1 /*

     2  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>

     3  *               2004, 2005, 2006, 2007, 2008 Rob Buis <buis@kde.org>

     4  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.

     5  *

     6  * This library is free software; you can redistribute it and/or

     7  * modify it under the terms of the GNU Library General Public

     8  * License as published by the Free Software Foundation; either

     9  * version 2 of the License, or (at your option) any later version.

    10  *

    11  * This library is distributed in the hope that it will be useful,

    12  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    14  * Library General Public License for more details.

    15  *

    16  * You should have received a copy of the GNU Library General Public License

    17  * along with this library; see the file COPYING.LIB.  If not, write to

    18  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

    19  * Boston, MA 02110-1301, USA.

    20  *

    21  */

    22 

    23 #include "config.h"

    24 #if ENABLE(SVG)

    25 #include "RenderSVGResourceClipper.h"

    26 

    27 #include "AffineTransform.h"

    28 #include "FloatRect.h"

    29 #include "GraphicsContext.h"

    30 #include "HitTestRequest.h"

    31 #include "HitTestResult.h"

    32 #include "ImageBuffer.h"

    33 #include "IntRect.h"

    34 #include "RenderObject.h"

    35 #include "RenderStyle.h"

    36 #include "RenderSVGResource.h"

    37 #include "SVGClipPathElement.h"

    38 #include "SVGElement.h"

    39 #include "SVGRenderSupport.h"

    40 #include "SVGStyledElement.h"

    41 #include "SVGStyledTransformableElement.h"

    42 #include "SVGUnitTypes.h"

    43 #include "SVGUseElement.h"

    44 #include <wtf/UnusedParam.h>

    45 

    46 namespace WebCore {

    47 

    48 RenderSVGResourceType RenderSVGResourceClipper::s_resourceType = ClipperResourceType;

    49 

    50 RenderSVGResourceClipper::RenderSVGResourceClipper(SVGClipPathElement* node)

    51     : RenderSVGResourceContainer(node)

    52     , m_invalidationBlocked(false)

    53 {

    54 }

    55 

    56 RenderSVGResourceClipper::~RenderSVGResourceClipper()

    57 {

    58     deleteAllValues(m_clipper);

    59     m_clipper.clear();

    60 }

    61 

    62 void RenderSVGResourceClipper::invalidateClients()

    63 {

    64     if (m_invalidationBlocked)

    65         return;

    66 

    67     HashMap<RenderObject*, ClipperData*>::const_iterator end = m_clipper.end();

    68     for (HashMap<RenderObject*, ClipperData*>::const_iterator it = m_clipper.begin(); it != end; ++it)

    69         markForLayoutAndResourceInvalidation(it->first);

    70 

    71     deleteAllValues(m_clipper);

    72     m_clipper.clear();

    73     m_clipBoundaries = FloatRect();

    74 }

    75 

    76 void RenderSVGResourceClipper::invalidateClient(RenderObject* object)

    77 {

    78     if (m_invalidationBlocked)

    79         return;

    80 

    81     ASSERT(object);

    82     if (!m_clipper.contains(object))

    83         return;

    84 

    85     delete m_clipper.take(object);

    86     markForLayoutAndResourceInvalidation(object);

    87 }

    88 

    89 bool RenderSVGResourceClipper::applyResource(RenderObject* object, RenderStyle*, GraphicsContext*& context, unsigned short resourceMode)

    90 {

    91     ASSERT(object);

    92     ASSERT(context);

    93 #ifndef NDEBUG

    94     ASSERT(resourceMode == ApplyToDefaultMode);

    95 #else

    96     UNUSED_PARAM(resourceMode);

    97 #endif

    98 

    99     // Early exit, if this resource contains a child which references ourselves.

   100     if (containsCyclicReference(node()))

   101         return false;

   102 

   103     applyClippingToContext(object, object->objectBoundingBox(), object->repaintRectInLocalCoordinates(), context);

   104     return true;

   105 }

   106 

   107 bool RenderSVGResourceClipper::pathOnlyClipping(GraphicsContext* context, const FloatRect& objectBoundingBox)

   108 {

   109     // If the current clip-path gets clipped itself, we have to fallback to masking.

   110     if (!style()->svgStyle()->clipperResource().isEmpty())

   111         return false;

   112     WindRule clipRule = RULE_NONZERO;

   113     Path clipPath = Path();

   114 

   115     // If clip-path only contains one visible shape or path, we can use path-based clipping. Invisible

   116     // shapes don't affect the clipping and can be ignored. If clip-path contains more than one

   117     // visible shape, the additive clipping may not work, caused by the clipRule. EvenOdd

   118     // as well as NonZero can cause self-clipping of the elements.

   119     // See also http://www.w3.org/TR/SVG/painting.html#FillRuleProperty

   120     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

   121         RenderObject* renderer = childNode->renderer();

   122         if (!renderer)

   123             continue;

   124         // Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.

