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
33namespace blink {
34
35CrossfadeGeneratedImage::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
44void 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
85void 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
98void 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