1/*
2 * Copyright (C) 2007, 2008 Rob Buis <buis@kde.org>
3 * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
4 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
5 * Copyright (C) 2009 Google, Inc.  All rights reserved.
6 * Copyright (C) 2009 Dirk Schulze <krit@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#include "SVGRenderingContext.h"
27
28#include "BasicShapes.h"
29#include "Frame.h"
30#include "FrameView.h"
31#include "Page.h"
32#include "RenderLayer.h"
33#include "RenderSVGImage.h"
34#include "RenderSVGResourceClipper.h"
35#include "RenderSVGResourceFilter.h"
36#include "RenderSVGResourceMasker.h"
37#include "RenderView.h"
38#include "SVGLengthContext.h"
39#include "SVGResources.h"
40#include "SVGResourcesCache.h"
41
42static int kMaxImageBufferSize = 4096;
43
44namespace WebCore {
45
46static inline bool isRenderingMaskImage(const RenderObject& object)
47{
48    return object.view().frameView().paintBehavior() & PaintBehaviorRenderingSVGMask;
49}
50
51SVGRenderingContext::~SVGRenderingContext()
52{
53    // Fast path if we don't need to restore anything.
54    if (!(m_renderingFlags & ActionsNeeded))
55        return;
56
57    ASSERT(m_renderer && m_paintInfo);
58
59#if ENABLE(FILTERS)
60    if (m_renderingFlags & EndFilterLayer) {
61        ASSERT(m_filter);
62        m_filter->postApplyResource(*m_renderer, m_paintInfo->context, ApplyToDefaultMode, 0, 0);
63        m_paintInfo->context = m_savedContext;
64        m_paintInfo->rect = m_savedPaintRect;
65    }
66#endif
67
68    if (m_renderingFlags & EndOpacityLayer)
69        m_paintInfo->context->endTransparencyLayer();
70
71    if (m_renderingFlags & EndShadowLayer)
72        m_paintInfo->context->endTransparencyLayer();
73
74    if (m_renderingFlags & RestoreGraphicsContext)
75        m_paintInfo->context->restore();
76}
77
78void SVGRenderingContext::prepareToRenderSVGContent(RenderElement& renderer, PaintInfo& paintInfo, NeedsGraphicsContextSave needsGraphicsContextSave)
79{
80#ifndef NDEBUG
81    // This function must not be called twice!
82    ASSERT(!(m_renderingFlags & PrepareToRenderSVGContentWasCalled));
83    m_renderingFlags |= PrepareToRenderSVGContentWasCalled;
84#endif
85
86    m_renderer = &renderer;
87    m_paintInfo = &paintInfo;
88#if ENABLE(FILTERS)
89    m_filter = 0;
90#endif
91
92    // We need to save / restore the context even if the initialization failed.
93    if (needsGraphicsContextSave == SaveGraphicsContext) {
94        m_paintInfo->context->save();
95        m_renderingFlags |= RestoreGraphicsContext;
96    }
97
98    RenderStyle& style = m_renderer->style();
99
100    const SVGRenderStyle& svgStyle = style.svgStyle();
101
102    // Setup transparency layers before setting up SVG resources!
103    bool isRenderingMask = isRenderingMaskImage(*m_renderer);
104    // RenderLayer takes care of root opacity.
