gecko-dev/layout/svg/nsSVGUtils.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// Main header first:
// This is also necessary to ensure our definition of M_SQRT1_2 is picked up
#include "nsSVGUtils.h"
#include <algorithm>

// Keep others in (case-insensitive) order:
#include "gfx2DGlue.h"
#include "gfxContext.h"
#include "gfxMatrix.h"
#include "gfxPlatform.h"
#include "gfxRect.h"
#include "gfxUtils.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/PatternHelpers.h"
#include "mozilla/Preferences.h"
#include "mozilla/SVGContextPaint.h"
#include "nsCSSClipPathInstance.h"
#include "nsCSSFrameConstructor.h"
#include "nsDisplayList.h"
#include "nsFilterInstance.h"
#include "nsFrameList.h"
#include "nsGkAtoms.h"
#include "nsIContent.h"
#include "nsIDocument.h"
#include "nsIFrame.h"
#include "nsIPresShell.h"
#include "nsSVGDisplayableFrame.h"
#include "nsLayoutUtils.h"
#include "nsPresContext.h"
#include "nsStyleCoord.h"
#include "nsStyleStruct.h"
#include "nsSVGClipPathFrame.h"
#include "nsSVGContainerFrame.h"
#include "SVGObserverUtils.h"
#include "nsSVGFilterPaintCallback.h"
#include "nsSVGForeignObjectFrame.h"
#include "nsSVGInnerSVGFrame.h"
#include "nsSVGIntegrationUtils.h"
#include "nsSVGLength2.h"
#include "nsSVGMaskFrame.h"
#include "nsSVGOuterSVGFrame.h"
#include "mozilla/dom/SVGClipPathElement.h"
#include "mozilla/dom/SVGPathElement.h"
#include "mozilla/dom/SVGUnitTypesBinding.h"
#include "SVGGeometryElement.h"
#include "SVGGeometryFrame.h"
#include "nsSVGPaintServerFrame.h"
#include "mozilla/dom/SVGViewportElement.h"
#include "nsTextFrame.h"
#include "SVGContentUtils.h"
#include "SVGTextFrame.h"
#include "mozilla/Unused.h"

using namespace mozilla;
using namespace mozilla::dom;
using namespace mozilla::dom::SVGUnitTypes_Binding;
using namespace mozilla::gfx;
using namespace mozilla::image;

static bool sSVGDisplayListHitTestingEnabled;
static bool sSVGDisplayListPaintingEnabled;
static bool sSVGNewGetBBoxEnabled;

bool NS_SVGDisplayListHitTestingEnabled() {
  return sSVGDisplayListHitTestingEnabled;
}

bool NS_SVGDisplayListPaintingEnabled() {
  return sSVGDisplayListPaintingEnabled;
}

bool NS_SVGNewGetBBoxEnabled() { return sSVGNewGetBBoxEnabled; }

// we only take the address of this:
static mozilla::gfx::UserDataKey sSVGAutoRenderStateKey;

SVGAutoRenderState::SVGAutoRenderState(
    DrawTarget* aDrawTarget MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL)
    : mDrawTarget(aDrawTarget),
      mOriginalRenderState(nullptr),
      mPaintingToWindow(false) {
  MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  mOriginalRenderState = aDrawTarget->RemoveUserData(&sSVGAutoRenderStateKey);
  // We always remove ourselves from aContext before it dies, so
  // passing nullptr as the destroy function is okay.
  aDrawTarget->AddUserData(&sSVGAutoRenderStateKey, this, nullptr);
}

SVGAutoRenderState::~SVGAutoRenderState() {
  mDrawTarget->RemoveUserData(&sSVGAutoRenderStateKey);
  if (mOriginalRenderState) {
    mDrawTarget->AddUserData(&sSVGAutoRenderStateKey, mOriginalRenderState,
                             nullptr);
  }
}

void SVGAutoRenderState::SetPaintingToWindow(bool aPaintingToWindow) {
  mPaintingToWindow = aPaintingToWindow;
}

/* static */ bool SVGAutoRenderState::IsPaintingToWindow(
    DrawTarget* aDrawTarget) {
  void* state = aDrawTarget->GetUserData(&sSVGAutoRenderStateKey);
  if (state) {
    return static_cast<SVGAutoRenderState*>(state)->mPaintingToWindow;
  }
  return false;
}

void nsSVGUtils::Init() {
  Preferences::AddBoolVarCache(&sSVGDisplayListHitTestingEnabled,
                               "svg.display-lists.hit-testing.enabled");

  Preferences::AddBoolVarCache(&sSVGDisplayListPaintingEnabled,
                               "svg.display-lists.painting.enabled");

  Preferences::AddBoolVarCache(&sSVGNewGetBBoxEnabled,
                               "svg.new-getBBox.enabled");
}

nsRect nsSVGUtils::GetPostFilterVisualOverflowRect(
    nsIFrame* aFrame, const nsRect& aPreFilterRect) {
  MOZ_ASSERT(aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT,
             "Called on invalid frame type");

  // Note: we do not return here for eHasNoRefs since we must still handle any
  // CSS filter functions.
  // TODO: We currently pass nullptr instead of an nsTArray* here, but we
  // actually should get the filter frames and then pass them into
  // GetPostFilterBounds below!  See bug 1494263.
  // TODO: we should really return an empty rect for eHasRefsSomeInvalid since
  // in that case we disable painting of the element.
  if (!aFrame->StyleEffects()->HasFilters() ||
      SVGObserverUtils::GetAndObserveFilters(aFrame, nullptr) ==
          SVGObserverUtils::eHasRefsSomeInvalid) {
    return aPreFilterRect;
  }

  return nsFilterInstance::GetPostFilterBounds(aFrame, nullptr,
                                               &aPreFilterRect);
}

bool nsSVGUtils::OuterSVGIsCallingReflowSVG(nsIFrame* aFrame) {
  return GetOuterSVGFrame(aFrame)->IsCallingReflowSVG();
}

bool nsSVGUtils::AnyOuterSVGIsCallingReflowSVG(nsIFrame* aFrame) {
  nsSVGOuterSVGFrame* outer = GetOuterSVGFrame(aFrame);
  do {
    if (outer->IsCallingReflowSVG()) {
      return true;
    }
    outer = GetOuterSVGFrame(outer->GetParent());
  } while (outer);
  return false;
}

void nsSVGUtils::ScheduleReflowSVG(nsIFrame* aFrame) {
  MOZ_ASSERT(aFrame->IsFrameOfType(nsIFrame::eSVG), "Passed bad frame!");

  // If this is triggered, the callers should be fixed to call us before
  // ReflowSVG is called. If we try to mark dirty bits on frames while we're
  // in the process of removing them, things will get messed up.
  NS_ASSERTION(!OuterSVGIsCallingReflowSVG(aFrame),
               "Do not call under nsSVGDisplayableFrame::ReflowSVG!");

  // We don't call SVGObserverUtils::InvalidateRenderingObservers here because
  // we should only be called under InvalidateAndScheduleReflowSVG (which
  // calls InvalidateBounds) or nsSVGDisplayContainerFrame::InsertFrames
  // (at which point the frame has no observers).

  if (aFrame->GetStateBits() & NS_FRAME_IS_NONDISPLAY) {
    return;
  }

  if (aFrame->GetStateBits() & (NS_FRAME_IS_DIRTY | NS_FRAME_FIRST_REFLOW)) {
    // Nothing to do if we're already dirty, or if the outer-<svg>
    // hasn't yet had its initial reflow.
    return;
  }

  nsSVGOuterSVGFrame* outerSVGFrame = nullptr;

  // We must not add dirty bits to the nsSVGOuterSVGFrame or else
  // PresShell::FrameNeedsReflow won't work when we pass it in below.
  if (aFrame->GetStateBits() & NS_STATE_IS_OUTER_SVG) {
    outerSVGFrame = static_cast<nsSVGOuterSVGFrame*>(aFrame);
  } else {
    aFrame->AddStateBits(NS_FRAME_IS_DIRTY);

    nsIFrame* f = aFrame->GetParent();
    while (f && !(f->GetStateBits() & NS_STATE_IS_OUTER_SVG)) {
      if (f->GetStateBits() &
          (NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN)) {
        return;
      }
      f->AddStateBits(NS_FRAME_HAS_DIRTY_CHILDREN);
      f = f->GetParent();
      MOZ_ASSERT(f->IsFrameOfType(nsIFrame::eSVG),
                 "NS_STATE_IS_OUTER_SVG check above not valid!");
    }

    outerSVGFrame = static_cast<nsSVGOuterSVGFrame*>(f);

