issue #908 - implement missing parts of CSS mask

4 files changed, 103 insertions, 182 deletions

diff --git a/layout/svg/nsCSSClipPathInstance.cpp b/layout/svg/nsCSSClipPathInstance.cpp
index 828b10eac..01f7de248 100644
--- a/layout/svg/nsCSSClipPathInstance.cpp
+++ b/layout/svg/nsCSSClipPathInstance.cpp
@@ -62,122 +62,12 @@ nsCSSClipPathInstance::HitTestBasicShapeClip(nsIFrame* aFrame,
   return path->ContainsPoint(ToPoint(aPoint) * pixelRatio, Matrix());
 }
 
-nsRect
-nsCSSClipPathInstance::ComputeSVGReferenceRect()
-{
-  MOZ_ASSERT(mTargetFrame->GetContent()->IsSVGElement());
-  nsRect r;
-
-  // For SVG elements without associated CSS layout box, the used value for
-  // content-box, padding-box, border-box and margin-box is fill-box.
-  switch (mClipPathStyle.GetReferenceBox()) {
-    case StyleClipPathGeometryBox::Stroke: {
-      // XXX Bug 1299876
-      // The size of srtoke-box is not correct if this graphic element has
-      // specific stroke-linejoin or stroke-linecap.
-      gfxRect bbox = nsSVGUtils::GetBBox(mTargetFrame,
-                nsSVGUtils::eBBoxIncludeFill | nsSVGUtils::eBBoxIncludeStroke);
-      r = nsLayoutUtils::RoundGfxRectToAppRect(bbox,
-                                         nsPresContext::AppUnitsPerCSSPixel());
-      break;
-    }
-    case StyleClipPathGeometryBox::View: {
-      nsIContent* content = mTargetFrame->GetContent();
-      nsSVGElement* element = static_cast<nsSVGElement*>(content);
-      SVGSVGElement* svgElement = element->GetCtx();
-      MOZ_ASSERT(svgElement);
-
-      if (svgElement && svgElement->HasViewBoxRect()) {
-        // If a ‘viewBox‘ attribute is specified for the SVG viewport creating
-        // element:
-        // 1. The reference box is positioned at the origin of the coordinate
-        //    system established by the ‘viewBox‘ attribute.
-        // 2. The dimension of the reference box is set to the width and height
-        //    values of the ‘viewBox‘ attribute.
-        nsSVGViewBox* viewBox = svgElement->GetViewBox();
-        const nsSVGViewBoxRect& value = viewBox->GetAnimValue();
-        r = nsRect(nsPresContext::CSSPixelsToAppUnits(value.x),
-                   nsPresContext::CSSPixelsToAppUnits(value.y),
-                   nsPresContext::CSSPixelsToAppUnits(value.width),
-                   nsPresContext::CSSPixelsToAppUnits(value.height));
-      } else {
-        // No viewBox is specified, uses the nearest SVG viewport as reference
-        // box.
-        svgFloatSize viewportSize = svgElement->GetViewportSize();
-        r = nsRect(0, 0,
-                   nsPresContext::CSSPixelsToAppUnits(viewportSize.width),
-                   nsPresContext::CSSPixelsToAppUnits(viewportSize.height));
-      }
-
-      break;
-    }
-    case StyleClipPathGeometryBox::NoBox:
-    case StyleClipPathGeometryBox::Border:
-    case StyleClipPathGeometryBox::Content:
-    case StyleClipPathGeometryBox::Padding:
-    case StyleClipPathGeometryBox::Margin:
-    case StyleClipPathGeometryBox::Fill: {
-      gfxRect bbox = nsSVGUtils::GetBBox(mTargetFrame,
-                                         nsSVGUtils::eBBoxIncludeFill);
-      r = nsLayoutUtils::RoundGfxRectToAppRect(bbox,
-                                         nsPresContext::AppUnitsPerCSSPixel());
-      break;
-    }
-    default:{
-      MOZ_ASSERT_UNREACHABLE("unknown StyleClipPathGeometryBox type");
-      gfxRect bbox = nsSVGUtils::GetBBox(mTargetFrame,
-                                         nsSVGUtils::eBBoxIncludeFill);
-      r = nsLayoutUtils::RoundGfxRectToAppRect(bbox,
-                                         nsPresContext::AppUnitsPerCSSPixel());
-      break;
-    }
-  }
-
-  return r;
-}
-
-nsRect
-nsCSSClipPathInstance::ComputeHTMLReferenceRect()
-{
-  nsRect r;
-
-  // For elements with associated CSS layout box, the used value for fill-box,
-  // stroke-box and view-box is border-box.
-  switch (mClipPathStyle.GetReferenceBox()) {
-    case StyleClipPathGeometryBox::Content:
-      r = mTargetFrame->GetContentRectRelativeToSelf();
-      break;
-    case StyleClipPathGeometryBox::Padding:
-      r = mTargetFrame->GetPaddingRectRelativeToSelf();
-      break;
-    case StyleClipPathGeometryBox::Margin:
-      r = mTargetFrame->GetMarginRectRelativeToSelf();
-      break;
-    case StyleClipPathGeometryBox::NoBox:
-    case StyleClipPathGeometryBox::Border:
-    case StyleClipPathGeometryBox::Fill:
-    case StyleClipPathGeometryBox::Stroke:
-    case StyleClipPathGeometryBox::View:
-      r = mTargetFrame->GetRectRelativeToSelf();
-      break;
-    default:
-      MOZ_ASSERT_UNREACHABLE("unknown StyleClipPathGeometryBox type");
-      r = mTargetFrame->GetRectRelativeToSelf();
-      break;
-  }
-
-  return r;
-}
-
 already_AddRefed<Path>
 nsCSSClipPathInstance::CreateClipPath(DrawTarget* aDrawTarget)
 {
-  // We use ComputeSVGReferenceRect for all SVG elements, except <svg>
-  // element, which does have an associated CSS layout box. In this case we
-  // should still use ComputeHTMLReferenceRect for region computing.
-  nsRect r = mTargetFrame->IsFrameOfType(nsIFrame::eSVG) &&
-             (mTargetFrame->GetType() != nsGkAtoms::svgOuterSVGFrame)
-             ? ComputeSVGReferenceRect() : ComputeHTMLReferenceRect();
+  nsRect r =
+    nsLayoutUtils::ComputeGeometryBox(mTargetFrame,
+                                      mClipPathStyle.GetReferenceBox());
 
