The Tor Browser: content/canvas/src/CanvasRenderingContext2D.cpp@deefc01c0e14 (annotated)

content/canvas/src/CanvasRenderingContext2D.cpp@deefc01c0e14 (annotated)

content/canvas/src/CanvasRenderingContext2D.cpp

Thu, 15 Jan 2015 21:03:48 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 21:03:48 +0100
branch: TOR_BUG_9701
changeset 11: deefc01c0e14
permissions: -rwxr-xr-x

Integrate friendly tips from Tor colleagues to make (or not) 4.5 alpha 3;
This includes removal of overloaded (but unused) methods, and addition of
a overlooked call to DataStruct::SetData(nsISupports, uint32_t, bool.)

 /* -*- 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/. */
 #include "CanvasRenderingContext2D.h"
 #include "nsXULElement.h"
 #include "nsIServiceManager.h"
 #include "nsMathUtils.h"
 #include "nsContentUtils.h"
 #include "nsIDocument.h"
 #include "mozilla/dom/HTMLCanvasElement.h"
 #include "nsSVGEffects.h"
 #include "nsPresContext.h"
 #include "nsIPresShell.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsIFrame.h"
 #include "nsError.h"
 #include "nsCSSParser.h"
 #include "mozilla/css/StyleRule.h"
 #include "mozilla/css/Declaration.h"
 #include "mozilla/css/Loader.h"
 #include "nsComputedDOMStyle.h"
 #include "nsStyleSet.h"
 #include "nsPrintfCString.h"
 #include "nsReadableUtils.h"
 #include "nsColor.h"
 #include "nsGfxCIID.h"
 #include "nsIDocShell.h"
 #include "nsIDOMWindow.h"
 #include "nsPIDOMWindow.h"
 #include "nsDisplayList.h"
 #include "nsFocusManager.h"
 #include "nsTArray.h"
 #include "ImageEncoder.h"
 #include "gfxContext.h"
 #include "gfxASurface.h"
 #include "gfxImageSurface.h"
 #include "gfxPlatform.h"
 #include "gfxFont.h"
 #include "gfxBlur.h"
 #include "gfxUtils.h"
 #include "nsFrameManager.h"
 #include "nsFrameLoader.h"
 #include "nsBidi.h"
 #include "nsBidiPresUtils.h"
 #include "Layers.h"
 #include "CanvasUtils.h"
 #include "nsIMemoryReporter.h"
 #include "nsStyleUtil.h"
 #include "CanvasImageCache.h"
 #include <algorithm>
 #include "jsapi.h"
 #include "jsfriendapi.h"
 #include "mozilla/Alignment.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/CheckedInt.h"
 #include "mozilla/dom/ContentParent.h"
 #include "mozilla/dom/ImageData.h"
 #include "mozilla/dom/PBrowserParent.h"
 #include "mozilla/dom/ToJSValue.h"
 #include "mozilla/dom/TypedArray.h"
 #include "mozilla/Endian.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/gfx/PathHelpers.h"
 #include "mozilla/gfx/DataSurfaceHelpers.h"
 #include "mozilla/ipc/DocumentRendererParent.h"
 #include "mozilla/ipc/PDocumentRendererParent.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/unused.h"
 #include "nsCCUncollectableMarker.h"
 #include "nsWrapperCacheInlines.h"
 #include "mozilla/dom/CanvasRenderingContext2DBinding.h"
 #include "mozilla/dom/HTMLImageElement.h"
 #include "mozilla/dom/HTMLVideoElement.h"
 #include "mozilla/dom/TextMetrics.h"
 #include "mozilla/dom/UnionTypes.h"
 #include "nsGlobalWindow.h"
 #include "GLContext.h"
 #include "GLContextProvider.h"
 #include "SVGContentUtils.h"
 #include "nsIScreenManager.h"
 #undef free // apparently defined by some windows header, clashing with a free()
             // method in SkTypes.h
 #ifdef USE_SKIA
 #include "SkiaGLGlue.h"
 #include "SurfaceStream.h"
 #include "SurfaceTypes.h"
 #endif
 using mozilla::gl::GLContext;
 using mozilla::gl::SkiaGLGlue;
 using mozilla::gl::GLContextProvider;
 #ifdef XP_WIN
 #include "gfxWindowsPlatform.h"
 #endif
 #ifdef MOZ_WIDGET_GONK
 #include "mozilla/layers/ShadowLayers.h"
 #endif
 // windows.h (included by chromium code) defines this, in its infinite wisdom
 #undef DrawText
 using namespace mozilla;
 using namespace mozilla::CanvasUtils;
 using namespace mozilla::css;
 using namespace mozilla::gfx;
 using namespace mozilla::ipc;
 using namespace mozilla::layers;
 namespace mgfx = mozilla::gfx;
 namespace mozilla {
 namespace dom {
 // Cap sigma to avoid overly large temp surfaces.
 const Float SIGMA_MAX = 100;
 /* Memory reporter stuff */
 static int64_t gCanvasAzureMemoryUsed = 0;
 // This is KIND_OTHER because it's not always clear where in memory the pixels
 // of a canvas are stored.  Furthermore, this memory will be tracked by the
 // underlying surface implementations.  See bug 655638 for details.
 class Canvas2dPixelsReporter MOZ_FINAL : public nsIMemoryReporter
 {
 public:
   NS_DECL_ISUPPORTS
   NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
                             nsISupports* aData)
   {
     return MOZ_COLLECT_REPORT(
       "canvas-2d-pixels", KIND_OTHER, UNITS_BYTES,
       gCanvasAzureMemoryUsed,
       "Memory used by 2D canvases. Each canvas requires "
       "(width * height * 4) bytes.");
   }
 };
 NS_IMPL_ISUPPORTS(Canvas2dPixelsReporter, nsIMemoryReporter)
 class CanvasRadialGradient : public CanvasGradient
 {
 public:
   CanvasRadialGradient(CanvasRenderingContext2D* aContext,
                        mozilla::css::Loader *aLoader,
                        const Point &aBeginOrigin, Float aBeginRadius,
                        const Point &aEndOrigin, Float aEndRadius)
     : CanvasGradient(aContext, aLoader, Type::RADIAL)
     , mCenter1(aBeginOrigin)
     , mCenter2(aEndOrigin)
     , mRadius1(aBeginRadius)
     , mRadius2(aEndRadius)
   {
   }
   Point mCenter1;
   Point mCenter2;
   Float mRadius1;
   Float mRadius2;
 };
 class CanvasLinearGradient : public CanvasGradient
 {
 public:
   CanvasLinearGradient(CanvasRenderingContext2D* aContext,
                        mozilla::css::Loader *aLoader,
                        const Point &aBegin, const Point &aEnd)
     : CanvasGradient(aContext, aLoader, Type::LINEAR)
     , mBegin(aBegin)
     , mEnd(aEnd)
   {
   }
 protected:
   friend class CanvasGeneralPattern;
   // Beginning of linear gradient.
   Point mBegin;
   // End of linear gradient.
   Point mEnd;
 };
 // This class is named 'GeneralCanvasPattern' instead of just
 // 'GeneralPattern' to keep Windows PGO builds from confusing the
 // GeneralPattern class in gfxContext.cpp with this one.
 class CanvasGeneralPattern
 {
 public:
   typedef CanvasRenderingContext2D::Style Style;
   typedef CanvasRenderingContext2D::ContextState ContextState;
   CanvasGeneralPattern() : mPattern(nullptr) {}
   ~CanvasGeneralPattern()
   {
     if (mPattern) {
       mPattern->~Pattern();
     }
   }
   Pattern& ForStyle(CanvasRenderingContext2D *aCtx,
                     Style aStyle,
                     DrawTarget *aRT)
   {
     // This should only be called once or the mPattern destructor will
     // not be executed.
     NS_ASSERTION(!mPattern, "ForStyle() should only be called once on CanvasGeneralPattern!");
     const ContextState &state = aCtx->CurrentState();
     if (state.StyleIsColor(aStyle)) {
       mPattern = new (mColorPattern.addr()) ColorPattern(Color::FromABGR(state.colorStyles[aStyle]));
     } else if (state.gradientStyles[aStyle] &&
                state.gradientStyles[aStyle]->GetType() == CanvasGradient::Type::LINEAR) {
       CanvasLinearGradient *gradient =
         static_cast<CanvasLinearGradient*>(state.gradientStyles[aStyle].get());
       mPattern = new (mLinearGradientPattern.addr())
         LinearGradientPattern(gradient->mBegin, gradient->mEnd,
                               gradient->GetGradientStopsForTarget(aRT));
     } else if (state.gradientStyles[aStyle] &&
                state.gradientStyles[aStyle]->GetType() == CanvasGradient::Type::RADIAL) {
       CanvasRadialGradient *gradient =
         static_cast<CanvasRadialGradient*>(state.gradientStyles[aStyle].get());
       mPattern = new (mRadialGradientPattern.addr())
         RadialGradientPattern(gradient->mCenter1, gradient->mCenter2, gradient->mRadius1,
                               gradient->mRadius2, gradient->GetGradientStopsForTarget(aRT));
     } else if (state.patternStyles[aStyle]) {
       if (aCtx->mCanvasElement) {
         CanvasUtils::DoDrawImageSecurityCheck(aCtx->mCanvasElement,
                                               state.patternStyles[aStyle]->mPrincipal,
                                               state.patternStyles[aStyle]->mForceWriteOnly,
                                               state.patternStyles[aStyle]->mCORSUsed);
       }
       ExtendMode mode;
       if (state.patternStyles[aStyle]->mRepeat == CanvasPattern::RepeatMode::NOREPEAT) {
         mode = ExtendMode::CLAMP;
       } else {
         mode = ExtendMode::REPEAT;
       }
       mPattern = new (mSurfacePattern.addr())
         SurfacePattern(state.patternStyles[aStyle]->mSurface, mode);
     }
     return *mPattern;
   }
   union {
     AlignedStorage2<ColorPattern> mColorPattern;
     AlignedStorage2<LinearGradientPattern> mLinearGradientPattern;
     AlignedStorage2<RadialGradientPattern> mRadialGradientPattern;
     AlignedStorage2<SurfacePattern> mSurfacePattern;
   };
   Pattern *mPattern;
 };
 /* This is an RAII based class that can be used as a drawtarget for
  * operations that need a shadow drawn. It will automatically provide a
  * temporary target when needed, and if so blend it back with a shadow.
  *
  * aBounds specifies the bounds of the drawing operation that will be
  * drawn to the target, it is given in device space! This function will
  * change aBounds to incorporate shadow bounds. If this is nullptr the drawing
  * operation will be assumed to cover an infinite rect.
  */
 class AdjustedTarget
 {
 public:
   typedef CanvasRenderingContext2D::ContextState ContextState;
   AdjustedTarget(CanvasRenderingContext2D *ctx,
                  mgfx::Rect *aBounds = nullptr)
     : mCtx(nullptr)
   {
     if (!ctx->NeedToDrawShadow()) {
       mTarget = ctx->mTarget;
       return;
     }
     mCtx = ctx;
     const ContextState &state = mCtx->CurrentState();
     mSigma = state.shadowBlur / 2.0f;
     if (mSigma > SIGMA_MAX) {
       mSigma = SIGMA_MAX;
     }
     Matrix transform = mCtx->mTarget->GetTransform();
     mTempRect = mgfx::Rect(0, 0, ctx->mWidth, ctx->mHeight);
     static const gfxFloat GAUSSIAN_SCALE_FACTOR = (3 * sqrt(2 * M_PI) / 4) * 1.5;
     int32_t blurRadius = (int32_t) floor(mSigma * GAUSSIAN_SCALE_FACTOR + 0.5);
     // We need to enlarge and possibly offset our temporary surface
     // so that things outside of the canvas may cast shadows.
     mTempRect.Inflate(Margin(blurRadius + std::max<Float>(state.shadowOffset.y, 0),
                              blurRadius + std::max<Float>(-state.shadowOffset.x, 0),
                              blurRadius + std::max<Float>(-state.shadowOffset.y, 0),
                              blurRadius + std::max<Float>(state.shadowOffset.x, 0)));
     if (aBounds) {
       // We actually include the bounds of the shadow blur, this makes it
       // easier to execute the actual blur on hardware, and shouldn't affect
       // the amount of pixels that need to be touched.
       aBounds->Inflate(Margin(blurRadius, blurRadius,
                               blurRadius, blurRadius));
       mTempRect = mTempRect.Intersect(*aBounds);
     }
     mTempRect.ScaleRoundOut(1.0f);
     transform._31 -= mTempRect.x;
     transform._32 -= mTempRect.y;
     mTarget =
       mCtx->mTarget->CreateShadowDrawTarget(IntSize(int32_t(mTempRect.width), int32_t(mTempRect.height)),
                                             SurfaceFormat::B8G8R8A8, mSigma);
     if (!mTarget) {
       // XXX - Deal with the situation where our temp size is too big to
       // fit in a texture.
       mTarget = ctx->mTarget;
       mCtx = nullptr;
     } else {
       mTarget->SetTransform(transform);
     }
   }
   ~AdjustedTarget()
   {
     if (!mCtx) {
       return;
     }
     RefPtr<SourceSurface> snapshot = mTarget->Snapshot();
     mCtx->mTarget->DrawSurfaceWithShadow(snapshot, mTempRect.TopLeft(),
                                          Color::FromABGR(mCtx->CurrentState().shadowColor),
                                          mCtx->CurrentState().shadowOffset, mSigma,
                                          mCtx->CurrentState().op);
   }
   operator DrawTarget*()
   {
     return mTarget;
   }
   DrawTarget* operator->()
   {
     return mTarget;
   }
 private:
   RefPtr<DrawTarget> mTarget;
   CanvasRenderingContext2D *mCtx;
   Float mSigma;
   mgfx::Rect mTempRect;
 };
 void
 CanvasGradient::AddColorStop(float offset, const nsAString& colorstr, ErrorResult& rv)
 {
   if (offset < 0.0 || offset > 1.0) {
     rv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   nsCSSValue value;
   nsCSSParser parser;
   if (!parser.ParseColorString(colorstr, nullptr, 0, value)) {
     rv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
     return;
   }
   nsIPresShell* presShell = nullptr;
   if (mCSSLoader) {
     nsIDocument *doc = mCSSLoader->GetDocument();
     if (doc)
       presShell = doc->GetShell();
   }
   nscolor color;
   if (!nsRuleNode::ComputeColor(value, presShell ? presShell->GetPresContext() : nullptr,
                                 nullptr, color)) {
     rv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
     return;
   }
   mStops = nullptr;
   GradientStop newStop;
   newStop.offset = offset;
   newStop.color = Color::FromABGR(color);
   mRawStops.AppendElement(newStop);
 }
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(CanvasGradient, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(CanvasGradient, Release)
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_1(CanvasGradient, mContext)
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(CanvasPattern, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(CanvasPattern, Release)
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_1(CanvasPattern, mContext)
 class CanvasRenderingContext2DUserData : public LayerUserData {
 public:
     CanvasRenderingContext2DUserData(CanvasRenderingContext2D *aContext)
     : mContext(aContext)
   {
     aContext->mUserDatas.AppendElement(this);
   }
   ~CanvasRenderingContext2DUserData()
   {
     if (mContext) {
       mContext->mUserDatas.RemoveElement(this);
     }
   }
   static void PreTransactionCallback(void* aData)
   {
     CanvasRenderingContext2DUserData* self =
       static_cast<CanvasRenderingContext2DUserData*>(aData);
     CanvasRenderingContext2D* context = self->mContext;
     if (!context || !context->mStream || !context->mTarget)
       return;
     // Since SkiaGL default to store drawing command until flush
     // We will have to flush it before present.
     context->mTarget->Flush();
   }
   static void DidTransactionCallback(void* aData)
   {
     CanvasRenderingContext2DUserData* self =
       static_cast<CanvasRenderingContext2DUserData*>(aData);
     if (self->mContext) {
       self->mContext->MarkContextClean();
     }
   }
   bool IsForContext(CanvasRenderingContext2D *aContext)
   {
     return mContext == aContext;
   }
   void Forget()
   {
     mContext = nullptr;
   }
 private:
   CanvasRenderingContext2D *mContext;
 };
 NS_IMPL_CYCLE_COLLECTING_ADDREF(CanvasRenderingContext2D)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(CanvasRenderingContext2D)
 NS_IMPL_CYCLE_COLLECTION_CLASS(CanvasRenderingContext2D)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CanvasRenderingContext2D)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mCanvasElement)
   for (uint32_t i = 0; i < tmp->mStyleStack.Length(); i++) {
     ImplCycleCollectionUnlink(tmp->mStyleStack[i].patternStyles[Style::STROKE]);
     ImplCycleCollectionUnlink(tmp->mStyleStack[i].patternStyles[Style::FILL]);
     ImplCycleCollectionUnlink(tmp->mStyleStack[i].gradientStyles[Style::STROKE]);
     ImplCycleCollectionUnlink(tmp->mStyleStack[i].gradientStyles[Style::FILL]);
   }
   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CanvasRenderingContext2D)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCanvasElement)
   for (uint32_t i = 0; i < tmp->mStyleStack.Length(); i++) {
     ImplCycleCollectionTraverse(cb, tmp->mStyleStack[i].patternStyles[Style::STROKE], "Stroke CanvasPattern");
     ImplCycleCollectionTraverse(cb, tmp->mStyleStack[i].patternStyles[Style::FILL], "Fill CanvasPattern");
     ImplCycleCollectionTraverse(cb, tmp->mStyleStack[i].gradientStyles[Style::STROKE], "Stroke CanvasGradient");
     ImplCycleCollectionTraverse(cb, tmp->mStyleStack[i].gradientStyles[Style::FILL], "Fill CanvasGradient");
   }
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(CanvasRenderingContext2D)
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(CanvasRenderingContext2D)
  if (nsCCUncollectableMarker::sGeneration && tmp->IsBlack()) {
    dom::Element* canvasElement = tmp->mCanvasElement;
     if (canvasElement) {
       if (canvasElement->IsPurple()) {
         canvasElement->RemovePurple();
       }
       dom::Element::MarkNodeChildren(canvasElement);
     }
     return true;
   }
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_END
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_BEGIN(CanvasRenderingContext2D)
   return nsCCUncollectableMarker::sGeneration && tmp->IsBlack();
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_END
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(CanvasRenderingContext2D)
   return nsCCUncollectableMarker::sGeneration && tmp->IsBlack();
 NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_END
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CanvasRenderingContext2D)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRY(nsICanvasRenderingContextInternal)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
 NS_INTERFACE_MAP_END
 /**
  ** CanvasRenderingContext2D impl
  **/
 // Initialize our static variables.
