WebImageCG.cpp   [plain text]

/*
 * Copyright (C) 2009 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met:
 *
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 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "config.h"
#include "platform/WebImage.h"

#include "Image.h"
#include "ImageSource.h"
#include "SharedBuffer.h"

#include "platform/WebData.h"
#include "platform/WebSize.h"

#include <CoreGraphics/CGImage.h>

#include <wtf/PassRefPtr.h>
#include <wtf/RetainPtr.h>

using namespace WebCore;

namespace WebKit {

WebImage WebImage::fromData(const WebData& data, const WebSize& desiredSize)
{
    ImageSource source;
    source.setData(PassRefPtr<SharedBuffer>(data).get(), true);
    if (!source.isSizeAvailable())
        return WebImage();

    // Frames are arranged by decreasing size, then decreasing bit depth.
    // Pick the frame closest to |desiredSize|'s area without being smaller,
    // which has the highest bit depth.
    const size_t frameCount = source.frameCount();
    size_t index = 0; // Default to first frame if none are large enough.
    int frameAreaAtIndex = 0;
    for (size_t i = 0; i < frameCount; ++i) {
        const IntSize frameSize = source.frameSizeAtIndex(i);
        if (WebSize(frameSize) == desiredSize) {
            index = i;
            break; // Perfect match.
        }
        const int frameArea = frameSize.width() * frameSize.height();
        if (frameArea < (desiredSize.width * desiredSize.height))
            break; // No more frames that are large enough.

        if (!i || (frameArea < frameAreaAtIndex)) {
            index = i; // Closer to desired area than previous best match.
            frameAreaAtIndex = frameArea;
        }
    }

    RetainPtr<CGImageRef> frame(AdoptCF, source.createFrameAtIndex(index));
    if (!frame)
        return WebImage();

    return WebImage(frame.get());
}

void WebImage::reset()
{
    CGImageRelease(m_imageRef);
    m_imageRef = 0;
}

void WebImage::assign(const WebImage& image)
{
    assign(image.m_imageRef);
}

bool WebImage::isNull() const
{
    return !m_imageRef;
}

WebSize WebImage::size() const
{
    return WebSize(CGImageGetWidth(m_imageRef), CGImageGetHeight(m_imageRef));
}

WebImage::WebImage(const PassRefPtr<Image>& image)
    : m_imageRef(0)
{
    NativeImagePtr p;
    if (image && (p = image->nativeImageForCurrentFrame()))
        assign(p);
}

WebImage& WebImage::operator=(const PassRefPtr<Image>& image)
{
    NativeImagePtr p;
    if (image && (p = image->nativeImageForCurrentFrame()))
        assign(p);
    else
        reset();
    return *this;
}

void WebImage::assign(CGImageRef imageRef)
{
    // Make sure to retain the imageRef first incase m_imageRef == imageRef.
    CGImageRetain(imageRef);
    CGImageRelease(m_imageRef);
    m_imageRef = imageRef;
}

} // namespace WebKit