import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

layout/svg/nsSVGClipPathFrame.cpp

@@ -0,0 +1,511 @@
+/* -*- 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/. */
+
+// Main header first:
+#include "nsSVGClipPathFrame.h"
+
+// Keep others in (case-insensitive) order:
+#include "gfxContext.h"
+#include "mozilla/dom/SVGClipPathElement.h"
+#include "nsGkAtoms.h"
+#include "nsSVGEffects.h"
+#include "nsSVGPathGeometryElement.h"
+#include "nsSVGPathGeometryFrame.h"
+#include "nsSVGUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+
+// Arbitrary number
+#define MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH int16_t(512)
+
+//----------------------------------------------------------------------
+// Implementation
+
+nsIFrame*
+NS_NewSVGClipPathFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
+{
+  return new (aPresShell) nsSVGClipPathFrame(aContext);
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsSVGClipPathFrame)
+
+void
+nsSVGClipPathFrame::ApplyClipPath(gfxContext& aContext,
+                                  nsIFrame* aClippedFrame,
+                                  const gfxMatrix& aMatrix)
+{
+  MOZ_ASSERT(IsTrivial(), "Caller needs to use GetClipMask");
+
+  DrawTarget& aDrawTarget = *aContext.GetDrawTarget();
+
+  // No need for AutoReferenceLimiter since simple clip paths can't create
+  // a reference loop (they don't reference other clip paths).
+
+  // Restore current transform after applying clip path:
+  gfxContextMatrixAutoSaveRestore autoRestore(&aContext);
+
+  RefPtr<Path> clipPath;
+
+  nsISVGChildFrame* singleClipPathChild = nullptr;
+  IsTrivial(&singleClipPathChild);
+
+  if (singleClipPathChild) {
+    nsSVGPathGeometryFrame* pathFrame = do_QueryFrame(singleClipPathChild);
+    if (pathFrame) {
+      nsSVGPathGeometryElement* pathElement =
+        static_cast<nsSVGPathGeometryElement*>(pathFrame->GetContent());
+      gfxMatrix toChildsUserSpace = pathElement->
+        PrependLocalTransformsTo(GetClipPathTransform(aClippedFrame) * aMatrix,
+                                 eUserSpaceToParent);
+      gfxMatrix newMatrix =
+        aContext.CurrentMatrix().PreMultiply(toChildsUserSpace).NudgeToIntegers();
+      if (!newMatrix.IsSingular()) {
+        aContext.SetMatrix(newMatrix);
+        FillRule clipRule =
+          nsSVGUtils::ToFillRule(pathFrame->StyleSVG()->mClipRule);
+        clipPath = pathElement->GetOrBuildPath(aDrawTarget, clipRule);
+      }
+    }
+  }
+
+  if (clipPath) {
+    aContext.Clip(clipPath);
+  } else {
+    // The spec says clip away everything if we have no children or the
+    // clipping path otherwise can't be resolved:
+    aContext.Clip(Rect());
+  }
+}
+
+already_AddRefed<SourceSurface>
+nsSVGClipPathFrame::GetClipMask(gfxContext& aReferenceContext,
+                                nsIFrame* aClippedFrame,
+                                const gfxMatrix& aMatrix,
+                                Matrix* aMaskTransform,
+                                SourceSurface* aExtraMask,
+                                const Matrix& aExtraMasksTransform,
+                                DrawResult* aResult)
+{
+  MOZ_ASSERT(!IsTrivial(), "Caller needs to use ApplyClipPath");
+
+  if (aResult) {
+    *aResult = DrawResult::SUCCESS;
+  }
+  DrawTarget& aReferenceDT = *aReferenceContext.GetDrawTarget();
+
+  // A clipPath can reference another clipPath.  We re-enter this method for
+  // each clipPath in a reference chain, so here we limit chain length:
+  static int16_t sRefChainLengthCounter = AutoReferenceLimiter::notReferencing;
+  AutoReferenceLimiter
+    refChainLengthLimiter(&sRefChainLengthCounter,
+                          MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH);
+  if (!refChainLengthLimiter.Reference()) {
+    return nullptr; // Reference chain is too long!
