1 /*
2  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
3  * Copyright (C) 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 #include "config.h"
23 
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 "RenderSVGResource.h"
36 #include "RenderStyle.h"
37 #include "SVGClipPathElement.h"
38 #include "SVGElement.h"
39 #include "SVGImageBufferTools.h"
40 #include "SVGNames.h"
41 #include "SVGRenderSupport.h"
42 #include "SVGResources.h"
43 #include "SVGStyledElement.h"
44 #include "SVGStyledTransformableElement.h"
45 #include "SVGUnitTypes.h"
46 #include "SVGUseElement.h"
47 #include <wtf/UnusedParam.h>
48 
49 namespace WebCore {
50 
51 RenderSVGResourceType RenderSVGResourceClipper::s_resourceType = ClipperResourceType;
52 
RenderSVGResourceClipper(SVGClipPathElement * node)53 RenderSVGResourceClipper::RenderSVGResourceClipper(SVGClipPathElement* node)
54     : RenderSVGResourceContainer(node)
55     , m_invalidationBlocked(false)
56 {
57 }
58 
~RenderSVGResourceClipper()59 RenderSVGResourceClipper::~RenderSVGResourceClipper()
60 {
61     if (m_clipper.isEmpty())
62         return;
63 
64     deleteAllValues(m_clipper);
65     m_clipper.clear();
66 }
67 
removeAllClientsFromCache(bool markForInvalidation)68 void RenderSVGResourceClipper::removeAllClientsFromCache(bool markForInvalidation)
69 {
70     if (m_invalidationBlocked)
71         return;
72 
73     m_clipBoundaries = FloatRect();
74     if (!m_clipper.isEmpty()) {
75         deleteAllValues(m_clipper);
76         m_clipper.clear();
77     }
78 
79     markAllClientsForInvalidation(markForInvalidation ? LayoutAndBoundariesInvalidation : ParentOnlyInvalidation);
80 }
81 
removeClientFromCache(RenderObject * client,bool markForInvalidation)82 void RenderSVGResourceClipper::removeClientFromCache(RenderObject* client, bool markForInvalidation)
83 {
84     ASSERT(client);
85     if (m_invalidationBlocked)
86         return;
87 
88     if (m_clipper.contains(client))
89         delete m_clipper.take(client);
90 
91     markClientForInvalidation(client, markForInvalidation ? BoundariesInvalidation : ParentOnlyInvalidation);
92 }
93 
applyResource(RenderObject * object,RenderStyle *,GraphicsContext * & context,unsigned short resourceMode)94 bool RenderSVGResourceClipper::applyResource(RenderObject* object, RenderStyle*, GraphicsContext*& context, unsigned short resourceMode)
95 {
96     ASSERT(object);
97     ASSERT(context);
98 #ifndef NDEBUG
99     ASSERT(resourceMode == ApplyToDefaultMode);
100 #else
101     UNUSED_PARAM(resourceMode);
102 #endif
103 
104     return applyClippingToContext(object, object->objectBoundingBox(), object->repaintRectInLocalCoordinates(), context);
105 }
106 
pathOnlyClipping(GraphicsContext * context,const FloatRect & objectBoundingBox)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             styled->toClipPath(clipPath);
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->clipPath(clipPath, clipRule);
155     return true;
156 }
157 
applyClippingToContext(RenderObject * object,const FloatRect & objectBoundingBox,const FloatRect & repaintRect,GraphicsContext * context)158 bool RenderSVGResourceClipper::applyClippingToContext(RenderObject* object, const FloatRect& objectBoundingBox,
159                                                       const FloatRect& repaintRect, GraphicsContext* context)
160 {
161     if (!m_clipper.contains(object))
162         m_clipper.set(object, new ClipperData);
163 
164     bool shouldCreateClipData = false;
165     ClipperData* clipperData = m_clipper.get(object);
166     if (!clipperData->clipMaskImage) {
167         if (pathOnlyClipping(context, objectBoundingBox))
168             return true;
169         shouldCreateClipData = true;
170     }
171 
172     AffineTransform absoluteTransform;
173     SVGImageBufferTools::calculateTransformationToOutermostSVGCoordinateSystem(object, absoluteTransform);
174 
175     FloatRect absoluteTargetRect = absoluteTransform.mapRect(repaintRect);
176     FloatRect clampedAbsoluteTargetRect = SVGImageBufferTools::clampedAbsoluteTargetRectForRenderer(object, absoluteTargetRect);
177 
178     if (shouldCreateClipData && !clampedAbsoluteTargetRect.isEmpty()) {
179         if (!SVGImageBufferTools::createImageBuffer(absoluteTargetRect, clampedAbsoluteTargetRect, clipperData->clipMaskImage, ColorSpaceDeviceRGB))
180             return false;
181 
182         GraphicsContext* maskContext = clipperData->clipMaskImage->context();
183         ASSERT(maskContext);
184 
185         // The save/restore pair is needed for clipToImageBuffer - it doesn't work without it on non-Cg platforms.