 uint32_t CanvasRenderingContext2D::sNumLivingContexts = 0;
 DrawTarget* CanvasRenderingContext2D::sErrorTarget = nullptr;
 CanvasRenderingContext2D::CanvasRenderingContext2D()
   : mForceSoftware(false), mZero(false), mOpaque(false), mResetLayer(true)
   , mIPC(false)
   , mStream(nullptr)
   , mIsEntireFrameInvalid(false)
   , mPredictManyRedrawCalls(false), mPathTransformWillUpdate(false)
   , mInvalidateCount(0)
 {
   sNumLivingContexts++;
   SetIsDOMBinding();
 }
 CanvasRenderingContext2D::~CanvasRenderingContext2D()
 {
   Reset();
   // Drop references from all CanvasRenderingContext2DUserData to this context
   for (uint32_t i = 0; i < mUserDatas.Length(); ++i) {
     mUserDatas[i]->Forget();
   }
   sNumLivingContexts--;
   if (!sNumLivingContexts) {
     NS_IF_RELEASE(sErrorTarget);
   }
   RemoveDemotableContext(this);
 }
 JSObject*
 CanvasRenderingContext2D::WrapObject(JSContext *cx)
 {
   return CanvasRenderingContext2DBinding::Wrap(cx, this);
 }
 bool
 CanvasRenderingContext2D::ParseColor(const nsAString& aString,
                                      nscolor* aColor)
 {
   nsIDocument* document = mCanvasElement
                           ? mCanvasElement->OwnerDoc()
                           : nullptr;
   // Pass the CSS Loader object to the parser, to allow parser error
   // reports to include the outer window ID.
   nsCSSParser parser(document ? document->CSSLoader() : nullptr);
   nsCSSValue value;
   if (!parser.ParseColorString(aString, nullptr, 0, value)) {
     return false;
   }
   if (value.IsNumericColorUnit()) {
     // if we already have a color we can just use it directly
     *aColor = value.GetColorValue();
   } else {
     // otherwise resolve it
     nsIPresShell* presShell = GetPresShell();
     nsRefPtr<nsStyleContext> parentContext;
     if (mCanvasElement && mCanvasElement->IsInDoc()) {
       // Inherit from the canvas element.
       parentContext = nsComputedDOMStyle::GetStyleContextForElement(
         mCanvasElement, nullptr, presShell);
     }
     unused << nsRuleNode::ComputeColor(
       value, presShell ? presShell->GetPresContext() : nullptr, parentContext,
       *aColor);
   }
   return true;
 }
 #ifdef ACCESSIBILITY
 PLDHashOperator
 CanvasRenderingContext2D::RemoveHitRegionProperty(RegionInfo* aEntry, void*)
 {
   aEntry->mElement->DeleteProperty(nsGkAtoms::hitregion);
   return PL_DHASH_NEXT;
 }
 #endif
 nsresult
 CanvasRenderingContext2D::Reset()
 {
   if (mCanvasElement) {
     mCanvasElement->InvalidateCanvas();
   }
   // only do this for non-docshell created contexts,
   // since those are the ones that we created a surface for
   if (mTarget && IsTargetValid() && !mDocShell) {
     gCanvasAzureMemoryUsed -= mWidth * mHeight * 4;
   }
   mTarget = nullptr;
   mStream = nullptr;
   // reset hit regions
 #ifdef ACCESSIBILITY
   mHitRegionsOptions.EnumerateEntries(RemoveHitRegionProperty, nullptr);
 #endif
   mHitRegionsOptions.Clear();
   // Since the target changes the backing texture will change, and this will
   // no longer be valid.
   mIsEntireFrameInvalid = false;
   mPredictManyRedrawCalls = false;
   return NS_OK;
 }
 void
 CanvasRenderingContext2D::SetStyleFromString(const nsAString& str,
                                              Style whichStyle)
 {
   MOZ_ASSERT(!str.IsVoid());
   nscolor color;
   if (!ParseColor(str, &color)) {
     return;
   }
   CurrentState().SetColorStyle(whichStyle, color);
 }
 void
 CanvasRenderingContext2D::GetStyleAsUnion(OwningStringOrCanvasGradientOrCanvasPattern& aValue,
                                           Style aWhichStyle)
 {
   const ContextState &state = CurrentState();
   if (state.patternStyles[aWhichStyle]) {
     aValue.SetAsCanvasPattern() = state.patternStyles[aWhichStyle];
   } else if (state.gradientStyles[aWhichStyle]) {
     aValue.SetAsCanvasGradient() = state.gradientStyles[aWhichStyle];
   } else {
     StyleColorToString(state.colorStyles[aWhichStyle], aValue.SetAsString());
   }
 }
 // static
 void
 CanvasRenderingContext2D::StyleColorToString(const nscolor& aColor, nsAString& aStr)
 {
   // We can't reuse the normal CSS color stringification code,
   // because the spec calls for a different algorithm for canvas.
   if (NS_GET_A(aColor) == 255) {
     CopyUTF8toUTF16(nsPrintfCString("#%02x%02x%02x",
                                     NS_GET_R(aColor),
                                     NS_GET_G(aColor),
                                     NS_GET_B(aColor)),
                     aStr);
   } else {
     CopyUTF8toUTF16(nsPrintfCString("rgba(%d, %d, %d, ",
                                     NS_GET_R(aColor),
                                     NS_GET_G(aColor),
                                     NS_GET_B(aColor)),
                     aStr);
     aStr.AppendFloat(nsStyleUtil::ColorComponentToFloat(NS_GET_A(aColor)));
     aStr.Append(')');
   }
 }
 nsresult
 CanvasRenderingContext2D::Redraw()
 {
   if (mIsEntireFrameInvalid) {
     return NS_OK;
   }
   mIsEntireFrameInvalid = true;
   if (!mCanvasElement) {
     NS_ASSERTION(mDocShell, "Redraw with no canvas element or docshell!");
     return NS_OK;
   }
   nsSVGEffects::InvalidateDirectRenderingObservers(mCanvasElement);
   mCanvasElement->InvalidateCanvasContent(nullptr);
   return NS_OK;
 }
 void
 CanvasRenderingContext2D::Redraw(const mgfx::Rect &r)
 {
   ++mInvalidateCount;
   if (mIsEntireFrameInvalid) {
     return;
   }
   if (mPredictManyRedrawCalls ||
     mInvalidateCount > kCanvasMaxInvalidateCount) {
     Redraw();
     return;
   }
   if (!mCanvasElement) {
     NS_ASSERTION(mDocShell, "Redraw with no canvas element or docshell!");
     return;
   }
   nsSVGEffects::InvalidateDirectRenderingObservers(mCanvasElement);
   mCanvasElement->InvalidateCanvasContent(&r);
 }
 void
 CanvasRenderingContext2D::RedrawUser(const gfxRect& r)
 {
   if (mIsEntireFrameInvalid) {
     ++mInvalidateCount;
     return;
   }
   mgfx::Rect newr =
     mTarget->GetTransform().TransformBounds(ToRect(r));
   Redraw(newr);
 }
 void CanvasRenderingContext2D::Demote()
 {
   if (!IsTargetValid() || mForceSoftware || !mStream)
     return;
   RemoveDemotableContext(this);
   RefPtr<SourceSurface> snapshot = mTarget->Snapshot();
   RefPtr<DrawTarget> oldTarget = mTarget;
   mTarget = nullptr;
   mStream = nullptr;
   mResetLayer = true;
   mForceSoftware = true;
   // Recreate target, now demoted to software only
   EnsureTarget();
   if (!IsTargetValid())
     return;
   // Restore the content from the old DrawTarget
   mgfx::Rect r(0, 0, mWidth, mHeight);
   mTarget->DrawSurface(snapshot, r, r);
   // Restore the clips and transform
   for (uint32_t i = 0; i < CurrentState().clipsPushed.size(); i++) {
     mTarget->PushClip(CurrentState().clipsPushed[i]);
   }
   mTarget->SetTransform(oldTarget->GetTransform());
 }
 std::vector<CanvasRenderingContext2D*>&
 CanvasRenderingContext2D::DemotableContexts()
 {
   static std::vector<CanvasRenderingContext2D*> contexts;
   return contexts;
 }
 void
 CanvasRenderingContext2D::DemoteOldestContextIfNecessary()
 {
   const size_t kMaxContexts = 64;
   std::vector<CanvasRenderingContext2D*>& contexts = DemotableContexts();
   if (contexts.size() < kMaxContexts)
     return;
   CanvasRenderingContext2D* oldest = contexts.front();
   oldest->Demote();
 }
 void
 CanvasRenderingContext2D::AddDemotableContext(CanvasRenderingContext2D* context)
 {
   std::vector<CanvasRenderingContext2D*>::iterator iter = std::find(DemotableContexts().begin(), DemotableContexts().end(), context);
   if (iter != DemotableContexts().end())
     return;
   DemotableContexts().push_back(context);
 }
 void
 CanvasRenderingContext2D::RemoveDemotableContext(CanvasRenderingContext2D* context)
 {
   std::vector<CanvasRenderingContext2D*>::iterator iter = std::find(DemotableContexts().begin(), DemotableContexts().end(), context);
   if (iter != DemotableContexts().end())
     DemotableContexts().erase(iter);
 }
 bool
 CheckSizeForSkiaGL(IntSize size) {
   MOZ_ASSERT(NS_IsMainThread());
   int minsize = Preferences::GetInt("gfx.canvas.min-size-for-skia-gl", 128);
   if (size.width < minsize || size.height < minsize) {
     return false;
   }
   // Maximum pref allows 3 different options:
   //  0   means unlimited size
   //  > 0 means use value as an absolute threshold
   //  < 0 means use the number of screen pixels as a threshold
   int maxsize = Preferences::GetInt("gfx.canvas.max-size-for-skia-gl", 0);
   // unlimited max size
   if (!maxsize) {
     return true;
   }
   // absolute max size threshold
   if (maxsize > 0) {
     return size.width <= maxsize && size.height <= maxsize;
   }
   // Cache the number of pixels on the primary screen
   static int32_t gScreenPixels = -1;
   if (gScreenPixels < 0) {
     nsCOMPtr<nsIScreenManager> screenManager =
       do_GetService("@mozilla.org/gfx/screenmanager;1");
     if (screenManager) {
       nsCOMPtr<nsIScreen> primaryScreen;
       screenManager->GetPrimaryScreen(getter_AddRefs(primaryScreen));
       if (primaryScreen) {
         int32_t x, y, width, height;
         primaryScreen->GetRect(&x, &y, &width, &height);
         gScreenPixels = width * height;
       }
     }
   }
   // screen size acts as max threshold
   return gScreenPixels < 0 || (size.width * size.height) <= gScreenPixels;
 }
 void
 CanvasRenderingContext2D::EnsureTarget()
 {
   if (mTarget) {
     return;
   }
    // Check that the dimensions are sane
   IntSize size(mWidth, mHeight);
   if (size.width <= 0xFFFF && size.height <= 0xFFFF &&
       size.width >= 0 && size.height >= 0) {
     SurfaceFormat format = GetSurfaceFormat();
     nsIDocument* ownerDoc = nullptr;
     if (mCanvasElement) {
       ownerDoc = mCanvasElement->OwnerDoc();
     }
     nsRefPtr<LayerManager> layerManager = nullptr;
     if (ownerDoc) {
       layerManager =
         nsContentUtils::PersistentLayerManagerForDocument(ownerDoc);
     }
      if (layerManager) {
       if (gfxPlatform::GetPlatform()->UseAcceleratedSkiaCanvas() &&
           !mForceSoftware &&
           CheckSizeForSkiaGL(size)) {
         DemoteOldestContextIfNecessary();
         SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
 #if USE_SKIA
         if (glue && glue->GetGrContext() && glue->GetGLContext()) {
           mTarget = Factory::CreateDrawTargetSkiaWithGrContext(glue->GetGrContext(), size, format);
           if (mTarget) {
             mStream = gfx::SurfaceStream::CreateForType(SurfaceStreamType::TripleBuffer, glue->GetGLContext());
             AddDemotableContext(this);
           } else {
             printf_stderr("Failed to create a SkiaGL DrawTarget, falling back to software\n");
           }
         }
 #endif
         if (!mTarget) {
           mTarget = layerManager->CreateDrawTarget(size, format);
         }
       } else
         mTarget = layerManager->CreateDrawTarget(size, format);
      } else {
         mTarget = gfxPlatform::GetPlatform()->CreateOffscreenCanvasDrawTarget(size, format);
      }
   }
   if (mTarget) {
     static bool registered = false;
     if (!registered) {
       registered = true;
       RegisterStrongMemoryReporter(new Canvas2dPixelsReporter());
     }
     gCanvasAzureMemoryUsed += mWidth * mHeight * 4;
     JSContext* context = nsContentUtils::GetCurrentJSContext();
     if (context) {
       JS_updateMallocCounter(context, mWidth * mHeight * 4);
     }
     mTarget->ClearRect(mgfx::Rect(Point(0, 0), Size(mWidth, mHeight)));
     // Force a full layer transaction since we didn't have a layer before
     // and now we might need one.
     if (mCanvasElement) {
       mCanvasElement->InvalidateCanvas();
     }
     // Calling Redraw() tells our invalidation machinery that the entire
     // canvas is already invalid, which can speed up future drawing.
     Redraw();
   } else {
     EnsureErrorTarget();
     mTarget = sErrorTarget;
   }
 }
 #ifdef DEBUG
 int32_t
 CanvasRenderingContext2D::GetWidth() const
 {
   return mWidth;
 }
 int32_t
 CanvasRenderingContext2D::GetHeight() const
 {
   return mHeight;
 }
 #endif
 NS_IMETHODIMP
 CanvasRenderingContext2D::SetDimensions(int32_t width, int32_t height)
 {
   ClearTarget();
   // Zero sized surfaces can cause problems.
   mZero = false;
   if (height == 0) {
     height = 1;
     mZero = true;
   }
   if (width == 0) {
     width = 1;
     mZero = true;
   }
   mWidth = width;
   mHeight = height;
   return NS_OK;
 }
 void
 CanvasRenderingContext2D::ClearTarget()
 {
   Reset();
   mResetLayer = true;
   // set up the initial canvas defaults
   mStyleStack.Clear();
   mPathBuilder = nullptr;
   mPath = nullptr;
   mDSPathBuilder = nullptr;
   ContextState *state = mStyleStack.AppendElement();
   state->globalAlpha = 1.0;
   state->colorStyles[Style::FILL] = NS_RGB(0,0,0);
   state->colorStyles[Style::STROKE] = NS_RGB(0,0,0);
   state->shadowColor = NS_RGBA(0,0,0,0);
 }
 NS_IMETHODIMP
 CanvasRenderingContext2D::InitializeWithSurface(nsIDocShell *shell,
                                                 gfxASurface *surface,
                                                 int32_t width,
                                                 int32_t height)
 {
   mDocShell = shell;
   SetDimensions(width, height);
   mTarget = gfxPlatform::GetPlatform()->
     CreateDrawTargetForSurface(surface, IntSize(width, height));
   if (!mTarget) {
     EnsureErrorTarget();
     mTarget = sErrorTarget;
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 CanvasRenderingContext2D::SetIsOpaque(bool isOpaque)
 {
   if (isOpaque != mOpaque) {
     mOpaque = isOpaque;
     ClearTarget();
   }
   if (mOpaque) {
     EnsureTarget();
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 CanvasRenderingContext2D::SetIsIPC(bool isIPC)
 {
   if (isIPC != mIPC) {
     mIPC = isIPC;
     ClearTarget();
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 CanvasRenderingContext2D::SetContextOptions(JSContext* aCx, JS::Handle<JS::Value> aOptions)
 {
   if (aOptions.isNullOrUndefined()) {
     return NS_OK;
   }
   ContextAttributes2D attributes;
   NS_ENSURE_TRUE(attributes.Init(aCx, aOptions), NS_ERROR_UNEXPECTED);
   if (Preferences::GetBool("gfx.canvas.willReadFrequently.enable", false)) {
     // Use software when there is going to be a lot of readback
     mForceSoftware = attributes.mWillReadFrequently;
   }
   if (!attributes.mAlpha) {
     SetIsOpaque(true);
   }
   return NS_OK;
 }
 void
 CanvasRenderingContext2D::GetImageBuffer(uint8_t** aImageBuffer,
                                          int32_t* aFormat)
 {
   *aImageBuffer = nullptr;
   *aFormat = 0;
   EnsureTarget();
   RefPtr<SourceSurface> snapshot = mTarget->Snapshot();
   if (!snapshot) {
     return;
   }
   RefPtr<DataSourceSurface> data = snapshot->GetDataSurface();
   if (!data || data->GetSize() != IntSize(mWidth, mHeight)) {
     return;
   }
   *aImageBuffer = SurfaceToPackedBGRA(data);
   *aFormat = imgIEncoder::INPUT_FORMAT_HOSTARGB;
 }
 NS_IMETHODIMP
 CanvasRenderingContext2D::GetInputStream(const char *aMimeType,
                                          const char16_t *aEncoderOptions,
                                          nsIInputStream **aStream)
 {
   nsCString enccid("@mozilla.org/image/encoder;2?type=");
   enccid += aMimeType;
   nsCOMPtr<imgIEncoder> encoder = do_CreateInstance(enccid.get());
   if (!encoder) {
     return NS_ERROR_FAILURE;
   }
   nsAutoArrayPtr<uint8_t> imageBuffer;
   int32_t format = 0;
   GetImageBuffer(getter_Transfers(imageBuffer), &format);
   if (!imageBuffer) {
     return NS_ERROR_FAILURE;
   }
   return ImageEncoder::GetInputStream(mWidth, mHeight, imageBuffer, format,
                                       encoder, aEncoderOptions, aStream);
 }
 SurfaceFormat
 CanvasRenderingContext2D::GetSurfaceFormat() const
 {
   return mOpaque ? SurfaceFormat::B8G8R8X8 : SurfaceFormat::B8G8R8A8;
 }
 //
 // state
 //
 void
 CanvasRenderingContext2D::Save()
 {
   EnsureTarget();
   mStyleStack[mStyleStack.Length() - 1].transform = mTarget->GetTransform();
   mStyleStack.SetCapacity(mStyleStack.Length() + 1);
   mStyleStack.AppendElement(CurrentState());
 }
 void
 CanvasRenderingContext2D::Restore()
 {
   if (mStyleStack.Length() - 1 == 0)
     return;
   TransformWillUpdate();
   for (uint32_t i = 0; i < CurrentState().clipsPushed.size(); i++) {
     mTarget->PopClip();
   }
   mStyleStack.RemoveElementAt(mStyleStack.Length() - 1);
   mTarget->SetTransform(CurrentState().transform);
 }
 //
 // transformations
 //
 void
 CanvasRenderingContext2D::Scale(double x, double y, ErrorResult& error)
 {
   TransformWillUpdate();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix newMatrix = mTarget->GetTransform();
   mTarget->SetTransform(newMatrix.Scale(x, y));
 }
 void
 CanvasRenderingContext2D::Rotate(double angle, ErrorResult& error)
 {
   TransformWillUpdate();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix rotation = Matrix::Rotation(angle);
   mTarget->SetTransform(rotation * mTarget->GetTransform());
 }
 void
 CanvasRenderingContext2D::Translate(double x, double y, ErrorResult& error)
 {
   TransformWillUpdate();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix newMatrix = mTarget->GetTransform();
   mTarget->SetTransform(newMatrix.Translate(x, y));
 }
 void
 CanvasRenderingContext2D::Transform(double m11, double m12, double m21,
                                     double m22, double dx, double dy,
                                     ErrorResult& error)
 {
   TransformWillUpdate();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix matrix(m11, m12, m21, m22, dx, dy);
   mTarget->SetTransform(matrix * mTarget->GetTransform());
 }
 void
 CanvasRenderingContext2D::SetTransform(double m11, double m12,
                                        double m21, double m22,
                                        double dx, double dy,
                                        ErrorResult& error)
 {
   TransformWillUpdate();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix matrix(m11, m12, m21, m22, dx, dy);
   mTarget->SetTransform(matrix);
 }
 static void
 MatrixToJSObject(JSContext* cx, const Matrix& matrix,
                  JS::MutableHandle<JSObject*> result, ErrorResult& error)
 {
   double elts[6] = { matrix._11, matrix._12,
                      matrix._21, matrix._22,
                      matrix._31, matrix._32 };
   // XXX Should we enter GetWrapper()'s compartment?
