Add support for SVG Clip paths in HTML

Source/core/rendering/RenderLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 1823 matching lines @@
         if (style->clipPath()->type() == ClipPathOperation::SHAPE) {
             clipStateSaver.save();
             ShapeClipPathOperation* clipPath = toShapeClipPathOperation(style->clipPath());
 
             if (!rootRelativeBoundsComputed) {
                 rootRelativeBounds = physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
                 rootRelativeBoundsComputed = true;
             }
 
             context->clipPath(clipPath->path(rootRelativeBounds), clipPath->windRule());
-        } else if (style->clipPath()->type() == ClipPathOperation::REFERENCE) {
-            ReferenceClipPathOperation* referenceClipPathOperation = toReferenceClipPathOperation(style->clipPath());
-            Document& document = renderer()->document();
+        } else if (m_clipPathInfo && m_clipPathInfo->getClipPathElement() && m_clipPathInfo->getClipPathElement()->renderer()) {
             // FIXME: It doesn't work with forward or external SVG references (https://bugs.webkit.org/show_bug.cgi?id=90405)
-            Element* element = document.getElementById(referenceClipPathOperation->fragment());
-            if (isSVGClipPathElement(element) && element->renderer()) {
-                // FIXME: Saving at this point is not required in the 'mask'-
-                // case, or if the clip ends up empty.
-                clipStateSaver.save();
-                if (!rootRelativeBoundsComputed) {
-                    rootRelativeBounds = physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
-                    rootRelativeBoundsComputed = true;
-                }
+            // FIXME: Saving at this point is not required in the 'mask'-
+            // case, or if the clip ends up empty.
+            clipStateSaver.save();
+            if (!rootRelativeBoundsComputed) {
+                rootRelativeBounds = physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
+                rootRelativeBoundsComputed = true;
+            }
 
-                resourceClipper = toRenderSVGResourceClipper(toRenderSVGResourceContainer(element->renderer()));
-                if (!resourceClipper->applyClippingToContext(renderer(), rootRelativeBounds,
-                    paintingInfo.paintDirtyRect, context, clipperContext)) {
-                    // No need to post-apply the clipper if this failed.
-                    resourceClipper = 0;
-                }
+            resourceClipper = toRenderSVGResourceClipper(toRenderSVGResourceContainer(m_clipPathInfo->getClipPathElement()->renderer()));
+            if (!resourceClipper->applyClippingToContext(renderer(), rootRelativeBounds,
+                paintingInfo.paintDirtyRect, context, clipperContext)) {
+                // No need to post-apply the clipper if this failed.
+                resourceClipper = 0;
             }
         }
     }
 
     // Blending operations must be performed only with the nearest ancestor stacking context.
     // Note that there is no need to create a transparency layer if we're painting the root.
     bool createTransparencyLayerForBlendMode = !renderer()->isDocumentElement() && m_stackingNode->isStackingContext() && m_blendInfo.childLayerHasBlendMode();
 
     if (createTransparencyLayerForBlendMode)
         beginTransparencyLayers(context, paintingInfo.rootLayer, paintingInfo.paintDirtyRect, paintingInfo.subPixelAccumulation, paintingInfo.paintBehavior);
@@ skipping 1668 matching lines @@
 
 void RenderLayer::updateFilters(const RenderStyle* oldStyle, const RenderStyle* newStyle)
 {
     if (!newStyle->hasFilter() && (!oldStyle || !oldStyle->hasFilter()))
         return;
 
     updateOrRemoveFilterClients();
     updateOrRemoveFilterEffectRenderer();
 }
 
+void RenderLayer::updateClipPathInfo(const RenderStyle* oldStyle, const RenderStyle* newStyle)
+{
+    if (!newStyle->clipPath() && (!oldStyle || !oldStyle->clipPath()))
+        return;
+
+    if (renderer()->hasClipPath() && renderer()->style()->clipPath()->type() == ClipPathOperation::REFERENCE) {
+        if (!m_clipPathInfo)
+            m_clipPathInfo = adoptPtr(new RenderLayerClipPathInfo(this));
+        m_clipPathInfo->updateReferenceClipPathClients(renderer()->style()->clipPath());
+    } else if (m_clipPathInfo) {
+        m_clipPathInfo = nullptr;
+    }
+}
+
 bool RenderLayer::attemptDirectCompositingUpdate(StyleDifference diff, const RenderStyle* oldStyle)
 {
     CompositingReasons oldPotentialCompositingReasonsFromStyle = m_potentialCompositingReasonsFromStyle;
     compositor()->updatePotentialCompositingReasonsFromStyle(this);
 