+  }
+
+  // And to prevent reference loops we check that this clipPath only appears
+  // once in the reference chain (if any) that we're currently processing:
+  AutoReferenceLimiter refLoopDetector(&mReferencing, 1);
+  if (!refLoopDetector.Reference()) {
+    return nullptr; // Reference loop!
+  }
+
+  IntRect devSpaceClipExtents;
+  {
+    gfxContextMatrixAutoSaveRestore autoRestoreMatrix(&aReferenceContext);
+
+    aReferenceContext.SetMatrix(gfxMatrix());
+    gfxRect rect = aReferenceContext.GetClipExtents();
+    devSpaceClipExtents = RoundedOut(ToRect(rect));
+    if (devSpaceClipExtents.IsEmpty()) {
+      // We don't need to create a mask surface, all drawing is clipped anyway.
+      return nullptr;
+    }
+  }
+
+  RefPtr<DrawTarget> maskDT =
+    aReferenceDT.CreateSimilarDrawTarget(devSpaceClipExtents.Size(),
+                                         SurfaceFormat::A8);
+
+  gfxMatrix mat = aReferenceContext.CurrentMatrix() *
+                    gfxMatrix::Translation(-devSpaceClipExtents.TopLeft());
+
+  // Paint this clipPath's contents into maskDT:
+  {
+    RefPtr<gfxContext> ctx = gfxContext::CreateOrNull(maskDT);
+    if (!ctx) {
+      gfxCriticalError() << "SVGClipPath context problem " << gfx::hexa(maskDT);
+      return nullptr;
+    }
+    ctx->SetMatrix(mat);
+
+    // We need to set mMatrixForChildren here so that under the PaintSVG calls
+    // on our children (below) our GetCanvasTM() method will return the correct
+    // transform.
+    mMatrixForChildren = GetClipPathTransform(aClippedFrame) * aMatrix;
+
+    // Check if this clipPath is itself clipped by another clipPath:
+    nsSVGClipPathFrame* clipPathThatClipsClipPath =
+      nsSVGEffects::GetEffectProperties(this).GetClipPathFrame(nullptr);
+    bool clippingOfClipPathRequiredMasking;
+    if (clipPathThatClipsClipPath) {
+      ctx->Save();
+      clippingOfClipPathRequiredMasking = !clipPathThatClipsClipPath->IsTrivial();
+      if (!clippingOfClipPathRequiredMasking) {
+        clipPathThatClipsClipPath->ApplyClipPath(*ctx, aClippedFrame, aMatrix);
+      } else {
+        Matrix maskTransform;
+        RefPtr<SourceSurface> mask =
+          clipPathThatClipsClipPath->GetClipMask(*ctx, aClippedFrame,
+                                                 aMatrix, &maskTransform);
+        ctx->PushGroupForBlendBack(gfxContentType::ALPHA, 1.0,
+                                   mask, maskTransform);
+        // The corresponding PopGroupAndBlend call below will mask the
+        // blend using |mask|.
+      }
+    }
+
+    // Paint our children into the mask:
+    for (nsIFrame* kid = mFrames.FirstChild(); kid;
+         kid = kid->GetNextSibling()) {
+      nsISVGChildFrame* SVGFrame = do_QueryFrame(kid);
+      if (SVGFrame) {
+        // The CTM of each frame referencing us can be different.
+        SVGFrame->NotifySVGChanged(nsISVGChildFrame::TRANSFORM_CHANGED);
+
+        bool isOK = true;
+        // Children of this clipPath may themselves be clipped.
+        nsSVGClipPathFrame *clipPathThatClipsChild =
+          nsSVGEffects::GetEffectProperties(kid).GetClipPathFrame(&isOK);
+        if (!isOK) {
+          continue;
+        }
+
+        bool childsClipPathRequiresMasking;
+
+        if (clipPathThatClipsChild) {
+          childsClipPathRequiresMasking = !clipPathThatClipsChild->IsTrivial();
+          ctx->Save();
+          if (!childsClipPathRequiresMasking) {
+            clipPathThatClipsChild->ApplyClipPath(*ctx, aClippedFrame, aMatrix);
+          } else {
+            Matrix maskTransform;
+            RefPtr<SourceSurface> mask =
+              clipPathThatClipsChild->GetClipMask(*ctx, aClippedFrame,
+                                                  aMatrix, &maskTransform);
+            ctx->PushGroupForBlendBack(gfxContentType::ALPHA, 1.0,
+                                       mask, maskTransform);
+            // The corresponding PopGroupAndBlend call below will mask the
+            // blend using |mask|.
