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      1 /*
      2  * Copyright (C) 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
     14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
     17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23  * THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "core/platform/graphics/GeneratorGeneratedImage.h"
     28 
     29 #include "core/platform/graphics/FloatRect.h"
     30 #include "core/platform/graphics/GraphicsContextStateSaver.h"
     31 
     32 #define SKIA_MAX_PATTERN_SIZE 32767
     33 
     34 namespace WebCore {
     35 
     36 void GeneratorGeneratedImage::draw(GraphicsContext* destContext, const FloatRect& destRect, const FloatRect& srcRect, CompositeOperator compositeOp, BlendMode blendMode)
     37 {
     38     GraphicsContextStateSaver stateSaver(*destContext);
     39     destContext->setCompositeOperation(compositeOp, blendMode);
     40     destContext->clip(destRect);
     41     destContext->translate(destRect.x(), destRect.y());
     42     if (destRect.size() != srcRect.size())
     43         destContext->scale(FloatSize(destRect.width() / srcRect.width(), destRect.height() / srcRect.height()));
     44     destContext->translate(-srcRect.x(), -srcRect.y());
     45     destContext->setFillGradient(m_gradient);
     46     destContext->fillRect(FloatRect(FloatPoint(), m_size));
     47 }
     48 
     49 void GeneratorGeneratedImage::drawPatternWithoutCache(GraphicsContext* destContext, const FloatRect& srcRect, const FloatSize& scale,
     50     const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& destRect, BlendMode blendMode)
     51 {
     52     int firstColumn = static_cast<int>(floorf((((destRect.x() - phase.x()) / scale.width()) - srcRect.x()) / srcRect.width()));
     53     int firstRow = static_cast<int>(floorf((((destRect.y() - phase.y()) / scale.height())  - srcRect.y()) / srcRect.height()));
     54     for (int i = firstColumn; ; ++i) {
     55         float dstX = (srcRect.x() + i * srcRect.width()) * scale.width() + phase.x();
     56         // assert that first column encroaches left edge of dstRect.
     57         ASSERT(i > firstColumn || dstX <= destRect.x());
     58         ASSERT(i == firstColumn || dstX > destRect.x());
     59 
     60         if (dstX >= destRect.maxX())
     61             break;
     62         float dstMaxX = dstX + srcRect.width() * scale.width();
     63         if (dstX < destRect.x())
     64             dstX = destRect.x();
     65         if (dstMaxX > destRect.maxX())
     66             dstMaxX = destRect.maxX();
     67         if (dstX >= dstMaxX)
     68             continue;
     69 
     70         FloatRect visibleSrcRect;
     71         FloatRect tileDstRect;
     72         tileDstRect.setX(dstX);
     73         tileDstRect.setWidth(dstMaxX - dstX);
     74         visibleSrcRect.setX((tileDstRect.x() - phase.x()) / scale.width() - i * srcRect.width());
     75         visibleSrcRect.setWidth(tileDstRect.width() / scale.width());
     76 
     77         for (int j = firstRow; ; j++) {
     78             float dstY = (srcRect.y() + j * srcRect.height()) * scale.height() + phase.y();
     79             // assert that first row encroaches top edge of dstRect.
     80             ASSERT(j > firstRow || dstY <= destRect.y());
     81             ASSERT(j == firstRow || dstY > destRect.y());
     82 
     83             if (dstY >= destRect.maxY())
     84                 break;
     85             float dstMaxY = dstY + srcRect.height() * scale.height();
     86             if (dstY < destRect.y())
     87                 dstY = destRect.y();
     88             if (dstMaxY > destRect.maxY())
     89                 dstMaxY = destRect.maxY();
     90             if (dstY >= dstMaxY)
     91                 continue;
     92 
     93             tileDstRect.setY(dstY);
     94             tileDstRect.setHeight(dstMaxY - dstY);
     95             visibleSrcRect.setY((tileDstRect.y() - phase.y()) / scale.height() - j * srcRect.height());
     96             visibleSrcRect.setHeight(tileDstRect.height() / scale.height());
     97             draw(destContext, tileDstRect, visibleSrcRect, compositeOp, blendMode);
     98         }
     99     }
    100 }
    101 
    102 void GeneratorGeneratedImage::drawPattern(GraphicsContext* destContext, const FloatRect& srcRect, const FloatSize& scale,
    103     const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& destRect, BlendMode blendMode)
    104 {
    105     // Allow the generator to provide visually-equivalent tiling parameters for better performance.
    106     IntSize adjustedSize = m_size;
    107     FloatRect adjustedSrcRect = srcRect;
    108 
    109     m_gradient->adjustParametersForTiledDrawing(adjustedSize, adjustedSrcRect);
    110 
    111     if (adjustedSize.width() > SKIA_MAX_PATTERN_SIZE || adjustedSize.height() > SKIA_MAX_PATTERN_SIZE) {
    112         // Workaround to fix crbug.com/241486
    113         // SkBitmapProcShader is unable to handle cached tiles >= 32k pixels high or wide.
    114         drawPatternWithoutCache(destContext, srcRect, scale, phase, compositeOp, destRect, blendMode);
    115         return;
    116     }
    117 
    118     // Factor in the destination context's scale to generate at the best resolution.
    119     // FIXME: No need to get the full CTM here, we just need the scale.
    120     AffineTransform destContextCTM = destContext->getCTM(GraphicsContext::DefinitelyIncludeDeviceScale);
    121     float xScale = fabs(destContextCTM.xScale());
    122     float yScale = fabs(destContextCTM.yScale());
    123     FloatSize scaleWithoutCTM(scale.width() / xScale, scale.height() / yScale);
    124     adjustedSrcRect.scale(xScale, yScale);
    125 
    126     unsigned generatorHash = m_gradient->hash();
    127 
    128     if (!m_cachedImageBuffer || m_cachedGeneratorHash != generatorHash || m_cachedAdjustedSize != adjustedSize || !destContext->isCompatibleWithBuffer(m_cachedImageBuffer.get())) {
    129         m_cachedImageBuffer = destContext->createCompatibleBuffer(adjustedSize, m_gradient->hasAlpha());
    130         if (!m_cachedImageBuffer)
    131             return;
    132 
    133         // Fill with the generated image.
    134         m_cachedImageBuffer->context()->setFillGradient(m_gradient);
    135         m_cachedImageBuffer->context()->fillRect(FloatRect(FloatPoint(), adjustedSize));
    136 
    137         m_cachedGeneratorHash = generatorHash;
    138         m_cachedAdjustedSize = adjustedSize;
    139     }
    140 
    141     // Tile the image buffer into the context.
    142     m_cachedImageBuffer->drawPattern(destContext, adjustedSrcRect, scaleWithoutCTM, phase, compositeOp, destRect, blendMode);
    143     m_cacheTimer.restart();
    144 }
    145 
    146 void GeneratorGeneratedImage::invalidateCacheTimerFired(DeferrableOneShotTimer<GeneratorGeneratedImage>*)
    147 {
    148     m_cachedImageBuffer.clear();
    149     m_cachedAdjustedSize = IntSize();
    150 }
    151 
    152 }
    153