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      1 /*
      2  * Copyright (C) 2007, 2008 Rob Buis <buis (at) kde.org>
      3  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann (at) kde.org>
      4  * Copyright (C) 2007 Eric Seidel <eric (at) webkit.org>
      5  * Copyright (C) 2009 Google, Inc.  All rights reserved.
      6  * Copyright (C) 2009 Dirk Schulze <krit (at) webkit.org>
      7  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
      8  *
      9  * This library is free software; you can redistribute it and/or
     10  * modify it under the terms of the GNU Library General Public
     11  * License as published by the Free Software Foundation; either
     12  * version 2 of the License, or (at your option) any later version.
     13  *
     14  * This library is distributed in the hope that it will be useful,
     15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     17  * Library General Public License for more details.
     18  *
     19  * You should have received a copy of the GNU Library General Public License
     20  * along with this library; see the file COPYING.LIB.  If not, write to
     21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     22  * Boston, MA 02110-1301, USA.
     23  */
     24 
     25 #include "config.h"
     26 
     27 #include "core/rendering/svg/SVGRenderingContext.h"
     28 
     29 #include "core/frame/Frame.h"
     30 #include "core/frame/FrameView.h"
     31 #include "core/page/Page.h"
     32 #include "core/rendering/RenderLayer.h"
     33 #include "core/rendering/svg/RenderSVGImage.h"
     34 #include "core/rendering/svg/RenderSVGResource.h"
     35 #include "core/rendering/svg/RenderSVGResourceFilter.h"
     36 #include "core/rendering/svg/RenderSVGResourceMasker.h"
     37 #include "core/rendering/svg/SVGResources.h"
     38 #include "core/rendering/svg/SVGResourcesCache.h"
     39 
     40 static int kMaxImageBufferSize = 4096;
     41 
     42 namespace WebCore {
     43 
     44 static inline bool isRenderingMaskImage(RenderObject* object)
     45 {
     46     if (object->frame() && object->frame()->view())
     47         return object->frame()->view()->paintBehavior() & PaintBehaviorRenderingSVGMask;
     48     return false;
     49 }
     50 
     51 SVGRenderingContext::~SVGRenderingContext()
     52 {
     53     // Fast path if we don't need to restore anything.
     54     if (!(m_renderingFlags & ActionsNeeded))
     55         return;
     56 
     57     ASSERT(m_object && m_paintInfo);
     58 
     59     if (m_renderingFlags & PostApplyResources) {
     60         ASSERT(m_masker || m_clipper || m_filter);
     61         ASSERT(SVGResourcesCache::cachedResourcesForRenderObject(m_object));
     62 
     63         if (m_filter) {
     64             ASSERT(SVGResourcesCache::cachedResourcesForRenderObject(m_object)->filter() == m_filter);
     65             m_filter->postApplyResource(m_object, m_paintInfo->context, ApplyToDefaultMode, 0, 0);
     66             m_paintInfo->context = m_savedContext;
     67             m_paintInfo->rect = m_savedPaintRect;
     68         }
     69 
     70         if (m_clipper) {
     71             ASSERT(SVGResourcesCache::cachedResourcesForRenderObject(m_object)->clipper() == m_clipper);
     72             m_clipper->postApplyStatefulResource(m_object, m_paintInfo->context, m_clipperContext);
     73         }
     74 
     75         if (m_masker) {
     76             ASSERT(SVGResourcesCache::cachedResourcesForRenderObject(m_object)->masker() == m_masker);
     77             m_masker->postApplyResource(m_object, m_paintInfo->context, ApplyToDefaultMode, 0, 0);
     78         }
     79     }
     80 
     81     if (m_renderingFlags & EndOpacityLayer)
     82         m_paintInfo->context->endLayer();
     83 
     84     if (m_renderingFlags & RestoreGraphicsContext)
     85         m_paintInfo->context->restore();
     86 }
     87 
     88 void SVGRenderingContext::prepareToRenderSVGContent(RenderObject* object, PaintInfo& paintInfo, NeedsGraphicsContextSave needsGraphicsContextSave)
     89 {
     90     ASSERT(object);
     91 
     92 #ifndef NDEBUG
     93     // This function must not be called twice!
     94     ASSERT(!(m_renderingFlags & PrepareToRenderSVGContentWasCalled));
     95     m_renderingFlags |= PrepareToRenderSVGContentWasCalled;
     96 #endif
     97 
     98     m_object = object;
     99     m_paintInfo = &paintInfo;
    100     m_filter = 0;
    101 
    102     // We need to save / restore the context even if the initialization failed.