+          }
+        }
+
+        gfxMatrix toChildsUserSpace = mMatrixForChildren;
+        nsIFrame* child = do_QueryFrame(SVGFrame);
+        nsIContent* childContent = child->GetContent();
+        if (childContent->IsSVGElement()) {
+          toChildsUserSpace =
+            static_cast<const nsSVGElement*>(childContent)->
+              PrependLocalTransformsTo(mMatrixForChildren, eUserSpaceToParent);
+        }
+
+        // Our children have NS_STATE_SVG_CLIPPATH_CHILD set on them, and
+        // nsSVGPathGeometryFrame::Render checks for that state bit and paints
+        // only the geometry (opaque black) if set.
+        DrawResult result = SVGFrame->PaintSVG(*ctx, toChildsUserSpace);
+        if (aResult) {
+          *aResult &= result;
+        }
+
+        if (clipPathThatClipsChild) {
+          if (childsClipPathRequiresMasking) {
+            ctx->PopGroupAndBlend();
+          }
+          ctx->Restore();
+        }
+      }
+    }
+
+
+    if (clipPathThatClipsClipPath) {
+      if (clippingOfClipPathRequiredMasking) {
+        ctx->PopGroupAndBlend();
+      }
+      ctx->Restore();
+    }
+  }
+
+  // Moz2D transforms in the opposite direction to Thebes
+  mat.Invert();
+
+  if (aExtraMask) {
+    // We could potentially due this more efficiently with OPERATOR_IN
+    // but that operator does not work well on CG or D2D
+    RefPtr<SourceSurface> currentMask = maskDT->Snapshot();
+    Matrix transform = maskDT->GetTransform();
+    maskDT->SetTransform(Matrix());
+    maskDT->ClearRect(Rect(0, 0,
+                           devSpaceClipExtents.width,
+                           devSpaceClipExtents.height));
+    maskDT->SetTransform(aExtraMasksTransform * transform);
+    // draw currentMask with the inverse of the transform that we just so that
+    // it ends up in the same spot with aExtraMask transformed by aExtraMasksTransform
+    maskDT->MaskSurface(SurfacePattern(currentMask, ExtendMode::CLAMP, aExtraMasksTransform.Inverse() * ToMatrix(mat)),
+                        aExtraMask,
+                        Point(0, 0));
+  }
+
+  *aMaskTransform = ToMatrix(mat);
+  return maskDT->Snapshot();
+}
+
+bool
+nsSVGClipPathFrame::PointIsInsideClipPath(nsIFrame* aClippedFrame,
+                                          const gfxPoint &aPoint)
+{
+  // A clipPath can reference another clipPath.  We re-enter this method for
+  // each clipPath in a reference chain, so here we limit chain length:
+  static int16_t sRefChainLengthCounter = AutoReferenceLimiter::notReferencing;
+  AutoReferenceLimiter
+    refChainLengthLimiter(&sRefChainLengthCounter,
+                          MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH);
+  if (!refChainLengthLimiter.Reference()) {
+    return false; // Reference chain is too long!
+  }
+
+  // And to prevent reference loops we check that this clipPath only appears
+  // once in the reference chain (if any) that we're currently processing:
+  AutoReferenceLimiter refLoopDetector(&mReferencing, 1);
+  if (!refLoopDetector.Reference()) {
+    return true; // Reference loop!