    MOZ_ASSERT(outerSVGFrame && outerSVGFrame->IsSVGOuterSVGFrame(),
               "Did not find nsSVGOuterSVGFrame!");
  }

  if (outerSVGFrame->GetStateBits() & NS_FRAME_IN_REFLOW) {
    // We're currently under an nsSVGOuterSVGFrame::Reflow call so there is no
    // need to call PresShell::FrameNeedsReflow, since we have an
    // nsSVGOuterSVGFrame::DidReflow call pending.
    return;
  }

  nsFrameState dirtyBit =
      (outerSVGFrame == aFrame ? NS_FRAME_IS_DIRTY
                               : NS_FRAME_HAS_DIRTY_CHILDREN);

  aFrame->PresShell()->FrameNeedsReflow(outerSVGFrame, nsIPresShell::eResize,
                                        dirtyBit);
}

bool nsSVGUtils::NeedsReflowSVG(nsIFrame* aFrame) {
  MOZ_ASSERT(aFrame->IsFrameOfType(nsIFrame::eSVG),
             "SVG uses bits differently!");

  // The flags we test here may change, hence why we have this separate
  // function.
  return NS_SUBTREE_DIRTY(aFrame);
}

Size nsSVGUtils::GetContextSize(const nsIFrame* aFrame) {
  Size size;

  MOZ_ASSERT(aFrame->GetContent()->IsSVGElement(), "bad cast");
  const nsSVGElement* element =
      static_cast<nsSVGElement*>(aFrame->GetContent());

  SVGViewportElement* ctx = element->GetCtx();
  if (ctx) {
    size.width = ctx->GetLength(SVGContentUtils::X);
    size.height = ctx->GetLength(SVGContentUtils::Y);
  }
  return size;
}

float nsSVGUtils::ObjectSpace(const gfxRect& aRect,
                              const nsSVGLength2* aLength) {
  float axis;

  switch (aLength->GetCtxType()) {
    case SVGContentUtils::X:
      axis = aRect.Width();
      break;
    case SVGContentUtils::Y:
      axis = aRect.Height();
      break;
    case SVGContentUtils::XY:
      axis = float(SVGContentUtils::ComputeNormalizedHypotenuse(
          aRect.Width(), aRect.Height()));
      break;
    default:
      MOZ_ASSERT_UNREACHABLE("unexpected ctx type");
      axis = 0.0f;
      break;
  }
  if (aLength->IsPercentage()) {
    // Multiply first to avoid precision errors:
    return axis * aLength->GetAnimValInSpecifiedUnits() / 100;
  }
  return aLength->GetAnimValue(static_cast<SVGViewportElement*>(nullptr)) *
         axis;
}

float nsSVGUtils::UserSpace(nsSVGElement* aSVGElement,
                            const nsSVGLength2* aLength) {
  return aLength->GetAnimValue(aSVGElement);
}

float nsSVGUtils::UserSpace(nsIFrame* aNonSVGContext,
                            const nsSVGLength2* aLength) {
  return aLength->GetAnimValue(aNonSVGContext);
}

float nsSVGUtils::UserSpace(const UserSpaceMetrics& aMetrics,
                            const nsSVGLength2* aLength) {
  return aLength->GetAnimValue(aMetrics);
}

nsSVGOuterSVGFrame* nsSVGUtils::GetOuterSVGFrame(nsIFrame* aFrame) {
  while (aFrame) {
    if (aFrame->GetStateBits() & NS_STATE_IS_OUTER_SVG) {
      return static_cast<nsSVGOuterSVGFrame*>(aFrame);
    }
    aFrame = aFrame->GetParent();
  }

  return nullptr;
}

nsIFrame* nsSVGUtils::GetOuterSVGFrameAndCoveredRegion(nsIFrame* aFrame,
                                                       nsRect* aRect) {
  nsSVGDisplayableFrame* svg = do_QueryFrame(aFrame);
  if (!svg) return nullptr;
  nsSVGOuterSVGFrame* outer = GetOuterSVGFrame(aFrame);
  if (outer == svg) {
    return nullptr;
  }

  if (aFrame->GetStateBits() & NS_FRAME_IS_NONDISPLAY) {
    *aRect = nsRect(0, 0, 0, 0);
  } else {
    uint32_t flags =
        nsSVGUtils::eForGetClientRects | nsSVGUtils::eBBoxIncludeFill |
        nsSVGUtils::eBBoxIncludeStroke | nsSVGUtils::eBBoxIncludeMarkers;
    gfxMatrix m = nsSVGUtils::GetUserToCanvasTM(aFrame);
    SVGBBox bbox = nsSVGUtils::GetBBox(aFrame, flags, &m);
    nsRect bounds = nsLayoutUtils::RoundGfxRectToAppRect(
        bbox, aFrame->PresContext()->AppUnitsPerDevPixel());
    nsMargin bp = outer->GetUsedBorderAndPadding();
    *aRect = bounds + nsPoint(bp.left, bp.top);
  }

  return outer;
}

gfxMatrix nsSVGUtils::GetCanvasTM(nsIFrame* aFrame) {
  // XXX yuck, we really need a common interface for GetCanvasTM

  if (!aFrame->IsFrameOfType(nsIFrame::eSVG)) {
    return GetCSSPxToDevPxMatrix(aFrame);
  }

  LayoutFrameType type = aFrame->Type();
  if (type == LayoutFrameType::SVGForeignObject) {
    return static_cast<nsSVGForeignObjectFrame*>(aFrame)->GetCanvasTM();
  }
  if (type == LayoutFrameType::SVGOuterSVG) {
    return GetCSSPxToDevPxMatrix(aFrame);
  }

  nsSVGContainerFrame* containerFrame = do_QueryFrame(aFrame);
  if (containerFrame) {
    return containerFrame->GetCanvasTM();
  }

  return static_cast<SVGGeometryFrame*>(aFrame)->GetCanvasTM();
}

gfxMatrix nsSVGUtils::GetUserToCanvasTM(nsIFrame* aFrame) {
  nsSVGDisplayableFrame* svgFrame = do_QueryFrame(aFrame);
  NS_ASSERTION(svgFrame, "bad frame");

  gfxMatrix tm;
  if (svgFrame) {
    nsSVGElement* content = static_cast<nsSVGElement*>(aFrame->GetContent());
    tm = content->PrependLocalTransformsTo(GetCanvasTM(aFrame->GetParent()),
                                           eUserSpaceToParent);
  }
  return tm;
}

void nsSVGUtils::NotifyChildrenOfSVGChange(nsIFrame* aFrame, uint32_t aFlags) {
  for (nsIFrame* kid : aFrame->PrincipalChildList()) {
    nsSVGDisplayableFrame* SVGFrame = do_QueryFrame(kid);
    if (SVGFrame) {
      SVGFrame->NotifySVGChanged(aFlags);
    } else {
      NS_ASSERTION(kid->IsFrameOfType(nsIFrame::eSVG) ||
                       nsSVGUtils::IsInSVGTextSubtree(kid),
                   "SVG frame expected");
      // recurse into the children of container frames e.g. <clipPath>, <mask>
      // in case they have child frames with transformation matrices
      if (kid->IsFrameOfType(nsIFrame::eSVG)) {
        NotifyChildrenOfSVGChange(kid, aFlags);
      }
    }
  }
}

// ************************************************************

class SVGPaintCallback : public nsSVGFilterPaintCallback {
 public:
  virtual void Paint(gfxContext& aContext, nsIFrame* aTarget,
                     const gfxMatrix& aTransform, const nsIntRect* aDirtyRect,
                     imgDrawingParams& aImgParams) override {
    nsSVGDisplayableFrame* svgFrame = do_QueryFrame(aTarget);
    NS_ASSERTION(svgFrame, "Expected SVG frame here");

    nsIntRect* dirtyRect = nullptr;
    nsIntRect tmpDirtyRect;

    // aDirtyRect is in user-space pixels, we need to convert to
    // outer-SVG-frame-relative device pixels.
    if (aDirtyRect) {
      gfxMatrix userToDeviceSpace = aTransform;
      if (userToDeviceSpace.IsSingular()) {
        return;
      }
      gfxRect dirtyBounds = userToDeviceSpace.TransformBounds(gfxRect(
          aDirtyRect->x, aDirtyRect->y, aDirtyRect->width, aDirtyRect->height));
      dirtyBounds.RoundOut();
      if (gfxUtils::GfxRectToIntRect(dirtyBounds, &tmpDirtyRect)) {
        dirtyRect = &tmpDirtyRect;
      }
    }

    svgFrame->PaintSVG(aContext, nsSVGUtils::GetCSSPxToDevPxMatrix(aTarget),
                       aImgParams, dirtyRect);
  }
};

float nsSVGUtils::ComputeOpacity(nsIFrame* aFrame, bool aHandleOpacity) {
  float opacity = aFrame->StyleEffects()->mOpacity;

  if (opacity != 1.0f &&
      (nsSVGUtils::CanOptimizeOpacity(aFrame) || !aHandleOpacity)) {
    return 1.0f;
  }

  return opacity;
}

void nsSVGUtils::DetermineMaskUsage(nsIFrame* aFrame, bool aHandleOpacity,
                                    MaskUsage& aUsage) {
  aUsage.opacity = ComputeOpacity(aFrame, aHandleOpacity);

