SetCanvasElement(this);
+ return ret.forget();
+}
+
+nsIntSize HTMLCanvasElement::GetWidthHeight() {
+ nsIntSize size(DEFAULT_CANVAS_WIDTH, DEFAULT_CANVAS_HEIGHT);
+ const nsAttrValue* value;
+
+ if ((value = GetParsedAttr(nsGkAtoms::width)) &&
+ value->Type() == nsAttrValue::eInteger) {
+ size.width = value->GetIntegerValue();
+ }
+
+ if ((value = GetParsedAttr(nsGkAtoms::height)) &&
+ value->Type() == nsAttrValue::eInteger) {
+ size.height = value->GetIntegerValue();
+ }
+
+ MOZ_ASSERT(size.width >= 0 && size.height >= 0,
+ "we should've required <canvas> width/height attrs to be "
+ "unsigned (non-negative) values");
+
+ return size;
+}
+
+void HTMLCanvasElement::AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
+ const nsAttrValue* aValue,
+ const nsAttrValue* aOldValue,
+ nsIPrincipal* aSubjectPrincipal,
+ bool aNotify) {
+ AfterMaybeChangeAttr(aNamespaceID, aName, aNotify);
+
+ return nsGenericHTMLElement::AfterSetAttr(
+ aNamespaceID, aName, aValue, aOldValue, aSubjectPrincipal, aNotify);
+}
+
+void HTMLCanvasElement::OnAttrSetButNotChanged(
+ int32_t aNamespaceID, nsAtom* aName, const nsAttrValueOrString& aValue,
+ bool aNotify) {
+ AfterMaybeChangeAttr(aNamespaceID, aName, aNotify);
+
+ return nsGenericHTMLElement::OnAttrSetButNotChanged(aNamespaceID, aName,
+ aValue, aNotify);
+}
+
+void HTMLCanvasElement::AfterMaybeChangeAttr(int32_t aNamespaceID,
+ nsAtom* aName, bool aNotify) {
+ if (mCurrentContext && aNamespaceID == kNameSpaceID_None &&
+ (aName == nsGkAtoms::width || aName == nsGkAtoms::height ||
+ aName == nsGkAtoms::moz_opaque)) {
+ ErrorResult dummy;
+ UpdateContext(nullptr, JS::NullHandleValue, dummy);
+ }
+}
+
+void HTMLCanvasElement::HandlePrintCallback(nsPresContext* aPresContext) {
+ // Only call the print callback here if 1) we're in a print testing mode or
+ // print preview mode, 2) the canvas has a print callback and 3) the callback
+ // hasn't already been called. For real printing the callback is handled in
+ // nsPageSequenceFrame::PrePrintNextSheet.
+ if ((aPresContext->Type() == nsPresContext::eContext_PageLayout ||
+ aPresContext->Type() == nsPresContext::eContext_PrintPreview) &&
+ !mPrintState && GetMozPrintCallback()) {
+ DispatchPrintCallback(nullptr);
+ }
+}
+
+nsresult HTMLCanvasElement::DispatchPrintCallback(nsITimerCallback* aCallback) {
+ // For print reftests the context may not be initialized yet, so get a context
+ // so mCurrentContext is set.
+ if (!mCurrentContext) {
+ nsresult rv;
+ nsCOMPtr<nsISupports> context;
+ rv = GetContext(u"2d"_ns, getter_AddRefs(context));
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+ mPrintState = new HTMLCanvasPrintState(this, mCurrentContext, aCallback);
+
+ RefPtr<nsRunnableMethod<HTMLCanvasElement>> renderEvent =
+ NewRunnableMethod("dom::HTMLCanvasElement::CallPrintCallback", this,
+ &HTMLCanvasElement::CallPrintCallback);
+ return OwnerDoc()->Dispatch(TaskCategory::Other, renderEvent.forget());
+}
+
+void HTMLCanvasElement::CallPrintCallback() {
+ if (!mPrintState) {
+ // `mPrintState` might have been destroyed by cancelling the previous
+ // printing (especially the canvas frame destruction) during processing
+ // event loops in the printing.
+ return;
+ }
+ RefPtr<PrintCallback> callback = GetMozPrintCallback();
+ RefPtr<HTMLCanvasPrintState> state = mPrintState;
+ callback->Call(*state);
+}
+
+void HTMLCanvasElement::ResetPrintCallback() {
+ if (mPrintState) {
+ mPrintState = nullptr;
+ }
+}
+
+bool HTMLCanvasElement::IsPrintCallbackDone() {
+ if (mPrintState == nullptr) {
+ return true;
+ }
+
+ return mPrintState->mIsDone;
+}
+
+HTMLCanvasElement* HTMLCanvasElement::GetOriginalCanvas() {
+ return mOriginalCanvas ? mOriginalCanvas.get() : this;
+}
+
+nsresult HTMLCanvasElement::CopyInnerTo(HTMLCanvasElement* aDest) {
+ nsresult rv = nsGenericHTMLElement::CopyInnerTo(aDest);
+ NS_ENSURE_SUCCESS(rv, rv);
+ Document* destDoc = aDest->OwnerDoc();
+ if (destDoc->IsStaticDocument()) {
+ // The Firefox print preview code can create a static clone from an
+ // existing static clone, so we may not be the original 'canvas' element.
+ aDest->mOriginalCanvas = GetOriginalCanvas();
+
+ if (GetMozPrintCallback()) {
+ destDoc->SetHasPrintCallbacks();
+ }
+
+ // We make sure that the canvas is not zero sized since that would cause
+ // the DrawImage call below to return an error, which would cause printing
+ // to fail.
+ nsIntSize size = GetWidthHeight();
+ if (size.height > 0 && size.width > 0) {
+ nsCOMPtr<nsISupports> cxt;
+ aDest->GetContext(u"2d"_ns, getter_AddRefs(cxt));
+ RefPtr<CanvasRenderingContext2D> context2d =
+ static_cast<CanvasRenderingContext2D*>(cxt.get());
+ if (context2d && !mPrintCallback) {
+ CanvasImageSource source;
+ source.SetAsHTMLCanvasElement() = this;
+ ErrorResult err;
+ context2d->DrawImage(source, 0.0, 0.0, err);
+ rv = err.StealNSResult();
+ }
+ }
+ }
+ return rv;
+}
+
+nsChangeHint HTMLCanvasElement::GetAttributeChangeHint(const nsAtom* aAttribute,
+ int32_t aModType) const {
+ nsChangeHint retval =
+ nsGenericHTMLElement::GetAttributeChangeHint(aAttribute, aModType);
+ if (aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height) {
+ retval |= NS_STYLE_HINT_REFLOW;
+ } else if (aAttribute == nsGkAtoms::moz_opaque) {
+ retval |= NS_STYLE_HINT_VISUAL;
+ }
+ return retval;
+}
+
+void HTMLCanvasElement::MapAttributesIntoRule(
+ const nsMappedAttributes* aAttributes, MappedDeclarations& aDecls) {
+ MapAspectRatioInto(aAttributes, aDecls);
+ MapCommonAttributesInto(aAttributes, aDecls);
+}
+
+nsMapRuleToAttributesFunc HTMLCanvasElement::GetAttributeMappingFunction()
+ const {
+ return &MapAttributesIntoRule;
+}
+
+NS_IMETHODIMP_(bool)
+HTMLCanvasElement::IsAttributeMapped(const nsAtom* aAttribute) const {
+ static const MappedAttributeEntry attributes[] = {
+ {nsGkAtoms::width}, {nsGkAtoms::height}, {nullptr}};
+ static const MappedAttributeEntry* const map[] = {attributes,
+ sCommonAttributeMap};
+ return FindAttributeDependence(aAttribute, map);
+}
+
+bool HTMLCanvasElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+ const nsAString& aValue,
+ nsIPrincipal* aMaybeScriptedPrincipal,
+ nsAttrValue& aResult) {
+ if (aNamespaceID == kNameSpaceID_None &&
+ (aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height)) {
+ return aResult.ParseNonNegativeIntValue(aValue);
+ }
+
+ return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
+ aMaybeScriptedPrincipal, aResult);
+}
+
+void HTMLCanvasElement::ToDataURL(JSContext* aCx, const nsAString& aType,
+ JS::Handle<JS::Value> aParams,
+ nsAString& aDataURL,
+ nsIPrincipal& aSubjectPrincipal,
+ ErrorResult& aRv) {
+ // mWriteOnly check is redundant, but optimizes for the common case.
+ if (mWriteOnly && !CallerCanRead(&aSubjectPrincipal)) {
+ aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+ return;
+ }
+
+ nsresult rv = ToDataURLImpl(aCx, aSubjectPrincipal, aType, aParams, aDataURL);
+ if (NS_FAILED(rv)) {
+ aDataURL.AssignLiteral("data:,");
+ }
+}
+
+void HTMLCanvasElement::SetMozPrintCallback(PrintCallback* aCallback) {
+ mPrintCallback = aCallback;
+}
+
+PrintCallback* HTMLCanvasElement::GetMozPrintCallback() const {
+ if (mOriginalCanvas) {
+ return mOriginalCanvas->GetMozPrintCallback();
+ }
+ return mPrintCallback;
+}
+
+static uint32_t sCaptureSourceId = 0;
+class CanvasCaptureTrackSource : public MediaStreamTrackSource {
+ public:
+ NS_DECL_ISUPPORTS_INHERITED
+ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CanvasCaptureTrackSource,
+ MediaStreamTrackSource)
+
+ CanvasCaptureTrackSource(nsIPrincipal* aPrincipal,
+ CanvasCaptureMediaStream* aCaptureStream)
+ : MediaStreamTrackSource(
+ aPrincipal, nsString(),
+ TrackingId(TrackingId::Source::Canvas, sCaptureSourceId++,
+ TrackingId::TrackAcrossProcesses::Yes)),
+ mCaptureStream(aCaptureStream) {}
+
+ MediaSourceEnum GetMediaSource() const override {
+ return MediaSourceEnum::Other;
+ }
+
+ bool HasAlpha() const override {
+ if (!mCaptureStream || !mCaptureStream->Canvas()) {
+ // In cycle-collection
+ return false;
+ }
+ return !mCaptureStream->Canvas()->GetIsOpaque();
+ }
+
+ void Stop() override {
+ if (!mCaptureStream) {
+ NS_ERROR("No stream");
+ return;
+ }
+
+ mCaptureStream->StopCapture();
+ }
+
+ void Disable() override {}
+
+ void Enable() override {}
+
+ private:
+ virtual ~CanvasCaptureTrackSource() = default;
+
+ RefPtr<CanvasCaptureMediaStream> mCaptureStream;
+};
+
+NS_IMPL_ADDREF_INHERITED(CanvasCaptureTrackSource, MediaStreamTrackSource)
+NS_IMPL_RELEASE_INHERITED(CanvasCaptureTrackSource, MediaStreamTrackSource)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CanvasCaptureTrackSource)
+NS_INTERFACE_MAP_END_INHERITING(MediaStreamTrackSource)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(CanvasCaptureTrackSource,
+ MediaStreamTrackSource, mCaptureStream)
+
+already_AddRefed<CanvasCaptureMediaStream> HTMLCanvasElement::CaptureStream(
+ const Optional<double>& aFrameRate, nsIPrincipal& aSubjectPrincipal,
+ ErrorResult& aRv) {
+ if (IsWriteOnly()) {
+ aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+ return nullptr;
+ }
+
+ nsPIDOMWindowInner* window = OwnerDoc()->GetInnerWindow();
+ if (!window) {
+ aRv.Throw(NS_ERROR_FAILURE);
+ return nullptr;
+ }
+
+ auto stream = MakeRefPtr<CanvasCaptureMediaStream>(window, this);
+
+ nsCOMPtr<nsIPrincipal> principal = NodePrincipal();
+ nsresult rv = stream->Init(aFrameRate, principal);
+ if (NS_FAILED(rv)) {
+ aRv.Throw(rv);
+ return nullptr;
+ }
+
+ RefPtr<MediaStreamTrack> track =
+ new VideoStreamTrack(window, stream->GetSourceStream(),
+ new CanvasCaptureTrackSource(principal, stream));
+ stream->AddTrackInternal(track);
+
+ // Check site-specific permission and display prompt if appropriate.