   if (mClipPathStyle.GetType() != StyleShapeSourceType::Shape) {
     // TODO Clip to border-radius/reference box if no shape
diff --git a/layout/svg/nsCSSClipPathInstance.h b/layout/svg/nsCSSClipPathInstance.h
index 3b0724dbd..33d92e738 100644
--- a/layout/svg/nsCSSClipPathInstance.h
+++ b/layout/svg/nsCSSClipPathInstance.h
@@ -48,10 +48,6 @@ private:
   already_AddRefed<Path> CreateClipPathInset(DrawTarget* aDrawTarget,
                                              const nsRect& aRefBox);
 
-
-  nsRect ComputeHTMLReferenceRect();
-  nsRect ComputeSVGReferenceRect();
-
   /**
    * The frame for the element that is currently being clipped.
    */
diff --git a/layout/svg/nsSVGIntegrationUtils.cpp b/layout/svg/nsSVGIntegrationUtils.cpp
index 498f69393..0003e1a73 100644
--- a/layout/svg/nsSVGIntegrationUtils.cpp
+++ b/layout/svg/nsSVGIntegrationUtils.cpp
@@ -509,71 +509,108 @@ PaintMaskSurface(const PaintFramesParams& aParams,
   return DrawResult::SUCCESS;
 }
 
-static DrawResult
+struct MaskPaintResult {
+  RefPtr<SourceSurface> maskSurface;
+  Matrix maskTransform;
+  DrawResult result;
+  bool transparentBlackMask;
+  bool opacityApplied;
+
+ MaskPaintResult()
+    : result(DrawResult::SUCCESS), transparentBlackMask(false),
+      opacityApplied(false)
+  {}
+};
+
+static MaskPaintResult
 CreateAndPaintMaskSurface(const PaintFramesParams& aParams,
                           float aOpacity, nsStyleContext* aSC,
                           const nsTArray<nsSVGMaskFrame*>& aMaskFrames,
-                          const nsPoint& aOffsetToUserSpace,
-                          Matrix& aOutMaskTransform,
-                          RefPtr<SourceSurface>& aOutMaskSurface,
-                          bool& aOpacityApplied)
+                          const nsPoint& aOffsetToUserSpace)
 {
   const nsStyleSVGReset *svgReset = aSC->StyleSVGReset();
   MOZ_ASSERT(aMaskFrames.Length() > 0);
+  MaskPaintResult paintResult;
 
   gfxContext& ctx = aParams.ctx;
 
-  // There is only one SVG mask.
+  // Optimization for single SVG mask.
   if (((aMaskFrames.Length() == 1) && aMaskFrames[0])) {
     gfxMatrix cssPxToDevPxMatrix =
     nsSVGIntegrationUtils::GetCSSPxToDevPxMatrix(aParams.frame);
+    paintResult.opacityApplied = true;
 