  nsIFrame* firstFrame =
      nsLayoutUtils::FirstContinuationOrIBSplitSibling(aFrame);

  const nsStyleSVGReset* svgReset = firstFrame->StyleSVGReset();

  nsTArray<nsSVGMaskFrame*> maskFrames;
  // XXX check return value?
  SVGObserverUtils::GetAndObserveMasks(firstFrame, &maskFrames);
  aUsage.shouldGenerateMaskLayer = (maskFrames.Length() > 0);

  nsSVGClipPathFrame* clipPathFrame;
  // XXX check return value?
  SVGObserverUtils::GetAndObserveClipPath(firstFrame, &clipPathFrame);
  MOZ_ASSERT(!clipPathFrame ||
             svgReset->mClipPath.GetType() == StyleShapeSourceType::URL);

  switch (svgReset->mClipPath.GetType()) {
    case StyleShapeSourceType::URL:
      if (clipPathFrame) {
        if (clipPathFrame->IsTrivial()) {
          aUsage.shouldApplyClipPath = true;
        } else {
          aUsage.shouldGenerateClipMaskLayer = true;
        }
      }
      break;
    case StyleShapeSourceType::Shape:
    case StyleShapeSourceType::Box:
    case StyleShapeSourceType::Path:
      aUsage.shouldApplyBasicShapeOrPath = true;
      break;
    case StyleShapeSourceType::None:
      MOZ_ASSERT(!aUsage.shouldGenerateClipMaskLayer &&
                 !aUsage.shouldApplyClipPath &&
                 !aUsage.shouldApplyBasicShapeOrPath);
      break;
    default:
      MOZ_ASSERT_UNREACHABLE("Unsupported clip-path type.");
      break;
  }
}

class MixModeBlender {
 public:
  typedef mozilla::gfx::Factory Factory;

  MixModeBlender(nsIFrame* aFrame, gfxContext* aContext)
      : mFrame(aFrame), mSourceCtx(aContext) {
    MOZ_ASSERT(mFrame && mSourceCtx);
  }

  bool ShouldCreateDrawTargetForBlend() const {
    return mFrame->StyleEffects()->mMixBlendMode != NS_STYLE_BLEND_NORMAL;
  }

  gfxContext* CreateBlendTarget(const gfxMatrix& aTransform) {
    MOZ_ASSERT(ShouldCreateDrawTargetForBlend());

    // Create a temporary context to draw to so we can blend it back with
    // another operator.
    IntRect drawRect = ComputeClipExtsInDeviceSpace(aTransform);

    RefPtr<DrawTarget> targetDT =
        mSourceCtx->GetDrawTarget()->CreateSimilarDrawTarget(
            drawRect.Size(), SurfaceFormat::B8G8R8A8);
    if (!targetDT || !targetDT->IsValid()) {
      return nullptr;
    }

    MOZ_ASSERT(!mTargetCtx,
               "CreateBlendTarget is designed to be used once only.");

    mTargetCtx = gfxContext::CreateOrNull(targetDT);
    MOZ_ASSERT(mTargetCtx);  // already checked the draw target above
    mTargetCtx->SetMatrix(mSourceCtx->CurrentMatrix() *
                          Matrix::Translation(-drawRect.TopLeft()));

    mTargetOffset = drawRect.TopLeft();

    return mTargetCtx;
  }

  void BlendToTarget() {
    MOZ_ASSERT(ShouldCreateDrawTargetForBlend());
    MOZ_ASSERT(mTargetCtx,
               "BlendToTarget should be used after CreateBlendTarget.");

    RefPtr<SourceSurface> targetSurf = mTargetCtx->GetDrawTarget()->Snapshot();

    gfxContextAutoSaveRestore save(mSourceCtx);
    mSourceCtx->SetMatrix(Matrix());  // This will be restored right after.
    RefPtr<gfxPattern> pattern = new gfxPattern(
        targetSurf, Matrix::Translation(mTargetOffset.x, mTargetOffset.y));
    mSourceCtx->SetPattern(pattern);
    mSourceCtx->Paint();
  }

 private:
  MixModeBlender() = delete;

  IntRect ComputeClipExtsInDeviceSpace(const gfxMatrix& aTransform) {
    // These are used if we require a temporary surface for a custom blend
    // mode. Clip the source context first, so that we can generate a smaller
    // temporary surface. (Since we will clip this context in
    // SetupContextMatrix, a pair of save/restore is needed.)
    gfxContextAutoSaveRestore saver(mSourceCtx);

    if (!(mFrame->GetStateBits() & NS_FRAME_IS_NONDISPLAY)) {
      // aFrame has a valid visual overflow rect, so clip to it before calling
      // PushGroup() to minimize the size of the surfaces we'll composite:
      gfxContextMatrixAutoSaveRestore matrixAutoSaveRestore(mSourceCtx);
      mSourceCtx->Multiply(aTransform);
      nsRect overflowRect = mFrame->GetVisualOverflowRectRelativeToSelf();
      if (mFrame->IsFrameOfType(nsIFrame::eSVGGeometry) ||
          nsSVGUtils::IsInSVGTextSubtree(mFrame)) {
        // Unlike containers, leaf frames do not include GetPosition() in
        // GetCanvasTM().
        overflowRect = overflowRect + mFrame->GetPosition();
      }
      mSourceCtx->Clip(NSRectToSnappedRect(
          overflowRect, mFrame->PresContext()->AppUnitsPerDevPixel(),
          *mSourceCtx->GetDrawTarget()));
    }

    // Get the clip extents in device space.
    gfxRect clippedFrameSurfaceRect =
        mSourceCtx->GetClipExtents(gfxContext::eDeviceSpace);
    clippedFrameSurfaceRect.RoundOut();

    IntRect result;
    ToRect(clippedFrameSurfaceRect).ToIntRect(&result);

    return Factory::CheckSurfaceSize(result.Size()) ? result : IntRect();
  }

  nsIFrame* mFrame;
  gfxContext* mSourceCtx;
  RefPtr<gfxContext> mTargetCtx;
  IntPoint mTargetOffset;
};

void nsSVGUtils::PaintFrameWithEffects(nsIFrame* aFrame, gfxContext& aContext,
                                       const gfxMatrix& aTransform,
                                       imgDrawingParams& aImgParams,
                                       const nsIntRect* aDirtyRect) {
  NS_ASSERTION(!NS_SVGDisplayListPaintingEnabled() ||
                   (aFrame->GetStateBits() & NS_FRAME_IS_NONDISPLAY) ||
                   aFrame->PresContext()->Document()->IsSVGGlyphsDocument(),
               "If display lists are enabled, only painting of non-display "
               "SVG should take this code path");

  nsSVGDisplayableFrame* svgFrame = do_QueryFrame(aFrame);
  if (!svgFrame) return;

  MaskUsage maskUsage;
  DetermineMaskUsage(aFrame, true, maskUsage);
  if (maskUsage.opacity == 0.0f) {
    return;
  }

  const nsIContent* content = aFrame->GetContent();
  if (content->IsSVGElement() &&
      !static_cast<const nsSVGElement*>(content)->HasValidDimensions()) {
    return;
  }

  if (aDirtyRect && !(aFrame->GetStateBits() & NS_FRAME_IS_NONDISPLAY)) {
    // Here we convert aFrame's paint bounds to outer-<svg> device space,
    // compare it to aDirtyRect, and return early if they don't intersect.
    // We don't do this optimization for nondisplay SVG since nondisplay
    // SVG doesn't maintain bounds/overflow rects.
    nsRect overflowRect = aFrame->GetVisualOverflowRectRelativeToSelf();
    if (aFrame->IsFrameOfType(nsIFrame::eSVGGeometry) ||
        nsSVGUtils::IsInSVGTextSubtree(aFrame)) {
      // Unlike containers, leaf frames do not include GetPosition() in
      // GetCanvasTM().
      overflowRect = overflowRect + aFrame->GetPosition();
    }
    int32_t appUnitsPerDevPx = aFrame->PresContext()->AppUnitsPerDevPixel();
    gfxMatrix tm = aTransform;
    if (aFrame->IsFrameOfType(nsIFrame::eSVG | nsIFrame::eSVGContainer)) {
      gfx::Matrix childrenOnlyTM;
      if (static_cast<nsSVGContainerFrame*>(aFrame)->HasChildrenOnlyTransform(
              &childrenOnlyTM)) {
        // Undo the children-only transform:
        if (!childrenOnlyTM.Invert()) {
          return;
        }
        tm = ThebesMatrix(childrenOnlyTM) * tm;
      }
    }
    nsIntRect bounds =
        TransformFrameRectToOuterSVG(overflowRect, tm, aFrame->PresContext())
            .ToOutsidePixels(appUnitsPerDevPx);
    if (!aDirtyRect->Intersects(bounds)) {
      return;
    }
  }

