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      1 /*
      2  * Copyright (C) 2011 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 COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "platform/graphics/CrossfadeGeneratedImage.h"
     28 
     29 #include "platform/geometry/FloatRect.h"
     30 #include "platform/graphics/GraphicsContextStateSaver.h"
     31 #include "platform/graphics/ImageBuffer.h"
     32 
     33 namespace blink {
     34 
     35 CrossfadeGeneratedImage::CrossfadeGeneratedImage(Image* fromImage, Image* toImage, float percentage, IntSize crossfadeSize, const IntSize& size)
     36     : m_fromImage(fromImage)
     37     , m_toImage(toImage)
     38     , m_percentage(percentage)
     39     , m_crossfadeSize(crossfadeSize)
     40 {
     41     m_size = size;
     42 }
     43 
     44 void CrossfadeGeneratedImage::drawCrossfade(GraphicsContext* context)
     45 {
     46     float inversePercentage = 1 - m_percentage;
     47 
     48     IntSize fromImageSize = m_fromImage->size();
     49     IntSize toImageSize = m_toImage->size();
     50 
     51     // Draw nothing if either of the images hasn't loaded yet.
     52     if (m_fromImage == Image::nullImage() || m_toImage == Image::nullImage())
     53         return;
     54 
     55     GraphicsContextStateSaver stateSaver(*context);
     56 
     57     context->clip(IntRect(IntPoint(), m_crossfadeSize));
     58     context->beginTransparencyLayer(1);
     59 
     60     // Draw the image we're fading away from.
     61     context->save();
     62     if (m_crossfadeSize != fromImageSize) {
     63         context->scale(
     64             static_cast<float>(m_crossfadeSize.width()) / fromImageSize.width(),
     65             static_cast<float>(m_crossfadeSize.height()) / fromImageSize.height());
     66     }
     67     context->setAlphaAsFloat(inversePercentage);
     68     context->drawImage(m_fromImage, IntPoint());
     69     context->restore();
     70 
     71     // Draw the image we're fading towards.
     72     context->save();
     73     if (m_crossfadeSize != toImageSize) {
     74         context->scale(
     75             static_cast<float>(m_crossfadeSize.width()) / toImageSize.width(),
     76             static_cast<float>(m_crossfadeSize.height()) / toImageSize.height());
     77     }
     78     context->setAlphaAsFloat(m_percentage);
     79     context->drawImage(m_toImage, IntPoint(), CompositePlusLighter);
     80     context->restore();
     81 
     82     context->endLayer();
     83 }
     84 
     85 void CrossfadeGeneratedImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, CompositeOperator compositeOp, WebBlendMode blendMode)
     86 {
     87     GraphicsContextStateSaver stateSaver(*context);
     88     context->setCompositeOperation(compositeOp, blendMode);
     89     context->clip(dstRect);
     90     context->translate(dstRect.x(), dstRect.y());
     91     if (dstRect.size() != srcRect.size())
     92         context->scale(dstRect.width() / srcRect.width(), dstRect.height() / srcRect.height());
     93     context->translate(-srcRect.x(), -srcRect.y());
     94 
     95     drawCrossfade(context);
     96 }
     97 
     98 void CrossfadeGeneratedImage::drawPattern(GraphicsContext* context, const FloatRect& srcRect, const FloatSize& scale, const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& dstRect, WebBlendMode blendMode, const IntSize& repeatSpacing)
     99 {
    100     OwnPtr<ImageBuffer> imageBuffer = context->createRasterBuffer(m_size);
    101     if (!imageBuffer)
    102         return;
    103 
    104     // Fill with the cross-faded image.
    105     GraphicsContext* graphicsContext = imageBuffer->context();
    106     drawCrossfade(graphicsContext);
    107 
    108     // Tile the image buffer into the context.
    109     imageBuffer->drawPattern(context, srcRect, scale, phase, compositeOp, dstRect, blendMode, repeatSpacing);
    110 }
    111 
    112 } // namespace blink
    113