+  }
+
+  gfxMatrix matrix = GetClipPathTransform(aClippedFrame);
+  if (!matrix.Invert()) {
+    return false;
+  }
+  gfxPoint point = matrix.Transform(aPoint);
+
+  // clipPath elements can themselves be clipped by a different clip path. In
+  // that case the other clip path further clips away the element that is being
+  // clipped by the original clipPath. If this clipPath is being clipped by a
+  // different clip path we need to check if it prevents the original element
+  // from recieving events at aPoint:
+  nsSVGClipPathFrame *clipPathFrame =
+    nsSVGEffects::GetEffectProperties(this).GetClipPathFrame(nullptr);
+  if (clipPathFrame &&
+      !clipPathFrame->PointIsInsideClipPath(aClippedFrame, aPoint)) {
+    return false;
+  }
+
+  for (nsIFrame* kid = mFrames.FirstChild(); kid;
+       kid = kid->GetNextSibling()) {
+    nsISVGChildFrame* SVGFrame = do_QueryFrame(kid);
+    if (SVGFrame) {
+      gfxPoint pointForChild = point;
+      gfxMatrix m = static_cast<nsSVGElement*>(kid->GetContent())->
+        PrependLocalTransformsTo(gfxMatrix(), eUserSpaceToParent);
+      if (!m.IsIdentity()) {
+        if (!m.Invert()) {
+          return false;
+        }
+        pointForChild = m.Transform(point);
+      }
+      if (SVGFrame->GetFrameForPoint(pointForChild)) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+bool
+nsSVGClipPathFrame::IsTrivial(nsISVGChildFrame **aSingleChild)
+{
+  // If the clip path is clipped then it's non-trivial
+  if (nsSVGEffects::GetEffectProperties(this).GetClipPathFrame(nullptr))
+    return false;
+
+  if (aSingleChild) {
+    *aSingleChild = nullptr;
+  }
+
+  nsISVGChildFrame *foundChild = nullptr;
+
+  for (nsIFrame* kid = mFrames.FirstChild(); kid;
+       kid = kid->GetNextSibling()) {
+    nsISVGChildFrame *svgChild = do_QueryFrame(kid);
+    if (svgChild) {
+      // We consider a non-trivial clipPath to be one containing
+      // either more than one svg child and/or a svg container
+      if (foundChild || svgChild->IsDisplayContainer())
+        return false;
+
+      // or where the child is itself clipped
+      if (nsSVGEffects::GetEffectProperties(kid).GetClipPathFrame(nullptr))
+        return false;
+
+      foundChild = svgChild;
+    }
+  }
+  if (aSingleChild) {
+    *aSingleChild = foundChild;
+  }
+  return true;
+}
+
+bool
+nsSVGClipPathFrame::IsValid()
+{
+  // A clipPath can reference another clipPath.  We re-enter this method for
+  // each clipPath in a reference chain, so here we limit chain length:
+  static int16_t sRefChainLengthCounter = AutoReferenceLimiter::notReferencing;
+  AutoReferenceLimiter
+    refChainLengthLimiter(&sRefChainLengthCounter,
+                          MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH);
+  if (!refChainLengthLimiter.Reference()) {
+    return false; // Reference chain is too long!
+  }
+
+  // And to prevent reference loops we check that this clipPath only appears
+  // once in the reference chain (if any) that we're currently processing:
+  AutoReferenceLimiter refLoopDetector(&mReferencing, 1);
+  if (!refLoopDetector.Reference()) {
+    return false; // Reference loop!