105    float opacity = (renderer.isSVGRoot() || isRenderingMask) ? 1 : style.opacity();
106    const ShadowData* shadow = svgStyle.shadow();
107    bool hasBlendMode = style.hasBlendMode();
108    bool hasIsolation = style.hasIsolation();
109    bool isolateMaskForBlending = false;
110
111#if ENABLE(CSS_COMPOSITING)
112    if (svgStyle.hasMasker() && toSVGElement(renderer.element())->isSVGGraphicsElement()) {
113        SVGGraphicsElement& graphicsElement = *toSVGGraphicsElement(renderer.element());
114        isolateMaskForBlending = graphicsElement.shouldIsolateBlending();
115    }
116#endif
117
118    if (opacity < 1 || shadow || hasBlendMode || isolateMaskForBlending || hasIsolation) {
119        FloatRect repaintRect = m_renderer->repaintRectInLocalCoordinates();
120        m_paintInfo->context->clip(repaintRect);
121
122        if (opacity < 1 || hasBlendMode || isolateMaskForBlending || hasIsolation) {
123
124            if (hasBlendMode)
125                m_paintInfo->context->setCompositeOperation(m_paintInfo->context->compositeOperation(), style.blendMode());
126
127            m_paintInfo->context->beginTransparencyLayer(opacity);
128
129            if (hasBlendMode)
130                m_paintInfo->context->setCompositeOperation(m_paintInfo->context->compositeOperation(), BlendModeNormal);
131
132            m_renderingFlags |= EndOpacityLayer;
133        }
134
135        if (shadow) {
136            m_paintInfo->context->setShadow(IntSize(roundToInt(shadow->x()), roundToInt(shadow->y())), shadow->radius(), shadow->color(), style.colorSpace());
137            m_paintInfo->context->beginTransparencyLayer(1);
138            m_renderingFlags |= EndShadowLayer;
139        }
140    }
141
142    ClipPathOperation* clipPathOperation = style.clipPath();
143    if (clipPathOperation && clipPathOperation->type() == ClipPathOperation::Shape) {
144        ShapeClipPathOperation& clipPath = toShapeClipPathOperation(*clipPathOperation);
145        FloatRect referenceBox;
146        if (clipPath.referenceBox() == Stroke)
147            // FIXME: strokeBoundingBox() takes dasharray into account but shouldn't.
148            referenceBox = renderer.strokeBoundingBox();
149        else if (clipPath.referenceBox() == ViewBox && renderer.element()) {
150            FloatSize viewportSize;
151            SVGLengthContext(toSVGElement(renderer.element())).determineViewport(viewportSize);
152            referenceBox.setWidth(viewportSize.width());
153            referenceBox.setHeight(viewportSize.height());
154        } else
155            referenceBox = renderer.objectBoundingBox();
156        m_paintInfo->context->clipPath(clipPath.pathForReferenceRect(referenceBox), clipPath.windRule());
157    }
158
159    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(*m_renderer);
160    if (!resources) {
161#if ENABLE(FILTERS)
162        if (svgStyle.hasFilter())
163            return;
164#endif
165        m_renderingFlags |= RenderingPrepared;
166        return;
167    }
168
169    if (!isRenderingMask) {
170        if (RenderSVGResourceMasker* masker = resources->masker()) {
171            if (!masker->applyResource(*m_renderer, style, m_paintInfo->context, ApplyToDefaultMode))
172                return;
173        }
174    }
175
176    RenderSVGResourceClipper* clipper = resources->clipper();
177    if (!clipPathOperation && clipper) {
178        if (!clipper->applyResource(*m_renderer, style, m_paintInfo->context, ApplyToDefaultMode))
179            return;
180    }
181
182#if ENABLE(FILTERS)
183    if (!isRenderingMask) {
184        m_filter = resources->filter();
185        if (m_filter) {
186            m_savedContext = m_paintInfo->context;
187            m_savedPaintRect = m_paintInfo->rect;
188            // Return with false here may mean that we don't need to draw the content
189            // (because it was either drawn before or empty) but we still need to apply the filter.
190            m_renderingFlags |= EndFilterLayer;
191            if (!m_filter->applyResource(*m_renderer, style, m_paintInfo->context, ApplyToDefaultMode))
192                return;
193
194            // Since we're caching the resulting bitmap and do not invalidate it on repaint rect
195            // changes, we need to paint the whole filter region. Otherwise, elements not visible
196            // at the time of the initial paint (due to scrolling, window size, etc.) will never
197            // be drawn.