   125         if (renderer->isSVGText())

   126             return false;

   127         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyledTransformable())

   128             continue;

   129         SVGStyledTransformableElement* styled = static_cast<SVGStyledTransformableElement*>(childNode);

   130         RenderStyle* style = renderer->style();

   131         if (!style || style->display() == NONE || style->visibility() != VISIBLE)

   132              continue;

   133         const SVGRenderStyle* svgStyle = style->svgStyle();

   134         // Current shape in clip-path gets clipped too. Fallback to masking.

   135         if (!svgStyle->clipperResource().isEmpty())

   136             return false;

   137         // Fallback to masking, if there is more than one clipping path.

   138         if (clipPath.isEmpty()) {

   139             clipPath = styled->toClipPath();

   140             clipRule = svgStyle->clipRule();

   141         } else

   142             return false;

   143     }

   144     // Only one visible shape/path was found. Directly continue clipping and transform the content to userspace if necessary.

   145     if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

   146         AffineTransform transform;

   147         transform.translate(objectBoundingBox.x(), objectBoundingBox.y());

   148         transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());

   149         clipPath.transform(transform);

   150     }

   151     // The SVG specification wants us to clip everything, if clip-path doesn't have a child.

   152     if (clipPath.isEmpty())

   153         clipPath.addRect(FloatRect());

   154     context->beginPath();

   155     context->addPath(clipPath);

   156     context->clipPath(clipRule);

   157     return true;

   158 }

   159 

   160 bool RenderSVGResourceClipper::applyClippingToContext(RenderObject* object, const FloatRect& objectBoundingBox,

   161                                                       const FloatRect& repaintRect, GraphicsContext* context)

   162 {

   163     if (!m_clipper.contains(object))

   164         m_clipper.set(object, new ClipperData);

   165 

   166     ClipperData* clipperData = m_clipper.get(object);

   167     if (!clipperData->clipMaskImage) {

   168         if (pathOnlyClipping(context, objectBoundingBox))

   169             return true;

   170         createClipData(clipperData, objectBoundingBox, repaintRect);

   171     }

   172 

   173     if (!clipperData->clipMaskImage)

   174         return false;

   175 

   176     context->clipToImageBuffer(repaintRect, clipperData->clipMaskImage.get());

   177     return true;

   178 }

   179 

   180 bool RenderSVGResourceClipper::createClipData(ClipperData* clipperData, const FloatRect& objectBoundingBox, const FloatRect& repaintRect)

   181 {

   182     IntRect clipMaskRect = enclosingIntRect(repaintRect);

   183     clipperData->clipMaskImage = ImageBuffer::create(clipMaskRect.size());

   184     if (!clipperData->clipMaskImage)

   185         return false;

   186 

   187     GraphicsContext* maskContext = clipperData->clipMaskImage->context();

   188     ASSERT(maskContext);

   189 

   190     maskContext->save();

   191     maskContext->translate(-repaintRect.x(), -repaintRect.y());

   192 

   193     // clipPath can also be clipped by another clipPath.

   194     if (RenderSVGResourceClipper* clipper = getRenderSVGResourceById<RenderSVGResourceClipper>(this->document(), style()->svgStyle()->clipperResource())) {

   195         if (!clipper->applyClippingToContext(this, objectBoundingBox, repaintRect, maskContext)) {

   196             maskContext->restore();

   197             return false;

   198         }            

   199     }

   200 

   201     SVGClipPathElement* clipPath = static_cast<SVGClipPathElement*>(node());

   202     if (clipPath->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

   203         maskContext->translate(objectBoundingBox.x(), objectBoundingBox.y());

   204         maskContext->scale(objectBoundingBox.size());

   205     }

   206 

   207     // Draw all clipPath children into a global mask.

   208     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

   209         RenderObject* renderer = childNode->renderer();

   210         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)

   211             continue;

   212         RenderStyle* style = renderer->style();

   213         if (!style || style->display() == NONE || style->visibility() != VISIBLE)

   214             continue;

   215 

   216         WindRule newClipRule = style->svgStyle()->clipRule();

   217         bool isUseElement = renderer->isSVGShadowTreeRootContainer();

   218         if (isUseElement) {

   219             SVGUseElement* useElement = static_cast<SVGUseElement*>(childNode);

   220             renderer = useElement->rendererClipChild();

   221             if (!renderer)

   222                 continue;

   223             if (!useElement->hasAttribute(SVGNames::clip_ruleAttr))

   224                 newClipRule = renderer->style()->svgStyle()->clipRule();

   225         }

   226 

   227         // Only shapes, paths and texts are allowed for clipping.

   228         if (!renderer->isRenderPath() && !renderer->isSVGText())

   229             continue;

   230 

   231         // Save the old RenderStyle of the current object for restoring after drawing

   232         // it to the MaskImage. The new intermediate RenderStyle needs to inherit from

   233         // the old one.