    103     if (needsGraphicsContextSave == SaveGraphicsContext) {
    104         m_paintInfo->context->save();
    105         m_renderingFlags |= RestoreGraphicsContext;
    106     }
    107 
    108     RenderStyle* style = m_object->style();
    109     ASSERT(style);
    110 
    111     const SVGRenderStyle* svgStyle = style->svgStyle();
    112     ASSERT(svgStyle);
    113 
    114     // Setup transparency layers before setting up SVG resources!
    115     bool isRenderingMask = isRenderingMaskImage(m_object);
    116     float opacity = isRenderingMask ? 1 : style->opacity();
    117     blink::WebBlendMode blendMode = isRenderingMask ? blink::WebBlendModeNormal : style->blendMode();
    118     if (opacity < 1 || blendMode != blink::WebBlendModeNormal) {
    119         FloatRect repaintRect = m_object->repaintRectInLocalCoordinates();
    120 
    121         if (opacity < 1 || blendMode != blink::WebBlendModeNormal) {
    122             m_paintInfo->context->clip(repaintRect);
    123             if (blendMode != blink::WebBlendModeNormal) {
    124                 if (!(m_renderingFlags & RestoreGraphicsContext)) {
    125                     m_paintInfo->context->save();
    126                     m_renderingFlags |= RestoreGraphicsContext;
    127                 }
    128                 m_paintInfo->context->setCompositeOperation(CompositeSourceOver, blendMode);
    129             }
    130             m_paintInfo->context->beginTransparencyLayer(opacity);
    131             m_renderingFlags |= EndOpacityLayer;
    132         }
    133     }
    134 
    135     ClipPathOperation* clipPathOperation = style->clipPath();
    136     if (clipPathOperation && clipPathOperation->type() == ClipPathOperation::SHAPE) {
    137         ShapeClipPathOperation* clipPath = toShapeClipPathOperation(clipPathOperation);
    138         m_paintInfo->context->clipPath(clipPath->path(object->objectBoundingBox()), clipPath->windRule());
    139     }
    140 
    141     SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(m_object);
    142     if (!resources) {
    143         if (svgStyle->hasFilter())
    144             return;
    145 
    146         m_renderingFlags |= RenderingPrepared;
    147         return;
    148     }
    149 
    150     if (!isRenderingMask) {
    151         if (RenderSVGResourceMasker* masker = resources->masker()) {
    152             if (!masker->applyResource(m_object, style, m_paintInfo->context, ApplyToDefaultMode))
    153                 return;
    154             m_masker = masker;
    155             m_renderingFlags |= PostApplyResources;
    156         }
    157     }
    158 
    159     RenderSVGResourceClipper* clipper = resources->clipper();
    160     if (!clipPathOperation && clipper) {
    161         if (!clipper->applyStatefulResource(m_object, m_paintInfo->context, m_clipperContext))
    162             return;
    163         m_clipper = clipper;
    164         m_renderingFlags |= PostApplyResources;
    165     }
    166 
    167     if (!isRenderingMask) {
    168         m_filter = resources->filter();
    169         if (m_filter) {
    170             m_savedContext = m_paintInfo->context;
    171             m_savedPaintRect = m_paintInfo->rect;
    172             // Return with false here may mean that we don't need to draw the content
    173             // (because it was either drawn before or empty) but we still need to apply the filter.
    174             m_renderingFlags |= PostApplyResources;
    175             if (!m_filter->applyResource(m_object, style, m_paintInfo->context, ApplyToDefaultMode))
    176                 return;
    177 
    178             // Since we're caching the resulting bitmap and do not invalidate it on repaint rect
    179             // changes, we need to paint the whole filter region. Otherwise, elements not visible
    180             // at the time of the initial paint (due to scrolling, window size, etc.) will never
    181             // be drawn.
    182             m_paintInfo->rect = IntRect(m_filter->drawingRegion(m_object));
    183         }
    184     }
    185 
    186     m_renderingFlags |= RenderingPrepared;
    187 }
    188 
    189 static AffineTransform& currentContentTransformation()
    190 {
    191     DEFINE_STATIC_LOCAL(AffineTransform, s_currentContentTransformation, ());
    192     return s_currentContentTransformation;
    193 }
    194 
    195 float SVGRenderingContext::calculateScreenFontSizeScalingFactor(const RenderObject* renderer)
    196 {
    197     ASSERT(renderer);
    198 
    199     AffineTransform ctm;
    200     calculateTransformationToOutermostCoordinateSystem(renderer, ctm);
    201     return narrowPrecisionToFloat(sqrt((pow(ctm.xScale(), 2) + pow(ctm.yScale(), 2)) / 2));
    202 }
    203 
    204 void SVGRenderingContext::calculateTransformationToOutermostCoordinateSystem(const RenderObject* renderer, AffineTransform& absoluteTransform)
    205 {
    206     ASSERT(renderer);
    207     absoluteTransform = currentContentTransformation();
    208 
    209     float deviceScaleFactor = 1;
    210     if (Page* page = renderer->document().page())
    211         deviceScaleFactor = page->deviceScaleFactor();
    212 
    213     // Walk up the render tree, accumulating SVG transforms.