     // This function implements an optimization for transforms and opacity.
     // A common pattern is for a touchmove handler to update the transform
     // and/or an opacity of an element every frame while the user moves their
     // finger across the screen. The conditions below recognize when the
     // compositing state is set up to receive a direct transform or opacity
     // update.
 
     if (!diff.hasAtMostPropertySpecificDifferences(StyleDifference::TransformChanged | StyleDifference::OpacityChanged))
         return false;
     // The potentialCompositingReasonsFromStyle could have changed without
     // a corresponding StyleDifference if an animation started or ended.
     if (m_potentialCompositingReasonsFromStyle != oldPotentialCompositingReasonsFromStyle)
         return false;
     // We could add support for reflections if we updated the transform on
     // the reflection layers.
     if (renderer()->hasReflection())
         return false;
-    // If we're unwinding a scheduleSVGFilterLayerUpdateHack(), then we can't
+    // If we're unwinding a scheduleSVGEffectsLayerUpdateHack(), then we can't
     // perform a direct compositing update because the filters code is going
     // to produce different output this time around. We can remove this code
     // once we fix the chicken/egg bugs in the filters code and delete the
-    // scheduleSVGFilterLayerUpdateHack().
-    if (renderer()->node() && renderer()->node()->svgFilterNeedsLayerUpdate())
+    // scheduleSVGEffectsLayerUpdateHack().
+    if (renderer()->node() && renderer()->node()->svgEffectsNeedLayerUpdate())
         return false;
     if (!m_compositedLayerMapping)
         return false;
 
     // To cut off almost all the work in the compositing update for
     // this case, we treat inline transforms has having assumed overlap
     // (similar to how we treat animated transforms). Notice that we read
     // CompositingReasonInlineTransform from the m_compositingReasons, which
     // means that the inline transform actually triggered assumed overlap in
     // the overlap map.
@@ skipping 30 matching lines @@
 
     // Overlay scrollbars can make this layer self-painting so we need
     // to recompute the bit once scrollbars have been updated.
     updateSelfPaintingLayer();
 
     if (!oldStyle || !renderer()->style()->reflectionDataEquivalent(oldStyle)) {
         ASSERT(!oldStyle || diff.needsFullLayout());
         updateReflectionInfo(oldStyle);
     }
 
+    updateClipPathInfo(oldStyle, renderer()->style());
+
     if (RuntimeEnabledFeatures::cssCompositingEnabled())
         m_blendInfo.updateBlendMode();
 
     updateDescendantDependentFlags();
 
     updateTransform(oldStyle, renderer()->style());
     updateFilters(oldStyle, renderer()->style());
 
     setNeedsCompositingInputsUpdate();
 }
@@ skipping 67 matching lines @@
         // We can optimize away code paths in other places if we know that there are no software filters.
         renderer()->document().view()->setHasSoftwareFilters(true);
     }
 
     // If the filter fails to build, remove it from the layer. It will still attempt to
     // go through regular processing (e.g. compositing), but never apply anything.
     if (!filterInfo->renderer()->build(renderer(), computeFilterOperations(renderer()->style())))
         filterInfo->setRenderer(nullptr);
 }
 
-void RenderLayer::filterNeedsPaintInvalidation()
+void RenderLayer::svgEffectsNeedPaintInvalidation()

[esprehn, 2014/08/06 17:25:10]

We should not be adding more callers of this or
scheduleSVGEffectsLayerUpdateHack.

 {
     {
         DeprecatedScheduleStyleRecalcDuringLayout marker(renderer()->document().lifecycle());
-        // It's possible for scheduleSVGFilterLayerUpdateHack to schedule a style recalc, which
+        // It's possible for scheduleSVGEffectsLayerUpdateHack to schedule a style recalc, which
         // is a problem because this function can be called while performing layout.
         // Presumably this represents an illegal data flow of layout or compositing
         // information into the style system.
-        toElement(renderer()->node())->scheduleSVGFilterLayerUpdateHack();
+        toElement(renderer()->node())->scheduleSVGEffectsLayerUpdateHack();
     }
 
     if (renderer()->view()) {
         if (renderer()->frameView()->isInPerformLayout())
             renderer()->setShouldDoFullPaintInvalidation(true);
         else
             renderer()->paintInvalidationForWholeRenderer();
     }
 }
 
@@ skipping 54 matching lines @@
     }
 }
 
 void showLayerTree(const blink::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif