1 files changed, 271 insertions, 0 deletions
diff --git a/WebCore/rendering/RenderSVGResourceClipper.cpp b/WebCore/rendering/RenderSVGResourceClipper.cpp
new file mode 100644
index 0000000..ccb7397
--- /dev/null
+++ b/WebCore/rendering/RenderSVGResourceClipper.cpp
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
+ *               2004, 2005, 2006, 2007, 2008 Rob Buis <buis@kde.org>
+ * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "config.h"
+#include "RenderSVGResourceClipper.h"
+
+#include "AffineTransform.h"
+#include "FloatRect.h"
+#include "GraphicsContext.h"
+#include "ImageBuffer.h"
+#include "IntRect.h"
+#include "RenderObject.h"
+#include "RenderStyle.h"
+#include "RenderSVGResource.h"
+#include "SVGClipPathElement.h"
+#include "SVGElement.h"
+#include "SVGRenderSupport.h"
+#include "SVGStyledElement.h"
+#include "SVGStyledTransformableElement.h"
+#include "SVGUnitTypes.h"
+#include "SVGUseElement.h"
+
+namespace WebCore {
+
+RenderSVGResourceType RenderSVGResourceClipper::s_resourceType = ClipperResourceType;
+
+RenderSVGResourceClipper::RenderSVGResourceClipper(SVGStyledElement* node)
+    : RenderSVGResource(node)
+{
+}
+
+RenderSVGResourceClipper::~RenderSVGResourceClipper()
+{
+    deleteAllValues(m_clipper);
+    m_clipper.clear();
+}
+
+void RenderSVGResourceClipper::invalidateClients()
+{
+    HashMap<RenderObject*, ClipperData*>::const_iterator end = m_clipper.end();
+    for (HashMap<RenderObject*, ClipperData*>::const_iterator it = m_clipper.begin(); it != end; ++it) {
+        RenderObject* renderer = it->first;
+        renderer->setNeedsBoundariesUpdate();
+        renderer->setNeedsLayout(true);
+    }
+    deleteAllValues(m_clipper);
+    m_clipper.clear();
+}
+
+void RenderSVGResourceClipper::invalidateClient(RenderObject* object)
+{
+    ASSERT(object);
+
+    // FIXME: The HashSet should always contain the object on calling invalidateClient. A race condition
+    // during the parsing can causes a call of invalidateClient right before the call of applyResource.
+    // We return earlier for the moment. This bug should be fixed in:
+    // https://bugs.webkit.org/show_bug.cgi?id=35181
+    if (!m_clipper.contains(object))
+        return;
+
+    delete m_clipper.take(object);
+}
+
+bool RenderSVGResourceClipper::applyResource(RenderObject* object, GraphicsContext*& context)
+{
+    applyClippingToContext(object, object->objectBoundingBox(), object->repaintRectInLocalCoordinates(), context);
+    return true;
+}
+
+bool RenderSVGResourceClipper::pathOnlyClipping(GraphicsContext* context, const FloatRect& objectBoundingBox)
+{
+    // If the current clip-path gets clipped itself, we have to fallback to masking.
+    if (!style()->svgStyle()->clipperResource().isEmpty())
+        return false;
+    WindRule clipRule = RULE_NONZERO;
+    Path clipPath = Path();
+
+    // If clip-path only contains one visible shape or path, we can use path-based clipping. Invisible
+    // shapes don't affect the clipping and can be ignored. If clip-path contains more than one
+    // visible shape, the additive clipping may not work, caused by the clipRule. EvenOdd
+    // as well as NonZero can cause self-clipping of the elements.
+    // See also http://www.w3.org/TR/SVG/painting.html#FillRuleProperty
+    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
+        RenderObject* renderer = childNode->renderer();
+        if (!renderer)
+            continue;
+        // Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.
+        if (renderer->isSVGText())
+            return false;
+        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyledTransformable())
+            continue;
+        SVGStyledTransformableElement* styled = static_cast<SVGStyledTransformableElement*>(childNode);
+        RenderStyle* style = renderer->style();
+        if (!style || style->display() == NONE || style->visibility() != VISIBLE)
+             continue;
+        const SVGRenderStyle* svgStyle = style->svgStyle();
+        // Current shape in clip-path gets clipped too. Fallback to masking.
+        if (!svgStyle->clipperResource().isEmpty())
+            return false;
+        // Fallback to masking, if there is more than one clipping path.
+        if (clipPath.isEmpty()) {
+            clipPath = styled->toClipPath();
+            clipRule = svgStyle->clipRule();
+        } else
+            return false;
+    }
+    // Only one visible shape/path was found. Directly continue clipping and transform the content to userspace if necessary.
+    if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
+        AffineTransform transform;
+        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
+        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
+        clipPath.transform(transform);
+    }
+    // The SVG specification wants us to clip everything, if clip-path doesn't have a child.
+    if (clipPath.isEmpty())
+        clipPath.addRect(FloatRect());
+    context->beginPath();
+    context->addPath(clipPath);
+    context->clipPath(clipRule);
+    return true;
+}
+
+bool RenderSVGResourceClipper::applyClippingToContext(RenderObject* object, const FloatRect& objectBoundingBox,
+                                                      const FloatRect& repaintRect, GraphicsContext* context)
+{
+    ASSERT(object);
+    ASSERT(context);
+
+    if (!m_clipper.contains(object))
+        m_clipper.set(object, new ClipperData);
+
+    ClipperData* clipperData = m_clipper.get(object);
+    if (!clipperData->clipMaskImage) {
+        if (pathOnlyClipping(context, objectBoundingBox))
+            return true;
+        createClipData(clipperData, objectBoundingBox, repaintRect);
+    }
+
+    if (!clipperData->clipMaskImage)
+        return false;
+
+    context->clipToImageBuffer(repaintRect, clipperData->clipMaskImage.get());
+    return true;
+}
+
+bool RenderSVGResourceClipper::createClipData(ClipperData* clipperData, const FloatRect& objectBoundingBox, const FloatRect& repaintRect)
+{
+    IntRect clipMaskRect = enclosingIntRect(repaintRect);
+    clipperData->clipMaskImage = ImageBuffer::create(clipMaskRect.size());
+    if (!clipperData->clipMaskImage)
+        return false;
+
+    GraphicsContext* maskContext = clipperData->clipMaskImage->context();
+    ASSERT(maskContext);
+
+    maskContext->save();
+    maskContext->translate(-repaintRect.x(), -repaintRect.y());
+
+    // clipPath can also be clipped by another clipPath.
+    bool clipperGetsClipped = false;
+    if (RenderSVGResourceClipper* clipper = getRenderSVGResourceById<RenderSVGResourceClipper>(this->document(), style()->svgStyle()->clipperResource())) {
+        clipperGetsClipped = true;
+        if (!clipper->applyClippingToContext(this, objectBoundingBox, repaintRect, maskContext)) {
+            maskContext->restore();
+            return false;
+        }            
+    }
+
+    SVGClipPathElement* clipPath = static_cast<SVGClipPathElement*>(node());
+    if (clipPath->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
+        maskContext->translate(objectBoundingBox.x(), objectBoundingBox.y());
+        maskContext->scale(objectBoundingBox.size());
+    }
+
+    // Draw all clipPath children into a global mask.
+    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
+        RenderObject* renderer = childNode->renderer();
+        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)
+            continue;
+        RenderStyle* style = renderer->style();
+        if (!style || style->display() == NONE || style->visibility() != VISIBLE)
+            continue;
+
+        WindRule newClipRule = style->svgStyle()->clipRule();
+        bool isUseElement = renderer->isSVGShadowTreeRootContainer();
+        if (isUseElement) {
+            SVGUseElement* useElement = static_cast<SVGUseElement*>(childNode);
+            renderer = useElement->rendererClipChild();
+            if (!renderer)
+                continue;
+            if (!useElement->hasAttribute(SVGNames::clip_ruleAttr))
+                newClipRule = renderer->style()->svgStyle()->clipRule();
+        }
+
+        // Only shapes, paths and texts are allowed for clipping.
+        if (!renderer->isRenderPath() && !renderer->isSVGText())
+            continue;
+
+        // Save the old RenderStyle of the current object for restoring after drawing
+        // it to the MaskImage. The new intermediate RenderStyle needs to inherit from
+        // the old one.
+        RefPtr<RenderStyle> oldRenderStyle = renderer->style();
+        RefPtr<RenderStyle> newRenderStyle = RenderStyle::clone(oldRenderStyle.get());
+        SVGRenderStyle* svgStyle = newRenderStyle.get()->accessSVGStyle();
+        svgStyle->setFillPaint(SVGPaint::defaultFill());
+        svgStyle->setStrokePaint(SVGPaint::defaultStroke());
+        svgStyle->setFillRule(newClipRule);
+        newRenderStyle.get()->setOpacity(1.0f);
+        svgStyle->setFillOpacity(1.0f);
+        svgStyle->setStrokeOpacity(1.0f);
+        svgStyle->setFilterResource(String());
+        svgStyle->setMaskerResource(String());
+        renderer->setStyle(newRenderStyle.release());
+
+        // Get the renderer of the element, that is referenced by the <use>-element.
+        if (isUseElement)
+            renderer = childNode->renderer();
+
+        renderSubtreeToImage(clipperData->clipMaskImage.get(), renderer);
+
+        renderer->setStyle(oldRenderStyle.release());
+    }
+
+    maskContext->restore();
+
+    return true;
+}
+
+FloatRect RenderSVGResourceClipper::resourceBoundingBox(const FloatRect& objectBoundingBox) const
+{
+    // This is a rough heuristic to appraise the clip size and doesn't consider clip on clip.
+    FloatRect clipRect;
+    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
+        RenderObject* renderer = childNode->renderer();
+        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)
+            continue;
+        if (!renderer->isRenderPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())
+            continue;
+        clipRect.unite(renderer->localToParentTransform().mapRect(renderer->repaintRectInLocalCoordinates()));
+    }
+
+    if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
+        AffineTransform transform;
+        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
+        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
+        return transform.mapRect(clipRect);
+    }
+
+    return clipRect;
+}
+
+}