+ // If no permission, arrange for the frame capture listener to return
+ // all-white, opaque image data.
+ bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(
+ OwnerDoc(), nsContentUtils::GetCurrentJSContext(),
+ Some(&aSubjectPrincipal));
+
+ rv = RegisterFrameCaptureListener(stream->FrameCaptureListener(),
+ usePlaceholder);
+ if (NS_FAILED(rv)) {
+ aRv.Throw(rv);
+ return nullptr;
+ }
+
+ return stream.forget();
+}
+
+nsresult HTMLCanvasElement::ExtractData(JSContext* aCx,
+ nsIPrincipal& aSubjectPrincipal,
+ nsAString& aType,
+ const nsAString& aOptions,
+ nsIInputStream** aStream) {
+ // Check site-specific permission and display prompt if appropriate.
+ // If no permission, return all-white, opaque image data.
+ bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(
+ OwnerDoc(), aCx, Some(&aSubjectPrincipal));
+ return ImageEncoder::ExtractData(aType, aOptions, GetSize(), usePlaceholder,
+ mCurrentContext, mCanvasRenderer, aStream);
+}
+
+nsresult HTMLCanvasElement::ToDataURLImpl(JSContext* aCx,
+ nsIPrincipal& aSubjectPrincipal,
+ const nsAString& aMimeType,
+ const JS::Value& aEncoderOptions,
+ nsAString& aDataURL) {
+ nsIntSize size = GetWidthHeight();
+ if (size.height == 0 || size.width == 0) {
+ aDataURL = u"data:,"_ns;
+ return NS_OK;
+ }
+
+ nsAutoString type;
+ nsContentUtils::ASCIIToLower(aMimeType, type);
+
+ nsAutoString params;
+ bool usingCustomParseOptions;
+ nsresult rv =
+ ParseParams(aCx, type, aEncoderOptions, params, &usingCustomParseOptions);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+
+ nsCOMPtr<nsIInputStream> stream;
+ rv =
+ ExtractData(aCx, aSubjectPrincipal, type, params, getter_AddRefs(stream));
+
+ // If there are unrecognized custom parse options, we should fall back to
+ // the default values for the encoder without any options at all.
+ if (rv == NS_ERROR_INVALID_ARG && usingCustomParseOptions) {
+ rv = ExtractData(aCx, aSubjectPrincipal, type, u""_ns,
+ getter_AddRefs(stream));
+ }
+
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ // build data URL string
+ aDataURL = u"data:"_ns + type + u";base64,"_ns;
+
+ uint64_t count;
+ rv = stream->Available(&count);
+ NS_ENSURE_SUCCESS(rv, rv);
+ NS_ENSURE_TRUE(count <= UINT32_MAX, NS_ERROR_FILE_TOO_BIG);
+
+ return Base64EncodeInputStream(stream, aDataURL, (uint32_t)count,
+ aDataURL.Length());
+}
+
+void HTMLCanvasElement::ToBlob(JSContext* aCx, BlobCallback& aCallback,
+ const nsAString& aType,
+ JS::Handle<JS::Value> aParams,
+ nsIPrincipal& aSubjectPrincipal,
+ ErrorResult& aRv) {
+ // mWriteOnly check is redundant, but optimizes for the common case.
+ if (mWriteOnly && !CallerCanRead(&aSubjectPrincipal)) {
+ aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+ return;
+ }
+
+ nsCOMPtr<nsIGlobalObject> global = OwnerDoc()->GetScopeObject();
+ MOZ_ASSERT(global);
+
+ nsIntSize elemSize = GetWidthHeight();
+ if (elemSize.width == 0 || elemSize.height == 0) {
+ // According to spec, blob should return null if either its horizontal
+ // dimension or its vertical dimension is zero. See link below.
+ // https://html.spec.whatwg.org/multipage/scripting.html#dom-canvas-toblob
+ OwnerDoc()->Dispatch(
+ TaskCategory::Other,
+ NewRunnableMethod<Blob*, const char*>(
+ "dom::HTMLCanvasElement::ToBlob", &aCallback,
+ static_cast<void (BlobCallback::*)(Blob*, const char*)>(
+ &BlobCallback::Call),
+ nullptr, nullptr));
+ return;
+ }
+
+ // Check site-specific permission and display prompt if appropriate.