-    aOpacityApplied = true;
-    aOutMaskSurface =
+    paintResult.maskSurface =
       aMaskFrames[0]->GetMaskForMaskedFrame(&ctx, aParams.frame,
                                             cssPxToDevPxMatrix, aOpacity,
-                                            &aOutMaskTransform,
+                                            &paintResult.maskTransform,
                                             svgReset->mMask.mLayers[0].mMaskMode);
-    return DrawResult::SUCCESS;
+    if (!paintResult.maskSurface) {
+      paintResult.transparentBlackMask = true;
+    }
+
+    return paintResult;
   }
 
   const IntRect& maskSurfaceRect = aParams.maskRect;
   if (maskSurfaceRect.IsEmpty()) {
-    return DrawResult::SUCCESS;
+    paintResult.transparentBlackMask = true;
+    return paintResult;
   }
 
   RefPtr<DrawTarget> maskDT =
       ctx.GetDrawTarget()->CreateSimilarDrawTarget(maskSurfaceRect.Size(),
                                                    SurfaceFormat::A8);
   if (!maskDT || !maskDT->IsValid()) {
-    return DrawResult::TEMPORARY_ERROR;
+    paintResult.result = DrawResult::TEMPORARY_ERROR;
+    return paintResult;
   }
 
   // Set aAppliedOpacity as true only if all mask layers are svg mask.
   // In this case, we will apply opacity into the final mask surface, so the
   // caller does not need to apply it again.
-  aOpacityApplied = !HasNonSVGMask(aMaskFrames);
+  paintResult.opacityApplied = !HasNonSVGMask(aMaskFrames);
 
   // Set context's matrix on maskContext, offset by the maskSurfaceRect's
   // position. This makes sure that we combine the masks in device space.
   gfxMatrix maskSurfaceMatrix =
     ctx.CurrentMatrix() * gfxMatrix::Translation(-aParams.maskRect.TopLeft());
 
-  DrawResult result = PaintMaskSurface(aParams, maskDT,
-                                       aOpacityApplied ? aOpacity : 1.0,
-                                       aSC, aMaskFrames, maskSurfaceMatrix,
-                                       aOffsetToUserSpace);
-  if (result != DrawResult::SUCCESS) {
-    return result;
-  }
-
-  aOutMaskTransform = ToMatrix(maskSurfaceMatrix);
-  if (!aOutMaskTransform.Invert()) {
-    return DrawResult::SUCCESS;
+  paintResult.result = PaintMaskSurface(aParams, maskDT,
+                                        paintResult.opacityApplied
+                                          ? aOpacity : 1.0,
+                                        aSC, aMaskFrames, maskSurfaceMatrix,
+                                        aOffsetToUserSpace);
+  if (paintResult.result != DrawResult::SUCCESS) {
+    // Now we know the status of mask resource since we used it while painting.
+    // According to the return value of PaintMaskSurface, we know whether mask
+    // resource is resolvable or not.
+    //
+    // For a HTML doc:
+    //   According to css-masking spec, always create a mask surface when
+    //   we have any item in maskFrame even if all of those items are
+    //   non-resolvable <mask-sources> or <images>.
+    //   Set paintResult.transparentBlackMask as true,  the caller should stop
+    //   painting masked content as if this mask is a transparent black one.
+    // For a SVG doc:
+    //   SVG 1.1 say that if we fail to resolve a mask, we should draw the
+    //   object unmasked.
+    //   Left patinResult.maskSurface empty, the caller should paint all
+    //   masked content as if this mask is an opaque white one(no mask).
+    paintResult.transparentBlackMask =
+      !(aParams.frame->GetStateBits() & NS_FRAME_SVG_LAYOUT);
+
+    MOZ_ASSERT(!paintResult.maskSurface);
+    return paintResult;
+ }
+
+  paintResult.maskTransform = ToMatrix(maskSurfaceMatrix);
+  if (!paintResult.maskTransform.Invert()) {
+    return paintResult;
   }
 
-  aOutMaskSurface = maskDT->Snapshot();
-  return DrawResult::SUCCESS;
+  paintResult.maskSurface = maskDT->Snapshot();
+  return paintResult;
 }
 
 static bool
@@ -783,6 +820,8 @@ nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
                              maskUsage.shouldGenerateClipMaskLayer ||
                              maskUsage.shouldGenerateMaskLayer);
 
