1/*
2 * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
3 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
4 * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
5 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Library General Public License for more details.
16 *
17 * You should have received a copy of the GNU Library General Public License
18 * along with this library; see the file COPYING.LIB.  If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
21 */
22
23#include "config.h"
24
25#if ENABLE(SVG)
26#include "RenderSVGResourceGradient.h"
27
28#include "GradientAttributes.h"
29#include "GraphicsContext.h"
30#include "RenderSVGText.h"
31#include "SVGImageBufferTools.h"
32#include "SVGRenderSupport.h"
33#include <wtf/UnusedParam.h>
34
35namespace WebCore {
36
37RenderSVGResourceGradient::RenderSVGResourceGradient(SVGGradientElement* node)
38    : RenderSVGResourceContainer(node)
39    , m_shouldCollectGradientAttributes(true)
40#if USE(CG)
41    , m_savedContext(0)
42#endif
43{
44}
45
46RenderSVGResourceGradient::~RenderSVGResourceGradient()
47{
48    if (m_gradient.isEmpty())
49        return;
50
51    deleteAllValues(m_gradient);
52    m_gradient.clear();
53}
54
55void RenderSVGResourceGradient::removeAllClientsFromCache(bool markForInvalidation)
56{
57    if (!m_gradient.isEmpty()) {
58        deleteAllValues(m_gradient);
59        m_gradient.clear();
60    }
61
62    m_shouldCollectGradientAttributes = true;
63    markAllClientsForInvalidation(markForInvalidation ? RepaintInvalidation : ParentOnlyInvalidation);
64}
65
66void RenderSVGResourceGradient::removeClientFromCache(RenderObject* client, bool markForInvalidation)
67{
68    ASSERT(client);
69
70    if (m_gradient.contains(client))
71        delete m_gradient.take(client);
72
73    markClientForInvalidation(client, markForInvalidation ? RepaintInvalidation : ParentOnlyInvalidation);
74}
75
76#if USE(CG)
77static inline bool createMaskAndSwapContextForTextGradient(GraphicsContext*& context,
78                                                           GraphicsContext*& savedContext,
79                                                           OwnPtr<ImageBuffer>& imageBuffer,
80                                                           RenderObject* object)
81{
82    RenderObject* textRootBlock = RenderSVGText::locateRenderSVGTextAncestor(object);
83    ASSERT(textRootBlock);
84
85    AffineTransform absoluteTransform;
86    SVGImageBufferTools::calculateTransformationToOutermostSVGCoordinateSystem(textRootBlock, absoluteTransform);
87
88    FloatRect absoluteTargetRect = absoluteTransform.mapRect(textRootBlock->repaintRectInLocalCoordinates());
89    FloatRect clampedAbsoluteTargetRect = SVGImageBufferTools::clampedAbsoluteTargetRectForRenderer(textRootBlock, absoluteTargetRect);
90    if (clampedAbsoluteTargetRect.isEmpty())
91        return false;
92
93    OwnPtr<ImageBuffer> maskImage;
94    if (!SVGImageBufferTools::createImageBuffer(absoluteTargetRect, clampedAbsoluteTargetRect, maskImage, ColorSpaceDeviceRGB))
95        return false;
96
97    GraphicsContext* maskImageContext = maskImage->context();
98    ASSERT(maskImageContext);
99
100    maskImageContext->translate(-clampedAbsoluteTargetRect.x(), -clampedAbsoluteTargetRect.y());
101    maskImageContext->concatCTM(absoluteTransform);
102
103    ASSERT(maskImage);
104    savedContext = context;
105    context = maskImageContext;
106    imageBuffer = maskImage.release();
107    return true;
108}
109
110static inline AffineTransform clipToTextMask(GraphicsContext* context,
111                                             OwnPtr<ImageBuffer>& imageBuffer,
112                                             FloatRect& targetRect,
113                                             RenderObject* object,
114                                             bool boundingBoxMode,
115                                             const AffineTransform& gradientTransform)
116{
117    RenderObject* textRootBlock = RenderSVGText::locateRenderSVGTextAncestor(object);
118    ASSERT(textRootBlock);
119
120    targetRect = textRootBlock->repaintRectInLocalCoordinates();
121
122    AffineTransform absoluteTransform;
123    SVGImageBufferTools::calculateTransformationToOutermostSVGCoordinateSystem(textRootBlock, absoluteTransform);
124
125    FloatRect absoluteTargetRect = absoluteTransform.mapRect(targetRect);
126    FloatRect clampedAbsoluteTargetRect = SVGImageBufferTools::clampedAbsoluteTargetRectForRenderer(textRootBlock, absoluteTargetRect);
127
128    SVGImageBufferTools::clipToImageBuffer(context, absoluteTransform, clampedAbsoluteTargetRect, imageBuffer);
129
130    AffineTransform matrix;
131    if (boundingBoxMode) {
132        FloatRect maskBoundingBox = textRootBlock->objectBoundingBox();
133        matrix.translate(maskBoundingBox.x(), maskBoundingBox.y());
134        matrix.scaleNonUniform(maskBoundingBox.width(), maskBoundingBox.height());
135    }
136    matrix *= gradientTransform;
137    return matrix;
138}
139#endif
140
141bool RenderSVGResourceGradient::applyResource(RenderObject* object, RenderStyle* style, GraphicsContext*& context, unsigned short resourceMode)
142{
143    ASSERT(object);
144    ASSERT(style);
145    ASSERT(context);
146    ASSERT(resourceMode != ApplyToDefaultMode);
147
148    // Be sure to synchronize all SVG properties on the gradientElement _before_ processing any further.