    214     while (renderer) {
    215         absoluteTransform = renderer->localToParentTransform() * absoluteTransform;
    216         if (renderer->isSVGRoot())
    217             break;
    218         renderer = renderer->parent();
    219     }
    220 
    221     // Continue walking up the layer tree, accumulating CSS transforms.
    222     RenderLayer* layer = renderer ? renderer->enclosingLayer() : 0;
    223     while (layer) {
    224         if (TransformationMatrix* layerTransform = layer->transform())
    225             absoluteTransform = layerTransform->toAffineTransform() * absoluteTransform;
    226 
    227         // We can stop at compositing layers, to match the backing resolution.
    228         // FIXME: should we be computing the transform to the nearest composited layer,
    229         // or the nearest composited layer that does not paint into its ancestor?
    230         // I think this is the nearest composited ancestor since we will inherit its
    231         // transforms in the composited layer tree.
    232         if (layer->hasCompositedLayerMapping())
    233             break;
    234 
    235         layer = layer->parent();
    236     }
    237 
    238     if (deviceScaleFactor != 1)
    239         absoluteTransform.scale(deviceScaleFactor);
    240 }
    241 
    242 void SVGRenderingContext::renderSubtree(GraphicsContext* context, RenderObject* item, const AffineTransform& subtreeContentTransformation)
    243 {
    244     ASSERT(item);
    245     ASSERT(context);
    246 
    247     PaintInfo info(context, PaintInfo::infiniteRect(), PaintPhaseForeground, PaintBehaviorNormal);
    248 
    249     AffineTransform& contentTransformation = currentContentTransformation();
    250     AffineTransform savedContentTransformation = contentTransformation;
    251     contentTransformation = subtreeContentTransformation * contentTransformation;
    252 
    253     ASSERT(!item->needsLayout());
    254     item->paint(info, IntPoint());
    255 
    256     contentTransformation = savedContentTransformation;
    257 }
    258 
    259 FloatRect SVGRenderingContext::clampedAbsoluteTargetRect(const FloatRect& absoluteTargetRect)
    260 {
    261     const FloatSize maxImageBufferSize(kMaxImageBufferSize, kMaxImageBufferSize);
    262     return FloatRect(absoluteTargetRect.location(), absoluteTargetRect.size().shrunkTo(maxImageBufferSize));
    263 }
    264 
    265 void SVGRenderingContext::clear2DRotation(AffineTransform& transform)
    266 {
    267     AffineTransform::DecomposedType decomposition;
    268     transform.decompose(decomposition);
    269     decomposition.angle = 0;
    270     transform.recompose(decomposition);
    271 }
    272 
    273 bool SVGRenderingContext::bufferForeground(OwnPtr<ImageBuffer>& imageBuffer)
    274 {
    275     ASSERT(m_paintInfo);
    276     ASSERT(m_object->isSVGImage());
    277     FloatRect boundingBox = m_object->objectBoundingBox();
    278 
    279     // Invalidate an existing buffer if the scale is not correct.
    280     if (imageBuffer) {
    281         AffineTransform transform = m_paintInfo->context->getCTM(GraphicsContext::DefinitelyIncludeDeviceScale);
    282         IntSize expandedBoundingBox = expandedIntSize(boundingBox.size());
    283         IntSize bufferSize(static_cast<int>(ceil(expandedBoundingBox.width() * transform.xScale())), static_cast<int>(ceil(expandedBoundingBox.height() * transform.yScale())));
    284         if (bufferSize != imageBuffer->size())
    285             imageBuffer.clear();
    286     }
    287 
    288     // Create a new buffer and paint the foreground into it.
    289     if (!imageBuffer) {
    290         if ((imageBuffer = m_paintInfo->context->createCompatibleBuffer(expandedIntSize(boundingBox.size())))) {
    291             GraphicsContext* bufferedRenderingContext = imageBuffer->context();
    292             bufferedRenderingContext->translate(-boundingBox.x(), -boundingBox.y());
    293             PaintInfo bufferedInfo(*m_paintInfo);
    294             bufferedInfo.context = bufferedRenderingContext;
    295             toRenderSVGImage(m_object)->paintForeground(bufferedInfo);
    296         } else
    297             return false;
    298     }
    299 
    300     m_paintInfo->context->drawImageBuffer(imageBuffer.get(), boundingBox);
    301     return true;
    302 }
    303 
    304 }
    305