+ // If no permission, return all-white, opaque image data.
+ bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(
+ OwnerDoc(), aCx, Some(&aSubjectPrincipal));
+ CanvasRenderingContextHelper::ToBlob(aCx, global, aCallback, aType, aParams,
+ usePlaceholder, aRv);
+}
+
+OffscreenCanvas* HTMLCanvasElement::TransferControlToOffscreen(
+ ErrorResult& aRv) {
+ if (mCurrentContext || mOffscreenCanvas) {
+ aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+ return nullptr;
+ }
+
+ MOZ_ASSERT(!mOffscreenDisplay);
+
+ nsPIDOMWindowInner* win = OwnerDoc()->GetInnerWindow();
+ if (!win) {
+ aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+ return nullptr;
+ }
+
+ LayersBackend backend = LayersBackend::LAYERS_NONE;
+ TextureType textureType = TextureType::Unknown;
+ nsIWidget* docWidget = nsContentUtils::WidgetForDocument(OwnerDoc());
+ if (docWidget) {
+ WindowRenderer* renderer = docWidget->GetWindowRenderer();
+ if (renderer) {
+ backend = renderer->GetCompositorBackendType();
+ textureType = TexTypeForWebgl(renderer->AsKnowsCompositor());
+ }
+ }
+
+ nsIntSize sz = GetWidthHeight();
+ mOffscreenDisplay =
+ MakeRefPtr<OffscreenCanvasDisplayHelper>(this, sz.width, sz.height);
+ mOffscreenCanvas =
+ new OffscreenCanvas(win->AsGlobal(), sz.width, sz.height, backend,
+ textureType, do_AddRef(mOffscreenDisplay));
+ if (mWriteOnly) {
+ mOffscreenCanvas->SetWriteOnly(mExpandedReader);
+ }
+
+ if (!mContextObserver) {
+ mContextObserver = new HTMLCanvasElementObserver(this);
+ }
+
+ return mOffscreenCanvas;
+}
+
+nsresult HTMLCanvasElement::GetContext(const nsAString& aContextId,
+ nsISupports** aContext) {
+ ErrorResult rv;
+ mMaybeModified = true; // For FirstContentfulPaint
+ *aContext = GetContext(nullptr, aContextId, JS::NullHandleValue, rv).take();
+ return rv.StealNSResult();
+}
+
+already_AddRefed<nsISupports> HTMLCanvasElement::GetContext(
+ JSContext* aCx, const nsAString& aContextId,
+ JS::Handle<JS::Value> aContextOptions, ErrorResult& aRv) {
+ if (mOffscreenCanvas) {
+ aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+ return nullptr;
+ }
+
+ mMaybeModified = true; // For FirstContentfulPaint
+ return CanvasRenderingContextHelper::GetOrCreateContext(
+ aCx, aContextId,
+ aContextOptions.isObject() ? aContextOptions : JS::NullHandleValue, aRv);
+}
+
+nsIntSize HTMLCanvasElement::GetSize() { return GetWidthHeight(); }
+
+bool HTMLCanvasElement::IsWriteOnly() const { return mWriteOnly; }
+
+void HTMLCanvasElement::SetWriteOnly(
+ nsIPrincipal* aExpandedReader /* = nullptr */) {
+ mExpandedReader = aExpandedReader;
+ mWriteOnly = true;
+ if (mOffscreenCanvas) {
+ mOffscreenCanvas->SetWriteOnly(aExpandedReader);
+ }
+}
+
+bool HTMLCanvasElement::CallerCanRead(nsIPrincipal* aPrincipal) const {
+ if (!mWriteOnly) {
+ return true;
+ }
+
+ if (!aPrincipal) {
+ return false;
+ }
+
+ // If mExpandedReader is set, this canvas was tainted only by
+ // mExpandedReader's resources. So allow reading if the subject
+ // principal subsumes mExpandedReader.
