imagesourcecg.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#include "config.h"
#include "ImageSource.h"

#if PLATFORM(CG)
#include "ImageSourceCG.h"

#include "IntSize.h"
#include "MIMETypeRegistry.h"
#include "SharedBuffer.h"
#include <ApplicationServices/ApplicationServices.h>

namespace WebCore {

static const CFStringRef kCGImageSourceShouldPreferRGB32 = CFSTR("kCGImageSourceShouldPreferRGB32");

ImageSource::ImageSource()
    : m_decoder(0)
{
}

ImageSource::~ImageSource()
{
    clear(true);
}

void ImageSource::clear(bool, size_t, SharedBuffer* data, bool allDataReceived)
{
    // We always destroy the decoder, because there is no API to get it to
    // selectively release some of the frames it's holding, and if we don't
    // release any of them, we use too much memory on large images.
    if (m_decoder) {
        CFRelease(m_decoder);
        m_decoder = 0;
    }
    if (data)
        setData(data, allDataReceived);
}

static CFDictionaryRef imageSourceOptions()
{
    static CFDictionaryRef options;
    
    if (!options) {
        const void* keys[2] = { kCGImageSourceShouldCache, kCGImageSourceShouldPreferRGB32 };
        const void* values[2] = { kCFBooleanTrue, kCFBooleanTrue };
        options = CFDictionaryCreate(NULL, keys, values, 2, 
            &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
    }
    return options;
}

bool ImageSource::initialized() const
{
    return m_decoder;
}

void ImageSource::setData(SharedBuffer* data, bool allDataReceived)
{
    if (!m_decoder)
        m_decoder = CGImageSourceCreateIncremental(NULL);
#if PLATFORM(MAC)
    // On Mac the NSData inside the SharedBuffer can be secretly appended to without the SharedBuffer's knowledge.  We use SharedBuffer's ability
    // to wrap itself inside CFData to get around this, ensuring that ImageIO is really looking at the SharedBuffer.
    CFDataRef cfData = data->createCFData();
#else
    // If no NSData is available, then we know SharedBuffer will always just be a vector.  That means no secret changes can occur to it behind the
    // scenes.  We use CFDataCreateWithBytesNoCopy in that case.
    CFDataRef cfData = CFDataCreateWithBytesNoCopy(0, reinterpret_cast<const UInt8*>(data->data()), data->size(), kCFAllocatorNull);
#endif
    CGImageSourceUpdateData(m_decoder, cfData, allDataReceived);
    CFRelease(cfData);
}

String ImageSource::filenameExtension() const
{
    if (!m_decoder)
        return String();
    CFStringRef imageSourceType = CGImageSourceGetType(m_decoder);
    return WebCore::preferredExtensionForImageSourceType(imageSourceType);
}

bool ImageSource::isSizeAvailable()
{
    bool result = false;
    CGImageSourceStatus imageSourceStatus = CGImageSourceGetStatus(m_decoder);

    // Ragnaros yells: TOO SOON! You have awakened me TOO SOON, Executus!
    if (imageSourceStatus >= kCGImageStatusIncomplete) {
        CFDictionaryRef image0Properties = CGImageSourceCopyPropertiesAtIndex(m_decoder, 0, imageSourceOptions());
        if (image0Properties) {
            CFNumberRef widthNumber = (CFNumberRef)CFDictionaryGetValue(image0Properties, kCGImagePropertyPixelWidth);
            CFNumberRef heightNumber = (CFNumberRef)CFDictionaryGetValue(image0Properties, kCGImagePropertyPixelHeight);
            result = widthNumber && heightNumber;
            CFRelease(image0Properties);
        }
    }
    
    return result;
}

IntSize ImageSource::frameSizeAtIndex(size_t index) const
{
    IntSize result;
    CFDictionaryRef properties = CGImageSourceCopyPropertiesAtIndex(m_decoder, index, imageSourceOptions());
    if (properties) {
        int w = 0, h = 0;
        CFNumberRef num = (CFNumberRef)CFDictionaryGetValue(properties, kCGImagePropertyPixelWidth);
        if (num)
            CFNumberGetValue(num, kCFNumberIntType, &w);
        num = (CFNumberRef)CFDictionaryGetValue(properties, kCGImagePropertyPixelHeight);
        if (num)
            CFNumberGetValue(num, kCFNumberIntType, &h);
        result = IntSize(w, h);
        CFRelease(properties);
    }
    return result;
}