+  }
+
+  bool isOK = true;
+  nsSVGEffects::GetEffectProperties(this).GetClipPathFrame(&isOK);
+  if (!isOK) {
+    return false;
+  }
+
+  for (nsIFrame* kid = mFrames.FirstChild(); kid;
+       kid = kid->GetNextSibling()) {
+
+    nsIAtom* kidType = kid->GetType();
+
+    if (kidType == nsGkAtoms::svgUseFrame) {
+      for (nsIFrame* grandKid : kid->PrincipalChildList()) {
+
+        nsIAtom* grandKidType = grandKid->GetType();
+
+        if (grandKidType != nsGkAtoms::svgPathGeometryFrame &&
+            grandKidType != nsGkAtoms::svgTextFrame) {
+          return false;
+        }
+      }
+      continue;
+    }
+
+    if (kidType != nsGkAtoms::svgPathGeometryFrame &&
+        kidType != nsGkAtoms::svgTextFrame) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+nsresult
+nsSVGClipPathFrame::AttributeChanged(int32_t         aNameSpaceID,
+                                     nsIAtom*        aAttribute,
+                                     int32_t         aModType)
+{
+  if (aNameSpaceID == kNameSpaceID_None) {
+    if (aAttribute == nsGkAtoms::transform) {
+      nsSVGEffects::InvalidateDirectRenderingObservers(this);
+      nsSVGUtils::NotifyChildrenOfSVGChange(this,
+                                            nsISVGChildFrame::TRANSFORM_CHANGED);
+    }
+    if (aAttribute == nsGkAtoms::clipPathUnits) {
+      nsSVGEffects::InvalidateDirectRenderingObservers(this);
+    }
+  }
+
+  return nsSVGContainerFrame::AttributeChanged(aNameSpaceID,
+                                               aAttribute, aModType);
+}
+
+void
+nsSVGClipPathFrame::Init(nsIContent*       aContent,
+                         nsContainerFrame* aParent,
+                         nsIFrame*         aPrevInFlow)
+{
+  NS_ASSERTION(aContent->IsSVGElement(nsGkAtoms::clipPath),
+               "Content is not an SVG clipPath!");
+
+  AddStateBits(NS_STATE_SVG_CLIPPATH_CHILD);
+  nsSVGContainerFrame::Init(aContent, aParent, aPrevInFlow);
+}
+
+nsIAtom *
+nsSVGClipPathFrame::GetType() const
+{
+  return nsGkAtoms::svgClipPathFrame;
+}
+
+gfxMatrix
+nsSVGClipPathFrame::GetCanvasTM()
+{
+  return mMatrixForChildren;
+}
+
+gfxMatrix
+nsSVGClipPathFrame::GetClipPathTransform(nsIFrame* aClippedFrame)
+{
+  SVGClipPathElement *content = static_cast<SVGClipPathElement*>(mContent);
+
+  gfxMatrix tm = content->PrependLocalTransformsTo(gfxMatrix());
+
+  nsSVGEnum* clipPathUnits =
+    &content->mEnumAttributes[SVGClipPathElement::CLIPPATHUNITS];
+
+  return nsSVGUtils::AdjustMatrixForUnits(tm, clipPathUnits, aClippedFrame);
+}
+
+SVGBBox
+nsSVGClipPathFrame::GetBBoxForClipPathFrame(const SVGBBox &aBBox, 
+                                            const gfxMatrix &aMatrix)
+{
+  nsIContent* node = GetContent()->GetFirstChild();
+  SVGBBox unionBBox, tmpBBox;
+  for (; node; node = node->GetNextSibling()) {
+    nsIFrame *frame = 
+      static_cast<nsSVGElement*>(node)->GetPrimaryFrame();
+    if (frame) {
+      nsISVGChildFrame *svg = do_QueryFrame(frame);
+      if (svg) {
+        tmpBBox = svg->GetBBoxContribution(mozilla::gfx::ToMatrix(aMatrix), 
+                                         nsSVGUtils::eBBoxIncludeFill);
+        nsSVGEffects::EffectProperties effectProperties =
+                              nsSVGEffects::GetEffectProperties(frame);
+        bool isOK = true;
+        nsSVGClipPathFrame *clipPathFrame = 
+                              effectProperties.GetClipPathFrame(&isOK);
+        if (clipPathFrame && isOK) {
+          tmpBBox = clipPathFrame->GetBBoxForClipPathFrame(tmpBBox, aMatrix);
+        } 
+        tmpBBox.Intersect(aBBox);
+        unionBBox.UnionEdges(tmpBBox);
+      }
+    }
+  }
+  nsSVGEffects::EffectProperties props = 
+    nsSVGEffects::GetEffectProperties(this);    
+  if (props.mClipPath) {
+    bool isOK = true;
+    nsSVGClipPathFrame *clipPathFrame = props.GetClipPathFrame(&isOK);
+    if (clipPathFrame && isOK) {
+      tmpBBox = clipPathFrame->GetBBoxForClipPathFrame(aBBox, aMatrix);                                                       
+      unionBBox.Intersect(tmpBBox);
+    } else if (!isOK) {
+      unionBBox = SVGBBox();
+    }
+  }
+  return unionBBox;
+}