149    // Otherwhise the call to collectGradientAttributes() in createTileImage(), may cause the SVG DOM property
150    // synchronization to kick in, which causes removeAllClientsFromCache() to be called, which in turn deletes our
151    // GradientData object! Leaving out the line below will cause svg/dynamic-updates/SVG*GradientElement-svgdom* to crash.
152    SVGGradientElement* gradientElement = static_cast<SVGGradientElement*>(node());
153    if (!gradientElement)
154        return false;
155
156    if (m_shouldCollectGradientAttributes) {
157        gradientElement->updateAnimatedSVGAttribute(anyQName());
158        collectGradientAttributes(gradientElement);
159        m_shouldCollectGradientAttributes = false;
160    }
161
162    // Spec: When the geometry of the applicable element has no width or height and objectBoundingBox is specified,
163    // then the given effect (e.g. a gradient or a filter) will be ignored.
164    FloatRect objectBoundingBox = object->objectBoundingBox();
165    if (boundingBoxMode() && objectBoundingBox.isEmpty())
166        return false;
167
168    if (!m_gradient.contains(object))
169        m_gradient.set(object, new GradientData);
170
171    GradientData* gradientData = m_gradient.get(object);
172    bool isPaintingText = resourceMode & ApplyToTextMode;
173
174    // Create gradient object
175    if (!gradientData->gradient) {
176        buildGradient(gradientData, gradientElement);
177
178        // CG platforms will handle the gradient space transform for text after applying the
179        // resource, so don't apply it here. For non-CG platforms, we want the text bounding
180        // box applied to the gradient space transform now, so the gradient shader can use it.
181#if USE(CG)
182        if (boundingBoxMode() && !objectBoundingBox.isEmpty() && !isPaintingText) {
183#else
184        if (boundingBoxMode() && !objectBoundingBox.isEmpty()) {
185#endif
186            gradientData->userspaceTransform.translate(objectBoundingBox.x(), objectBoundingBox.y());
187            gradientData->userspaceTransform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
188        }
189
190        AffineTransform gradientTransform;
191        calculateGradientTransform(gradientTransform);
192
193        gradientData->userspaceTransform *= gradientTransform;
194        gradientData->gradient->setGradientSpaceTransform(gradientData->userspaceTransform);
195    }
196
197    if (!gradientData->gradient)
198        return false;
199
200    // Draw gradient
201    context->save();
202
203    if (isPaintingText) {
204#if USE(CG)
205        if (!createMaskAndSwapContextForTextGradient(context, m_savedContext, m_imageBuffer, object)) {
206            context->restore();
207            return false;
208        }
209#endif
210
211        context->setTextDrawingMode(resourceMode & ApplyToFillMode ? TextModeFill : TextModeStroke);
212    }
213
214    const SVGRenderStyle* svgStyle = style->svgStyle();
215    ASSERT(svgStyle);
216
217    if (resourceMode & ApplyToFillMode) {
218        context->setAlpha(svgStyle->fillOpacity());
219        context->setFillGradient(gradientData->gradient);
220        context->setFillRule(svgStyle->fillRule());
221    } else if (resourceMode & ApplyToStrokeMode) {
222        if (svgStyle->vectorEffect() == VE_NON_SCALING_STROKE)
223            gradientData->gradient->setGradientSpaceTransform(transformOnNonScalingStroke(object, gradientData->userspaceTransform));
224        context->setAlpha(svgStyle->strokeOpacity());
225        context->setStrokeGradient(gradientData->gradient);
226        SVGRenderSupport::applyStrokeStyleToContext(context, style, object);
227    }
228
229    return true;
230}
231
232void RenderSVGResourceGradient::postApplyResource(RenderObject* object, GraphicsContext*& context, unsigned short resourceMode, const Path* path)
233{
234    ASSERT(context);
235    ASSERT(resourceMode != ApplyToDefaultMode);
236
237    if (resourceMode & ApplyToTextMode) {
238#if USE(CG)
239        // CG requires special handling for gradient on text
240        if (m_savedContext && m_gradient.contains(object)) {
241            GradientData* gradientData = m_gradient.get(object);
242
243            // Restore on-screen drawing context
244            context = m_savedContext;
245            m_savedContext = 0;
246
247            AffineTransform gradientTransform;
248            calculateGradientTransform(gradientTransform);
249
250            FloatRect targetRect;
251            gradientData->gradient->setGradientSpaceTransform(clipToTextMask(context, m_imageBuffer, targetRect, object, boundingBoxMode(), gradientTransform));
252            context->setFillGradient(gradientData->gradient);
253
254            context->fillRect(targetRect);
255            m_imageBuffer.clear();
256        }
257#else
258        UNUSED_PARAM(object);
259#endif
260    } else if (path) {
261        if (resourceMode & ApplyToFillMode)
262            context->fillPath(*path);
263        else if (resourceMode & ApplyToStrokeMode)
264            context->strokePath(*path);
265    }
266
267    context->restore();
268}
269
270void RenderSVGResourceGradient::addStops(GradientData* gradientData, const Vector<Gradient::ColorStop>& stops) const
271{
272    ASSERT(gradientData->gradient);
273
274    const Vector<Gradient::ColorStop>::const_iterator end = stops.end();
275    for (Vector<Gradient::ColorStop>::const_iterator it = stops.begin(); it != end; ++it)
276        gradientData->gradient->addColorStop(*it);
277}
278
279}
280
281#endif
282