198            m_paintInfo->rect = IntRect(m_filter->drawingRegion(m_renderer));
199        }
200    }
201#endif
202
203    m_renderingFlags |= RenderingPrepared;
204}
205
206static AffineTransform& currentContentTransformation()
207{
208    DEPRECATED_DEFINE_STATIC_LOCAL(AffineTransform, s_currentContentTransformation, ());
209    return s_currentContentTransformation;
210}
211
212float SVGRenderingContext::calculateScreenFontSizeScalingFactor(const RenderObject& renderer)
213{
214    AffineTransform ctm;
215    calculateTransformationToOutermostCoordinateSystem(renderer, ctm);
216    return narrowPrecisionToFloat(sqrt((pow(ctm.xScale(), 2) + pow(ctm.yScale(), 2)) / 2));
217}
218
219void SVGRenderingContext::calculateTransformationToOutermostCoordinateSystem(const RenderObject& renderer, AffineTransform& absoluteTransform)
220{
221    absoluteTransform = currentContentTransformation();
222
223    float deviceScaleFactor = renderer.document().deviceScaleFactor();
224    // Walk up the render tree, accumulating SVG transforms.
225    const RenderObject* ancestor = &renderer;
226    while (ancestor) {
227        absoluteTransform = ancestor->localToParentTransform() * absoluteTransform;
228        if (ancestor->isSVGRoot())
229            break;
230        ancestor = ancestor->parent();
231    }
232
233    // Continue walking up the layer tree, accumulating CSS transforms.
234    RenderLayer* layer = ancestor ? ancestor->enclosingLayer() : nullptr;
235    while (layer) {
236        if (TransformationMatrix* layerTransform = layer->transform())
237            absoluteTransform = layerTransform->toAffineTransform() * absoluteTransform;
238
239        // We can stop at compositing layers, to match the backing resolution.
240        if (layer->isComposited())
241            break;
242
243        layer = layer->parent();
244    }
245
246    absoluteTransform.scale(deviceScaleFactor);
247}
248
249bool SVGRenderingContext::createImageBuffer(const FloatRect& targetRect, const AffineTransform& absoluteTransform, std::unique_ptr<ImageBuffer>& imageBuffer, ColorSpace colorSpace, RenderingMode renderingMode)
250{
251    IntRect paintRect = calculateImageBufferRect(targetRect, absoluteTransform);
252    // Don't create empty ImageBuffers.
253    if (paintRect.isEmpty())
254        return false;
255
256    IntSize clampedSize = clampedAbsoluteSize(paintRect.size());
257    std::unique_ptr<ImageBuffer> image = ImageBuffer::create(clampedSize, 1, colorSpace, renderingMode);
258    if (!image)
259        return false;
260
261    GraphicsContext* imageContext = image->context();
262    ASSERT(imageContext);
263
264    imageContext->scale(FloatSize(static_cast<float>(clampedSize.width()) / paintRect.width(),
265                                  static_cast<float>(clampedSize.height()) / paintRect.height()));
266    imageContext->translate(-paintRect.x(), -paintRect.y());
267    imageContext->concatCTM(absoluteTransform);
268
269    imageBuffer = WTF::move(image);
270    return true;
271}
272
273bool SVGRenderingContext::createImageBufferForPattern(const FloatRect& absoluteTargetRect, const FloatRect& clampedAbsoluteTargetRect, std::unique_ptr<ImageBuffer>& imageBuffer, ColorSpace colorSpace, RenderingMode renderingMode)
274{
275    IntSize imageSize(roundedIntSize(clampedAbsoluteTargetRect.size()));
276    IntSize unclampedImageSize(roundedIntSize(absoluteTargetRect.size()));
277
278    // Don't create empty ImageBuffers.
279    if (imageSize.isEmpty())
280        return false;
281
282    std::unique_ptr<ImageBuffer> image = ImageBuffer::create(imageSize, 1, colorSpace, renderingMode);
283    if (!image)
284        return false;
285
286    GraphicsContext* imageContext = image->context();
287    ASSERT(imageContext);
288
289    // Compensate rounding effects, as the absolute target rect is using floating-point numbers and the image buffer size is integer.