  /* SVG defines the following rendering model:
   *
   *  1. Render fill
   *  2. Render stroke
   *  3. Render markers
   *  4. Apply filter
   *  5. Apply clipping, masking, group opacity
   *
   * We follow this, but perform a couple of optimizations:
   *
   * + Use cairo's clipPath when representable natively (single object
   *   clip region).
   *f
   * + Merge opacity and masking if both used together.
   */

  /* Properties are added lazily and may have been removed by a restyle,
     so make sure all applicable ones are set again. */
  nsSVGClipPathFrame* clipPathFrame;
  nsTArray<nsSVGMaskFrame*> maskFrames;
  // TODO: We currently pass nullptr instead of an nsTArray* here, but we
  // actually should get the filter frames and then pass them into
  // PaintFilteredFrame below!  See bug 1494263.
  if (SVGObserverUtils::GetAndObserveFilters(aFrame, nullptr) ==
          SVGObserverUtils::eHasRefsSomeInvalid ||
      SVGObserverUtils::GetAndObserveClipPath(aFrame, &clipPathFrame) ==
          SVGObserverUtils::eHasRefsSomeInvalid ||
      SVGObserverUtils::GetAndObserveMasks(aFrame, &maskFrames) ==
          SVGObserverUtils::eHasRefsSomeInvalid) {
    // Some resource is invalid. We shouldn't paint anything.
    return;
  }

  nsSVGMaskFrame* maskFrame = maskFrames.IsEmpty() ? nullptr : maskFrames[0];

  MixModeBlender blender(aFrame, &aContext);
  gfxContext* target = blender.ShouldCreateDrawTargetForBlend()
                           ? blender.CreateBlendTarget(aTransform)
                           : &aContext;

  if (!target) {
    return;
  }

  /* Check if we need to do additional operations on this child's
   * rendering, which necessitates rendering into another surface. */
  bool shouldGenerateMask =
      (maskUsage.opacity != 1.0f || maskUsage.shouldGenerateClipMaskLayer ||
       maskUsage.shouldGenerateMaskLayer);
  bool shouldPushMask = false;

  if (shouldGenerateMask) {
    Matrix maskTransform;
    RefPtr<SourceSurface> maskSurface;

    // maskFrame can be nullptr even if maskUsage.shouldGenerateMaskLayer is
    // true. That happens when a user gives an unresolvable mask-id, such as
    //   mask:url()
    //   mask:url(#id-which-does-not-exist)
    // Since we only uses nsSVGUtils with SVG elements, not like mask on an
    // HTML element, we should treat an unresolvable mask as no-mask here.
    if (maskUsage.shouldGenerateMaskLayer && maskFrame) {
      uint8_t maskMode = aFrame->StyleSVGReset()->mMask.mLayers[0].mMaskMode;
      nsSVGMaskFrame::MaskParams params(&aContext, aFrame, aTransform,
                                        maskUsage.opacity, &maskTransform,
                                        maskMode, aImgParams);
      maskSurface = maskFrame->GetMaskForMaskedFrame(params);

      if (!maskSurface) {
        // Either entire surface is clipped out, or gfx buffer allocation
        // failure in nsSVGMaskFrame::GetMaskForMaskedFrame.
        return;
      }
      shouldPushMask = true;
    }

    if (maskUsage.shouldGenerateClipMaskLayer) {
      Matrix clippedMaskTransform;
      RefPtr<SourceSurface> clipMaskSurface = clipPathFrame->GetClipMask(
          aContext, aFrame, aTransform, &clippedMaskTransform, maskSurface,
          maskTransform);
      if (clipMaskSurface) {
        maskSurface = clipMaskSurface;
        maskTransform = clippedMaskTransform;
      } else {
        // Either entire surface is clipped out, or gfx buffer allocation
        // failure in nsSVGClipPathFrame::GetClipMask.
        return;
      }
      shouldPushMask = true;
    }

    if (!maskUsage.shouldGenerateClipMaskLayer &&
        !maskUsage.shouldGenerateMaskLayer) {
      shouldPushMask = true;
    }

    // SVG mask multiply opacity into maskSurface already, so we do not bother
    // to apply opacity again.
    if (shouldPushMask) {
      target->PushGroupForBlendBack(gfxContentType::COLOR_ALPHA,
                                    maskFrame ? 1.0 : maskUsage.opacity,
                                    maskSurface, maskTransform);
    }
  }

  /* If this frame has only a trivial clipPath, set up cairo's clipping now so
   * we can just do normal painting and get it clipped appropriately.
   */
  if (maskUsage.shouldApplyClipPath || maskUsage.shouldApplyBasicShapeOrPath) {
    if (maskUsage.shouldApplyClipPath) {
      clipPathFrame->ApplyClipPath(aContext, aFrame, aTransform);
    } else {
      nsCSSClipPathInstance::ApplyBasicShapeOrPathClip(aContext, aFrame);
    }
  }

  /* Paint the child */

  // We know we don't have eHasRefsSomeInvalid due to the check above.  We
  // don't test for eHasNoRefs here though since even if we have that we may
  // still have CSS filter functions to handle.  We have to check the style.
  if (aFrame->StyleEffects()->HasFilters()) {
    nsRegion* dirtyRegion = nullptr;
    nsRegion tmpDirtyRegion;
    if (aDirtyRect) {
      // aDirtyRect is in outer-<svg> device pixels, but the filter code needs
      // it in frame space.
      gfxMatrix userToDeviceSpace = aTransform;
      if (userToDeviceSpace.IsSingular()) {
        return;
      }
      gfxMatrix deviceToUserSpace = userToDeviceSpace;
      deviceToUserSpace.Invert();
      gfxRect dirtyBounds = deviceToUserSpace.TransformBounds(gfxRect(
          aDirtyRect->x, aDirtyRect->y, aDirtyRect->width, aDirtyRect->height));
      tmpDirtyRegion = nsLayoutUtils::RoundGfxRectToAppRect(
                           dirtyBounds, AppUnitsPerCSSPixel()) -
                       aFrame->GetPosition();
      dirtyRegion = &tmpDirtyRegion;
    }

    gfxContextMatrixAutoSaveRestore autoSR(target);

    // 'target' is currently scaled such that its user space units are CSS
    // pixels (SVG user space units). But PaintFilteredFrame expects it to be
    // scaled in such a way that its user space units are device pixels. So we
    // have to adjust the scale.
    gfxMatrix reverseScaleMatrix = nsSVGUtils::GetCSSPxToDevPxMatrix(aFrame);
    DebugOnly<bool> invertible = reverseScaleMatrix.Invert();
    target->SetMatrixDouble(reverseScaleMatrix * aTransform *
                            target->CurrentMatrixDouble());

    SVGPaintCallback paintCallback;
    nsFilterInstance::PaintFilteredFrame(aFrame, target, &paintCallback,
                                         dirtyRegion, aImgParams);
  } else {
    svgFrame->PaintSVG(*target, aTransform, aImgParams, aDirtyRect);
  }

  if (maskUsage.shouldApplyClipPath || maskUsage.shouldApplyBasicShapeOrPath) {
    aContext.PopClip();
  }

  if (shouldPushMask) {
    target->PopGroupAndBlend();
  }

  if (blender.ShouldCreateDrawTargetForBlend()) {
    MOZ_ASSERT(target != &aContext);
    blender.BlendToTarget();
  }
}

bool nsSVGUtils::HitTestClip(nsIFrame* aFrame, const gfxPoint& aPoint) {
  // If the clip-path property references non-existent or invalid clipPath
  // element(s) we ignore it.
  nsSVGClipPathFrame* clipPathFrame;
  SVGObserverUtils::GetAndObserveClipPath(aFrame, &clipPathFrame);
  if (clipPathFrame) {
    return clipPathFrame->PointIsInsideClipPath(aFrame, aPoint);
  }
  if (aFrame->StyleSVGReset()->HasClipPath()) {
    return nsCSSClipPathInstance::HitTestBasicShapeOrPathClip(aFrame, aPoint);
  }
  return true;
}

nsIFrame* nsSVGUtils::HitTestChildren(nsSVGDisplayContainerFrame* aFrame,
                                      const gfxPoint& aPoint) {
  // First we transform aPoint into the coordinate space established by aFrame
  // for its children (e.g. take account of any 'viewBox' attribute):
  gfxPoint point = aPoint;
  if (aFrame->GetContent()->IsSVGElement()) {  // must check before cast
    gfxMatrix m =
        static_cast<const nsSVGElement*>(aFrame->GetContent())
            ->PrependLocalTransformsTo(gfxMatrix(), eChildToUserSpace);
    if (!m.IsIdentity()) {
      if (!m.Invert()) {
        return nullptr;
      }
      point = m.TransformPoint(point);
    }
  }