+  bool shouldPushMask = false;
+
   /* Check if we need to do additional operations on this child's
    * rendering, which necessitates rendering into another surface. */
   if (shouldGenerateMask) {
@@ -800,14 +839,23 @@ nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
       // instead of the first continuation frame.
       SetupContextMatrix(frame, aParams, offsetToBoundingBox,
                          offsetToUserSpace);
-      result = CreateAndPaintMaskSurface(aParams, maskUsage.opacity,
-                                         firstFrame->StyleContext(),
-                                         maskFrames, offsetToUserSpace,
-                                         maskTransform, maskSurface,
-                                         opacityApplied);
-      if (!maskSurface) {
-        // Entire surface is clipped out.
-        return result;
+      MaskPaintResult paintResult =
+        CreateAndPaintMaskSurface(aParams, maskUsage.opacity,
+                                  firstFrame->StyleContext(),
+                                  maskFrames, offsetToUserSpace);
+
+      if (paintResult.transparentBlackMask) {
+        MOZ_ASSERT(paintResult.result != DrawResult::SUCCESS);
+        return paintResult.result;
+      }
+
+      result &= paintResult.result;
+      maskSurface = paintResult.maskSurface;
+      if (maskSurface) {
+        MOZ_ASSERT(paintResult.result == DrawResult::SUCCESS);
+        shouldPushMask = true;
+        maskTransform = paintResult.maskTransform;
+        opacityApplied = paintResult.opacityApplied;
       }
     }
 
@@ -831,6 +879,8 @@ nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
         // failure in nsSVGClipPathFrame::GetClipMask.
         return result;
       }
+
+      shouldPushMask = true;
     }
 
     // opacity != 1.0f.
@@ -841,18 +891,22 @@ nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
       matSR.SetContext(&context);
       SetupContextMatrix(firstFrame, aParams, offsetToBoundingBox,
                          offsetToUserSpace);
+      shouldPushMask = true;
     }
 
-    if (aParams.layerManager->GetRoot()->GetContentFlags() & Layer::CONTENT_COMPONENT_ALPHA) {
-      context.PushGroupAndCopyBackground(gfxContentType::COLOR_ALPHA,
-                                         opacityApplied
-                                           ? 1.0
-                                           : maskUsage.opacity,
-                                         maskSurface, maskTransform);
-    } else {
-      context.PushGroupForBlendBack(gfxContentType::COLOR_ALPHA,
-                                    opacityApplied ? 1.0 : maskUsage.opacity,
-                                    maskSurface, maskTransform);
+    if (shouldPushMask) {
+      if (aParams.layerManager->GetRoot()->GetContentFlags() &
+          Layer::CONTENT_COMPONENT_ALPHA) {
+        context.PushGroupAndCopyBackground(gfxContentType::COLOR_ALPHA,
+                                           opacityApplied
+                                             ? 1.0
+                                             : maskUsage.opacity,
+                                           maskSurface, maskTransform);
+      } else {
+        context.PushGroupForBlendBack(gfxContentType::COLOR_ALPHA,
+                                      opacityApplied ? 1.0 : maskUsage.opacity,
+                                      maskSurface, maskTransform);
+      }
     }
   }
 
@@ -899,7 +953,7 @@ nsSVGIntegrationUtils::PaintMaskAndClipPath(const PaintFramesParams& aParams)
     context.PopClip();
   }
 
-  if (shouldGenerateMask) {
+  if (shouldPushMask) {
     context.PopGroupAndBlend();
   }
 
diff --git a/layout/svg/nsSVGUtils.cpp b/layout/svg/nsSVGUtils.cpp
index 344ebf645..0bded21ff 100644
--- a/layout/svg/nsSVGUtils.cpp
+++ b/layout/svg/nsSVGUtils.cpp
@@ -514,26 +514,7 @@ nsSVGUtils::DetermineMaskUsage(nsIFrame* aFrame, bool aHandleOpacity,
 
   nsTArray<nsSVGMaskFrame*> maskFrames = effectProperties.GetMaskFrames();
 
-#ifdef MOZ_ENABLE_MASK_AS_SHORTHAND
-  // For a HTML doc:
-  //   According to css-masking spec, always create a mask surface when we
-  //   have any item in maskFrame even if all of those items are
-  //   non-resolvable <mask-sources> or <images>, we still need to create a
-  //   transparent black mask layer under this condition.
-  // For a SVG doc:
-  //   SVG 1.1 say that  if we fail to resolve a mask, we should draw the
-  //   object unmasked.
-  aUsage.shouldGenerateMaskLayer =
-    (aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT)
-      ? maskFrames.Length() == 1 && maskFrames[0]
-      : maskFrames.Length() > 0;
-#else
-  // Since we do not support image mask so far, we should treat any
-  // unresolvable mask as no mask. Otherwise, any object with a valid image
-  // mask, e.g. url("xxx.png"), will become invisible just because we can not
-  // handle image mask correctly. (See bug 1294171)
-  aUsage.shouldGenerateMaskLayer = maskFrames.Length() == 1 && maskFrames[0];
-#endif
+  aUsage.shouldGenerateMaskLayer = (maskFrames.Length() > 0);
 
   bool isOK = effectProperties.HasNoFilterOrHasValidFilter();
   nsSVGClipPathFrame *clipPathFrame = effectProperties.GetClipPathFrame(&isOK);