   JS::Rooted<JS::Value> val(cx);
   if (!ToJSValue(cx, elts, &val)) {
     error.Throw(NS_ERROR_OUT_OF_MEMORY);
   } else {
     result.set(&val.toObject());
   }
 }
 static bool
 ObjectToMatrix(JSContext* cx, JS::Handle<JSObject*> obj, Matrix& matrix,
                ErrorResult& error)
 {
   uint32_t length;
   if (!JS_GetArrayLength(cx, obj, &length) || length != 6) {
     // Not an array-like thing or wrong size
     error.Throw(NS_ERROR_INVALID_ARG);
     return false;
   }
   Float* elts[] = { &matrix._11, &matrix._12, &matrix._21, &matrix._22,
                     &matrix._31, &matrix._32 };
   for (uint32_t i = 0; i < 6; ++i) {
     JS::Rooted<JS::Value> elt(cx);
     double d;
     if (!JS_GetElement(cx, obj, i, &elt)) {
       error.Throw(NS_ERROR_FAILURE);
       return false;
     }
     if (!CoerceDouble(elt, &d)) {
       error.Throw(NS_ERROR_INVALID_ARG);
       return false;
     }
     if (!FloatValidate(d)) {
       // This is weird, but it's the behavior of SetTransform()
       return false;
     }
     *elts[i] = Float(d);
   }
   return true;
 }
 void
 CanvasRenderingContext2D::SetMozCurrentTransform(JSContext* cx,
                                                  JS::Handle<JSObject*> currentTransform,
                                                  ErrorResult& error)
 {
   EnsureTarget();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix newCTM;
   if (ObjectToMatrix(cx, currentTransform, newCTM, error)) {
     mTarget->SetTransform(newCTM);
   }
 }
 void
 CanvasRenderingContext2D::GetMozCurrentTransform(JSContext* cx,
                                                  JS::MutableHandle<JSObject*> result,
                                                  ErrorResult& error) const
 {
   MatrixToJSObject(cx, mTarget ? mTarget->GetTransform() : Matrix(),
                    result, error);
 }
 void
 CanvasRenderingContext2D::SetMozCurrentTransformInverse(JSContext* cx,
                                                         JS::Handle<JSObject*> currentTransform,
                                                         ErrorResult& error)
 {
   EnsureTarget();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   Matrix newCTMInverse;
   if (ObjectToMatrix(cx, currentTransform, newCTMInverse, error)) {
     // XXX ERRMSG we need to report an error to developers here! (bug 329026)
     if (newCTMInverse.Invert()) {
       mTarget->SetTransform(newCTMInverse);
     }
   }
 }
 void
 CanvasRenderingContext2D::GetMozCurrentTransformInverse(JSContext* cx,
                                                         JS::MutableHandle<JSObject*> result,
                                                         ErrorResult& error) const
 {
   if (!mTarget) {
     MatrixToJSObject(cx, Matrix(), result, error);
     return;
   }
   Matrix ctm = mTarget->GetTransform();
   if (!ctm.Invert()) {
     double NaN = JSVAL_TO_DOUBLE(JS_GetNaNValue(cx));
     ctm = Matrix(NaN, NaN, NaN, NaN, NaN, NaN);
   }
   MatrixToJSObject(cx, ctm, result, error);
 }
 //
 // colors
 //
 void
 CanvasRenderingContext2D::SetStyleFromUnion(const StringOrCanvasGradientOrCanvasPattern& value,
                                             Style whichStyle)
 {
   if (value.IsString()) {
     SetStyleFromString(value.GetAsString(), whichStyle);
     return;
   }
   if (value.IsCanvasGradient()) {
     SetStyleFromGradient(value.GetAsCanvasGradient(), whichStyle);
     return;
   }
   if (value.IsCanvasPattern()) {
     SetStyleFromPattern(value.GetAsCanvasPattern(), whichStyle);
     return;
   }
   MOZ_ASSUME_UNREACHABLE("Invalid union value");
 }
 void
 CanvasRenderingContext2D::SetFillRule(const nsAString& aString)
 {
   FillRule rule;
   if (aString.EqualsLiteral("evenodd"))
     rule = FillRule::FILL_EVEN_ODD;
   else if (aString.EqualsLiteral("nonzero"))
     rule = FillRule::FILL_WINDING;
   else
     return;
   CurrentState().fillRule = rule;
 }
 void
 CanvasRenderingContext2D::GetFillRule(nsAString& aString)
 {
   switch (CurrentState().fillRule) {
   case FillRule::FILL_WINDING:
     aString.AssignLiteral("nonzero"); break;
   case FillRule::FILL_EVEN_ODD:
     aString.AssignLiteral("evenodd"); break;
   }
 }
 //
 // gradients and patterns
 //
 already_AddRefed<CanvasGradient>
 CanvasRenderingContext2D::CreateLinearGradient(double x0, double y0, double x1, double y1)
 {
   nsIDocument *doc = mCanvasElement ? mCanvasElement->OwnerDoc() : nullptr;
   mozilla::css::Loader *cssLoader = doc ? doc->CSSLoader() : nullptr;
   nsRefPtr<CanvasGradient> grad =
     new CanvasLinearGradient(this, cssLoader, Point(x0, y0), Point(x1, y1));
   return grad.forget();
 }
 already_AddRefed<CanvasGradient>
 CanvasRenderingContext2D::CreateRadialGradient(double x0, double y0, double r0,
                                                double x1, double y1, double r1,
                                                ErrorResult& aError)
 {
   if (r0 < 0.0 || r1 < 0.0) {
     aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return nullptr;
   }
   nsIDocument *doc = mCanvasElement ? mCanvasElement->OwnerDoc() : nullptr;
   mozilla::css::Loader *cssLoader = doc ? doc->CSSLoader() : nullptr;
   nsRefPtr<CanvasGradient> grad =
     new CanvasRadialGradient(this, cssLoader, Point(x0, y0), r0, Point(x1, y1), r1);
   return grad.forget();
 }
 already_AddRefed<CanvasPattern>
 CanvasRenderingContext2D::CreatePattern(const HTMLImageOrCanvasOrVideoElement& element,
                                         const nsAString& repeat,
                                         ErrorResult& error)
 {
   CanvasPattern::RepeatMode repeatMode =
     CanvasPattern::RepeatMode::NOREPEAT;
   if (repeat.IsEmpty() || repeat.EqualsLiteral("repeat")) {
     repeatMode = CanvasPattern::RepeatMode::REPEAT;
   } else if (repeat.EqualsLiteral("repeat-x")) {
     repeatMode = CanvasPattern::RepeatMode::REPEATX;
   } else if (repeat.EqualsLiteral("repeat-y")) {
     repeatMode = CanvasPattern::RepeatMode::REPEATY;
   } else if (repeat.EqualsLiteral("no-repeat")) {
     repeatMode = CanvasPattern::RepeatMode::NOREPEAT;
   } else {
     error.Throw(NS_ERROR_DOM_SYNTAX_ERR);
     return nullptr;
   }
   Element* htmlElement;
   if (element.IsHTMLCanvasElement()) {
     HTMLCanvasElement* canvas = &element.GetAsHTMLCanvasElement();
     htmlElement = canvas;
     nsIntSize size = canvas->GetSize();
     if (size.width == 0 || size.height == 0) {
       error.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
       return nullptr;
     }
     // Special case for Canvas, which could be an Azure canvas!
     nsICanvasRenderingContextInternal *srcCanvas = canvas->GetContextAtIndex(0);
     if (srcCanvas) {
       // This might not be an Azure canvas!
       RefPtr<SourceSurface> srcSurf = srcCanvas->GetSurfaceSnapshot();
       nsRefPtr<CanvasPattern> pat =
         new CanvasPattern(this, srcSurf, repeatMode, htmlElement->NodePrincipal(), canvas->IsWriteOnly(), false);
       return pat.forget();
     }
   } else if (element.IsHTMLImageElement()) {
     htmlElement = &element.GetAsHTMLImageElement();
   } else {
     htmlElement = &element.GetAsHTMLVideoElement();
   }
   EnsureTarget();
   // The canvas spec says that createPattern should use the first frame
   // of animated images
   nsLayoutUtils::SurfaceFromElementResult res =
     nsLayoutUtils::SurfaceFromElement(htmlElement,
       nsLayoutUtils::SFE_WANT_FIRST_FRAME, mTarget);
   if (!res.mSourceSurface) {
     error.Throw(NS_ERROR_NOT_AVAILABLE);
     return nullptr;
   }
   nsRefPtr<CanvasPattern> pat =
     new CanvasPattern(this, res.mSourceSurface, repeatMode, res.mPrincipal,
                              res.mIsWriteOnly, res.mCORSUsed);
   return pat.forget();
 }
 //
 // shadows
 //
 void
 CanvasRenderingContext2D::SetShadowColor(const nsAString& shadowColor)
 {
   nscolor color;
   if (!ParseColor(shadowColor, &color)) {
     return;
   }
   CurrentState().shadowColor = color;
 }
 //
 // rects
 //
 void
 CanvasRenderingContext2D::ClearRect(double x, double y, double w,
                                     double h)
 {
   if (!mTarget) {
     return;
   }
   mTarget->ClearRect(mgfx::Rect(x, y, w, h));
   RedrawUser(gfxRect(x, y, w, h));
 }
 void
 CanvasRenderingContext2D::FillRect(double x, double y, double w,
                                    double h)
 {
   const ContextState &state = CurrentState();
   if (state.patternStyles[Style::FILL]) {
     CanvasPattern::RepeatMode repeat =
       state.patternStyles[Style::FILL]->mRepeat;
     // In the FillRect case repeat modes are easy to deal with.
     bool limitx = repeat == CanvasPattern::RepeatMode::NOREPEAT || repeat == CanvasPattern::RepeatMode::REPEATY;
     bool limity = repeat == CanvasPattern::RepeatMode::NOREPEAT || repeat == CanvasPattern::RepeatMode::REPEATX;
     IntSize patternSize =
       state.patternStyles[Style::FILL]->mSurface->GetSize();
     // We always need to execute painting for non-over operators, even if
     // we end up with w/h = 0.
     if (limitx) {
       if (x < 0) {
         w += x;
         if (w < 0) {
           w = 0;
         }
         x = 0;
       }
       if (x + w > patternSize.width) {
         w = patternSize.width - x;
         if (w < 0) {
           w = 0;
         }
       }
     }
     if (limity) {
       if (y < 0) {
         h += y;
         if (h < 0) {
           h = 0;
         }
         y = 0;
       }
       if (y + h > patternSize.height) {
         h = patternSize.height - y;
         if (h < 0) {
           h = 0;
         }
       }
     }
   }
   mgfx::Rect bounds;
   EnsureTarget();
   if (NeedToDrawShadow()) {
     bounds = mgfx::Rect(x, y, w, h);
     bounds = mTarget->GetTransform().TransformBounds(bounds);
   }
   AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
     FillRect(mgfx::Rect(x, y, w, h),
              CanvasGeneralPattern().ForStyle(this, Style::FILL, mTarget),
              DrawOptions(state.globalAlpha, UsedOperation()));
   RedrawUser(gfxRect(x, y, w, h));
 }
 void
 CanvasRenderingContext2D::StrokeRect(double x, double y, double w,
                                      double h)
 {
   const ContextState &state = CurrentState();
   mgfx::Rect bounds;
   if (!w && !h) {
     return;
   }
   EnsureTarget();
   if (!IsTargetValid()) {
     return;
   }
   if (NeedToDrawShadow()) {
     bounds = mgfx::Rect(x - state.lineWidth / 2.0f, y - state.lineWidth / 2.0f,
                         w + state.lineWidth, h + state.lineWidth);
     bounds = mTarget->GetTransform().TransformBounds(bounds);
   }
   if (!h) {
     CapStyle cap = CapStyle::BUTT;
     if (state.lineJoin == JoinStyle::ROUND) {
       cap = CapStyle::ROUND;
     }
     AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
       StrokeLine(Point(x, y), Point(x + w, y),
                   CanvasGeneralPattern().ForStyle(this, Style::STROKE, mTarget),
                   StrokeOptions(state.lineWidth, state.lineJoin,
                                 cap, state.miterLimit,
                                 state.dash.Length(),
                                 state.dash.Elements(),
                                 state.dashOffset),
                   DrawOptions(state.globalAlpha, UsedOperation()));
     return;
   }
   if (!w) {
     CapStyle cap = CapStyle::BUTT;
     if (state.lineJoin == JoinStyle::ROUND) {
       cap = CapStyle::ROUND;
     }
     AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
       StrokeLine(Point(x, y), Point(x, y + h),
                   CanvasGeneralPattern().ForStyle(this, Style::STROKE, mTarget),
                   StrokeOptions(state.lineWidth, state.lineJoin,
                                 cap, state.miterLimit,
                                 state.dash.Length(),
                                 state.dash.Elements(),
                                 state.dashOffset),
                   DrawOptions(state.globalAlpha, UsedOperation()));
     return;
   }
   AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
     StrokeRect(mgfx::Rect(x, y, w, h),
                 CanvasGeneralPattern().ForStyle(this, Style::STROKE, mTarget),
                 StrokeOptions(state.lineWidth, state.lineJoin,
                               state.lineCap, state.miterLimit,
                               state.dash.Length(),
                               state.dash.Elements(),
                               state.dashOffset),
                 DrawOptions(state.globalAlpha, UsedOperation()));
   Redraw();
 }
 //
 // path bits
 //
 void
 CanvasRenderingContext2D::BeginPath()
 {
   mPath = nullptr;
   mPathBuilder = nullptr;
   mDSPathBuilder = nullptr;
   mPathTransformWillUpdate = false;
 }
 void
 CanvasRenderingContext2D::Fill(const CanvasWindingRule& winding)
 {
   EnsureUserSpacePath(winding);
   if (!mPath) {
     return;
   }
   mgfx::Rect bounds;
   if (NeedToDrawShadow()) {
     bounds = mPath->GetBounds(mTarget->GetTransform());
   }
   AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
     Fill(mPath, CanvasGeneralPattern().ForStyle(this, Style::FILL, mTarget),
          DrawOptions(CurrentState().globalAlpha, UsedOperation()));
   Redraw();
 }
 void CanvasRenderingContext2D::Fill(const CanvasPath& path, const CanvasWindingRule& winding)
 {
   EnsureTarget();
   RefPtr<gfx::Path> gfxpath = path.GetPath(winding, mTarget);
   if (!gfxpath) {
     return;
   }
   mgfx::Rect bounds;
   if (NeedToDrawShadow()) {
     bounds = gfxpath->GetBounds(mTarget->GetTransform());
   }
   AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
     Fill(gfxpath, CanvasGeneralPattern().ForStyle(this, Style::FILL, mTarget),
          DrawOptions(CurrentState().globalAlpha, UsedOperation()));
   Redraw();
 }
 void
 CanvasRenderingContext2D::Stroke()
 {
   EnsureUserSpacePath();
   if (!mPath) {
     return;
   }
   const ContextState &state = CurrentState();
   StrokeOptions strokeOptions(state.lineWidth, state.lineJoin,
                               state.lineCap, state.miterLimit,
                               state.dash.Length(), state.dash.Elements(),
                               state.dashOffset);
   mgfx::Rect bounds;
   if (NeedToDrawShadow()) {
     bounds =
       mPath->GetStrokedBounds(strokeOptions, mTarget->GetTransform());
   }
   AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
     Stroke(mPath, CanvasGeneralPattern().ForStyle(this, Style::STROKE, mTarget),
            strokeOptions, DrawOptions(state.globalAlpha, UsedOperation()));
   Redraw();
 }
 void
 CanvasRenderingContext2D::Stroke(const CanvasPath& path)
 {
   EnsureTarget();
   RefPtr<gfx::Path> gfxpath = path.GetPath(CanvasWindingRule::Nonzero, mTarget);
   if (!gfxpath) {
     return;
   }
   const ContextState &state = CurrentState();
   StrokeOptions strokeOptions(state.lineWidth, state.lineJoin,
                               state.lineCap, state.miterLimit,
                               state.dash.Length(), state.dash.Elements(),
                               state.dashOffset);
   mgfx::Rect bounds;
   if (NeedToDrawShadow()) {
     bounds =
       gfxpath->GetStrokedBounds(strokeOptions, mTarget->GetTransform());
   }
   AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
     Stroke(gfxpath, CanvasGeneralPattern().ForStyle(this, Style::STROKE, mTarget),
            strokeOptions, DrawOptions(state.globalAlpha, UsedOperation()));
   Redraw();
 }
 void CanvasRenderingContext2D::DrawFocusIfNeeded(mozilla::dom::Element& aElement)
 {
   EnsureUserSpacePath();
   if (!mPath) {
     return;
   }
   if(DrawCustomFocusRing(aElement)) {
     Save();
     // set state to conforming focus state
     ContextState& state = CurrentState();
     state.globalAlpha = 1.0;
     state.shadowBlur = 0;
     state.shadowOffset.x = 0;
     state.shadowOffset.y = 0;
     state.op = mozilla::gfx::CompositionOp::OP_OVER;
     state.lineCap = CapStyle::BUTT;
     state.lineJoin = mozilla::gfx::JoinStyle::MITER_OR_BEVEL;
     state.lineWidth = 1;
     CurrentState().dash.Clear();
     // color and style of the rings is the same as for image maps
     // set the background focus color
     CurrentState().SetColorStyle(Style::STROKE, NS_RGBA(255, 255, 255, 255));
     // draw the focus ring
     Stroke();
     // set dashing for foreground
     FallibleTArray<mozilla::gfx::Float>& dash = CurrentState().dash;
     dash.AppendElement(1);
     dash.AppendElement(1);
     // set the foreground focus color
     CurrentState().SetColorStyle(Style::STROKE, NS_RGBA(0,0,0, 255));
     // draw the focus ring
     Stroke();
     Restore();
   }
 }
 bool CanvasRenderingContext2D::DrawCustomFocusRing(mozilla::dom::Element& aElement)
 {
   EnsureUserSpacePath();
   HTMLCanvasElement* canvas = GetCanvas();
   if (!canvas|| !nsContentUtils::ContentIsDescendantOf(&aElement, canvas)) {
     return false;
   }
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();
   if (fm) {
     // check that the element i focused
     nsCOMPtr<nsIDOMElement> focusedElement;
     fm->GetFocusedElement(getter_AddRefs(focusedElement));
     if (SameCOMIdentity(aElement.AsDOMNode(), focusedElement)) {
       return true;
     }
   }
   return false;
 }
 void
 CanvasRenderingContext2D::Clip(const CanvasWindingRule& winding)
 {
   EnsureUserSpacePath(winding);
   if (!mPath) {
     return;
   }
   mTarget->PushClip(mPath);
   CurrentState().clipsPushed.push_back(mPath);
 }
 void
 CanvasRenderingContext2D::Clip(const CanvasPath& path, const CanvasWindingRule& winding)
 {
   EnsureTarget();
   RefPtr<gfx::Path> gfxpath = path.GetPath(winding, mTarget);
   if (!gfxpath) {
     return;
   }
   mTarget->PushClip(gfxpath);
   CurrentState().clipsPushed.push_back(gfxpath);
 }
 void
 CanvasRenderingContext2D::ArcTo(double x1, double y1, double x2,
                                 double y2, double radius,
                                 ErrorResult& error)
 {
   if (radius < 0) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   EnsureWritablePath();
   // Current point in user space!
   Point p0;
   if (mPathBuilder) {
     p0 = mPathBuilder->CurrentPoint();
   } else {
     Matrix invTransform = mTarget->GetTransform();
     if (!invTransform.Invert()) {
       return;
     }
     p0 = invTransform * mDSPathBuilder->CurrentPoint();
   }
   Point p1(x1, y1);
   Point p2(x2, y2);
   // Execute these calculations in double precision to avoid cumulative
   // rounding errors.
   double dir, a2, b2, c2, cosx, sinx, d, anx, any,
          bnx, bny, x3, y3, x4, y4, cx, cy, angle0, angle1;
   bool anticlockwise;
   if (p0 == p1 || p1 == p2 || radius == 0) {
     LineTo(p1.x, p1.y);
     return;
   }
   // Check for colinearity
   dir = (p2.x - p1.x) * (p0.y - p1.y) + (p2.y - p1.y) * (p1.x - p0.x);
   if (dir == 0) {
     LineTo(p1.x, p1.y);
     return;
   }
   // XXX - Math for this code was already available from the non-azure code
   // and would be well tested. Perhaps converting to bezier directly might
   // be more efficient longer run.
   a2 = (p0.x-x1)*(p0.x-x1) + (p0.y-y1)*(p0.y-y1);
   b2 = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
   c2 = (p0.x-x2)*(p0.x-x2) + (p0.y-y2)*(p0.y-y2);
   cosx = (a2+b2-c2)/(2*sqrt(a2*b2));
   sinx = sqrt(1 - cosx*cosx);
   d = radius / ((1 - cosx) / sinx);
   anx = (x1-p0.x) / sqrt(a2);
   any = (y1-p0.y) / sqrt(a2);
   bnx = (x1-x2) / sqrt(b2);
   bny = (y1-y2) / sqrt(b2);
   x3 = x1 - anx*d;
   y3 = y1 - any*d;
   x4 = x1 - bnx*d;
   y4 = y1 - bny*d;
   anticlockwise = (dir < 0);
   cx = x3 + any*radius*(anticlockwise ? 1 : -1);
   cy = y3 - anx*radius*(anticlockwise ? 1 : -1);
   angle0 = atan2((y3-cy), (x3-cx));
   angle1 = atan2((y4-cy), (x4-cx));
   LineTo(x3, y3);
   Arc(cx, cy, radius, angle0, angle1, anticlockwise, error);
 }
 void
 CanvasRenderingContext2D::Arc(double x, double y, double r,
                               double startAngle, double endAngle,
                               bool anticlockwise, ErrorResult& error)
 {
   if (r < 0.0) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   EnsureWritablePath();
   ArcToBezier(this, Point(x, y), Size(r, r), startAngle, endAngle, anticlockwise);
 }
 void
 CanvasRenderingContext2D::Rect(double x, double y, double w, double h)
 {
   EnsureWritablePath();
   if (mPathBuilder) {
     mPathBuilder->MoveTo(Point(x, y));
     mPathBuilder->LineTo(Point(x + w, y));
     mPathBuilder->LineTo(Point(x + w, y + h));
     mPathBuilder->LineTo(Point(x, y + h));
     mPathBuilder->Close();
   } else {
     mDSPathBuilder->MoveTo(mTarget->GetTransform() * Point(x, y));
     mDSPathBuilder->LineTo(mTarget->GetTransform() * Point(x + w, y));
     mDSPathBuilder->LineTo(mTarget->GetTransform() * Point(x + w, y + h));
     mDSPathBuilder->LineTo(mTarget->GetTransform() * Point(x, y + h));
     mDSPathBuilder->Close();
   }
 }
 void
 CanvasRenderingContext2D::EnsureWritablePath()
 {
   if (mDSPathBuilder) {
     return;
   }
   FillRule fillRule = CurrentState().fillRule;
   if (mPathBuilder) {
     if (mPathTransformWillUpdate) {
       mPath = mPathBuilder->Finish();
       mDSPathBuilder =
         mPath->TransformedCopyToBuilder(mPathToDS, fillRule);
       mPath = nullptr;
       mPathBuilder = nullptr;
       mPathTransformWillUpdate = false;
     }
     return;
   }
   EnsureTarget();
   if (!mPath) {
     NS_ASSERTION(!mPathTransformWillUpdate, "mPathTransformWillUpdate should be false, if all paths are null");
     mPathBuilder = mTarget->CreatePathBuilder(fillRule);
   } else if (!mPathTransformWillUpdate) {
     mPathBuilder = mPath->CopyToBuilder(fillRule);
   } else {
     mDSPathBuilder =
       mPath->TransformedCopyToBuilder(mPathToDS, fillRule);
     mPathTransformWillUpdate = false;
     mPath = nullptr;
   }
 }
 void
 CanvasRenderingContext2D::EnsureUserSpacePath(const CanvasWindingRule& winding)
 {
   FillRule fillRule = CurrentState().fillRule;
   if(winding == CanvasWindingRule::Evenodd)
     fillRule = FillRule::FILL_EVEN_ODD;
   if (!mPath && !mPathBuilder && !mDSPathBuilder) {
     EnsureTarget();
     mPathBuilder = mTarget->CreatePathBuilder(fillRule);
   }
   if (mPathBuilder) {
     mPath = mPathBuilder->Finish();
     mPathBuilder = nullptr;
   }
   if (mPath &&
       mPathTransformWillUpdate) {
     mDSPathBuilder =
       mPath->TransformedCopyToBuilder(mPathToDS, fillRule);
     mPath = nullptr;
     mPathTransformWillUpdate = false;
   }
   if (mDSPathBuilder) {
     RefPtr<Path> dsPath;
     dsPath = mDSPathBuilder->Finish();
     mDSPathBuilder = nullptr;
     Matrix inverse = mTarget->GetTransform();
     if (!inverse.Invert()) {
       NS_WARNING("Could not invert transform");
       return;
     }
     mPathBuilder =
       dsPath->TransformedCopyToBuilder(inverse, fillRule);
     mPath = mPathBuilder->Finish();
     mPathBuilder = nullptr;
   }
   if (mPath && mPath->GetFillRule() != fillRule) {
     mPathBuilder = mPath->CopyToBuilder(fillRule);
     mPath = mPathBuilder->Finish();
     mPathBuilder = nullptr;
   }
   NS_ASSERTION(mPath, "mPath should exist");
 }
 void
 CanvasRenderingContext2D::TransformWillUpdate()
 {
   EnsureTarget();
   // Store the matrix that would transform the current path to device
   // space.
   if (mPath || mPathBuilder) {
     if (!mPathTransformWillUpdate) {
       // If the transform has already been updated, but a device space builder
       // has not been created yet mPathToDS contains the right transform to
       // transform the current mPath into device space.
       // We should leave it alone.
       mPathToDS = mTarget->GetTransform();
     }
     mPathTransformWillUpdate = true;
   }
 }
 //
 // text
 //
 /**
  * Helper function for SetFont that creates a style rule for the given font.
  * @param aFont The CSS font string
  * @param aNode The canvas element
  * @param aResult Pointer in which to place the new style rule.
  * @remark Assumes all pointer arguments are non-null.
  */
 static nsresult
 CreateFontStyleRule(const nsAString& aFont,
                     nsINode* aNode,
                     StyleRule** aResult)
 {
   nsRefPtr<StyleRule> rule;
   bool changed;
   nsIPrincipal* principal = aNode->NodePrincipal();
   nsIDocument* document = aNode->OwnerDoc();
   nsIURI* docURL = document->GetDocumentURI();
   nsIURI* baseURL = document->GetDocBaseURI();
   // Pass the CSS Loader object to the parser, to allow parser error reports
   // to include the outer window ID.
   nsCSSParser parser(document->CSSLoader());
   nsresult rv = parser.ParseStyleAttribute(EmptyString(), docURL, baseURL,
                                            principal, getter_AddRefs(rule));
   if (NS_FAILED(rv)) {
     return rv;
   }
   rv = parser.ParseProperty(eCSSProperty_font, aFont, docURL, baseURL,
                             principal, rule->GetDeclaration(), &changed,
                             false);
   if (NS_FAILED(rv))
     return rv;
   rv = parser.ParseProperty(eCSSProperty_line_height,
                             NS_LITERAL_STRING("normal"), docURL, baseURL,
                             principal, rule->GetDeclaration(), &changed,
                             false);
   if (NS_FAILED(rv)) {
     return rv;
   }
   rule->RuleMatched();
   rule.forget(aResult);
   return NS_OK;
 }
 void
 CanvasRenderingContext2D::SetFont(const nsAString& font,
                                   ErrorResult& error)
 {
   /*
     * If font is defined with relative units (e.g. ems) and the parent
     * style context changes in between calls, setting the font to the
     * same value as previous could result in a different computed value,
     * so we cannot have the optimization where we check if the new font
     * string is equal to the old one.
     */
   if (!mCanvasElement && !mDocShell) {
     NS_WARNING("Canvas element must be non-null or a docshell must be provided");
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   nsIPresShell* presShell = GetPresShell();
   if (!presShell) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   nsIDocument* document = presShell->GetDocument();
   nsRefPtr<css::StyleRule> rule;
   error = CreateFontStyleRule(font, document, getter_AddRefs(rule));
   if (error.Failed()) {
     return;
   }
   css::Declaration *declaration = rule->GetDeclaration();
   // The easiest way to see whether we got a syntax error or whether
   // we got 'inherit' or 'initial' is to look at font-size-adjust,
   // which the shorthand resets to either 'none' or
   // '-moz-system-font'.
   // We know the declaration is not !important, so we can use
   // GetNormalBlock().
   const nsCSSValue *fsaVal =
     declaration->GetNormalBlock()->ValueFor(eCSSProperty_font_size_adjust);
   if (!fsaVal || (fsaVal->GetUnit() != eCSSUnit_None &&
                   fsaVal->GetUnit() != eCSSUnit_System_Font)) {
       // We got an all-property value or a syntax error.  The spec says
       // this value must be ignored.
     return;
   }
   nsTArray< nsCOMPtr<nsIStyleRule> > rules;
   rules.AppendElement(rule);
   nsStyleSet* styleSet = presShell->StyleSet();
   // have to get a parent style context for inherit-like relative
   // values (2em, bolder, etc.)
   nsRefPtr<nsStyleContext> parentContext;
   if (mCanvasElement && mCanvasElement->IsInDoc()) {
       // inherit from the canvas element
       parentContext = nsComputedDOMStyle::GetStyleContextForElement(
               mCanvasElement,
               nullptr,
               presShell);
   } else {
     // otherwise inherit from default (10px sans-serif)
     nsRefPtr<css::StyleRule> parentRule;
     error = CreateFontStyleRule(NS_LITERAL_STRING("10px sans-serif"),
                                 document,
                                 getter_AddRefs(parentRule));
     if (error.Failed()) {
       return;
     }
     nsTArray< nsCOMPtr<nsIStyleRule> > parentRules;
     parentRules.AppendElement(parentRule);
     parentContext = styleSet->ResolveStyleForRules(nullptr, parentRules);
   }
   if (!parentContext) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   // add a rule to prevent text zoom from affecting the style
   rules.AppendElement(new nsDisableTextZoomStyleRule);
   nsRefPtr<nsStyleContext> sc =
       styleSet->ResolveStyleForRules(parentContext, rules);
   if (!sc) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   const nsStyleFont* fontStyle = sc->StyleFont();
   NS_ASSERTION(fontStyle, "Could not obtain font style");
   nsIAtom* language = sc->StyleFont()->mLanguage;
   if (!language) {
     language = presShell->GetPresContext()->GetLanguageFromCharset();
   }
   // use CSS pixels instead of dev pixels to avoid being affected by page zoom
   const uint32_t aupcp = nsPresContext::AppUnitsPerCSSPixel();
   bool printerFont = (presShell->GetPresContext()->Type() == nsPresContext::eContext_PrintPreview ||
                       presShell->GetPresContext()->Type() == nsPresContext::eContext_Print);
   // Purposely ignore the font size that respects the user's minimum
   // font preference (fontStyle->mFont.size) in favor of the computed
   // size (fontStyle->mSize).  See
   // https://bugzilla.mozilla.org/show_bug.cgi?id=698652.
   MOZ_ASSERT(!fontStyle->mAllowZoom,
              "expected text zoom to be disabled on this nsStyleFont");
   gfxFontStyle style(fontStyle->mFont.style,
                      fontStyle->mFont.weight,
                      fontStyle->mFont.stretch,
                      NSAppUnitsToFloatPixels(fontStyle->mSize, float(aupcp)),
                      language,
                      fontStyle->mFont.sizeAdjust,
                      fontStyle->mFont.systemFont,
                      printerFont,
                      fontStyle->mFont.languageOverride);
   fontStyle->mFont.AddFontFeaturesToStyle(&style);
   nsPresContext *c = presShell->GetPresContext();
   CurrentState().fontGroup =
       gfxPlatform::GetPlatform()->CreateFontGroup(fontStyle->mFont.name,
                                                   &style,
                                                   c->GetUserFontSet());
   NS_ASSERTION(CurrentState().fontGroup, "Could not get font group");
   CurrentState().fontGroup->SetTextPerfMetrics(c->GetTextPerfMetrics());
   // The font getter is required to be reserialized based on what we
   // parsed (including having line-height removed).  (Older drafts of
   // the spec required font sizes be converted to pixels, but that no
   // longer seems to be required.)
   declaration->GetValue(eCSSProperty_font, CurrentState().font);
 }
 void
 CanvasRenderingContext2D::SetTextAlign(const nsAString& ta)
 {
   if (ta.EqualsLiteral("start"))
     CurrentState().textAlign = TextAlign::START;
   else if (ta.EqualsLiteral("end"))
     CurrentState().textAlign = TextAlign::END;
   else if (ta.EqualsLiteral("left"))
     CurrentState().textAlign = TextAlign::LEFT;
   else if (ta.EqualsLiteral("right"))
     CurrentState().textAlign = TextAlign::RIGHT;
   else if (ta.EqualsLiteral("center"))
     CurrentState().textAlign = TextAlign::CENTER;
 }
 void
 CanvasRenderingContext2D::GetTextAlign(nsAString& ta)
 {
   switch (CurrentState().textAlign)
   {
   case TextAlign::START:
     ta.AssignLiteral("start");
     break;
   case TextAlign::END:
     ta.AssignLiteral("end");
     break;
   case TextAlign::LEFT:
     ta.AssignLiteral("left");
     break;
   case TextAlign::RIGHT:
     ta.AssignLiteral("right");
     break;
   case TextAlign::CENTER:
     ta.AssignLiteral("center");
     break;
   }
 }
 void
 CanvasRenderingContext2D::SetTextBaseline(const nsAString& tb)
 {
   if (tb.EqualsLiteral("top"))
     CurrentState().textBaseline = TextBaseline::TOP;
   else if (tb.EqualsLiteral("hanging"))
     CurrentState().textBaseline = TextBaseline::HANGING;
   else if (tb.EqualsLiteral("middle"))
     CurrentState().textBaseline = TextBaseline::MIDDLE;
   else if (tb.EqualsLiteral("alphabetic"))
     CurrentState().textBaseline = TextBaseline::ALPHABETIC;
   else if (tb.EqualsLiteral("ideographic"))
     CurrentState().textBaseline = TextBaseline::IDEOGRAPHIC;
   else if (tb.EqualsLiteral("bottom"))
     CurrentState().textBaseline = TextBaseline::BOTTOM;
 }
 void
 CanvasRenderingContext2D::GetTextBaseline(nsAString& tb)
 {
   switch (CurrentState().textBaseline)
   {
   case TextBaseline::TOP:
     tb.AssignLiteral("top");
     break;
   case TextBaseline::HANGING:
     tb.AssignLiteral("hanging");
     break;
   case TextBaseline::MIDDLE:
     tb.AssignLiteral("middle");
     break;
   case TextBaseline::ALPHABETIC:
     tb.AssignLiteral("alphabetic");
     break;
   case TextBaseline::IDEOGRAPHIC:
     tb.AssignLiteral("ideographic");
     break;
   case TextBaseline::BOTTOM:
     tb.AssignLiteral("bottom");
     break;
   }
 }
 /*
  * Helper function that replaces the whitespace characters in a string
  * with U+0020 SPACE. The whitespace characters are defined as U+0020 SPACE,
  * U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), U+000B LINE
  * TABULATION, U+000C FORM FEED (FF), and U+000D CARRIAGE RETURN (CR).
  * @param str The string whose whitespace characters to replace.
  */
 static inline void
 TextReplaceWhitespaceCharacters(nsAutoString& str)
 {
   str.ReplaceChar("\x09\x0A\x0B\x0C\x0D", char16_t(' '));
 }
 void
 CanvasRenderingContext2D::FillText(const nsAString& text, double x,
                                    double y,
                                    const Optional<double>& maxWidth,
                                    ErrorResult& error)
 {
   error = DrawOrMeasureText(text, x, y, maxWidth, TextDrawOperation::FILL, nullptr);
 }
 void
 CanvasRenderingContext2D::StrokeText(const nsAString& text, double x,
                                      double y,
                                      const Optional<double>& maxWidth,
                                      ErrorResult& error)
 {
   error = DrawOrMeasureText(text, x, y, maxWidth, TextDrawOperation::STROKE, nullptr);
 }
 TextMetrics*
 CanvasRenderingContext2D::MeasureText(const nsAString& rawText,
                                       ErrorResult& error)
 {
   float width;
   Optional<double> maxWidth;
   error = DrawOrMeasureText(rawText, 0, 0, maxWidth, TextDrawOperation::MEASURE, &width);
   if (error.Failed()) {
     return nullptr;
   }
   return new TextMetrics(width);
 }
 void
 CanvasRenderingContext2D::AddHitRegion(const HitRegionOptions& options, ErrorResult& error)
 {
   // remove old hit region first
   RemoveHitRegion(options.mId);
   // for now, we require a fallback element
   if (options.mControl == NULL) {
     error.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return;
   }
   // check if the control is a descendant of our canvas
   HTMLCanvasElement* canvas = GetCanvas();
   bool isDescendant = true;
   if (!canvas || !nsContentUtils::ContentIsDescendantOf(options.mControl, canvas)) {
     isDescendant = false;
   }
   // check if the path is valid
   EnsureUserSpacePath(CanvasWindingRule::Nonzero);
   if(!mPath) {
     error.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return;
   }
   // get the bounds of the current path. They are relative to the canvas
   mgfx::Rect bounds(mPath->GetBounds(mTarget->GetTransform()));
   if ((bounds.width == 0) || (bounds.height == 0) || !bounds.IsFinite()) {
     // The specified region has no pixels.
     error.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return;
   }
 #ifdef ACCESSIBILITY
   if (isDescendant) {
     nsRect* nsBounds = new nsRect();
     gfxRect rect(bounds.x, bounds.y, bounds.width, bounds.height);
     *nsBounds = nsLayoutUtils::RoundGfxRectToAppRect(rect, AppUnitsPerCSSPixel());
     options.mControl->DeleteProperty(nsGkAtoms::hitregion);
     options.mControl->SetProperty(nsGkAtoms::hitregion, nsBounds,
                                   nsINode::DeleteProperty<nsRect>);
   }
 #endif
   // finally, add the region to the list if it has an ID
   if (options.mId.Length() != 0) {
     mHitRegionsOptions.PutEntry(options.mId)->mElement = options.mControl;
   }
 }
 void
 CanvasRenderingContext2D::RemoveHitRegion(const nsAString& id)
 {
   RegionInfo* info = mHitRegionsOptions.GetEntry(id);
   if (!info) {
     return;
   }
 #ifdef ACCESSIBILITY
   info->mElement->DeleteProperty(nsGkAtoms::hitregion);
 #endif
   mHitRegionsOptions.RemoveEntry(id);
 }
 /**
  * Used for nsBidiPresUtils::ProcessText
  */
 struct MOZ_STACK_CLASS CanvasBidiProcessor : public nsBidiPresUtils::BidiProcessor
 {
   typedef CanvasRenderingContext2D::ContextState ContextState;
   virtual void SetText(const char16_t* text, int32_t length, nsBidiDirection direction)
   {
     mFontgrp->UpdateFontList(); // ensure user font generation is current
     mTextRun = mFontgrp->MakeTextRun(text,
                                      length,
                                      mThebes,
                                      mAppUnitsPerDevPixel,
                                      direction==NSBIDI_RTL ? gfxTextRunFactory::TEXT_IS_RTL : 0);
   }
   virtual nscoord GetWidth()
   {
     gfxTextRun::Metrics textRunMetrics = mTextRun->MeasureText(0,
                                                                mTextRun->GetLength(),
                                                                mDoMeasureBoundingBox ?
                                                                  gfxFont::TIGHT_INK_EXTENTS :
                                                                  gfxFont::LOOSE_INK_EXTENTS,
                                                                mThebes,
                                                                nullptr);
     // this only measures the height; the total width is gotten from the
     // the return value of ProcessText.
     if (mDoMeasureBoundingBox) {
       textRunMetrics.mBoundingBox.Scale(1.0 / mAppUnitsPerDevPixel);
       mBoundingBox = mBoundingBox.Union(textRunMetrics.mBoundingBox);
     }
     return NSToCoordRound(textRunMetrics.mAdvanceWidth);
   }
   virtual void DrawText(nscoord xOffset, nscoord width)
   {
     gfxPoint point = mPt;
     point.x += xOffset;
     // offset is given in terms of left side of string
     if (mTextRun->IsRightToLeft()) {
       // Bug 581092 - don't use rounded pixel width to advance to
       // right-hand end of run, because this will cause different
       // glyph positioning for LTR vs RTL drawing of the same
       // glyph string on OS X and DWrite where textrun widths may
       // involve fractional pixels.
       gfxTextRun::Metrics textRunMetrics =
         mTextRun->MeasureText(0,
                               mTextRun->GetLength(),
                               mDoMeasureBoundingBox ?
                                   gfxFont::TIGHT_INK_EXTENTS :
                                   gfxFont::LOOSE_INK_EXTENTS,
                               mThebes,
                               nullptr);
       point.x += textRunMetrics.mAdvanceWidth;
       // old code was:
       //   point.x += width * mAppUnitsPerDevPixel;
       // TODO: restore this if/when we move to fractional coords
       // throughout the text layout process
     }
     uint32_t numRuns;
     const gfxTextRun::GlyphRun *runs = mTextRun->GetGlyphRuns(&numRuns);
     const int32_t appUnitsPerDevUnit = mAppUnitsPerDevPixel;
     const double devUnitsPerAppUnit = 1.0/double(appUnitsPerDevUnit);
     Point baselineOrigin =
       Point(point.x * devUnitsPerAppUnit, point.y * devUnitsPerAppUnit);
     float advanceSum = 0;
     mCtx->EnsureTarget();
     for (uint32_t c = 0; c < numRuns; c++) {
       gfxFont *font = runs[c].mFont;
       uint32_t endRun = 0;
       if (c + 1 < numRuns) {
         endRun = runs[c + 1].mCharacterOffset;
       } else {
         endRun = mTextRun->GetLength();
       }
       const gfxTextRun::CompressedGlyph *glyphs = mTextRun->GetCharacterGlyphs();
       RefPtr<ScaledFont> scaledFont =
         gfxPlatform::GetPlatform()->GetScaledFontForFont(mCtx->mTarget, font);
       if (!scaledFont) {
         // This can occur when something switched DirectWrite off.
         return;
       }
       RefPtr<GlyphRenderingOptions> renderingOptions = font->GetGlyphRenderingOptions();
       GlyphBuffer buffer;
       std::vector<Glyph> glyphBuf;
       for (uint32_t i = runs[c].mCharacterOffset; i < endRun; i++) {
         Glyph newGlyph;
         if (glyphs[i].IsSimpleGlyph()) {
           newGlyph.mIndex = glyphs[i].GetSimpleGlyph();
           if (mTextRun->IsRightToLeft()) {
             newGlyph.mPosition.x = baselineOrigin.x - advanceSum -
               glyphs[i].GetSimpleAdvance() * devUnitsPerAppUnit;
           } else {
             newGlyph.mPosition.x = baselineOrigin.x + advanceSum;
           }
           newGlyph.mPosition.y = baselineOrigin.y;
           advanceSum += glyphs[i].GetSimpleAdvance() * devUnitsPerAppUnit;
           glyphBuf.push_back(newGlyph);
           continue;
         }
         if (!glyphs[i].GetGlyphCount()) {
           continue;
         }
         gfxTextRun::DetailedGlyph *detailedGlyphs =
           mTextRun->GetDetailedGlyphs(i);
         if (glyphs[i].IsMissing()) {
           newGlyph.mIndex = 0;
           if (mTextRun->IsRightToLeft()) {
             newGlyph.mPosition.x = baselineOrigin.x - advanceSum -
               detailedGlyphs[0].mAdvance * devUnitsPerAppUnit;
           } else {
             newGlyph.mPosition.x = baselineOrigin.x + advanceSum;
           }
           newGlyph.mPosition.y = baselineOrigin.y;
           advanceSum += detailedGlyphs[0].mAdvance * devUnitsPerAppUnit;
           glyphBuf.push_back(newGlyph);
           continue;
         }
         for (uint32_t c = 0; c < glyphs[i].GetGlyphCount(); c++) {
           newGlyph.mIndex = detailedGlyphs[c].mGlyphID;
           if (mTextRun->IsRightToLeft()) {
             newGlyph.mPosition.x = baselineOrigin.x + detailedGlyphs[c].mXOffset * devUnitsPerAppUnit -
               advanceSum - detailedGlyphs[c].mAdvance * devUnitsPerAppUnit;
           } else {
             newGlyph.mPosition.x = baselineOrigin.x + detailedGlyphs[c].mXOffset * devUnitsPerAppUnit + advanceSum;
           }
           newGlyph.mPosition.y = baselineOrigin.y + detailedGlyphs[c].mYOffset * devUnitsPerAppUnit;
           glyphBuf.push_back(newGlyph);
           advanceSum += detailedGlyphs[c].mAdvance * devUnitsPerAppUnit;
         }
       }
       if (!glyphBuf.size()) {
         // This may happen for glyph runs for a 0 size font.
         continue;
       }
       buffer.mGlyphs = &glyphBuf.front();
       buffer.mNumGlyphs = glyphBuf.size();
       Rect bounds = mCtx->mTarget->GetTransform().
         TransformBounds(Rect(mBoundingBox.x, mBoundingBox.y,
                              mBoundingBox.width, mBoundingBox.height));
       if (mOp == CanvasRenderingContext2D::TextDrawOperation::FILL) {
         AdjustedTarget(mCtx, &bounds)->
           FillGlyphs(scaledFont, buffer,
                      CanvasGeneralPattern().
                        ForStyle(mCtx, CanvasRenderingContext2D::Style::FILL, mCtx->mTarget),
                      DrawOptions(mState->globalAlpha, mCtx->UsedOperation()),
                      renderingOptions);
       } else if (mOp == CanvasRenderingContext2D::TextDrawOperation::STROKE) {
         // stroke glyphs one at a time to avoid poor CoreGraphics performance
         // when stroking a path with a very large number of points
         buffer.mGlyphs = &glyphBuf.front();
         buffer.mNumGlyphs = 1;
         const ContextState& state = *mState;
         AdjustedTarget target(mCtx, &bounds);
         const StrokeOptions strokeOpts(state.lineWidth, state.lineJoin,
                                        state.lineCap, state.miterLimit,
                                        state.dash.Length(),
                                        state.dash.Elements(),
                                        state.dashOffset);
         CanvasGeneralPattern cgp;
         const Pattern& patForStyle
           (cgp.ForStyle(mCtx, CanvasRenderingContext2D::Style::STROKE, mCtx->mTarget));
         const DrawOptions drawOpts(state.globalAlpha, mCtx->UsedOperation());
         for (unsigned i = glyphBuf.size(); i > 0; --i) {
           RefPtr<Path> path = scaledFont->GetPathForGlyphs(buffer, mCtx->mTarget);
           target->Stroke(path, patForStyle, strokeOpts, drawOpts);
           buffer.mGlyphs++;
         }
       }
     }
   }
   // current text run
   nsAutoPtr<gfxTextRun> mTextRun;
   // pointer to a screen reference context used to measure text and such
   nsRefPtr<gfxContext> mThebes;
   // Pointer to the draw target we should fill our text to
   CanvasRenderingContext2D *mCtx;
   // position of the left side of the string, alphabetic baseline
   gfxPoint mPt;
   // current font
   gfxFontGroup* mFontgrp;
   // dev pixel conversion factor
   int32_t mAppUnitsPerDevPixel;
   // operation (fill or stroke)
   CanvasRenderingContext2D::TextDrawOperation mOp;
   // context state
   ContextState *mState;
   // union of bounding boxes of all runs, needed for shadows
   gfxRect mBoundingBox;
   // true iff the bounding box should be measured
   bool mDoMeasureBoundingBox;
 };
 nsresult
 CanvasRenderingContext2D::DrawOrMeasureText(const nsAString& aRawText,
                                             float aX,
                                             float aY,
                                             const Optional<double>& aMaxWidth,
                                             TextDrawOperation aOp,
                                             float* aWidth)
 {
   nsresult rv;
   // spec isn't clear on what should happen if aMaxWidth <= 0, so
   // treat it as an invalid argument
   // technically, 0 should be an invalid value as well, but 0 is the default
   // arg, and there is no way to tell if the default was used
   if (aMaxWidth.WasPassed() && aMaxWidth.Value() < 0)
     return NS_ERROR_INVALID_ARG;
   if (!mCanvasElement && !mDocShell) {
     NS_WARNING("Canvas element must be non-null or a docshell must be provided");
     return NS_ERROR_FAILURE;
   }
   nsCOMPtr<nsIPresShell> presShell = GetPresShell();
   if (!presShell)
     return NS_ERROR_FAILURE;
   nsIDocument* document = presShell->GetDocument();
   // replace all the whitespace characters with U+0020 SPACE
   nsAutoString textToDraw(aRawText);
   TextReplaceWhitespaceCharacters(textToDraw);
   // for now, default to ltr if not in doc
   bool isRTL = false;
   if (mCanvasElement && mCanvasElement->IsInDoc()) {
     // try to find the closest context
     nsRefPtr<nsStyleContext> canvasStyle =
       nsComputedDOMStyle::GetStyleContextForElement(mCanvasElement,
                                                     nullptr,
                                                     presShell);
     if (!canvasStyle) {
       return NS_ERROR_FAILURE;
     }
     isRTL = canvasStyle->StyleVisibility()->mDirection ==
       NS_STYLE_DIRECTION_RTL;
   } else {
     isRTL = GET_BIDI_OPTION_DIRECTION(document->GetBidiOptions()) == IBMBIDI_TEXTDIRECTION_RTL;
   }
   gfxFontGroup* currentFontStyle = GetCurrentFontStyle();
   NS_ASSERTION(currentFontStyle, "font group is null");
   // ensure user font set is up to date
   currentFontStyle->
     SetUserFontSet(presShell->GetPresContext()->GetUserFontSet());
   if (currentFontStyle->GetStyle()->size == 0.0F) {
     if (aWidth) {
       *aWidth = 0;
     }
     return NS_OK;
   }
   const ContextState &state = CurrentState();
   // This is only needed to know if we can know the drawing bounding box easily.
   bool doDrawShadow = NeedToDrawShadow();
   CanvasBidiProcessor processor;
   GetAppUnitsValues(&processor.mAppUnitsPerDevPixel, nullptr);
   processor.mPt = gfxPoint(aX, aY);
   processor.mThebes =
     new gfxContext(gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget());
   // If we don't have a target then we don't have a transform. A target won't
   // be needed in the case where we're measuring the text size. This allows
   // to avoid creating a target if it's only being used to measure text sizes.
   if (mTarget) {
     Matrix matrix = mTarget->GetTransform();
     processor.mThebes->SetMatrix(gfxMatrix(matrix._11, matrix._12, matrix._21, matrix._22, matrix._31, matrix._32));
   }
   processor.mCtx = this;
   processor.mOp = aOp;
   processor.mBoundingBox = gfxRect(0, 0, 0, 0);
   processor.mDoMeasureBoundingBox = doDrawShadow || !mIsEntireFrameInvalid;
   processor.mState = &CurrentState();
   processor.mFontgrp = currentFontStyle;
   nscoord totalWidthCoord;
   // calls bidi algo twice since it needs the full text width and the
   // bounding boxes before rendering anything
   nsBidi bidiEngine;
   rv = nsBidiPresUtils::ProcessText(textToDraw.get(),
                                     textToDraw.Length(),
                                     isRTL ? NSBIDI_RTL : NSBIDI_LTR,
                                     presShell->GetPresContext(),
                                     processor,
                                     nsBidiPresUtils::MODE_MEASURE,
                                     nullptr,
 ,
                                     &totalWidthCoord,
                                     &bidiEngine);
   if (NS_FAILED(rv)) {
     return rv;
   }
   float totalWidth = float(totalWidthCoord) / processor.mAppUnitsPerDevPixel;
   if (aWidth) {
     *aWidth = totalWidth;
   }
   // if only measuring, don't need to do any more work
   if (aOp==TextDrawOperation::MEASURE) {
     return NS_OK;
   }
   // offset pt.x based on text align
   gfxFloat anchorX;
   if (state.textAlign == TextAlign::CENTER) {
     anchorX = .5;
   } else if (state.textAlign == TextAlign::LEFT ||
             (!isRTL && state.textAlign == TextAlign::START) ||
             (isRTL && state.textAlign == TextAlign::END)) {
     anchorX = 0;
   } else {
     anchorX = 1;
   }
   processor.mPt.x -= anchorX * totalWidth;
   // offset pt.y based on text baseline
   processor.mFontgrp->UpdateFontList(); // ensure user font generation is current
   NS_ASSERTION(processor.mFontgrp->FontListLength()>0, "font group contains no fonts");
   const gfxFont::Metrics& fontMetrics = processor.mFontgrp->GetFontAt(0)->GetMetrics();
   gfxFloat anchorY;
   switch (state.textBaseline)
   {
   case TextBaseline::HANGING:
       // fall through; best we can do with the information available
   case TextBaseline::TOP:
     anchorY = fontMetrics.emAscent;
     break;
   case TextBaseline::MIDDLE:
     anchorY = (fontMetrics.emAscent - fontMetrics.emDescent) * .5f;
     break;
   case TextBaseline::IDEOGRAPHIC:
     // fall through; best we can do with the information available
   case TextBaseline::ALPHABETIC:
     anchorY = 0;
     break;
   case TextBaseline::BOTTOM:
     anchorY = -fontMetrics.emDescent;
     break;
   default:
     MOZ_CRASH("unexpected TextBaseline");
   }
   processor.mPt.y += anchorY;
   // correct bounding box to get it to be the correct size/position
   processor.mBoundingBox.width = totalWidth;
   processor.mBoundingBox.MoveBy(processor.mPt);
   processor.mPt.x *= processor.mAppUnitsPerDevPixel;
   processor.mPt.y *= processor.mAppUnitsPerDevPixel;
   EnsureTarget();
   Matrix oldTransform = mTarget->GetTransform();
   // if text is over aMaxWidth, then scale the text horizontally such that its
   // width is precisely aMaxWidth
   if (aMaxWidth.WasPassed() && aMaxWidth.Value() > 0 &&
       totalWidth > aMaxWidth.Value()) {
     Matrix newTransform = oldTransform;
     // Translate so that the anchor point is at 0,0, then scale and then
     // translate back.