186         GraphicsContextStateSaver stateSaver(*maskContext);
187         maskContext->translate(-clampedAbsoluteTargetRect.x(), -clampedAbsoluteTargetRect.y());
188         maskContext->concatCTM(absoluteTransform);
189 
190         // clipPath can also be clipped by another clipPath.
191         if (SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(this)) {
192             if (RenderSVGResourceClipper* clipper = resources->clipper()) {
193                 if (!clipper->applyClippingToContext(this, objectBoundingBox, repaintRect, maskContext))
194                     return false;
195             }
196         }
197 
198         drawContentIntoMaskImage(clipperData, objectBoundingBox);
199     }
200 
201     if (!clipperData->clipMaskImage)
202         return false;
203 
204     SVGImageBufferTools::clipToImageBuffer(context, absoluteTransform, clampedAbsoluteTargetRect, clipperData->clipMaskImage);
205     return true;
206 }
207 
drawContentIntoMaskImage(ClipperData * clipperData,const FloatRect & objectBoundingBox)208 bool RenderSVGResourceClipper::drawContentIntoMaskImage(ClipperData* clipperData, const FloatRect& objectBoundingBox)
209 {
210     ASSERT(clipperData);
211     ASSERT(clipperData->clipMaskImage);
212 
213     GraphicsContext* maskContext = clipperData->clipMaskImage->context();
214     ASSERT(maskContext);
215 
216     AffineTransform maskContentTransformation;
217     SVGClipPathElement* clipPath = static_cast<SVGClipPathElement*>(node());
218     if (clipPath->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
219         maskContentTransformation.translate(objectBoundingBox.x(), objectBoundingBox.y());
220         maskContentTransformation.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
221         maskContext->concatCTM(maskContentTransformation);
222     }
223 
224     // Draw all clipPath children into a global mask.
225     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
226         RenderObject* renderer = childNode->renderer();
227         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)
228             continue;
229         RenderStyle* style = renderer->style();
230         if (!style || style->display() == NONE || style->visibility() != VISIBLE)
231             continue;
232 
233         WindRule newClipRule = style->svgStyle()->clipRule();
234         bool isUseElement = renderer->isSVGShadowTreeRootContainer();
235         if (isUseElement) {
236             SVGUseElement* useElement = static_cast<SVGUseElement*>(childNode);
237             renderer = useElement->rendererClipChild();
238             if (!renderer)
239                 continue;
240             if (!useElement->hasAttribute(SVGNames::clip_ruleAttr))
241                 newClipRule = renderer->style()->svgStyle()->clipRule();
242         }
243 
244         // Only shapes, paths and texts are allowed for clipping.
245         if (!renderer->isSVGPath() && !renderer->isSVGText())
246             continue;
247 
248         // Save the old RenderStyle of the current object for restoring after drawing
249         // it to the MaskImage. The new intermediate RenderStyle needs to inherit from
250         // the old one.
