bitmapimage.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) 2006 Samuel Weinig ([e-mail])
 * 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 "BitmapImage.h"

#include "FloatRect.h"
#include "ImageObserver.h"
#include "IntRect.h"
#include "MIMETypeRegistry.h"
#include "PlatformString.h"
#include "Timer.h"
#include <wtf/CurrentTime.h>
#include <wtf/Vector.h>

namespace WebCore {

static int frameBytes(const IntSize& frameSize)
{
    return frameSize.width() * frameSize.height() * 4;
}

BitmapImage::BitmapImage(ImageObserver* observer)
    : Image(observer)
    , m_currentFrame(0)
    , m_frames(0)
    , m_frameTimer(0)
    , m_repetitionCount(cAnimationNone)
    , m_repetitionCountStatus(Unknown)
    , m_repetitionsComplete(0)
    , m_desiredFrameStartTime(0)
    , m_isSolidColor(false)
    , m_checkedForSolidColor(false)
    , m_animationFinished(false)
    , m_allDataReceived(false)
    , m_haveSize(false)
    , m_sizeAvailable(false)
    , m_hasUniformFrameSize(true)
    , m_decodedSize(0)
    , m_haveFrameCount(false)
    , m_frameCount(0)
{
    initPlatformData();
}

BitmapImage::~BitmapImage()
{
    invalidatePlatformData();
    stopAnimation();
}

void BitmapImage::destroyDecodedData(bool destroyAll)
{
    int framesCleared = 0;
    const size_t clearBeforeFrame = destroyAll ? m_frames.size() : m_currentFrame;
    for (size_t i = 0; i < clearBeforeFrame; ++i) {
        // The underlying frame isn't actually changing (we're just trying to
        // save the memory for the framebuffer data), so we don't need to clear
        // the metadata.
        if (m_frames[i].clear(false))
          ++framesCleared;
    }

    destroyMetadataAndNotify(framesCleared);

    m_source.clear(destroyAll, clearBeforeFrame, m_data.get(), m_allDataReceived);
    return;
}

void BitmapImage::destroyDecodedDataIfNecessary(bool destroyAll)
{
    // Animated images >5MB are considered large enough that we'll only hang on
    // to one frame at a time.
    static const unsigned cLargeAnimationCutoff = 5242880;
    if (frameCount() * frameBytes(m_size) > cLargeAnimationCutoff)
        destroyDecodedData(destroyAll);
}

void BitmapImage::destroyMetadataAndNotify(int framesCleared)
{
    m_isSolidColor = false;
    invalidatePlatformData();

    const int deltaBytes = framesCleared * -frameBytes(m_size);
    m_decodedSize += deltaBytes;
    if (deltaBytes && imageObserver())
        imageObserver()->decodedSizeChanged(this, deltaBytes);
}

void BitmapImage::cacheFrame(size_t index)
{
    size_t numFrames = frameCount();
    ASSERT(m_decodedSize == 0 || numFrames > 1);
    
    if (m_frames.size() < numFrames)
        m_frames.grow(numFrames);

    m_frames[index].m_frame = m_source.createFrameAtIndex(index);
    if (numFrames == 1 && m_frames[index].m_frame)
        checkForSolidColor();

    m_frames[index].m_haveMetadata = true;
    m_frames[index].m_isComplete = m_source.frameIsCompleteAtIndex(index);
    if (repetitionCount(false) != cAnimationNone)
        m_frames[index].m_duration = m_source.frameDurationAtIndex(index);
    m_frames[index].m_hasAlpha = m_source.frameHasAlphaAtIndex(index);

    const IntSize frameSize(index ? m_source.frameSizeAtIndex(index) : m_size);
    if (frameSize != m_size)
        m_hasUniformFrameSize = false;
    if (m_frames[index].m_frame) {
        const int deltaBytes = frameBytes(frameSize);
        m_decodedSize += deltaBytes;
        if (imageObserver())
            imageObserver()->decodedSizeChanged(this, deltaBytes);
    }
}

IntSize BitmapImage::size() const
{
    if (m_sizeAvailable && !m_haveSize) {
        m_size = m_source.size();
        m_haveSize = true;
    }
    return m_size;
}

IntSize BitmapImage::currentFrameSize() const
{
    if (!m_currentFrame || m_hasUniformFrameSize)
        return size();
    return m_source.frameSizeAtIndex(m_currentFrame);
}

bool BitmapImage::dataChanged(bool allDataReceived)
{
    // Because we're modifying the current frame, clear its (now possibly
    // inaccurate) metadata as well.
    destroyMetadataAndNotify((!m_frames.isEmpty() && m_frames[m_frames.size() - 1].clear(true)) ? 1 : 0);
    
    // Feed all the data we've seen so far to the image decoder.
    m_allDataReceived = allDataReceived;
    m_source.setData(m_data.get(), allDataReceived);
    
    // Clear the frame count.
    m_haveFrameCount = false;

    m_hasUniformFrameSize = true;

    // Image properties will not be available until the first frame of the file
    // reaches kCGImageStatusIncomplete.
    return isSizeAvailable();
}

String BitmapImage::filenameExtension() const
{
    return m_source.filenameExtension();
}

size_t BitmapImage::frameCount()
{
    if (!m_haveFrameCount) {
        m_haveFrameCount = true;
        m_frameCount = m_source.frameCount();
    }
    return m_frameCount;
}

bool BitmapImage::isSizeAvailable()
{
    if (m_sizeAvailable)
        return true;

    m_sizeAvailable = m_source.isSizeAvailable();

    return m_sizeAvailable;
}

NativeImagePtr BitmapImage::frameAtIndex(size_t index)
{
    if (index >= frameCount())
        return 0;

    if (index >= m_frames.size() || !m_frames[index].m_frame)
        cacheFrame(index);

    return m_frames[index].m_frame;
}

bool BitmapImage::frameIsCompleteAtIndex(size_t index)
{