  // Traverse the list in reverse order, so that if we get a hit we know that's
  // the topmost frame that intersects the point; then we can just return it.
  nsIFrame* result = nullptr;
  for (nsIFrame* current = aFrame->PrincipalChildList().LastChild(); current;
       current = current->GetPrevSibling()) {
    nsSVGDisplayableFrame* SVGFrame = do_QueryFrame(current);
    if (SVGFrame) {
      const nsIContent* content = current->GetContent();
      if (content->IsSVGElement() &&
          !static_cast<const nsSVGElement*>(content)->HasValidDimensions()) {
        continue;
      }
      // GetFrameForPoint() expects a point in its frame's SVG user space, so
      // we need to convert to that space:
      gfxPoint p = point;
      if (content->IsSVGElement()) {  // must check before cast
        gfxMatrix m =
            static_cast<const nsSVGElement*>(content)->PrependLocalTransformsTo(
                gfxMatrix(), eUserSpaceToParent);
        if (!m.IsIdentity()) {
          if (!m.Invert()) {
            continue;
          }
          p = m.TransformPoint(p);
        }
      }
      result = SVGFrame->GetFrameForPoint(p);
      if (result) break;
    }
  }

  if (result && !HitTestClip(aFrame, aPoint)) result = nullptr;

  return result;
}

nsRect nsSVGUtils::TransformFrameRectToOuterSVG(const nsRect& aRect,
                                                const gfxMatrix& aMatrix,
                                                nsPresContext* aPresContext) {
  gfxRect r(aRect.x, aRect.y, aRect.width, aRect.height);
  r.Scale(1.0 / AppUnitsPerCSSPixel());
  return nsLayoutUtils::RoundGfxRectToAppRect(
      aMatrix.TransformBounds(r), aPresContext->AppUnitsPerDevPixel());
}

IntSize nsSVGUtils::ConvertToSurfaceSize(const gfxSize& aSize,
                                         bool* aResultOverflows) {
  IntSize surfaceSize(ClampToInt(ceil(aSize.width)),
                      ClampToInt(ceil(aSize.height)));

  *aResultOverflows = surfaceSize.width != ceil(aSize.width) ||
                      surfaceSize.height != ceil(aSize.height);

  if (!Factory::AllowedSurfaceSize(surfaceSize)) {
    surfaceSize.width =
        std::min(NS_SVG_OFFSCREEN_MAX_DIMENSION, surfaceSize.width);
    surfaceSize.height =
        std::min(NS_SVG_OFFSCREEN_MAX_DIMENSION, surfaceSize.height);
    *aResultOverflows = true;
  }

  return surfaceSize;
}

bool nsSVGUtils::HitTestRect(const gfx::Matrix& aMatrix, float aRX, float aRY,
                             float aRWidth, float aRHeight, float aX,
                             float aY) {
  gfx::Rect rect(aRX, aRY, aRWidth, aRHeight);
  if (rect.IsEmpty() || aMatrix.IsSingular()) {
    return false;
  }
  gfx::Matrix toRectSpace = aMatrix;
  toRectSpace.Invert();
  gfx::Point p = toRectSpace.TransformPoint(gfx::Point(aX, aY));
  return rect.x <= p.x && p.x <= rect.XMost() && rect.y <= p.y &&
         p.y <= rect.YMost();
}

gfxRect nsSVGUtils::GetClipRectForFrame(nsIFrame* aFrame, float aX, float aY,
                                        float aWidth, float aHeight) {
  const nsStyleDisplay* disp = aFrame->StyleDisplay();
  const nsStyleEffects* effects = aFrame->StyleEffects();

  if (!(effects->mClipFlags & NS_STYLE_CLIP_RECT)) {
    NS_ASSERTION(effects->mClipFlags == NS_STYLE_CLIP_AUTO,
                 "We don't know about this type of clip.");
    return gfxRect(aX, aY, aWidth, aHeight);
  }

  if (disp->mOverflowX == NS_STYLE_OVERFLOW_HIDDEN ||
      disp->mOverflowY == NS_STYLE_OVERFLOW_HIDDEN) {
    nsIntRect clipPxRect = effects->mClip.ToOutsidePixels(
        aFrame->PresContext()->AppUnitsPerDevPixel());
    gfxRect clipRect = gfxRect(clipPxRect.x, clipPxRect.y, clipPxRect.width,
                               clipPxRect.height);

    if (NS_STYLE_CLIP_RIGHT_AUTO & effects->mClipFlags) {
      clipRect.width = aWidth - clipRect.X();
    }
    if (NS_STYLE_CLIP_BOTTOM_AUTO & effects->mClipFlags) {
      clipRect.height = aHeight - clipRect.Y();
    }

    if (disp->mOverflowX != NS_STYLE_OVERFLOW_HIDDEN) {
      clipRect.x = aX;
      clipRect.width = aWidth;
    }
    if (disp->mOverflowY != NS_STYLE_OVERFLOW_HIDDEN) {
      clipRect.y = aY;
      clipRect.height = aHeight;
    }

    return clipRect;
  }
  return gfxRect(aX, aY, aWidth, aHeight);
}

void nsSVGUtils::SetClipRect(gfxContext* aContext, const gfxMatrix& aCTM,
                             const gfxRect& aRect) {
  if (aCTM.IsSingular()) return;

  gfxContextMatrixAutoSaveRestore matrixAutoSaveRestore(aContext);
  aContext->Multiply(aCTM);
  aContext->Clip(aRect);
}

gfxRect nsSVGUtils::GetBBox(nsIFrame* aFrame, uint32_t aFlags,
                            const gfxMatrix* aToBoundsSpace) {
  if (aFrame->GetContent()->IsText()) {
    aFrame = aFrame->GetParent();
  }

  if (nsSVGUtils::IsInSVGTextSubtree(aFrame)) {
    // It is possible to apply a gradient, pattern, clipping path, mask or
    // filter to text. When one of these facilities is applied to text
    // the bounding box is the entire text element in all
    // cases.
    nsIFrame* ancestor = GetFirstNonAAncestorFrame(aFrame);
    if (ancestor && nsSVGUtils::IsInSVGTextSubtree(ancestor)) {
      while (!ancestor->IsSVGTextFrame()) {
        ancestor = ancestor->GetParent();
      }
    }
    aFrame = ancestor;
  }

  nsSVGDisplayableFrame* svg = do_QueryFrame(aFrame);
  const bool hasSVGLayout = aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT;
  if (hasSVGLayout && !svg) {
    // An SVG frame, but not one that can be displayed directly (for
    // example, nsGradientFrame). These can't contribute to the bbox.
    return gfxRect();
  }

  const bool isOuterSVG = svg && !hasSVGLayout;
  MOZ_ASSERT(!isOuterSVG || aFrame->IsSVGOuterSVGFrame());
  if (!svg || (isOuterSVG && (aFlags & eUseFrameBoundsForOuterSVG))) {
    // An HTML element or an SVG outer frame.
    MOZ_ASSERT(!hasSVGLayout);
    bool onlyCurrentFrame = aFlags & eIncludeOnlyCurrentFrameForNonSVGElement;
    return nsSVGIntegrationUtils::GetSVGBBoxForNonSVGFrame(
        aFrame,
        /* aUnionContinuations = */ !onlyCurrentFrame);
  }

  MOZ_ASSERT(svg);

  nsIContent* content = aFrame->GetContent();
  if (content->IsSVGElement() &&
      !static_cast<const nsSVGElement*>(content)->HasValidDimensions()) {
    return gfxRect();
  }

  // Clean out flags which have no effects on returning bbox from now, so that
  // we can cache and reuse ObjectBoundingBoxProperty() in the code below.
  aFlags &= ~eIncludeOnlyCurrentFrameForNonSVGElement;
  aFlags &= ~eUseFrameBoundsForOuterSVG;
  if (!aFrame->IsSVGUseFrame()) {
    aFlags &= ~eUseUserSpaceOfUseElement;
  }

  if (aFlags == eBBoxIncludeFillGeometry &&
      // We only cache bbox in element's own user space
      !aToBoundsSpace) {
    gfxRect* prop = aFrame->GetProperty(ObjectBoundingBoxProperty());
    if (prop) {
      return *prop;
    }
  }