   234         RefPtr<RenderStyle> oldRenderStyle = renderer->style();

   235         RefPtr<RenderStyle> newRenderStyle = RenderStyle::clone(oldRenderStyle.get());

   236         SVGRenderStyle* svgStyle = newRenderStyle.get()->accessSVGStyle();

   237         svgStyle->setFillPaint(SVGPaint::defaultFill());

   238         svgStyle->setStrokePaint(SVGPaint::defaultStroke());

   239         svgStyle->setFillRule(newClipRule);

   240         newRenderStyle.get()->setOpacity(1.0f);

   241         svgStyle->setFillOpacity(1.0f);

   242         svgStyle->setStrokeOpacity(1.0f);

   243         svgStyle->setFilterResource(String());

   244         svgStyle->setMaskerResource(String());

   245 

   246         // The setStyle() call results in a styleDidChange() call, which in turn invalidations the resources.

   247         // As we're mutating the resource on purpose, block updates until we've resetted the style again.

   248         m_invalidationBlocked = true;

   249         renderer->setStyle(newRenderStyle.release());

   250 

   251         // In the case of a <use> element, we obtained its renderere above, to retrieve its clipRule.

   252         // We hsve to pass the <use> renderer itself to renderSubtreeToImage() to apply it's x/y/transform/etc. values when rendering.

   253         // So if isUseElement is true, refetch the childNode->renderer(), as renderer got overriden above.

   254         SVGRenderSupport::renderSubtreeToImage(clipperData->clipMaskImage.get(), isUseElement ? childNode->renderer() : renderer);

   255 

   256         renderer->setStyle(oldRenderStyle.release());

   257         m_invalidationBlocked = false;

   258     }

   259 

   260     maskContext->restore();

   261 

   262     return true;

   263 }

   264 

   265 void RenderSVGResourceClipper::calculateClipContentRepaintRect()

   266 {

   267     // This is a rough heuristic to appraise the clip size and doesn't consider clip on clip.

   268     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

   269         RenderObject* renderer = childNode->renderer();

   270         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)

   271             continue;

   272         if (!renderer->isRenderPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())

   273             continue;

   274         RenderStyle* style = renderer->style();

   275         if (!style || style->display() == NONE || style->visibility() != VISIBLE)

   276              continue;

   277         m_clipBoundaries.unite(renderer->localToParentTransform().mapRect(renderer->repaintRectInLocalCoordinates()));

   278     }

   279 }

   280 

   281 bool RenderSVGResourceClipper::hitTestClipContent(const FloatRect& objectBoundingBox, const FloatPoint& nodeAtPoint)

   282 {

   283     // FIXME: We should be able to check whether m_clipper.contains(object) - this doesn't work at the moment

   284     // as resourceBoundingBox() has already created ClipperData, even if applyResource() returned false.

   285     // Early exit, if this resource contains a child which references ourselves.

   286     if (containsCyclicReference(node()))

   287         return false;

   288 

   289     FloatPoint point = nodeAtPoint;

   290     if (!SVGRenderSupport::pointInClippingArea(this, point))

   291         return false;

   292 

   293     if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

   294         AffineTransform transform;

   295         transform.translate(objectBoundingBox.x(), objectBoundingBox.y());

   296         transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());

   297         point = transform.inverse().mapPoint(point);

   298     }

   299 

   300     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

   301         RenderObject* renderer = childNode->renderer();

   302         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)

   303             continue;

   304         if (!renderer->isRenderPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())

   305             continue;

   306         IntPoint hitPoint;

   307         HitTestResult result(hitPoint);

   308         if (renderer->nodeAtFloatPoint(HitTestRequest(HitTestRequest::SVGClipContent), result, point, HitTestForeground))

   309             return true;

   310     }

   311 

   312     return false;

   313 }

   314 

   315 bool RenderSVGResourceClipper::childElementReferencesResource(const SVGRenderStyle* style, const String& referenceId) const

   316 {

   317     if (!style->hasClipper())

   318         return false;

   319 

   320     return style->clipperResource() == referenceId;

   321 }

   322 

   323 FloatRect RenderSVGResourceClipper::resourceBoundingBox(RenderObject* object)

   324 {

   325     // Resource was not layouted yet. Give back the boundingBox of the object.

   326     if (selfNeedsLayout())

   327         return object->objectBoundingBox();

   328     

   329     if (m_clipBoundaries.isEmpty())

   330         calculateClipContentRepaintRect();

   331 

   332     if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

   333         FloatRect objectBoundingBox = object->objectBoundingBox();

   334         AffineTransform transform;

   335         transform.translate(objectBoundingBox.x(), objectBoundingBox.y());

   336         transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());

   337         return transform.mapRect(m_clipBoundaries);

   338     }

   339 

   340     return m_clipBoundaries;

   341 }

   342 

   343 }

   344 

   345 #endif // ENABLE(SVG)