IntSize ImageSource::size() const
{
    return frameSizeAtIndex(0);
}

int ImageSource::repetitionCount()
{
    int result = cAnimationLoopOnce; // No property means loop once.
    if (!initialized())
        return result;

    // A property with value 0 means loop forever.
    CFDictionaryRef properties = CGImageSourceCopyProperties(m_decoder, imageSourceOptions());
    if (properties) {
        CFDictionaryRef gifProperties = (CFDictionaryRef)CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (gifProperties) {
            CFNumberRef num = (CFNumberRef)CFDictionaryGetValue(gifProperties, kCGImagePropertyGIFLoopCount);
            if (num)
                CFNumberGetValue(num, kCFNumberIntType, &result);
        } else
            result = cAnimationNone; // Turns out we're not a GIF after all, so we don't animate.
        
        CFRelease(properties);
    }
    
    return result;
}

size_t ImageSource::frameCount() const
{
    return m_decoder ? CGImageSourceGetCount(m_decoder) : 0;
}

CGImageRef ImageSource::createFrameAtIndex(size_t index)
{
    if (!initialized())
        return 0;

    CGImageRef image = CGImageSourceCreateImageAtIndex(m_decoder, index, imageSourceOptions());
    CFStringRef imageUTI = CGImageSourceGetType(m_decoder);
    static const CFStringRef xbmUTI = CFSTR("public.xbitmap-image");
    if (!imageUTI || !CFEqual(imageUTI, xbmUTI))
        return image;
    
    // If it is an xbm image, mask out all the white areas to render them transparent.
    const CGFloat maskingColors[6] = {255, 255,  255, 255, 255, 255};
    CGImageRef maskedImage = CGImageCreateWithMaskingColors(image, maskingColors);
    if (!maskedImage)
        return image;
        
    CGImageRelease(image);
    return maskedImage; 
}

bool ImageSource::frameIsCompleteAtIndex(size_t index)
{
    return CGImageSourceGetStatusAtIndex(m_decoder, index) == kCGImageStatusComplete;
}

float ImageSource::frameDurationAtIndex(size_t index)
{
    if (!initialized())
        return 0;

    float duration = 0;
    CFDictionaryRef properties = CGImageSourceCopyPropertiesAtIndex(m_decoder, index, imageSourceOptions());
    if (properties) {
        CFDictionaryRef typeProperties = (CFDictionaryRef)CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (typeProperties) {
            CFNumberRef num = (CFNumberRef)CFDictionaryGetValue(typeProperties, kCGImagePropertyGIFDelayTime);
            if (num)
                CFNumberGetValue(num, kCFNumberFloatType, &duration);
        }
        CFRelease(properties);
    }

    // Many annoying ads specify a 0 duration to make an image flash as quickly as possible.
    // We follow WinIE's behavior and use a duration of 100 ms for any frames that specify
    // a duration of <= 50 ms. See <http://bugs.webkit.org/show_bug.cgi?id=14413> or Radar 4051389 for more.
    if (duration < 0.051f)
        return 0.100f;
    return duration;
}

bool ImageSource::frameHasAlphaAtIndex(size_t)
{
    // Might be interesting to do this optimization on Mac some day, but for now we're just using this
    // for the Cairo source, since it uses our decoders, and our decoders can answer this question.
    // FIXME: Could return false for JPEG and other non-transparent image formats.
    // FIXME: Could maybe return false for a GIF Frame if we have enough info in the GIF properties dictionary
    // to determine whether or not a transparent color was defined.
    return true;
}

}

#endif // PLATFORM(CG)