  gfxMatrix matrix;
  if (aToBoundsSpace) {
    matrix = *aToBoundsSpace;
  }

  if (aFrame->IsSVGForeignObjectFrame() ||
      aFlags & nsSVGUtils::eUseUserSpaceOfUseElement) {
    // The spec says getBBox "Returns the tight bounding box in *current user
    // space*". So we should really be doing this for all elements, but that
    // needs investigation to check that we won't break too much content.
    // NOTE: When changing this to apply to other frame types, make sure to
    // also update nsSVGUtils::FrameSpaceInCSSPxToUserSpaceOffset.
    MOZ_ASSERT(content->IsSVGElement(), "bad cast");
    nsSVGElement* element = static_cast<nsSVGElement*>(content);
    matrix = element->PrependLocalTransformsTo(matrix, eChildToUserSpace);
  }
  gfxRect bbox =
      svg->GetBBoxContribution(ToMatrix(matrix), aFlags).ToThebesRect();
  // Account for 'clipped'.
  if (aFlags & nsSVGUtils::eBBoxIncludeClipped) {
    gfxRect clipRect(0, 0, 0, 0);
    float x, y, width, height;
    gfxMatrix tm;
    gfxRect fillBBox =
        svg->GetBBoxContribution(ToMatrix(tm), nsSVGUtils::eBBoxIncludeFill)
            .ToThebesRect();
    x = fillBBox.x;
    y = fillBBox.y;
    width = fillBBox.width;
    height = fillBBox.height;
    bool hasClip = aFrame->StyleDisplay()->IsScrollableOverflow();
    if (hasClip) {
      clipRect = nsSVGUtils::GetClipRectForFrame(aFrame, x, y, width, height);
      if (aFrame->IsSVGForeignObjectFrame() || aFrame->IsSVGUseFrame()) {
        clipRect = matrix.TransformBounds(clipRect);
      }
    }
    nsSVGClipPathFrame* clipPathFrame;
    if (SVGObserverUtils::GetAndObserveClipPath(aFrame, &clipPathFrame) ==
        SVGObserverUtils::eHasRefsSomeInvalid) {
      bbox = gfxRect(0, 0, 0, 0);
    } else {
      if (clipPathFrame) {
        SVGClipPathElement* clipContent =
            static_cast<SVGClipPathElement*>(clipPathFrame->GetContent());
        if (clipContent->IsUnitsObjectBoundingBox()) {
          matrix.PreTranslate(gfxPoint(x, y));
          matrix.PreScale(width, height);
        } else if (aFrame->IsSVGForeignObjectFrame()) {
          matrix = gfxMatrix();
        }
        matrix =
            clipContent->PrependLocalTransformsTo(matrix, eUserSpaceToParent);
        bbox = clipPathFrame->GetBBoxForClipPathFrame(bbox, matrix, aFlags)
                   .ToThebesRect();
      }

      if (hasClip) {
        bbox = bbox.Intersect(clipRect);
      }

      if (bbox.IsEmpty()) {
        bbox = gfxRect(0, 0, 0, 0);
      }
    }
  }

  if (aFlags == eBBoxIncludeFillGeometry &&
      // We only cache bbox in element's own user space
      !aToBoundsSpace) {
    // Obtaining the bbox for objectBoundingBox calculations is common so we
    // cache the result for future calls, since calculation can be expensive:
    aFrame->SetProperty(ObjectBoundingBoxProperty(), new gfxRect(bbox));
  }

  return bbox;
}

gfxPoint nsSVGUtils::FrameSpaceInCSSPxToUserSpaceOffset(nsIFrame* aFrame) {
  if (!(aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT)) {
    // The user space for non-SVG frames is defined as the bounding box of the
    // frame's border-box rects over all continuations.
    return gfxPoint();
  }

  // Leaf frames apply their own offset inside their user space.
  if (aFrame->IsFrameOfType(nsIFrame::eSVGGeometry) ||
      nsSVGUtils::IsInSVGTextSubtree(aFrame)) {
    return nsLayoutUtils::RectToGfxRect(aFrame->GetRect(),
                                        AppUnitsPerCSSPixel())
        .TopLeft();
  }

  // For foreignObject frames, nsSVGUtils::GetBBox applies their local
  // transform, so we need to do the same here.
  if (aFrame->IsSVGForeignObjectFrame()) {
    gfxMatrix transform =
        static_cast<nsSVGElement*>(aFrame->GetContent())
            ->PrependLocalTransformsTo(gfxMatrix(), eChildToUserSpace);
    NS_ASSERTION(!transform.HasNonTranslation(),
                 "we're relying on this being an offset-only transform");
    return transform.GetTranslation();
  }

  return gfxPoint();
}

static gfxRect GetBoundingBoxRelativeRect(const nsSVGLength2* aXYWH,
                                          const gfxRect& aBBox) {
  return gfxRect(aBBox.x + nsSVGUtils::ObjectSpace(aBBox, &aXYWH[0]),
                 aBBox.y + nsSVGUtils::ObjectSpace(aBBox, &aXYWH[1]),
                 nsSVGUtils::ObjectSpace(aBBox, &aXYWH[2]),
                 nsSVGUtils::ObjectSpace(aBBox, &aXYWH[3]));
}

gfxRect nsSVGUtils::GetRelativeRect(uint16_t aUnits, const nsSVGLength2* aXYWH,
                                    const gfxRect& aBBox,
                                    const UserSpaceMetrics& aMetrics) {
  if (aUnits == SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
    return GetBoundingBoxRelativeRect(aXYWH, aBBox);
  }
  return gfxRect(UserSpace(aMetrics, &aXYWH[0]), UserSpace(aMetrics, &aXYWH[1]),
                 UserSpace(aMetrics, &aXYWH[2]),
                 UserSpace(aMetrics, &aXYWH[3]));
}

gfxRect nsSVGUtils::GetRelativeRect(uint16_t aUnits, const nsSVGLength2* aXYWH,
                                    const gfxRect& aBBox, nsIFrame* aFrame) {
  if (aUnits == SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
    return GetBoundingBoxRelativeRect(aXYWH, aBBox);
  }
  nsIContent* content = aFrame->GetContent();
  if (content->IsSVGElement()) {
    nsSVGElement* svgElement = static_cast<nsSVGElement*>(content);
    return GetRelativeRect(aUnits, aXYWH, aBBox, SVGElementMetrics(svgElement));
  }
  return GetRelativeRect(aUnits, aXYWH, aBBox,
                         NonSVGFrameUserSpaceMetrics(aFrame));
}

bool nsSVGUtils::CanOptimizeOpacity(nsIFrame* aFrame) {
  if (!(aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT)) {
    return false;
  }
  LayoutFrameType type = aFrame->Type();
  if (type != LayoutFrameType::SVGImage &&
      type != LayoutFrameType::SVGGeometry) {
    return false;
  }
  if (aFrame->StyleEffects()->HasFilters()) {
    return false;
  }
  // XXX The SVG WG is intending to allow fill, stroke and markers on <image>
  if (type == LayoutFrameType::SVGImage) {
    return true;
  }
  const nsStyleSVG* style = aFrame->StyleSVG();
  if (style->HasMarker()) {
    return false;
  }

  if (nsLayoutUtils::HasAnimationOfProperty(aFrame, eCSSProperty_opacity)) {
    return false;
  }

  if (!style->HasFill() || !HasStroke(aFrame)) {
    return true;
  }
  return false;
}

gfxMatrix nsSVGUtils::AdjustMatrixForUnits(const gfxMatrix& aMatrix,
                                           nsSVGEnum* aUnits, nsIFrame* aFrame,
                                           uint32_t aFlags) {
  if (aFrame && aUnits->GetAnimValue() == SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
    gfxRect bbox = GetBBox(aFrame, aFlags);
    gfxMatrix tm = aMatrix;
    tm.PreTranslate(gfxPoint(bbox.X(), bbox.Y()));
    tm.PreScale(bbox.Width(), bbox.Height());
    return tm;
  }
  return aMatrix;
}

nsIFrame* nsSVGUtils::GetFirstNonAAncestorFrame(nsIFrame* aStartFrame) {
  for (nsIFrame* ancestorFrame = aStartFrame; ancestorFrame;
       ancestorFrame = ancestorFrame->GetParent()) {
    if (!ancestorFrame->IsSVGAFrame()) {
      return ancestorFrame;
    }
  }
  return nullptr;
}

bool nsSVGUtils::GetNonScalingStrokeTransform(nsIFrame* aFrame,
                                              gfxMatrix* aUserToOuterSVG) {
  if (aFrame->GetContent()->IsText()) {
    aFrame = aFrame->GetParent();
  }

  if (!aFrame->StyleSVGReset()->HasNonScalingStroke()) {
    return false;
  }

  nsIContent* content = aFrame->GetContent();
  MOZ_ASSERT(content->IsSVGElement(), "bad cast");

  *aUserToOuterSVG = ThebesMatrix(
      SVGContentUtils::GetCTM(static_cast<nsSVGElement*>(content), true));

  return !aUserToOuterSVG->IsIdentity();
}

// The logic here comes from _cairo_stroke_style_max_distance_from_path
static gfxRect PathExtentsToMaxStrokeExtents(const gfxRect& aPathExtents,
                                             nsIFrame* aFrame,
                                             double aStyleExpansionFactor,
                                             const gfxMatrix& aMatrix) {
  double style_expansion =
      aStyleExpansionFactor * nsSVGUtils::GetStrokeWidth(aFrame);

  gfxMatrix matrix = aMatrix;

  gfxMatrix outerSVGToUser;
  if (nsSVGUtils::GetNonScalingStrokeTransform(aFrame, &outerSVGToUser)) {
    outerSVGToUser.Invert();
    matrix.PreMultiply(outerSVGToUser);
  }

  double dx = style_expansion * (fabs(matrix._11) + fabs(matrix._21));
  double dy = style_expansion * (fabs(matrix._22) + fabs(matrix._12));

  gfxRect strokeExtents = aPathExtents;
  strokeExtents.Inflate(dx, dy);
  return strokeExtents;
}