     newTransform.Translate(aX, 0);
     newTransform.Scale(aMaxWidth.Value() / totalWidth, 1);
     newTransform.Translate(-aX, 0);
     /* we do this to avoid an ICE in the android compiler */
     Matrix androidCompilerBug = newTransform;
     mTarget->SetTransform(androidCompilerBug);
   }
   // save the previous bounding box
   gfxRect boundingBox = processor.mBoundingBox;
   // don't ever need to measure the bounding box twice
   processor.mDoMeasureBoundingBox = false;
   rv = nsBidiPresUtils::ProcessText(textToDraw.get(),
                                     textToDraw.Length(),
                                     isRTL ? NSBIDI_RTL : NSBIDI_LTR,
                                     presShell->GetPresContext(),
                                     processor,
                                     nsBidiPresUtils::MODE_DRAW,
                                     nullptr,
 ,
                                     nullptr,
                                     &bidiEngine);
   mTarget->SetTransform(oldTransform);
   if (aOp == CanvasRenderingContext2D::TextDrawOperation::FILL &&
       !doDrawShadow) {
     RedrawUser(boundingBox);
     return NS_OK;
   }
   Redraw();
   return NS_OK;
 }
 gfxFontGroup *CanvasRenderingContext2D::GetCurrentFontStyle()
 {
   // use lazy initilization for the font group since it's rather expensive
   if (!CurrentState().fontGroup) {
     ErrorResult err;
     NS_NAMED_LITERAL_STRING(kDefaultFontStyle, "10px sans-serif");
     static float kDefaultFontSize = 10.0;
     SetFont(kDefaultFontStyle, err);
     if (err.Failed()) {
       gfxFontStyle style;
       style.size = kDefaultFontSize;
       CurrentState().fontGroup =
         gfxPlatform::GetPlatform()->CreateFontGroup(NS_LITERAL_STRING("sans-serif"),
                                                     &style,
                                                     nullptr);
       if (CurrentState().fontGroup) {
         CurrentState().font = kDefaultFontStyle;
         nsIPresShell* presShell = GetPresShell();
         if (presShell) {
           CurrentState().fontGroup->SetTextPerfMetrics(
             presShell->GetPresContext()->GetTextPerfMetrics());
         }
       } else {
         NS_ERROR("Default canvas font is invalid");
       }
     }
   }
   return CurrentState().fontGroup;
 }
 //
 // line caps/joins
 //
 void
 CanvasRenderingContext2D::SetLineCap(const nsAString& capstyle)
 {
   CapStyle cap;
   if (capstyle.EqualsLiteral("butt")) {
     cap = CapStyle::BUTT;
   } else if (capstyle.EqualsLiteral("round")) {
     cap = CapStyle::ROUND;
   } else if (capstyle.EqualsLiteral("square")) {
     cap = CapStyle::SQUARE;
   } else {
     // XXX ERRMSG we need to report an error to developers here! (bug 329026)
     return;
   }
   CurrentState().lineCap = cap;
 }
 void
 CanvasRenderingContext2D::GetLineCap(nsAString& capstyle)
 {
   switch (CurrentState().lineCap) {
   case CapStyle::BUTT:
     capstyle.AssignLiteral("butt");
     break;
   case CapStyle::ROUND:
     capstyle.AssignLiteral("round");
     break;
   case CapStyle::SQUARE:
     capstyle.AssignLiteral("square");
     break;
   }
 }
 void
 CanvasRenderingContext2D::SetLineJoin(const nsAString& joinstyle)
 {
   JoinStyle j;
   if (joinstyle.EqualsLiteral("round")) {
     j = JoinStyle::ROUND;
   } else if (joinstyle.EqualsLiteral("bevel")) {
     j = JoinStyle::BEVEL;
   } else if (joinstyle.EqualsLiteral("miter")) {
     j = JoinStyle::MITER_OR_BEVEL;
   } else {
     // XXX ERRMSG we need to report an error to developers here! (bug 329026)
     return;
   }
   CurrentState().lineJoin = j;
 }
 void
 CanvasRenderingContext2D::GetLineJoin(nsAString& joinstyle, ErrorResult& error)
 {
   switch (CurrentState().lineJoin) {
   case JoinStyle::ROUND:
     joinstyle.AssignLiteral("round");
     break;
   case JoinStyle::BEVEL:
     joinstyle.AssignLiteral("bevel");
     break;
   case JoinStyle::MITER_OR_BEVEL:
     joinstyle.AssignLiteral("miter");
     break;
   default:
     error.Throw(NS_ERROR_FAILURE);
   }
 }
 void
 CanvasRenderingContext2D::SetMozDash(JSContext* cx,
                                      const JS::Value& mozDash,
                                      ErrorResult& error)
 {
   FallibleTArray<Float> dash;
   error = JSValToDashArray(cx, mozDash, dash);
   if (!error.Failed()) {
     ContextState& state = CurrentState();
     state.dash = dash;
     if (state.dash.IsEmpty()) {
       state.dashOffset = 0;
     }
   }
 }
 void
 CanvasRenderingContext2D::GetMozDash(JSContext* cx,
                                      JS::MutableHandle<JS::Value> retval,
                                      ErrorResult& error)
 {
   DashArrayToJSVal(CurrentState().dash, cx, retval, error);
 }
 void
 CanvasRenderingContext2D::SetMozDashOffset(double mozDashOffset)
 {
   ContextState& state = CurrentState();
   if (!state.dash.IsEmpty()) {
     state.dashOffset = mozDashOffset;
   }
 }
 void
 CanvasRenderingContext2D::SetLineDash(const Sequence<double>& aSegments)
 {
   FallibleTArray<mozilla::gfx::Float>& dash = CurrentState().dash;
   dash.Clear();
   for (uint32_t x = 0; x < aSegments.Length(); x++) {
     dash.AppendElement(aSegments[x]);
   }
   if (aSegments.Length() % 2) { // If the number of elements is odd, concatenate again
     for (uint32_t x = 0; x < aSegments.Length(); x++) {
       dash.AppendElement(aSegments[x]);
     }
   }
 }
 void
 CanvasRenderingContext2D::GetLineDash(nsTArray<double>& aSegments) const {
   const FallibleTArray<mozilla::gfx::Float>& dash = CurrentState().dash;
   aSegments.Clear();
   for (uint32_t x = 0; x < dash.Length(); x++) {
     aSegments.AppendElement(dash[x]);
   }
 }
 void
 CanvasRenderingContext2D::SetLineDashOffset(double mOffset) {
   CurrentState().dashOffset = mOffset;
 }
 double
 CanvasRenderingContext2D::LineDashOffset() const {
   return CurrentState().dashOffset;
 }
 bool
 CanvasRenderingContext2D::IsPointInPath(JSContext* aCx, double x, double y, const CanvasWindingRule& winding)
 {
   if (!FloatValidate(x,y)) {
     return false;
   }
   // Check for site-specific permission and return false if no permission.
   if (mCanvasElement) {
     nsCOMPtr<nsIDocument> ownerDoc = mCanvasElement->OwnerDoc();
     if (!ownerDoc || !CanvasUtils::IsImageExtractionAllowed(ownerDoc, aCx))
       return false;
   }
   EnsureUserSpacePath(winding);
   if (!mPath) {
     return false;
   }
   if (mPathTransformWillUpdate) {
     return mPath->ContainsPoint(Point(x, y), mPathToDS);
   }
   return mPath->ContainsPoint(Point(x, y), mTarget->GetTransform());
 }
 bool CanvasRenderingContext2D::IsPointInPath(JSContext* aCx, const CanvasPath& mPath, double x, double y, const CanvasWindingRule& mWinding)
 {
   if (!FloatValidate(x,y)) {
     return false;
   }
   // Check for site-specific permission and return false if no permission.
   if (mCanvasElement) {
     nsCOMPtr<nsIDocument> ownerDoc = mCanvasElement->OwnerDoc();
     if (!ownerDoc || !CanvasUtils::IsImageExtractionAllowed(ownerDoc, aCx))
       return false;
   }
   EnsureTarget();
   RefPtr<gfx::Path> tempPath = mPath.GetPath(mWinding, mTarget);
   return tempPath->ContainsPoint(Point(x, y), mTarget->GetTransform());
 }
 bool
 CanvasRenderingContext2D::IsPointInStroke(JSContext* aCx, double x, double y)
 {
   if (!FloatValidate(x,y)) {
     return false;
   }
   // Check for site-specific permission and return false if no permission.
   if (mCanvasElement) {
     nsCOMPtr<nsIDocument> ownerDoc = mCanvasElement->OwnerDoc();
     if (!ownerDoc || !CanvasUtils::IsImageExtractionAllowed(ownerDoc, aCx))
       return false;
   }
   EnsureUserSpacePath();
   if (!mPath) {
     return false;
   }
   const ContextState &state = CurrentState();
   StrokeOptions strokeOptions(state.lineWidth,
                               state.lineJoin,
                               state.lineCap,
                               state.miterLimit,
                               state.dash.Length(),
                               state.dash.Elements(),
                               state.dashOffset);
   if (mPathTransformWillUpdate) {
     return mPath->StrokeContainsPoint(strokeOptions, Point(x, y), mPathToDS);
   }
   return mPath->StrokeContainsPoint(strokeOptions, Point(x, y), mTarget->GetTransform());
 }
 bool CanvasRenderingContext2D::IsPointInStroke(JSContext* aCx, const CanvasPath& mPath, double x, double y)
 {
   if (!FloatValidate(x,y)) {
     return false;
   }
   // Check for site-specific permission and return false if no permission.
   if (mCanvasElement) {
     nsCOMPtr<nsIDocument> ownerDoc = mCanvasElement->OwnerDoc();
     if (!ownerDoc || !CanvasUtils::IsImageExtractionAllowed(ownerDoc, aCx))
       return false;
   }
   EnsureTarget();
   RefPtr<gfx::Path> tempPath = mPath.GetPath(CanvasWindingRule::Nonzero, mTarget);
   const ContextState &state = CurrentState();
   StrokeOptions strokeOptions(state.lineWidth,
                               state.lineJoin,
                               state.lineCap,
                               state.miterLimit,
                               state.dash.Length(),
                               state.dash.Elements(),
                               state.dashOffset);
   return tempPath->StrokeContainsPoint(strokeOptions, Point(x, y), mTarget->GetTransform());
 }
 //
 // image
 //
 // drawImage(in HTMLImageElement image, in float dx, in float dy);
 //   -- render image from 0,0 at dx,dy top-left coords
 // drawImage(in HTMLImageElement image, in float dx, in float dy, in float sw, in float sh);
 //   -- render image from 0,0 at dx,dy top-left coords clipping it to sw,sh
 // drawImage(in HTMLImageElement image, in float sx, in float sy, in float sw, in float sh, in float dx, in float dy, in float dw, in float dh);
 //   -- render the region defined by (sx,sy,sw,wh) in image-local space into the region (dx,dy,dw,dh) on the canvas
 // If only dx and dy are passed in then optional_argc should be 0. If only
 // dx, dy, dw and dh are passed in then optional_argc should be 2. The only
 // other valid value for optional_argc is 6 if sx, sy, sw, sh, dx, dy, dw and dh
 // are all passed in.
 void
 CanvasRenderingContext2D::DrawImage(const HTMLImageOrCanvasOrVideoElement& image,
                                     double sx, double sy, double sw,
                                     double sh, double dx, double dy,
                                     double dw, double dh,
                                     uint8_t optional_argc,
                                     ErrorResult& error)
 {
   MOZ_ASSERT(optional_argc == 0 || optional_argc == 2 || optional_argc == 6);
   RefPtr<SourceSurface> srcSurf;
   gfxIntSize imgSize;
   Element* element;
   EnsureTarget();
   if (image.IsHTMLCanvasElement()) {
     HTMLCanvasElement* canvas = &image.GetAsHTMLCanvasElement();
     element = canvas;
     nsIntSize size = canvas->GetSize();
     if (size.width == 0 || size.height == 0) {
       error.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
       return;
     }
   } else {
     if (image.IsHTMLImageElement()) {
       HTMLImageElement* img = &image.GetAsHTMLImageElement();
       element = img;
     } else {
       HTMLVideoElement* video = &image.GetAsHTMLVideoElement();
       element = video;
     }
     srcSurf =
       CanvasImageCache::Lookup(element, mCanvasElement, &imgSize);
   }
   nsLayoutUtils::DirectDrawInfo drawInfo;
   if (!srcSurf) {
     // The canvas spec says that drawImage should draw the first frame
     // of animated images. We also don't want to rasterize vector images.
     uint32_t sfeFlags = nsLayoutUtils::SFE_WANT_FIRST_FRAME |
                         nsLayoutUtils::SFE_NO_RASTERIZING_VECTORS;
     nsLayoutUtils::SurfaceFromElementResult res =
       nsLayoutUtils::SurfaceFromElement(element, sfeFlags, mTarget);
     if (!res.mSourceSurface && !res.mDrawInfo.mImgContainer) {
       // Spec says to silently do nothing if the element is still loading.
       if (!res.mIsStillLoading) {
         error.Throw(NS_ERROR_NOT_AVAILABLE);
       }
       return;
     }
     imgSize = res.mSize;
     // Scale sw/sh based on aspect ratio
     if (image.IsHTMLVideoElement()) {
       HTMLVideoElement* video = &image.GetAsHTMLVideoElement();
       int32_t displayWidth = video->VideoWidth();
       int32_t displayHeight = video->VideoHeight();
       sw *= (double)imgSize.width / (double)displayWidth;
       sh *= (double)imgSize.height / (double)displayHeight;
     }
     if (mCanvasElement) {
       CanvasUtils::DoDrawImageSecurityCheck(mCanvasElement,
                                             res.mPrincipal, res.mIsWriteOnly,
                                             res.mCORSUsed);
     }
     if (res.mSourceSurface) {
       if (res.mImageRequest) {
         CanvasImageCache::NotifyDrawImage(element, mCanvasElement, res.mImageRequest,
                                           res.mSourceSurface, imgSize);
       }
       srcSurf = res.mSourceSurface;
     } else {
       drawInfo = res.mDrawInfo;
     }
   }
   if (optional_argc == 0) {
     sx = sy = 0.0;
     dw = sw = (double) imgSize.width;
     dh = sh = (double) imgSize.height;
   } else if (optional_argc == 2) {
     sx = sy = 0.0;
     sw = (double) imgSize.width;
     sh = (double) imgSize.height;
   }
   if (sw == 0.0 || sh == 0.0) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   if (dw == 0.0 || dh == 0.0) {
     // not really failure, but nothing to do --
     // and noone likes a divide-by-zero
     return;
   }
   if (sx < 0.0 || sy < 0.0 ||
       sw < 0.0 || sw > (double) imgSize.width ||
       sh < 0.0 || sh > (double) imgSize.height ||
       dw < 0.0 || dh < 0.0) {
     // XXX - Unresolved spec issues here, for now return error.
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   Filter filter;
   if (CurrentState().imageSmoothingEnabled)
     filter = mgfx::Filter::LINEAR;
   else
     filter = mgfx::Filter::POINT;
   mgfx::Rect bounds;
   if (NeedToDrawShadow()) {
     bounds = mgfx::Rect(dx, dy, dw, dh);
     bounds = mTarget->GetTransform().TransformBounds(bounds);
   }
   if (srcSurf) {
     AdjustedTarget(this, bounds.IsEmpty() ? nullptr : &bounds)->
       DrawSurface(srcSurf,
                   mgfx::Rect(dx, dy, dw, dh),
                   mgfx::Rect(sx, sy, sw, sh),
                   DrawSurfaceOptions(filter),
                   DrawOptions(CurrentState().globalAlpha, UsedOperation()));
   } else {
     DrawDirectlyToCanvas(drawInfo, &bounds, dx, dy, dw, dh,
                          sx, sy, sw, sh, imgSize);
   }
   RedrawUser(gfxRect(dx, dy, dw, dh));
 }
 void
 CanvasRenderingContext2D::DrawDirectlyToCanvas(
                           const nsLayoutUtils::DirectDrawInfo& image,
                           mgfx::Rect* bounds, double dx, double dy,
                           double dw, double dh, double sx, double sy,
                           double sw, double sh, gfxIntSize imgSize)
 {
   gfxMatrix contextMatrix;
   AdjustedTarget tempTarget(this, bounds->IsEmpty() ? nullptr: bounds);
   // get any already existing transforms on the context. Include transformations used for context shadow
   if (tempTarget) {
     Matrix matrix = tempTarget->GetTransform();
     contextMatrix = gfxMatrix(matrix._11, matrix._12, matrix._21,
                               matrix._22, matrix._31, matrix._32);
   }
   gfxMatrix transformMatrix;
   transformMatrix.Translate(gfxPoint(sx, sy));
   if (dw > 0 && dh > 0) {
     transformMatrix.Scale(sw/dw, sh/dh);
   }
   transformMatrix.Translate(gfxPoint(-dx, -dy));
   nsRefPtr<gfxContext> context = new gfxContext(tempTarget);
   context->SetMatrix(contextMatrix);
   // FLAG_CLAMP is added for increased performance
   uint32_t modifiedFlags = image.mDrawingFlags | imgIContainer::FLAG_CLAMP;
   nsresult rv = image.mImgContainer->
     Draw(context, GraphicsFilter::FILTER_GOOD, transformMatrix,
          gfxRect(gfxPoint(dx, dy), gfxIntSize(dw, dh)),
          nsIntRect(nsIntPoint(0, 0), gfxIntSize(imgSize.width, imgSize.height)),
          gfxIntSize(imgSize.width, imgSize.height), nullptr, image.mWhichFrame,
          modifiedFlags);
   NS_ENSURE_SUCCESS_VOID(rv);
 }
 static bool
 IsStandardCompositeOp(CompositionOp op)
 {
     return (op == CompositionOp::OP_SOURCE ||
             op == CompositionOp::OP_ATOP ||
             op == CompositionOp::OP_IN ||
             op == CompositionOp::OP_OUT ||
             op == CompositionOp::OP_OVER ||
             op == CompositionOp::OP_DEST_IN ||
             op == CompositionOp::OP_DEST_OUT ||
             op == CompositionOp::OP_DEST_OVER ||
             op == CompositionOp::OP_DEST_ATOP ||
             op == CompositionOp::OP_ADD ||
             op == CompositionOp::OP_XOR);
 }
 void
 CanvasRenderingContext2D::SetGlobalCompositeOperation(const nsAString& op,
                                                       ErrorResult& error)
 {
   CompositionOp comp_op;
 #define CANVAS_OP_TO_GFX_OP(cvsop, op2d) \