290    imageContext->scale(FloatSize(unclampedImageSize.width() / absoluteTargetRect.width(), unclampedImageSize.height() / absoluteTargetRect.height()));
291
292    imageBuffer = WTF::move(image);
293    return true;
294}
295
296void SVGRenderingContext::renderSubtreeToImageBuffer(ImageBuffer* image, RenderElement& item, const AffineTransform& subtreeContentTransformation)
297{
298    ASSERT(image);
299    ASSERT(image->context());
300
301    PaintInfo info(image->context(), LayoutRect::infiniteRect(), PaintPhaseForeground, PaintBehaviorNormal);
302
303    AffineTransform& contentTransformation = currentContentTransformation();
304    AffineTransform savedContentTransformation = contentTransformation;
305    contentTransformation = subtreeContentTransformation * contentTransformation;
306
307    ASSERT(!item.needsLayout());
308    item.paint(info, IntPoint());
309
310    contentTransformation = savedContentTransformation;
311}
312
313void SVGRenderingContext::clipToImageBuffer(GraphicsContext* context, const AffineTransform& absoluteTransform, const FloatRect& targetRect, std::unique_ptr<ImageBuffer>& imageBuffer, bool safeToClear)
314{
315    ASSERT(context);
316    ASSERT(imageBuffer);
317
318    FloatRect absoluteTargetRect = calculateImageBufferRect(targetRect, absoluteTransform);
319
320    // The mask image has been created in the absolute coordinate space, as the image should not be scaled.
321    // So the actual masking process has to be done in the absolute coordinate space as well.
322    context->concatCTM(absoluteTransform.inverse());
323    context->clipToImageBuffer(imageBuffer.get(), absoluteTargetRect);
324    context->concatCTM(absoluteTransform);
325
326    // When nesting resources, with objectBoundingBox as content unit types, there's no use in caching the
327    // resulting image buffer as the parent resource already caches the result.
328    if (safeToClear && !currentContentTransformation().isIdentity())
329        imageBuffer.reset();
330}
331
332FloatRect SVGRenderingContext::clampedAbsoluteTargetRect(const FloatRect& absoluteTargetRect)
333{
334    const FloatSize maxImageBufferSize(kMaxImageBufferSize, kMaxImageBufferSize);
335    return FloatRect(absoluteTargetRect.location(), absoluteTargetRect.size().shrunkTo(maxImageBufferSize));
336}
337
338IntSize SVGRenderingContext::clampedAbsoluteSize(const IntSize& absoluteSize)
339{
340    const IntSize maxImageBufferSize(kMaxImageBufferSize, kMaxImageBufferSize);
341    return absoluteSize.shrunkTo(maxImageBufferSize);
342}
343
344void SVGRenderingContext::clear2DRotation(AffineTransform& transform)
345{
346    AffineTransform::DecomposedType decomposition;
347    transform.decompose(decomposition);
348    decomposition.angle = 0;
349    transform.recompose(decomposition);
350}
351
352bool SVGRenderingContext::bufferForeground(std::unique_ptr<ImageBuffer>& imageBuffer)
353{
354    ASSERT(m_paintInfo);
355    ASSERT(m_renderer->isSVGImage());
356    FloatRect boundingBox = m_renderer->objectBoundingBox();
357
358    // Invalidate an existing buffer if the scale is not correct.
359    if (imageBuffer) {
360        AffineTransform transform = m_paintInfo->context->getCTM(GraphicsContext::DefinitelyIncludeDeviceScale);
361        IntSize expandedBoundingBox = expandedIntSize(boundingBox.size());
362        IntSize bufferSize(static_cast<int>(ceil(expandedBoundingBox.width() * transform.xScale())), static_cast<int>(ceil(expandedBoundingBox.height() * transform.yScale())));
363        if (bufferSize != imageBuffer->internalSize())
364            imageBuffer.reset();
365    }
366
367    // Create a new buffer and paint the foreground into it.
368    if (!imageBuffer) {
369        if ((imageBuffer = m_paintInfo->context->createCompatibleBuffer(expandedIntSize(boundingBox.size()), true))) {
370            GraphicsContext* bufferedRenderingContext = imageBuffer->context();
371            bufferedRenderingContext->translate(-boundingBox.x(), -boundingBox.y());
372            PaintInfo bufferedInfo(*m_paintInfo);
373            bufferedInfo.context = bufferedRenderingContext;
374            toRenderSVGImage(m_renderer)->paintForeground(bufferedInfo);
375        } else
376            return false;
377    }
378
379    m_paintInfo->context->drawImageBuffer(imageBuffer.get(), ColorSpaceDeviceRGB, boundingBox);
380    return true;
381}
382
383}
384