/*static*/ gfxRect nsSVGUtils::PathExtentsToMaxStrokeExtents(
    const gfxRect& aPathExtents, nsTextFrame* aFrame,
    const gfxMatrix& aMatrix) {
  NS_ASSERTION(nsSVGUtils::IsInSVGTextSubtree(aFrame),
               "expected an nsTextFrame for SVG text");
  return ::PathExtentsToMaxStrokeExtents(aPathExtents, aFrame, 0.5, aMatrix);
}

/*static*/ gfxRect nsSVGUtils::PathExtentsToMaxStrokeExtents(
    const gfxRect& aPathExtents, SVGGeometryFrame* aFrame,
    const gfxMatrix& aMatrix) {
  bool strokeMayHaveCorners =
      !SVGContentUtils::ShapeTypeHasNoCorners(aFrame->GetContent());

  // For a shape without corners the stroke can only extend half the stroke
  // width from the path in the x/y-axis directions. For shapes with corners
  // the stroke can extend by sqrt(1/2) (think 45 degree rotated rect, or line
  // with stroke-linecaps="square").
  double styleExpansionFactor = strokeMayHaveCorners ? M_SQRT1_2 : 0.5;

  // The stroke can extend even further for paths that can be affected by
  // stroke-miterlimit.
  bool affectedByMiterlimit = aFrame->GetContent()->IsAnyOfSVGElements(
      nsGkAtoms::path, nsGkAtoms::polyline, nsGkAtoms::polygon);

  if (affectedByMiterlimit) {
    const nsStyleSVG* style = aFrame->StyleSVG();
    if (style->mStrokeLinejoin == NS_STYLE_STROKE_LINEJOIN_MITER &&
        styleExpansionFactor < style->mStrokeMiterlimit / 2.0) {
      styleExpansionFactor = style->mStrokeMiterlimit / 2.0;
    }
  }

  return ::PathExtentsToMaxStrokeExtents(aPathExtents, aFrame,
                                         styleExpansionFactor, aMatrix);
}

// ----------------------------------------------------------------------

/* static */ nscolor nsSVGUtils::GetFallbackOrPaintColor(
    ComputedStyle* aComputedStyle, nsStyleSVGPaint nsStyleSVG::*aFillOrStroke) {
  const nsStyleSVGPaint& paint = aComputedStyle->StyleSVG()->*aFillOrStroke;
  ComputedStyle* styleIfVisited = aComputedStyle->GetStyleIfVisited();
  nscolor color;
  switch (paint.Type()) {
    case eStyleSVGPaintType_Server:
    case eStyleSVGPaintType_ContextStroke:
      color = paint.GetFallbackType() == eStyleSVGFallbackType_Color
                  ? paint.GetFallbackColor(aComputedStyle)
                  : NS_RGBA(0, 0, 0, 0);
      break;
    case eStyleSVGPaintType_ContextFill:
      color = paint.GetFallbackType() == eStyleSVGFallbackType_Color
                  ? paint.GetFallbackColor(aComputedStyle)
                  : NS_RGB(0, 0, 0);
      break;
    default:
      color = paint.GetColor(aComputedStyle);
      break;
  }
  if (styleIfVisited) {
    const nsStyleSVGPaint& paintIfVisited =
        styleIfVisited->StyleSVG()->*aFillOrStroke;
    // To prevent Web content from detecting if a user has visited a URL
    // (via URL loading triggered by paint servers or performance
    // differences between paint servers or between a paint server and a
    // color), we do not allow whether links are visited to change which
    // paint server is used or switch between paint servers and simple
    // colors.  A :visited style may only override a simple color with
    // another simple color.
    if (paintIfVisited.Type() == eStyleSVGPaintType_Color &&
        paint.Type() == eStyleSVGPaintType_Color) {
      nscolor colors[2] = {color, paintIfVisited.GetColor(aComputedStyle)};
      return ComputedStyle::CombineVisitedColors(
          colors, aComputedStyle->RelevantLinkVisited());
    }
  }
  return color;
}

/* static */ void nsSVGUtils::MakeFillPatternFor(
    nsIFrame* aFrame, gfxContext* aContext, GeneralPattern* aOutPattern,
    imgDrawingParams& aImgParams, SVGContextPaint* aContextPaint) {
  const nsStyleSVG* style = aFrame->StyleSVG();
  if (style->mFill.Type() == eStyleSVGPaintType_None) {
    return;
  }

  const float opacity = aFrame->StyleEffects()->mOpacity;

  float fillOpacity = GetOpacity(style->FillOpacitySource(),
                                 style->mFillOpacity, aContextPaint);
  if (opacity < 1.0f && nsSVGUtils::CanOptimizeOpacity(aFrame)) {
    // Combine the group opacity into the fill opacity (we will have skipped
    // creating an offscreen surface to apply the group opacity).
    fillOpacity *= opacity;
  }

  const DrawTarget* dt = aContext->GetDrawTarget();

  nsSVGPaintServerFrame* ps =
      SVGObserverUtils::GetAndObservePaintServer(aFrame, &nsStyleSVG::mFill);

  if (ps) {
    RefPtr<gfxPattern> pattern =
        ps->GetPaintServerPattern(aFrame, dt, aContext->CurrentMatrixDouble(),
                                  &nsStyleSVG::mFill, fillOpacity, aImgParams);
    if (pattern) {
      pattern->CacheColorStops(dt);
      aOutPattern->Init(*pattern->GetPattern(dt));
      return;
    }
  }

  if (aContextPaint) {
    RefPtr<gfxPattern> pattern;
    switch (style->mFill.Type()) {
      case eStyleSVGPaintType_ContextFill:
        pattern = aContextPaint->GetFillPattern(
            dt, fillOpacity, aContext->CurrentMatrixDouble(), aImgParams);
        break;
      case eStyleSVGPaintType_ContextStroke:
        pattern = aContextPaint->GetStrokePattern(
            dt, fillOpacity, aContext->CurrentMatrixDouble(), aImgParams);
        break;
      default:;
    }
    if (pattern) {
      aOutPattern->Init(*pattern->GetPattern(dt));
      return;
    }
  }

  if (style->mFill.GetFallbackType() == eStyleSVGFallbackType_None) {
    return;
  }

  // On failure, use the fallback colour in case we have an
  // objectBoundingBox where the width or height of the object is zero.
  // See http://www.w3.org/TR/SVG11/coords.html#ObjectBoundingBox
  Color color(Color::FromABGR(
      GetFallbackOrPaintColor(aFrame->Style(), &nsStyleSVG::mFill)));
  color.a *= fillOpacity;
  aOutPattern->InitColorPattern(ToDeviceColor(color));
}

/* static */ void nsSVGUtils::MakeStrokePatternFor(
    nsIFrame* aFrame, gfxContext* aContext, GeneralPattern* aOutPattern,
    imgDrawingParams& aImgParams, SVGContextPaint* aContextPaint) {
  const nsStyleSVG* style = aFrame->StyleSVG();
  if (style->mStroke.Type() == eStyleSVGPaintType_None) {
    return;
  }

  const float opacity = aFrame->StyleEffects()->mOpacity;

  float strokeOpacity = GetOpacity(style->StrokeOpacitySource(),
                                   style->mStrokeOpacity, aContextPaint);
  if (opacity < 1.0f && nsSVGUtils::CanOptimizeOpacity(aFrame)) {
    // Combine the group opacity into the stroke opacity (we will have skipped
    // creating an offscreen surface to apply the group opacity).
    strokeOpacity *= opacity;
  }

  const DrawTarget* dt = aContext->GetDrawTarget();

  nsSVGPaintServerFrame* ps =
      SVGObserverUtils::GetAndObservePaintServer(aFrame, &nsStyleSVG::mStroke);

  if (ps) {
    RefPtr<gfxPattern> pattern = ps->GetPaintServerPattern(
        aFrame, dt, aContext->CurrentMatrixDouble(), &nsStyleSVG::mStroke,
        strokeOpacity, aImgParams);
    if (pattern) {
      pattern->CacheColorStops(dt);
      aOutPattern->Init(*pattern->GetPattern(dt));
      return;
    }
  }

  if (aContextPaint) {
    RefPtr<gfxPattern> pattern;
    switch (style->mStroke.Type()) {
      case eStyleSVGPaintType_ContextFill:
        pattern = aContextPaint->GetFillPattern(
            dt, strokeOpacity, aContext->CurrentMatrixDouble(), aImgParams);
        break;
      case eStyleSVGPaintType_ContextStroke:
        pattern = aContextPaint->GetStrokePattern(
            dt, strokeOpacity, aContext->CurrentMatrixDouble(), aImgParams);
        break;
      default:;
    }
    if (pattern) {
      aOutPattern->Init(*pattern->GetPattern(dt));
      return;
    }
  }

  if (style->mStroke.GetFallbackType() == eStyleSVGFallbackType_None) {
    return;
  }