   if (op.EqualsLiteral(cvsop))   \
     comp_op = CompositionOp::OP_##op2d;
   CANVAS_OP_TO_GFX_OP("copy", SOURCE)
   else CANVAS_OP_TO_GFX_OP("source-atop", ATOP)
   else CANVAS_OP_TO_GFX_OP("source-in", IN)
   else CANVAS_OP_TO_GFX_OP("source-out", OUT)
   else CANVAS_OP_TO_GFX_OP("source-over", OVER)
   else CANVAS_OP_TO_GFX_OP("destination-in", DEST_IN)
   else CANVAS_OP_TO_GFX_OP("destination-out", DEST_OUT)
   else CANVAS_OP_TO_GFX_OP("destination-over", DEST_OVER)
   else CANVAS_OP_TO_GFX_OP("destination-atop", DEST_ATOP)
   else CANVAS_OP_TO_GFX_OP("lighter", ADD)
   else CANVAS_OP_TO_GFX_OP("xor", XOR)
   else CANVAS_OP_TO_GFX_OP("multiply", MULTIPLY)
   else CANVAS_OP_TO_GFX_OP("screen", SCREEN)
   else CANVAS_OP_TO_GFX_OP("overlay", OVERLAY)
   else CANVAS_OP_TO_GFX_OP("darken", DARKEN)
   else CANVAS_OP_TO_GFX_OP("lighten", LIGHTEN)
   else CANVAS_OP_TO_GFX_OP("color-dodge", COLOR_DODGE)
   else CANVAS_OP_TO_GFX_OP("color-burn", COLOR_BURN)
   else CANVAS_OP_TO_GFX_OP("hard-light", HARD_LIGHT)
   else CANVAS_OP_TO_GFX_OP("soft-light", SOFT_LIGHT)
   else CANVAS_OP_TO_GFX_OP("difference", DIFFERENCE)
   else CANVAS_OP_TO_GFX_OP("exclusion", EXCLUSION)
   else CANVAS_OP_TO_GFX_OP("hue", HUE)
   else CANVAS_OP_TO_GFX_OP("saturation", SATURATION)
   else CANVAS_OP_TO_GFX_OP("color", COLOR)
   else CANVAS_OP_TO_GFX_OP("luminosity", LUMINOSITY)
   // XXX ERRMSG we need to report an error to developers here! (bug 329026)
   else return;
   if (!IsStandardCompositeOp(comp_op)) {
     Demote();
   }
 #undef CANVAS_OP_TO_GFX_OP
   CurrentState().op = comp_op;
 }
 void
 CanvasRenderingContext2D::GetGlobalCompositeOperation(nsAString& op,
                                                       ErrorResult& error)
 {
   CompositionOp comp_op = CurrentState().op;
 #define CANVAS_OP_TO_GFX_OP(cvsop, op2d) \
   if (comp_op == CompositionOp::OP_##op2d) \
     op.AssignLiteral(cvsop);
   CANVAS_OP_TO_GFX_OP("copy", SOURCE)
   else CANVAS_OP_TO_GFX_OP("destination-atop", DEST_ATOP)
   else CANVAS_OP_TO_GFX_OP("destination-in", DEST_IN)
   else CANVAS_OP_TO_GFX_OP("destination-out", DEST_OUT)
   else CANVAS_OP_TO_GFX_OP("destination-over", DEST_OVER)
   else CANVAS_OP_TO_GFX_OP("lighter", ADD)
   else CANVAS_OP_TO_GFX_OP("source-atop", ATOP)
   else CANVAS_OP_TO_GFX_OP("source-in", IN)
   else CANVAS_OP_TO_GFX_OP("source-out", OUT)
   else CANVAS_OP_TO_GFX_OP("source-over", OVER)
   else CANVAS_OP_TO_GFX_OP("xor", XOR)
   else CANVAS_OP_TO_GFX_OP("multiply", MULTIPLY)
   else CANVAS_OP_TO_GFX_OP("screen", SCREEN)
   else CANVAS_OP_TO_GFX_OP("overlay", OVERLAY)
   else CANVAS_OP_TO_GFX_OP("darken", DARKEN)
   else CANVAS_OP_TO_GFX_OP("lighten", LIGHTEN)
   else CANVAS_OP_TO_GFX_OP("color-dodge", COLOR_DODGE)
   else CANVAS_OP_TO_GFX_OP("color-burn", COLOR_BURN)
   else CANVAS_OP_TO_GFX_OP("hard-light", HARD_LIGHT)
   else CANVAS_OP_TO_GFX_OP("soft-light", SOFT_LIGHT)
   else CANVAS_OP_TO_GFX_OP("difference", DIFFERENCE)
   else CANVAS_OP_TO_GFX_OP("exclusion", EXCLUSION)
   else CANVAS_OP_TO_GFX_OP("hue", HUE)
   else CANVAS_OP_TO_GFX_OP("saturation", SATURATION)
   else CANVAS_OP_TO_GFX_OP("color", COLOR)
   else CANVAS_OP_TO_GFX_OP("luminosity", LUMINOSITY)
   else {
     error.Throw(NS_ERROR_FAILURE);
   }
   if (!IsStandardCompositeOp(comp_op)) {
     Demote();
   }
 #undef CANVAS_OP_TO_GFX_OP
 }
 void
 CanvasRenderingContext2D::DrawWindow(nsGlobalWindow& window, double x,
                                      double y, double w, double h,
                                      const nsAString& bgColor,
                                      uint32_t flags, ErrorResult& error)
 {
   // protect against too-large surfaces that will cause allocation
   // or overflow issues
   if (!gfxASurface::CheckSurfaceSize(gfxIntSize(int32_t(w), int32_t(h)),
 xffff)) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   EnsureTarget();
   // We can't allow web apps to call this until we fix at least the
   // following potential security issues:
   // -- rendering cross-domain IFRAMEs and then extracting the results
   // -- rendering the user's theme and then extracting the results
   // -- rendering native anonymous content (e.g., file input paths;
   // scrollbars should be allowed)
   if (!nsContentUtils::IsCallerChrome()) {
     // not permitted to use DrawWindow
     // XXX ERRMSG we need to report an error to developers here! (bug 329026)
     error.Throw(NS_ERROR_DOM_SECURITY_ERR);
     return;
   }
   // Flush layout updates
   if (!(flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DO_NOT_FLUSH)) {
     nsContentUtils::FlushLayoutForTree(&window);
   }
   nsRefPtr<nsPresContext> presContext;
   nsIDocShell* docshell = window.GetDocShell();
   if (docshell) {
     docshell->GetPresContext(getter_AddRefs(presContext));
   }
   if (!presContext) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   nscolor backgroundColor;
   if (!ParseColor(bgColor, &backgroundColor)) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   nsRect r(nsPresContext::CSSPixelsToAppUnits((float)x),
            nsPresContext::CSSPixelsToAppUnits((float)y),
            nsPresContext::CSSPixelsToAppUnits((float)w),
            nsPresContext::CSSPixelsToAppUnits((float)h));
   uint32_t renderDocFlags = (nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING |
                              nsIPresShell::RENDER_DOCUMENT_RELATIVE);
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DRAW_CARET) {
     renderDocFlags |= nsIPresShell::RENDER_CARET;
   }
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DRAW_VIEW) {
     renderDocFlags &= ~(nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING |
                         nsIPresShell::RENDER_DOCUMENT_RELATIVE);
   }
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_USE_WIDGET_LAYERS) {
     renderDocFlags |= nsIPresShell::RENDER_USE_WIDGET_LAYERS;
   }
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_ASYNC_DECODE_IMAGES) {
     renderDocFlags |= nsIPresShell::RENDER_ASYNC_DECODE_IMAGES;
   }
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DO_NOT_FLUSH) {
     renderDocFlags |= nsIPresShell::RENDER_DRAWWINDOW_NOT_FLUSHING;
   }
   // gfxContext-over-Azure may modify the DrawTarget's transform, so
   // save and restore it
   Matrix matrix = mTarget->GetTransform();
   double sw = matrix._11 * w;
   double sh = matrix._22 * h;
   if (!sw || !sh) {
     return;
   }
   nsRefPtr<gfxContext> thebes;
   RefPtr<DrawTarget> drawDT;
   if (gfxPlatform::GetPlatform()->SupportsAzureContentForDrawTarget(mTarget)) {
     thebes = new gfxContext(mTarget);
     thebes->SetMatrix(gfxMatrix(matrix._11, matrix._12, matrix._21,
                                 matrix._22, matrix._31, matrix._32));
   } else {
     drawDT =
       gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(IntSize(ceil(sw), ceil(sh)),
                                                                    SurfaceFormat::B8G8R8A8);
     if (!drawDT) {
       error.Throw(NS_ERROR_FAILURE);
       return;
     }
     thebes = new gfxContext(drawDT);
     thebes->Scale(matrix._11, matrix._22);
   }
   nsCOMPtr<nsIPresShell> shell = presContext->PresShell();
   unused << shell->RenderDocument(r, renderDocFlags, backgroundColor, thebes);
   if (drawDT) {
     RefPtr<SourceSurface> snapshot = drawDT->Snapshot();
     RefPtr<DataSourceSurface> data = snapshot->GetDataSurface();
     RefPtr<SourceSurface> source =
       mTarget->CreateSourceSurfaceFromData(data->GetData(),
                                            data->GetSize(),
                                            data->Stride(),
                                            data->GetFormat());
     if (!source) {
       error.Throw(NS_ERROR_FAILURE);
       return;
     }
     mgfx::Rect destRect(0, 0, w, h);
     mgfx::Rect sourceRect(0, 0, sw, sh);
     mTarget->DrawSurface(source, destRect, sourceRect,
                          DrawSurfaceOptions(mgfx::Filter::POINT),
                          DrawOptions(1.0f, CompositionOp::OP_OVER,
                                      AntialiasMode::NONE));
     mTarget->Flush();
   } else {
     mTarget->SetTransform(matrix);
   }
   // note that x and y are coordinates in the document that
   // we're drawing; x and y are drawn to 0,0 in current user
   // space.
   RedrawUser(gfxRect(0, 0, w, h));
 }
 void
 CanvasRenderingContext2D::AsyncDrawXULElement(nsXULElement& elem,
                                               double x, double y,
                                               double w, double h,
                                               const nsAString& bgColor,
                                               uint32_t flags,
                                               ErrorResult& error)
 {
   // We can't allow web apps to call this until we fix at least the
   // following potential security issues:
   // -- rendering cross-domain IFRAMEs and then extracting the results
   // -- rendering the user's theme and then extracting the results
   // -- rendering native anonymous content (e.g., file input paths;
   // scrollbars should be allowed)
   if (!nsContentUtils::IsCallerChrome()) {
     // not permitted to use DrawWindow
     // XXX ERRMSG we need to report an error to developers here! (bug 329026)
     error.Throw(NS_ERROR_DOM_SECURITY_ERR);
     return;
   }
 #if 0
   nsCOMPtr<nsIFrameLoaderOwner> loaderOwner = do_QueryInterface(&elem);
   if (!loaderOwner) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   nsRefPtr<nsFrameLoader> frameloader = loaderOwner->GetFrameLoader();
   if (!frameloader) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   PBrowserParent *child = frameloader->GetRemoteBrowser();
   if (!child) {
     nsCOMPtr<nsIDOMWindow> window =
       do_GetInterface(frameloader->GetExistingDocShell());
     if (!window) {
       error.Throw(NS_ERROR_FAILURE);
       return;
     }
     return DrawWindow(window, x, y, w, h, bgColor, flags);
   }
   // protect against too-large surfaces that will cause allocation
   // or overflow issues
   if (!gfxASurface::CheckSurfaceSize(gfxIntSize(w, h), 0xffff)) {
     error.Throw(NS_ERROR_FAILURE);
     return;
   }
   bool flush =
     (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DO_NOT_FLUSH) == 0;
   uint32_t renderDocFlags = nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING;
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DRAW_CARET) {
     renderDocFlags |= nsIPresShell::RENDER_CARET;
   }
   if (flags & nsIDOMCanvasRenderingContext2D::DRAWWINDOW_DRAW_VIEW) {
     renderDocFlags &= ~nsIPresShell::RENDER_IGNORE_VIEWPORT_SCROLLING;
   }
   nsRect rect(nsPresContext::CSSPixelsToAppUnits(x),
               nsPresContext::CSSPixelsToAppUnits(y),
               nsPresContext::CSSPixelsToAppUnits(w),
               nsPresContext::CSSPixelsToAppUnits(h));
   if (mIPC) {
     PDocumentRendererParent *pdocrender =
       child->SendPDocumentRendererConstructor(rect,
                                               mThebes->CurrentMatrix(),
                                               nsString(aBGColor),
                                               renderDocFlags, flush,
                                               nsIntSize(mWidth, mHeight));
     if (!pdocrender)
       return NS_ERROR_FAILURE;
     DocumentRendererParent *docrender =
       static_cast<DocumentRendererParent *>(pdocrender);
     docrender->SetCanvasContext(this, mThebes);
   }
 #endif
 }
 //
 // device pixel getting/setting
 //
 already_AddRefed<ImageData>
 CanvasRenderingContext2D::GetImageData(JSContext* aCx, double aSx,
                                        double aSy, double aSw,
                                        double aSh, ErrorResult& error)
 {
   EnsureTarget();
   if (!IsTargetValid()) {
     error.Throw(NS_ERROR_FAILURE);
     return nullptr;
   }
   if (!mCanvasElement && !mDocShell) {
     NS_ERROR("No canvas element and no docshell in GetImageData!!!");
     error.Throw(NS_ERROR_DOM_SECURITY_ERR);
     return nullptr;
   }
   // Check only if we have a canvas element; if we were created with a docshell,
   // then it's special internal use.
   if (mCanvasElement && mCanvasElement->IsWriteOnly() &&
       !nsContentUtils::IsCallerChrome())
   {
     // XXX ERRMSG we need to report an error to developers here! (bug 329026)
     error.Throw(NS_ERROR_DOM_SECURITY_ERR);
     return nullptr;
   }
   if (!NS_finite(aSx) || !NS_finite(aSy) ||
       !NS_finite(aSw) || !NS_finite(aSh)) {
     error.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
     return nullptr;
   }
   if (!aSw || !aSh) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return nullptr;
   }
   int32_t x = JS_DoubleToInt32(aSx);
   int32_t y = JS_DoubleToInt32(aSy);
   int32_t wi = JS_DoubleToInt32(aSw);
   int32_t hi = JS_DoubleToInt32(aSh);
   // Handle negative width and height by flipping the rectangle over in the
   // relevant direction.
   uint32_t w, h;
   if (aSw < 0) {
     w = -wi;
     x -= w;
   } else {
     w = wi;
   }
   if (aSh < 0) {
     h = -hi;
     y -= h;
   } else {
     h = hi;
   }
   if (w == 0) {
     w = 1;
   }
   if (h == 0) {
     h = 1;
   }
   JS::Rooted<JSObject*> array(aCx);
   error = GetImageDataArray(aCx, x, y, w, h, array.address());
   if (error.Failed()) {
     return nullptr;
   }
   MOZ_ASSERT(array);
   nsRefPtr<ImageData> imageData = new ImageData(w, h, *array);
   return imageData.forget();
 }
 nsresult
 CanvasRenderingContext2D::GetImageDataArray(JSContext* aCx,
                                             int32_t aX,
                                             int32_t aY,
                                             uint32_t aWidth,
                                             uint32_t aHeight,
                                             JSObject** aRetval)
 {
   MOZ_ASSERT(aWidth && aHeight);
   CheckedInt<uint32_t> len = CheckedInt<uint32_t>(aWidth) * aHeight * 4;
   if (!len.isValid()) {
     return NS_ERROR_DOM_INDEX_SIZE_ERR;
   }
   CheckedInt<int32_t> rightMost = CheckedInt<int32_t>(aX) + aWidth;
   CheckedInt<int32_t> bottomMost = CheckedInt<int32_t>(aY) + aHeight;
   if (!rightMost.isValid() || !bottomMost.isValid()) {
     return NS_ERROR_DOM_SYNTAX_ERR;
   }
   IntRect srcRect(0, 0, mWidth, mHeight);
   IntRect destRect(aX, aY, aWidth, aHeight);
   IntRect srcReadRect = srcRect.Intersect(destRect);
   RefPtr<DataSourceSurface> readback;
   if (!srcReadRect.IsEmpty() && !mZero) {
     RefPtr<SourceSurface> snapshot = mTarget->Snapshot();
     if (snapshot) {
       readback = snapshot->GetDataSurface();
     }
     if (!readback || !readback->GetData()) {
       return NS_ERROR_OUT_OF_MEMORY;
     }
   }
   JS::Rooted<JSObject*> darray(aCx, JS_NewUint8ClampedArray(aCx, len.value()));
   if (!darray) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
   if (mZero) {
     *aRetval = darray;
     return NS_OK;
   }
   uint8_t* data = JS_GetUint8ClampedArrayData(darray);
   // Check for site-specific permission and return all-white, opaque pixel
   // data if no permission.  This check is not needed if the canvas was
   // created with a docshell (that is only done for special internal uses).
   bool usePlaceholder = false;
   if (mCanvasElement) {
     nsCOMPtr<nsIDocument> ownerDoc = mCanvasElement->OwnerDoc();
     usePlaceholder = !ownerDoc ||
       !CanvasUtils::IsImageExtractionAllowed(ownerDoc, aCx);
   }
   if (usePlaceholder) {
     memset(data, 0xFF, len.value());
     *aRetval = darray;
     return NS_OK;
   }
   IntRect dstWriteRect = srcReadRect;
   dstWriteRect.MoveBy(-aX, -aY);
   uint8_t* src = data;
   uint32_t srcStride = aWidth * 4;
   if (readback) {
     srcStride = readback->Stride();
     src = readback->GetData() + srcReadRect.y * srcStride + srcReadRect.x * 4;
   }
   // NOTE! dst is the same as src, and this relies on reading
   // from src and advancing that ptr before writing to dst.
   // NOTE! I'm not sure that it is, I think this comment might have been
   // inherited from Thebes canvas and is no longer true
   uint8_t* dst = data + dstWriteRect.y * (aWidth * 4) + dstWriteRect.x * 4;
   if (mOpaque) {
     for (int32_t j = 0; j < dstWriteRect.height; ++j) {
       for (int32_t i = 0; i < dstWriteRect.width; ++i) {
         // XXX Is there some useful swizzle MMX we can use here?
 #if MOZ_LITTLE_ENDIAN
         uint8_t b = *src++;
         uint8_t g = *src++;
         uint8_t r = *src++;
         src++;
 #else
         src++;
         uint8_t r = *src++;
         uint8_t g = *src++;
         uint8_t b = *src++;
 #endif
         *dst++ = r;
         *dst++ = g;
         *dst++ = b;
         *dst++ = 255;
       }
       src += srcStride - (dstWriteRect.width * 4);
       dst += (aWidth * 4) - (dstWriteRect.width * 4);
     }
   } else
   for (int32_t j = 0; j < dstWriteRect.height; ++j) {
     for (int32_t i = 0; i < dstWriteRect.width; ++i) {
       // XXX Is there some useful swizzle MMX we can use here?
