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