root/Source/core/css/CSSCrossfadeValue.cpp

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DEFINITIONS

This source file includes following definitions.
  1. subimageIsPending
  2. subimageKnownToBeOpaque
  3. cachedImageForCSSValue
  4. customCSSText
  5. fixedSize
  6. isPending
  7. knownToBeOpaque
  8. loadSubimages
  9. image
  10. crossfadeChanged
  11. imageChanged
  12. hasFailedOrCanceledSubresources
  13. equals
  14. traceAfterDispatch

/*
 * Copyright (C) 2011 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 "core/css/CSSCrossfadeValue.h"

#include "core/css/CSSImageValue.h"
#include "core/rendering/RenderObject.h"
#include "core/rendering/style/StyleFetchedImage.h"
#include "platform/graphics/CrossfadeGeneratedImage.h"
#include "wtf/text/StringBuilder.h"

namespace WebCore {

static bool subimageIsPending(CSSValue* value)
{
    if (value->isImageValue())
        return toCSSImageValue(value)->cachedOrPendingImage()->isPendingImage();

    if (value->isImageGeneratorValue())
        return toCSSImageGeneratorValue(value)->isPending();

    ASSERT_NOT_REACHED();

    return false;
}

static bool subimageKnownToBeOpaque(CSSValue* value, const RenderObject* renderer)
{
    if (value->isImageValue())
        return toCSSImageValue(value)->knownToBeOpaque(renderer);

    if (value->isImageGeneratorValue())
        return toCSSImageGeneratorValue(value)->knownToBeOpaque(renderer);

    ASSERT_NOT_REACHED();

    return false;
}

static ImageResource* cachedImageForCSSValue(CSSValue* value, ResourceFetcher* fetcher)
{
    if (!value)
        return 0;

    if (value->isImageValue()) {
        StyleFetchedImage* styleImageResource = toCSSImageValue(value)->cachedImage(fetcher);
        if (!styleImageResource)
            return 0;

        return styleImageResource->cachedImage();
    }

    if (value->isImageGeneratorValue()) {
        toCSSImageGeneratorValue(value)->loadSubimages(fetcher);
        // FIXME: Handle CSSImageGeneratorValue (and thus cross-fades with gradients and canvas).
        return 0;
    }

    ASSERT_NOT_REACHED();

    return 0;
}

CSSCrossfadeValue::~CSSCrossfadeValue()
{
    if (m_cachedFromImage)
        m_cachedFromImage->removeClient(&m_crossfadeSubimageObserver);
    if (m_cachedToImage)
        m_cachedToImage->removeClient(&m_crossfadeSubimageObserver);
}

String CSSCrossfadeValue::customCSSText() const
{
    StringBuilder result;
    result.appendLiteral("-webkit-cross-fade(");
    result.append(m_fromValue->cssText());
    result.appendLiteral(", ");
    result.append(m_toValue->cssText());
    result.appendLiteral(", ");
    result.append(m_percentageValue->cssText());
    result.append(')');
    return result.toString();
}

IntSize CSSCrossfadeValue::fixedSize(const RenderObject* renderer)
{
    float percentage = m_percentageValue->getFloatValue();
    float inversePercentage = 1 - percentage;

    ResourceFetcher* fetcher = renderer->document().fetcher();
    ImageResource* cachedFromImage = cachedImageForCSSValue(m_fromValue.get(), fetcher);
    ImageResource* cachedToImage = cachedImageForCSSValue(m_toValue.get(), fetcher);

    if (!cachedFromImage || !cachedToImage)
        return IntSize();

    IntSize fromImageSize = cachedFromImage->imageForRenderer(renderer)->size();
    IntSize toImageSize = cachedToImage->imageForRenderer(renderer)->size();