 #if MOZ_LITTLE_ENDIAN
       uint8_t b = *src++;
       uint8_t g = *src++;
       uint8_t r = *src++;
       uint8_t a = *src++;
 #else
       uint8_t a = *src++;
       uint8_t r = *src++;
       uint8_t g = *src++;
       uint8_t b = *src++;
 #endif
       // Convert to non-premultiplied color
       *dst++ = gfxUtils::sUnpremultiplyTable[a * 256 + r];
       *dst++ = gfxUtils::sUnpremultiplyTable[a * 256 + g];
       *dst++ = gfxUtils::sUnpremultiplyTable[a * 256 + b];
       *dst++ = a;
     }
     src += srcStride - (dstWriteRect.width * 4);
     dst += (aWidth * 4) - (dstWriteRect.width * 4);
   }
   *aRetval = darray;
   return NS_OK;
 }
 void
 CanvasRenderingContext2D::EnsureErrorTarget()
 {
   if (sErrorTarget) {
     return;
   }
   RefPtr<DrawTarget> errorTarget = gfxPlatform::GetPlatform()->CreateOffscreenCanvasDrawTarget(IntSize(1, 1), SurfaceFormat::B8G8R8A8);
   MOZ_ASSERT(errorTarget, "Failed to allocate the error target!");
   sErrorTarget = errorTarget;
   NS_ADDREF(sErrorTarget);
 }
 void
 CanvasRenderingContext2D::FillRuleChanged()
 {
   if (mPath) {
     mPathBuilder = mPath->CopyToBuilder(CurrentState().fillRule);
     mPath = nullptr;
   }
 }
 void
 CanvasRenderingContext2D::PutImageData(ImageData& imageData, double dx,
                                        double dy, ErrorResult& error)
 {
   dom::Uint8ClampedArray arr(imageData.GetDataObject());
   error = PutImageData_explicit(JS_DoubleToInt32(dx), JS_DoubleToInt32(dy),
                                 imageData.Width(), imageData.Height(),
                                 &arr, false, 0, 0, 0, 0);
 }
 void
 CanvasRenderingContext2D::PutImageData(ImageData& imageData, double dx,
                                        double dy, double dirtyX,
                                        double dirtyY, double dirtyWidth,
                                        double dirtyHeight,
                                        ErrorResult& error)
 {
   dom::Uint8ClampedArray arr(imageData.GetDataObject());
   error = PutImageData_explicit(JS_DoubleToInt32(dx), JS_DoubleToInt32(dy),
                                 imageData.Width(), imageData.Height(),
                                 &arr, true,
                                 JS_DoubleToInt32(dirtyX),
                                 JS_DoubleToInt32(dirtyY),
                                 JS_DoubleToInt32(dirtyWidth),
                                 JS_DoubleToInt32(dirtyHeight));
 }
 // void putImageData (in ImageData d, in float x, in float y);
 // void putImageData (in ImageData d, in double x, in double y, in double dirtyX, in double dirtyY, in double dirtyWidth, in double dirtyHeight);
 nsresult
 CanvasRenderingContext2D::PutImageData_explicit(int32_t x, int32_t y, uint32_t w, uint32_t h,
                                                 dom::Uint8ClampedArray* aArray,
                                                 bool hasDirtyRect, int32_t dirtyX, int32_t dirtyY,
                                                 int32_t dirtyWidth, int32_t dirtyHeight)
 {
   if (w == 0 || h == 0) {
     return NS_ERROR_DOM_SYNTAX_ERR;
   }
   IntRect dirtyRect;
   IntRect imageDataRect(0, 0, w, h);
   if (hasDirtyRect) {
     // fix up negative dimensions
     if (dirtyWidth < 0) {
       NS_ENSURE_TRUE(dirtyWidth != INT_MIN, NS_ERROR_DOM_INDEX_SIZE_ERR);
       CheckedInt32 checkedDirtyX = CheckedInt32(dirtyX) + dirtyWidth;
       if (!checkedDirtyX.isValid())
         return NS_ERROR_DOM_INDEX_SIZE_ERR;
       dirtyX = checkedDirtyX.value();
       dirtyWidth = -dirtyWidth;
     }
     if (dirtyHeight < 0) {
       NS_ENSURE_TRUE(dirtyHeight != INT_MIN, NS_ERROR_DOM_INDEX_SIZE_ERR);
       CheckedInt32 checkedDirtyY = CheckedInt32(dirtyY) + dirtyHeight;
       if (!checkedDirtyY.isValid())
         return NS_ERROR_DOM_INDEX_SIZE_ERR;
       dirtyY = checkedDirtyY.value();
       dirtyHeight = -dirtyHeight;
     }
     // bound the dirty rect within the imageData rectangle
     dirtyRect = imageDataRect.Intersect(IntRect(dirtyX, dirtyY, dirtyWidth, dirtyHeight));
     if (dirtyRect.Width() <= 0 || dirtyRect.Height() <= 0)
       return NS_OK;
   } else {
     dirtyRect = imageDataRect;
   }
   dirtyRect.MoveBy(IntPoint(x, y));
   dirtyRect = IntRect(0, 0, mWidth, mHeight).Intersect(dirtyRect);
   if (dirtyRect.Width() <= 0 || dirtyRect.Height() <= 0) {
     return NS_OK;
   }
   aArray->ComputeLengthAndData();
   uint32_t dataLen = aArray->Length();
   uint32_t len = w * h * 4;
   if (dataLen != len) {
     return NS_ERROR_DOM_SYNTAX_ERR;
   }
   nsRefPtr<gfxImageSurface> imgsurf = new gfxImageSurface(gfxIntSize(w, h),
                                                           gfxImageFormat::ARGB32,
                                                           false);
   if (!imgsurf || imgsurf->CairoStatus()) {
     return NS_ERROR_FAILURE;
   }
   uint8_t *src = aArray->Data();
   uint8_t *dst = imgsurf->Data();
   for (uint32_t j = 0; j < h; j++) {
     for (uint32_t i = 0; i < w; i++) {
       uint8_t r = *src++;
       uint8_t g = *src++;
       uint8_t b = *src++;
       uint8_t a = *src++;
       // Convert to premultiplied color (losslessly if the input came from getImageData)
 #if MOZ_LITTLE_ENDIAN
       *dst++ = gfxUtils::sPremultiplyTable[a * 256 + b];
       *dst++ = gfxUtils::sPremultiplyTable[a * 256 + g];
       *dst++ = gfxUtils::sPremultiplyTable[a * 256 + r];
       *dst++ = a;
 #else
       *dst++ = a;
       *dst++ = gfxUtils::sPremultiplyTable[a * 256 + r];
       *dst++ = gfxUtils::sPremultiplyTable[a * 256 + g];
       *dst++ = gfxUtils::sPremultiplyTable[a * 256 + b];
 #endif
     }
   }
   EnsureTarget();
   if (!IsTargetValid()) {
     return NS_ERROR_FAILURE;
   }
   RefPtr<SourceSurface> sourceSurface =
     mTarget->CreateSourceSurfaceFromData(imgsurf->Data(), IntSize(w, h), imgsurf->Stride(), SurfaceFormat::B8G8R8A8);
   // In certain scenarios, requesting larger than 8k image fails.  Bug 803568
   // covers the details of how to run into it, but the full detailed
   // investigation hasn't been done to determine the underlying cause.  We
   // will just handle the failure to allocate the surface to avoid a crash.
   if (!sourceSurface) {
     return NS_ERROR_FAILURE;
   }
   mTarget->CopySurface(sourceSurface,
                        IntRect(dirtyRect.x - x, dirtyRect.y - y,
                                dirtyRect.width, dirtyRect.height),
                        IntPoint(dirtyRect.x, dirtyRect.y));
   Redraw(mgfx::Rect(dirtyRect.x, dirtyRect.y, dirtyRect.width, dirtyRect.height));
   return NS_OK;
 }
 static already_AddRefed<ImageData>
 CreateImageData(JSContext* cx, CanvasRenderingContext2D* context,
                 uint32_t w, uint32_t h, ErrorResult& error)
 {
   if (w == 0)
       w = 1;
   if (h == 0)
       h = 1;
   CheckedInt<uint32_t> len = CheckedInt<uint32_t>(w) * h * 4;
   if (!len.isValid()) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return nullptr;
   }
   // Create the fast typed array; it's initialized to 0 by default.
   JSObject* darray = Uint8ClampedArray::Create(cx, context, len.value());
   if (!darray) {
     error.Throw(NS_ERROR_OUT_OF_MEMORY);
     return nullptr;
   }
   nsRefPtr<mozilla::dom::ImageData> imageData =
     new mozilla::dom::ImageData(w, h, *darray);
   return imageData.forget();
 }
 already_AddRefed<ImageData>
 CanvasRenderingContext2D::CreateImageData(JSContext* cx, double sw,
                                           double sh, ErrorResult& error)
 {
   if (!sw || !sh) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return nullptr;
   }
   int32_t wi = JS_DoubleToInt32(sw);
   int32_t hi = JS_DoubleToInt32(sh);
   uint32_t w = Abs(wi);
   uint32_t h = Abs(hi);
   return mozilla::dom::CreateImageData(cx, this, w, h, error);
 }
 already_AddRefed<ImageData>
 CanvasRenderingContext2D::CreateImageData(JSContext* cx,
                                           ImageData& imagedata,
                                           ErrorResult& error)
 {
   return mozilla::dom::CreateImageData(cx, this, imagedata.Width(),
                                        imagedata.Height(), error);
 }
 static uint8_t g2DContextLayerUserData;
 already_AddRefed<CanvasLayer>
 CanvasRenderingContext2D::GetCanvasLayer(nsDisplayListBuilder* aBuilder,
                                          CanvasLayer *aOldLayer,
                                          LayerManager *aManager)
 {
   // Don't call EnsureTarget() ... if there isn't already a surface, then
   // we have nothing to paint and there is no need to create a surface just
   // to paint nothing. Also, EnsureTarget() can cause creation of a persistent
   // layer manager which must NOT happen during a paint.
   if (!mTarget || !IsTargetValid()) {
     // No DidTransactionCallback will be received, so mark the context clean
     // now so future invalidations will be dispatched.
     MarkContextClean();
     return nullptr;
   }
   mTarget->Flush();
   if (!mResetLayer && aOldLayer) {
     CanvasRenderingContext2DUserData* userData =
       static_cast<CanvasRenderingContext2DUserData*>(
         aOldLayer->GetUserData(&g2DContextLayerUserData));
     CanvasLayer::Data data;
     if (mStream) {
 #ifdef USE_SKIA
       SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
       if (glue) {
         data.mGLContext = glue->GetGLContext();
         data.mStream = mStream.get();
       }
 #endif
     } else {
       data.mDrawTarget = mTarget;
     }
     if (userData && userData->IsForContext(this) && aOldLayer->IsDataValid(data)) {
       nsRefPtr<CanvasLayer> ret = aOldLayer;
       return ret.forget();
     }
   }
   nsRefPtr<CanvasLayer> canvasLayer = aManager->CreateCanvasLayer();
   if (!canvasLayer) {
     NS_WARNING("CreateCanvasLayer returned null!");
     // No DidTransactionCallback will be received, so mark the context clean
     // now so future invalidations will be dispatched.
     MarkContextClean();
     return nullptr;
   }
   CanvasRenderingContext2DUserData *userData = nullptr;
   // Make the layer tell us whenever a transaction finishes (including
   // the current transaction), so we can clear our invalidation state and
   // start invalidating again. We need to do this for all layers since
   // callers of DrawWindow may be expecting to receive normal invalidation
   // notifications after this paint.
   // The layer will be destroyed when we tear down the presentation
   // (at the latest), at which time this userData will be destroyed,
   // releasing the reference to the element.
   // The userData will receive DidTransactionCallbacks, which flush the
   // the invalidation state to indicate that the canvas is up to date.
   userData = new CanvasRenderingContext2DUserData(this);
   canvasLayer->SetDidTransactionCallback(
           CanvasRenderingContext2DUserData::DidTransactionCallback, userData);
   canvasLayer->SetUserData(&g2DContextLayerUserData, userData);
   CanvasLayer::Data data;
   if (mStream) {
     SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
     if (glue) {
       canvasLayer->SetPreTransactionCallback(
               CanvasRenderingContext2DUserData::PreTransactionCallback, userData);
 #if USE_SKIA
       data.mGLContext = glue->GetGLContext();
 #endif
       data.mStream = mStream.get();
       data.mTexID = (uint32_t)((uintptr_t)mTarget->GetNativeSurface(NativeSurfaceType::OPENGL_TEXTURE));
     }
   } else {
     data.mDrawTarget = mTarget;
   }
   data.mSize = nsIntSize(mWidth, mHeight);
   canvasLayer->Initialize(data);
   uint32_t flags = mOpaque ? Layer::CONTENT_OPAQUE : 0;
   canvasLayer->SetContentFlags(flags);
   canvasLayer->Updated();
   mResetLayer = false;
   return canvasLayer.forget();
 }
 void
 CanvasRenderingContext2D::MarkContextClean()
 {
   if (mInvalidateCount > 0) {
     mPredictManyRedrawCalls = mInvalidateCount > kCanvasMaxInvalidateCount;
   }
   mIsEntireFrameInvalid = false;
   mInvalidateCount = 0;
 }
 bool
 CanvasRenderingContext2D::ShouldForceInactiveLayer(LayerManager *aManager)
 {
   return !aManager->CanUseCanvasLayerForSize(IntSize(mWidth, mHeight));
 }
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(CanvasPath, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(CanvasPath, Release)
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_1(CanvasPath, mParent)
 CanvasPath::CanvasPath(nsISupports* aParent)
   : mParent(aParent)
 {
   SetIsDOMBinding();
   mPathBuilder = gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget()->CreatePathBuilder();
 }
 CanvasPath::CanvasPath(nsISupports* aParent, RefPtr<PathBuilder> aPathBuilder)
   : mParent(aParent), mPathBuilder(aPathBuilder)
 {
   SetIsDOMBinding();
   if (!mPathBuilder) {
     mPathBuilder = gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget()->CreatePathBuilder();
   }
 }
 JSObject*
 CanvasPath::WrapObject(JSContext* aCx)
 {
   return Path2DBinding::Wrap(aCx, this);
 }
 already_AddRefed<CanvasPath>
 CanvasPath::Constructor(const GlobalObject& aGlobal, ErrorResult& aRv)
 {
   nsRefPtr<CanvasPath> path = new CanvasPath(aGlobal.GetAsSupports());
   return path.forget();
 }
 already_AddRefed<CanvasPath>
 CanvasPath::Constructor(const GlobalObject& aGlobal, CanvasPath& aCanvasPath, ErrorResult& aRv)
 {
   RefPtr<gfx::Path> tempPath = aCanvasPath.GetPath(CanvasWindingRule::Nonzero,
                                                    gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget());
   nsRefPtr<CanvasPath> path = new CanvasPath(aGlobal.GetAsSupports(), tempPath->CopyToBuilder());
   return path.forget();
 }
 already_AddRefed<CanvasPath>
 CanvasPath::Constructor(const GlobalObject& aGlobal, const nsAString& aPathString, ErrorResult& aRv)
 {
   RefPtr<gfx::Path> tempPath = SVGContentUtils::GetPath(aPathString);
   if (!tempPath) {
     return Constructor(aGlobal, aRv);
   }
   nsRefPtr<CanvasPath> path = new CanvasPath(aGlobal.GetAsSupports(), tempPath->CopyToBuilder());
   return path.forget();
 }
 void
 CanvasPath::ClosePath()
 {
   EnsurePathBuilder();
   mPathBuilder->Close();
 }
 void
 CanvasPath::MoveTo(double x, double y)
 {
   EnsurePathBuilder();
   mPathBuilder->MoveTo(Point(ToFloat(x), ToFloat(y)));
 }
 void
 CanvasPath::LineTo(double x, double y)
 {
   EnsurePathBuilder();
   mPathBuilder->LineTo(Point(ToFloat(x), ToFloat(y)));
 }
 void
 CanvasPath::QuadraticCurveTo(double cpx, double cpy, double x, double y)
 {
   EnsurePathBuilder();
   mPathBuilder->QuadraticBezierTo(gfx::Point(ToFloat(cpx), ToFloat(cpy)),
                                   gfx::Point(ToFloat(x), ToFloat(y)));
 }
 void
 CanvasPath::BezierCurveTo(double cp1x, double cp1y,
                           double cp2x, double cp2y,
                           double x, double y)
 {
   BezierTo(gfx::Point(ToFloat(cp1x), ToFloat(cp1y)),
              gfx::Point(ToFloat(cp2x), ToFloat(cp2y)),
              gfx::Point(ToFloat(x), ToFloat(y)));
 }
 void
 CanvasPath::ArcTo(double x1, double y1, double x2, double y2, double radius,
                   ErrorResult& error)
 {
   if (radius < 0) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   // Current point in user space!
   Point p0 = mPathBuilder->CurrentPoint();
   Point p1(x1, y1);
   Point p2(x2, y2);
   // Execute these calculations in double precision to avoid cumulative
   // rounding errors.
   double dir, a2, b2, c2, cosx, sinx, d, anx, any,
          bnx, bny, x3, y3, x4, y4, cx, cy, angle0, angle1;
   bool anticlockwise;
   if (p0 == p1 || p1 == p2 || radius == 0) {
     LineTo(p1.x, p1.y);
     return;
   }
   // Check for colinearity
   dir = (p2.x - p1.x) * (p0.y - p1.y) + (p2.y - p1.y) * (p1.x - p0.x);
   if (dir == 0) {
     LineTo(p1.x, p1.y);
     return;
   }
   // XXX - Math for this code was already available from the non-azure code
   // and would be well tested. Perhaps converting to bezier directly might
   // be more efficient longer run.
   a2 = (p0.x-x1)*(p0.x-x1) + (p0.y-y1)*(p0.y-y1);
   b2 = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
   c2 = (p0.x-x2)*(p0.x-x2) + (p0.y-y2)*(p0.y-y2);
   cosx = (a2+b2-c2)/(2*sqrt(a2*b2));
   sinx = sqrt(1 - cosx*cosx);
   d = radius / ((1 - cosx) / sinx);
   anx = (x1-p0.x) / sqrt(a2);
   any = (y1-p0.y) / sqrt(a2);
   bnx = (x1-x2) / sqrt(b2);
   bny = (y1-y2) / sqrt(b2);
   x3 = x1 - anx*d;
   y3 = y1 - any*d;
   x4 = x1 - bnx*d;
   y4 = y1 - bny*d;
   anticlockwise = (dir < 0);
   cx = x3 + any*radius*(anticlockwise ? 1 : -1);
   cy = y3 - anx*radius*(anticlockwise ? 1 : -1);
   angle0 = atan2((y3-cy), (x3-cx));
   angle1 = atan2((y4-cy), (x4-cx));
   LineTo(x3, y3);
   Arc(cx, cy, radius, angle0, angle1, anticlockwise, error);
 }
 void
 CanvasPath::Rect(double x, double y, double w, double h)
 {
   MoveTo(x, y);
   LineTo(x + w, y);
   LineTo(x + w, y + h);
   LineTo(x, y + h);
   ClosePath();
 }
 void
 CanvasPath::Arc(double x, double y, double radius,
                 double startAngle, double endAngle, bool anticlockwise,
                 ErrorResult& error)
 {
   if (radius < 0.0) {
     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
   }
   ArcToBezier(this, Point(x, y), Size(radius, radius), startAngle, endAngle, anticlockwise);
 }
 void
 CanvasPath::LineTo(const gfx::Point& aPoint)
 {
   EnsurePathBuilder();
   mPathBuilder->LineTo(aPoint);
 }
 void
 CanvasPath::BezierTo(const gfx::Point& aCP1,
                      const gfx::Point& aCP2,
                      const gfx::Point& aCP3)
 {
   EnsurePathBuilder();
   mPathBuilder->BezierTo(aCP1, aCP2, aCP3);
 }
 RefPtr<gfx::Path>
 CanvasPath::GetPath(const CanvasWindingRule& winding, const mozilla::RefPtr<mozilla::gfx::DrawTarget>& mTarget) const
 {
   FillRule fillRule = FillRule::FILL_WINDING;
   if (winding == CanvasWindingRule::Evenodd) {
     fillRule = FillRule::FILL_EVEN_ODD;
   }
   if (mPath &&
       (mPath->GetBackendType() == mTarget->GetType()) &&
       (mPath->GetFillRule() == fillRule)) {
     return mPath;
   }
   if (!mPath) {
     // if there is no path, there must be a pathbuilder
     MOZ_ASSERT(mPathBuilder);
     mPath = mPathBuilder->Finish();
     if (!mPath)
       return mPath;
     mPathBuilder = nullptr;
   }
   // retarget our backend if we're used with a different backend
   if (mPath->GetBackendType() != mTarget->GetType()) {
     RefPtr<PathBuilder> tmpPathBuilder = mTarget->CreatePathBuilder(fillRule);
     mPath->StreamToSink(tmpPathBuilder);
     mPath = tmpPathBuilder->Finish();
   } else if (mPath->GetFillRule() != fillRule) {
     RefPtr<PathBuilder> tmpPathBuilder = mPath->CopyToBuilder(fillRule);
     mPath = tmpPathBuilder->Finish();
   }
   return mPath;
 }
 void
 CanvasPath::EnsurePathBuilder() const
 {
   if (mPathBuilder) {
     return;
   }
   // if there is not pathbuilder, there must be a path
   MOZ_ASSERT(mPath);
   mPathBuilder = mPath->CopyToBuilder();
   mPath = nullptr;
 }
 }
 }

The Tor Browser / annotate

content/canvas/src/CanvasRenderingContext2D.cpp@deefc01c0e14 (annotated)

content/canvas/src/CanvasRenderingContext2D.cpp