251         RefPtr<RenderStyle> oldRenderStyle = renderer->style();
252         RefPtr<RenderStyle> newRenderStyle = RenderStyle::clone(oldRenderStyle.get());
253         SVGRenderStyle* svgStyle = newRenderStyle.get()->accessSVGStyle();
254         svgStyle->setFillPaint(SVGRenderStyle::initialFillPaintType(), SVGRenderStyle::initialFillPaintColor(), SVGRenderStyle::initialFillPaintUri());
255         svgStyle->setStrokePaint(SVGRenderStyle::initialStrokePaintType(), SVGRenderStyle::initialStrokePaintColor(), SVGRenderStyle::initialStrokePaintUri());
256         svgStyle->setFillRule(newClipRule);
257         newRenderStyle.get()->setOpacity(1.0f);
258         svgStyle->setFillOpacity(1.0f);
259         svgStyle->setStrokeOpacity(1.0f);
260         svgStyle->setFilterResource(String());
261         svgStyle->setMaskerResource(String());
262 
263         // The setStyle() call results in a styleDidChange() call, which in turn invalidations the resources.
264         // As we're mutating the resource on purpose, block updates until we've resetted the style again.
265         m_invalidationBlocked = true;
266         renderer->setStyle(newRenderStyle.release());
267 
268         // In the case of a <use> element, we obtained its renderere above, to retrieve its clipRule.
269         // We have to pass the <use> renderer itself to renderSubtreeToImageBuffer() to apply it's x/y/transform/etc. values when rendering.
270         // So if isUseElement is true, refetch the childNode->renderer(), as renderer got overriden above.
271         SVGImageBufferTools::renderSubtreeToImageBuffer(clipperData->clipMaskImage.get(), isUseElement ? childNode->renderer() : renderer, maskContentTransformation);
272 
273         renderer->setStyle(oldRenderStyle.release());
274         m_invalidationBlocked = false;
275     }
276 
277     return true;
278 }
279 
calculateClipContentRepaintRect()280 void RenderSVGResourceClipper::calculateClipContentRepaintRect()
281 {
282     // This is a rough heuristic to appraise the clip size and doesn't consider clip on clip.
283     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
284         RenderObject* renderer = childNode->renderer();
285         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)
286             continue;
287         if (!renderer->isSVGPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())
288             continue;
289         RenderStyle* style = renderer->style();
290         if (!style || style->display() == NONE || style->visibility() != VISIBLE)
291              continue;
292         m_clipBoundaries.unite(renderer->localToParentTransform().mapRect(renderer->repaintRectInLocalCoordinates()));
293     }
294 }
295 
hitTestClipContent(const FloatRect & objectBoundingBox,const FloatPoint & nodeAtPoint)296 bool RenderSVGResourceClipper::hitTestClipContent(const FloatRect& objectBoundingBox, const FloatPoint& nodeAtPoint)
297 {
298     FloatPoint point = nodeAtPoint;
299     if (!SVGRenderSupport::pointInClippingArea(this, point))
300         return false;
301 
302     if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
303         AffineTransform transform;
304         transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
305         transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
306         point = transform.inverse().mapPoint(point);
307     }
308 
309     for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
310         RenderObject* renderer = childNode->renderer();
311         if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)
312             continue;
313         if (!renderer->isSVGPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())
314             continue;
315         IntPoint hitPoint;
316         HitTestResult result(hitPoint);
317         if (renderer->nodeAtFloatPoint(HitTestRequest(HitTestRequest::SVGClipContent), result, point, HitTestForeground))
318             return true;
319     }
320 
321     return false;
322 }
323 
resourceBoundingBox(RenderObject * object)324 FloatRect RenderSVGResourceClipper::resourceBoundingBox(RenderObject* object)
325 {
326     // Resource was not layouted yet. Give back the boundingBox of the object.
327     if (selfNeedsLayout())
328         return object->objectBoundingBox();
329 
330     if (m_clipBoundaries.isEmpty())
331         calculateClipContentRepaintRect();
332 
333     if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
334         FloatRect objectBoundingBox = object->objectBoundingBox();
335         AffineTransform transform;
336         transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
337         transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
338         return transform.mapRect(m_clipBoundaries);
339     }
340 
341     return m_clipBoundaries;
342 }
343 
344 }
345 
346 #endif // ENABLE(SVG)
347