    // Rounding issues can cause transitions between images of equal size to return
    // a different fixed size; avoid performing the interpolation if the images are the same size.
    if (fromImageSize == toImageSize)
        return fromImageSize;

    return IntSize(fromImageSize.width() * inversePercentage + toImageSize.width() * percentage,
        fromImageSize.height() * inversePercentage + toImageSize.height() * percentage);
}

bool CSSCrossfadeValue::isPending() const
{
    return subimageIsPending(m_fromValue.get()) || subimageIsPending(m_toValue.get());
}

bool CSSCrossfadeValue::knownToBeOpaque(const RenderObject* renderer) const
{
    return subimageKnownToBeOpaque(m_fromValue.get(), renderer) && subimageKnownToBeOpaque(m_toValue.get(), renderer);
}

void CSSCrossfadeValue::loadSubimages(ResourceFetcher* fetcher)
{
    ResourcePtr<ImageResource> oldCachedFromImage = m_cachedFromImage;
    ResourcePtr<ImageResource> oldCachedToImage = m_cachedToImage;

    m_cachedFromImage = cachedImageForCSSValue(m_fromValue.get(), fetcher);
    m_cachedToImage = cachedImageForCSSValue(m_toValue.get(), fetcher);

    if (m_cachedFromImage != oldCachedFromImage) {
        if (oldCachedFromImage)
            oldCachedFromImage->removeClient(&m_crossfadeSubimageObserver);
        if (m_cachedFromImage)
            m_cachedFromImage->addClient(&m_crossfadeSubimageObserver);
    }

    if (m_cachedToImage != oldCachedToImage) {
        if (oldCachedToImage)
            oldCachedToImage->removeClient(&m_crossfadeSubimageObserver);
        if (m_cachedToImage)
            m_cachedToImage->addClient(&m_crossfadeSubimageObserver);
    }

    m_crossfadeSubimageObserver.setReady(true);
}

PassRefPtr<Image> CSSCrossfadeValue::image(RenderObject* renderer, const IntSize& size)
{
    if (size.isEmpty())
        return nullptr;

    ResourceFetcher* fetcher = renderer->document().fetcher();
    ImageResource* cachedFromImage = cachedImageForCSSValue(m_fromValue.get(), fetcher);
    ImageResource* cachedToImage = cachedImageForCSSValue(m_toValue.get(), fetcher);

    if (!cachedFromImage || !cachedToImage)
        return Image::nullImage();

    Image* fromImage = cachedFromImage->imageForRenderer(renderer);
    Image* toImage = cachedToImage->imageForRenderer(renderer);

    if (!fromImage || !toImage)
        return Image::nullImage();

    m_generatedImage = CrossfadeGeneratedImage::create(fromImage, toImage, m_percentageValue->getFloatValue(), fixedSize(renderer), size);

    return m_generatedImage.release();
}

void CSSCrossfadeValue::crossfadeChanged(const IntRect&)
{
    RenderObjectSizeCountMap::const_iterator end = clients().end();
    for (RenderObjectSizeCountMap::const_iterator curr = clients().begin(); curr != end; ++curr) {
        RenderObject* client = const_cast<RenderObject*>(curr->key);
        client->imageChanged(static_cast<WrappedImagePtr>(this));
    }
}

void CSSCrossfadeValue::CrossfadeSubimageObserverProxy::imageChanged(ImageResource*, const IntRect* rect)
{
    if (m_ready)
        m_ownerValue->crossfadeChanged(*rect);
}

bool CSSCrossfadeValue::hasFailedOrCanceledSubresources() const
{
    if (m_cachedFromImage && m_cachedFromImage->loadFailedOrCanceled())
        return true;
    if (m_cachedToImage && m_cachedToImage->loadFailedOrCanceled())
        return true;
    return false;
}

bool CSSCrossfadeValue::equals(const CSSCrossfadeValue& other) const
{
    return compareCSSValuePtr(m_fromValue, other.m_fromValue)
        && compareCSSValuePtr(m_toValue, other.m_toValue)
        && compareCSSValuePtr(m_percentageValue, other.m_percentageValue);
}

void CSSCrossfadeValue::traceAfterDispatch(Visitor* visitor)
{
    visitor->trace(m_fromValue);
    visitor->trace(m_toValue);
    visitor->trace(m_percentageValue);
    CSSImageGeneratorValue::traceAfterDispatch(visitor);
}

} // namespace WebCore

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