+ if (mExpandedReader && aPrincipal->Subsumes(mExpandedReader)) {
+ return true;
+ }
+
+ return nsContentUtils::PrincipalHasPermission(*aPrincipal,
+ nsGkAtoms::all_urlsPermission);
+}
+
+void HTMLCanvasElement::SetWidth(uint32_t aWidth, ErrorResult& aRv) {
+ if (mOffscreenCanvas) {
+ aRv.ThrowInvalidStateError(
+ "Cannot set width of placeholder canvas transferred to "
+ "OffscreenCanvas.");
+ return;
+ }
+
+ SetUnsignedIntAttr(nsGkAtoms::width, aWidth, DEFAULT_CANVAS_WIDTH, aRv);
+}
+
+void HTMLCanvasElement::SetHeight(uint32_t aHeight, ErrorResult& aRv) {
+ if (mOffscreenCanvas) {
+ aRv.ThrowInvalidStateError(
+ "Cannot set height of placeholder canvas transferred to "
+ "OffscreenCanvas.");
+ return;
+ }
+
+ SetUnsignedIntAttr(nsGkAtoms::height, aHeight, DEFAULT_CANVAS_HEIGHT, aRv);
+}
+
+void HTMLCanvasElement::FlushOffscreenCanvas() {
+ if (mOffscreenDisplay) {
+ mOffscreenDisplay->FlushForDisplay();
+ }
+}
+
+void HTMLCanvasElement::InvalidateCanvasPlaceholder(uint32_t aWidth,
+ uint32_t aHeight) {
+ ErrorResult rv;
+ SetUnsignedIntAttr(nsGkAtoms::width, aWidth, DEFAULT_CANVAS_WIDTH, rv);
+ MOZ_ASSERT(!rv.Failed());
+ SetUnsignedIntAttr(nsGkAtoms::height, aHeight, DEFAULT_CANVAS_HEIGHT, rv);
+ MOZ_ASSERT(!rv.Failed());
+}
+
+void HTMLCanvasElement::InvalidateCanvasContent(const gfx::Rect* damageRect) {
+ // Cache the current ImageContainer to avoid contention on the mutex.
+ if (mOffscreenDisplay) {
+ mImageContainer = mOffscreenDisplay->GetImageContainer();
+ }
+
+ // We don't need to flush anything here; if there's no frame or if
+ // we plan to reframe we don't need to invalidate it anyway.
+ nsIFrame* frame = GetPrimaryFrame();
+ if (!frame) return;
+
+ // When using layers-free WebRender, we cannot invalidate the layer (because
+ // there isn't one). Instead, we mark the CanvasRenderer dirty and scheduling
+ // an empty transaction which is effectively equivalent.
+ CanvasRenderer* renderer = nullptr;
+ const auto key = static_cast<uint32_t>(DisplayItemType::TYPE_CANVAS);
+ RefPtr<WebRenderCanvasData> data =
+ GetWebRenderUserData<WebRenderCanvasData>(frame, key);
+ if (data) {
+ renderer = data->GetCanvasRenderer();
+ }
+
+ if (renderer) {
+ renderer->SetDirty();
+ frame->SchedulePaint(nsIFrame::PAINT_COMPOSITE_ONLY);
+ } else {
+ if (damageRect) {
+ nsIntSize size = GetWidthHeight();
+ if (size.width != 0 && size.height != 0) {
+ gfx::IntRect invalRect = gfx::IntRect::Truncate(*damageRect);
+ frame->InvalidateLayer(DisplayItemType::TYPE_CANVAS, &invalRect);
+ }
+ } else {
+ frame->InvalidateLayer(DisplayItemType::TYPE_CANVAS);
+ }
+
+ // This path is taken in two situations:
+ // 1) WebRender is enabled and has not yet processed a display list.
+ // 2) WebRender is disabled and layer invalidation failed.
+ // In both cases, schedule a full paint to properly update canvas.
+ frame->SchedulePaint(nsIFrame::PAINT_DEFAULT, false);
+ }
+
+ /*
+ * Treat canvas invalidations as animation activity for JS. Frequently
+ * invalidating a canvas will feed into heuristics and cause JIT code to be
+ * kept around longer, for smoother animations.
+ */
+ nsPIDOMWindowInner* win = OwnerDoc()->GetInnerWindow();
+
+ if (win) {
+ if (JSObject* obj = win->AsGlobal()->GetGlobalJSObject()) {
+ js::NotifyAnimationActivity(obj);
+ }
+ }
+}
+
+void HTMLCanvasElement::InvalidateCanvas() {
+ // We don't need to flush anything here; if there's no frame or if
+ // we plan to reframe we don't need to invalidate it anyway.
+ nsIFrame* frame = GetPrimaryFrame();
+ if (!frame) return;
+
+ frame->InvalidateFrame();
+}
+
+bool HTMLCanvasElement::GetIsOpaque() {
+ if (mCurrentContext) {
+ return mCurrentContext->GetIsOpaque();
+ }
+
+ return GetOpaqueAttr();
+}
+
+bool HTMLCanvasElement::GetOpaqueAttr() {
+ return HasAttr(kNameSpaceID_None, nsGkAtoms::moz_opaque);
+}
+
+CanvasContextType HTMLCanvasElement::GetCurrentContextType() {
+ if (mCurrentContextType == CanvasContextType::NoContext &&
+ mOffscreenDisplay) {
+ mCurrentContextType = mOffscreenDisplay->GetContextType();
+ }
+ return mCurrentContextType;
+}
+
+already_AddRefed<Image> HTMLCanvasElement::GetAsImage() {
+ if (mOffscreenDisplay) {
+ return mOffscreenDisplay->GetAsImage();
+ }
+
+ if (mCurrentContext) {
+ return mCurrentContext->GetAsImage();
+ }
+
+ return nullptr;
+}
+
+bool HTMLCanvasElement::UpdateWebRenderCanvasData(
+ nsDisplayListBuilder* aBuilder, WebRenderCanvasData* aCanvasData) {
+ MOZ_ASSERT(!mOffscreenDisplay);
+
+ if (mCurrentContext) {
+ return mCurrentContext->UpdateWebRenderCanvasData(aBuilder, aCanvasData);
+ }
+
+ // Clear CanvasRenderer of WebRenderCanvasData
+ aCanvasData->ClearCanvasRenderer();
+ return false;
+}
+
+bool HTMLCanvasElement::InitializeCanvasRenderer(nsDisplayListBuilder* aBuilder,
+ CanvasRenderer* aRenderer) {
+ MOZ_ASSERT(!mOffscreenDisplay);
+
+ if (mCurrentContext) {
+ return mCurrentContext->InitializeCanvasRenderer(aBuilder, aRenderer);
+ }
+
+ return false;
+}
+
+void HTMLCanvasElement::MarkContextClean() {
+ if (!mCurrentContext) return;
+
+ mCurrentContext->MarkContextClean();
+}
+
+void HTMLCanvasElement::MarkContextCleanForFrameCapture() {
+ if (!mCurrentContext) return;
+
+ mCurrentContext->MarkContextCleanForFrameCapture();
+}
+
+Watchable<FrameCaptureState>* HTMLCanvasElement::GetFrameCaptureState() {
+ if (!mCurrentContext) {
+ return nullptr;
+ }
+ return mCurrentContext->GetFrameCaptureState();
+}
+
+nsresult HTMLCanvasElement::RegisterFrameCaptureListener(
+ FrameCaptureListener* aListener, bool aReturnPlaceholderData) {
+ WeakPtr<FrameCaptureListener> listener = aListener;
+
+ if (mRequestedFrameListeners.Contains(listener)) {
+ return NS_OK;
+ }
+
+ if (!mRequestedFrameRefreshObserver) {
+ Document* doc = OwnerDoc();
+ if (!doc) {
+ return NS_ERROR_FAILURE;
+ }
+
+ PresShell* shell = nsContentUtils::FindPresShellForDocument(doc);
+ if (!shell) {
+ return NS_ERROR_FAILURE;
+ }
+
+ nsPresContext* context = shell->GetPresContext();
+ if (!context) {
+ return NS_ERROR_FAILURE;
+ }
+
+ context = context->GetRootPresContext();
+ if (!context) {
+ return NS_ERROR_FAILURE;
+ }
+
+ nsRefreshDriver* driver = context->RefreshDriver();
+ if (!driver) {
+ return NS_ERROR_FAILURE;
+ }
+
+ mRequestedFrameRefreshObserver =
+ new RequestedFrameRefreshObserver(this, driver, aReturnPlaceholderData);
+ } else {
+ mRequestedFrameRefreshObserver->SetReturnPlaceholderData(
+ aReturnPlaceholderData);
+ }
+
+ mRequestedFrameListeners.AppendElement(listener);
+ mRequestedFrameRefreshObserver->Register();
+ return NS_OK;
+}
+
+bool HTMLCanvasElement::IsFrameCaptureRequested(const TimeStamp& aTime) const {
+ for (WeakPtr<FrameCaptureListener> listener : mRequestedFrameListeners) {
+ if (!listener) {
+ continue;
+ }
+
+ if (listener->FrameCaptureRequested(aTime)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+void HTMLCanvasElement::ProcessDestroyedFrameListeners() {
+ // Remove destroyed listeners from the list.
+ mRequestedFrameListeners.RemoveElementsBy(
+ [](const auto& weakListener) { return !weakListener; });
+
+ if (mRequestedFrameListeners.IsEmpty()) {
+ mRequestedFrameRefreshObserver->Unregister();
+ }
+}
+
+void HTMLCanvasElement::SetFrameCapture(
+ already_AddRefed<SourceSurface> aSurface, const TimeStamp& aTime) {
+ RefPtr<SourceSurface> surface = aSurface;
+ RefPtr<SourceSurfaceImage> image =
+ new SourceSurfaceImage(surface->GetSize(), surface);
+
+ for (WeakPtr<FrameCaptureListener> listener : mRequestedFrameListeners) {
+ if (!listener) {
+ continue;
+ }
+
+ RefPtr<Image> imageRefCopy = image.get();
+ listener->NewFrame(imageRefCopy.forget(), aTime);
+ }
+}
+
+already_AddRefed<SourceSurface> HTMLCanvasElement::GetSurfaceSnapshot(
+ gfxAlphaType* const aOutAlphaType, DrawTarget* aTarget) {
+ if (mCurrentContext) {
+ return mCurrentContext->GetOptimizedSnapshot(aTarget, aOutAlphaType);
+ } else if (mOffscreenDisplay) {
+ return mOffscreenDisplay->GetSurfaceSnapshot();
+ }
+ return nullptr;
+}
+
+layers::LayersBackend HTMLCanvasElement::GetCompositorBackendType() const {
+ nsIWidget* docWidget = nsContentUtils::WidgetForDocument(OwnerDoc());
+ if (docWidget) {
+ WindowRenderer* renderer = docWidget->GetWindowRenderer();
+ if (renderer) {
+ return renderer->GetCompositorBackendType();
+ }
+ }
+
+ return LayersBackend::LAYERS_NONE;
+}
+
+void HTMLCanvasElement::OnMemoryPressure() {
+ // FIXME(aosmond): We need to implement memory pressure handling for
+ // OffscreenCanvas when it is on worker threads. See bug 1746260.
+
+ if (mCurrentContext) {
+ mCurrentContext->OnMemoryPressure();
+ }
+}
+
+void HTMLCanvasElement::OnDeviceReset() {
+ if (!mOffscreenCanvas && mCurrentContext) {
+ mCurrentContext->ResetBitmap();
+ }
+}
+
+ClientWebGLContext* HTMLCanvasElement::GetWebGLContext() {
+ if (GetCurrentContextType() != CanvasContextType::WebGL1 &&
+ GetCurrentContextType() != CanvasContextType::WebGL2) {
+ return nullptr;
+ }
+
+ return static_cast<ClientWebGLContext*>(GetCurrentContext());
+}
+
+webgpu::CanvasContext* HTMLCanvasElement::GetWebGPUContext() {
+ if (GetCurrentContextType() != CanvasContextType::WebGPU) {
+ return nullptr;
+ }
+
+ return static_cast<webgpu::CanvasContext*>(GetCurrentContext());
+}
+
+} // namespace mozilla::dom