  // On failure, use the fallback colour in case we have an
  // objectBoundingBox where the width or height of the object is zero.
  // See http://www.w3.org/TR/SVG11/coords.html#ObjectBoundingBox
  Color color(Color::FromABGR(
      GetFallbackOrPaintColor(aFrame->Style(), &nsStyleSVG::mStroke)));
  color.a *= strokeOpacity;
  aOutPattern->InitColorPattern(ToDeviceColor(color));
}

/* static */ float nsSVGUtils::GetOpacity(nsStyleSVGOpacitySource aOpacityType,
                                          const float& aOpacity,
                                          SVGContextPaint* aContextPaint) {
  float opacity = 1.0f;
  switch (aOpacityType) {
    case eStyleSVGOpacitySource_Normal:
      opacity = aOpacity;
      break;
    case eStyleSVGOpacitySource_ContextFillOpacity:
      if (aContextPaint) {
        opacity = aContextPaint->GetFillOpacity();
      } else {
        NS_WARNING(
            "Content used context-fill-opacity when not in a context element");
      }
      break;
    case eStyleSVGOpacitySource_ContextStrokeOpacity:
      if (aContextPaint) {
        opacity = aContextPaint->GetStrokeOpacity();
      } else {
        NS_WARNING(
            "Content used context-stroke-opacity when not in a context "
            "element");
      }
      break;
    default:
      MOZ_ASSERT_UNREACHABLE(
          "Unknown object opacity inheritance type for SVG "
          "glyph");
  }
  return opacity;
}

bool nsSVGUtils::HasStroke(nsIFrame* aFrame, SVGContextPaint* aContextPaint) {
  const nsStyleSVG* style = aFrame->StyleSVG();
  return style->HasStroke() && GetStrokeWidth(aFrame, aContextPaint) > 0;
}

float nsSVGUtils::GetStrokeWidth(nsIFrame* aFrame,
                                 SVGContextPaint* aContextPaint) {
  const nsStyleSVG* style = aFrame->StyleSVG();
  if (aContextPaint && style->StrokeWidthFromObject()) {
    return aContextPaint->GetStrokeWidth();
  }

  nsIContent* content = aFrame->GetContent();
  if (content->IsText()) {
    content = content->GetParent();
  }

  nsSVGElement* ctx = static_cast<nsSVGElement*>(content);

  return SVGContentUtils::CoordToFloat(ctx, style->mStrokeWidth);
}

void nsSVGUtils::SetupStrokeGeometry(nsIFrame* aFrame, gfxContext* aContext,
                                     SVGContextPaint* aContextPaint) {
  SVGContentUtils::AutoStrokeOptions strokeOptions;
  SVGContentUtils::GetStrokeOptions(
      &strokeOptions, static_cast<nsSVGElement*>(aFrame->GetContent()),
      aFrame->Style(), aContextPaint);

  if (strokeOptions.mLineWidth <= 0) {
    return;
  }

  aContext->SetLineWidth(strokeOptions.mLineWidth);
  aContext->SetLineCap(strokeOptions.mLineCap);
  aContext->SetMiterLimit(strokeOptions.mMiterLimit);
  aContext->SetLineJoin(strokeOptions.mLineJoin);
  aContext->SetDash(strokeOptions.mDashPattern, strokeOptions.mDashLength,
                    strokeOptions.mDashOffset);
}

uint16_t nsSVGUtils::GetGeometryHitTestFlags(nsIFrame* aFrame) {
  uint16_t flags = 0;

  switch (aFrame->StyleUI()->mPointerEvents) {
    case NS_STYLE_POINTER_EVENTS_NONE:
      break;
    case NS_STYLE_POINTER_EVENTS_AUTO:
    case NS_STYLE_POINTER_EVENTS_VISIBLEPAINTED:
      if (aFrame->StyleVisibility()->IsVisible()) {
        if (aFrame->StyleSVG()->mFill.Type() != eStyleSVGPaintType_None)
          flags |= SVG_HIT_TEST_FILL;
        if (aFrame->StyleSVG()->mStroke.Type() != eStyleSVGPaintType_None)
          flags |= SVG_HIT_TEST_STROKE;
        if (aFrame->StyleSVG()->mStrokeOpacity > 0)
          flags |= SVG_HIT_TEST_CHECK_MRECT;
      }
      break;
    case NS_STYLE_POINTER_EVENTS_VISIBLEFILL:
      if (aFrame->StyleVisibility()->IsVisible()) {
        flags |= SVG_HIT_TEST_FILL;
      }
      break;
    case NS_STYLE_POINTER_EVENTS_VISIBLESTROKE:
      if (aFrame->StyleVisibility()->IsVisible()) {
        flags |= SVG_HIT_TEST_STROKE;
      }
      break;
    case NS_STYLE_POINTER_EVENTS_VISIBLE:
      if (aFrame->StyleVisibility()->IsVisible()) {
        flags |= SVG_HIT_TEST_FILL | SVG_HIT_TEST_STROKE;
      }
      break;
    case NS_STYLE_POINTER_EVENTS_PAINTED:
      if (aFrame->StyleSVG()->mFill.Type() != eStyleSVGPaintType_None)
        flags |= SVG_HIT_TEST_FILL;
      if (aFrame->StyleSVG()->mStroke.Type() != eStyleSVGPaintType_None)
        flags |= SVG_HIT_TEST_STROKE;
      if (aFrame->StyleSVG()->mStrokeOpacity) flags |= SVG_HIT_TEST_CHECK_MRECT;
      break;
    case NS_STYLE_POINTER_EVENTS_FILL:
      flags |= SVG_HIT_TEST_FILL;
      break;
    case NS_STYLE_POINTER_EVENTS_STROKE:
      flags |= SVG_HIT_TEST_STROKE;
      break;
    case NS_STYLE_POINTER_EVENTS_ALL:
      flags |= SVG_HIT_TEST_FILL | SVG_HIT_TEST_STROKE;
      break;
    default:
      NS_ERROR("not reached");
      break;
  }

  return flags;
}

void nsSVGUtils::PaintSVGGlyph(Element* aElement, gfxContext* aContext) {
  nsIFrame* frame = aElement->GetPrimaryFrame();
  nsSVGDisplayableFrame* svgFrame = do_QueryFrame(frame);
  if (!svgFrame) {
    return;
  }
  gfxMatrix m;
  if (frame->GetContent()->IsSVGElement()) {
    // PaintSVG() expects the passed transform to be the transform to its own
    // SVG user space, so we need to account for any 'transform' attribute:
    m = static_cast<nsSVGElement*>(frame->GetContent())
            ->PrependLocalTransformsTo(gfxMatrix(), eUserSpaceToParent);
  }

  // SVG-in-OpenType is not allowed to paint external resources, so we can
  // just pass a dummy params into PatintSVG.
  imgDrawingParams dummy;
  svgFrame->PaintSVG(*aContext, m, dummy);
}

bool nsSVGUtils::GetSVGGlyphExtents(Element* aElement,
                                    const gfxMatrix& aSVGToAppSpace,
                                    gfxRect* aResult) {
  nsIFrame* frame = aElement->GetPrimaryFrame();
  nsSVGDisplayableFrame* svgFrame = do_QueryFrame(frame);
  if (!svgFrame) {
    return false;
  }

  gfxMatrix transform(aSVGToAppSpace);
  nsIContent* content = frame->GetContent();
  if (content->IsSVGElement()) {
    transform = static_cast<nsSVGElement*>(content)->PrependLocalTransformsTo(
        aSVGToAppSpace);
  }

  *aResult =
      svgFrame
          ->GetBBoxContribution(gfx::ToMatrix(transform),
                                nsSVGUtils::eBBoxIncludeFill |
                                    nsSVGUtils::eBBoxIncludeFillGeometry |
                                    nsSVGUtils::eBBoxIncludeStroke |
                                    nsSVGUtils::eBBoxIncludeStrokeGeometry |
                                    nsSVGUtils::eBBoxIncludeMarkers)
          .ToThebesRect();
  return true;
}

nsRect nsSVGUtils::ToCanvasBounds(const gfxRect& aUserspaceRect,
                                  const gfxMatrix& aToCanvas,
                                  const nsPresContext* presContext) {
  return nsLayoutUtils::RoundGfxRectToAppRect(
      aToCanvas.TransformBounds(aUserspaceRect),
      presContext->AppUnitsPerDevPixel());
}

gfxMatrix nsSVGUtils::GetCSSPxToDevPxMatrix(nsIFrame* aNonSVGFrame) {
  int32_t appUnitsPerDevPixel =
      aNonSVGFrame->PresContext()->AppUnitsPerDevPixel();
  float devPxPerCSSPx =
      1 / nsPresContext::AppUnitsToFloatCSSPixels(appUnitsPerDevPixel);

  return gfxMatrix(devPxPerCSSPx, 0.0, 0.0, devPxPerCSSPx, 0.0, 0.0);
}