Source/platform/graphics/Image.cpp

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This source file includes following definitions.
nullImage
loadPlatformResource
supportsType
setData
fillWithSolidColor
adjustForNegativeSize
draw
drawTiled
drawTiled
drawPattern
computeIntrinsicDimensions
/*
 * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
 * Copyright (C) 2004, 2005, 2006 Apple Computer, 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 "platform/graphics/Image.h"

#include "platform/Length.h"
#include "platform/MIMETypeRegistry.h"
#include "platform/SharedBuffer.h"
#include "platform/TraceEvent.h"
#include "platform/geometry/FloatPoint.h"
#include "platform/geometry/FloatRect.h"
#include "platform/geometry/FloatSize.h"
#include "platform/graphics/BitmapImage.h"
#include "platform/graphics/GraphicsContext.h"
#include "platform/graphics/GraphicsContextStateSaver.h"
#include "public/platform/Platform.h"
#include "public/platform/WebData.h"
#include "wtf/MainThread.h"
#include "wtf/StdLibExtras.h"

#include <math.h>

namespace WebCore {

Image::Image(ImageObserver* observer)
    : m_imageObserver(observer)
{
}

Image::~Image()
{
}

Image* Image::nullImage()
{
    ASSERT(isMainThread());
    DEFINE_STATIC_REF(Image, nullImage, (BitmapImage::create()));
    return nullImage;
}

PassRefPtr<Image> Image::loadPlatformResource(const char *name)
{
    const blink::WebData& resource = blink::Platform::current()->loadResource(name);
    if (resource.isEmpty())
        return Image::nullImage();

    RefPtr<Image> image = BitmapImage::create();
    image->setData(resource, true);
    return image.release();
}

bool Image::supportsType(const String& type)
{
    return MIMETypeRegistry::isSupportedImageResourceMIMEType(type);
}

bool Image::setData(PassRefPtr<SharedBuffer> data, bool allDataReceived)
{
    m_encodedImageData = data;
    if (!m_encodedImageData.get())
        return true;

    int length = m_encodedImageData->size();
    if (!length)
        return true;

    return dataChanged(allDataReceived);
}

void Image::fillWithSolidColor(GraphicsContext* ctxt, const FloatRect& dstRect, const Color& color, CompositeOperator op)
{
    if (!color.alpha())
        return;

    CompositeOperator previousOperator = ctxt->compositeOperation();
    ctxt->setCompositeOperation(!color.hasAlpha() && op == CompositeSourceOver ? CompositeCopy : op);
    ctxt->fillRect(dstRect, color);
    ctxt->setCompositeOperation(previousOperator);
}

FloatRect Image::adjustForNegativeSize(const FloatRect& rect)
{
    FloatRect norm = rect;
    if (norm.width() < 0) {
        norm.setX(norm.x() + norm.width());
        norm.setWidth(-norm.width());
    }
    if (norm.height() < 0) {
        norm.setY(norm.y() + norm.height());
        norm.setHeight(-norm.height());
    }
    return norm;
}

void Image::draw(GraphicsContext* ctx, const FloatRect& dstRect, const FloatRect& srcRect, CompositeOperator op, blink::WebBlendMode blendMode, RespectImageOrientationEnum)
{
    draw(ctx, dstRect, srcRect, op, blendMode);
}

void Image::drawTiled(GraphicsContext* ctxt, const FloatRect& destRect, const FloatPoint& srcPoint, const FloatSize& scaledTileSize, CompositeOperator op, blink::WebBlendMode blendMode, const IntSize& repeatSpacing)
{
    if (mayFillWithSolidColor()) {
        fillWithSolidColor(ctxt, destRect, solidColor(), op);
        return;
    }

    // See <https://webkit.org/b/59043>.
    ASSERT(!isBitmapImage() || notSolidColor());

    FloatSize intrinsicTileSize = size();
    if (hasRelativeWidth())
        intrinsicTileSize.setWidth(scaledTileSize.width());
    if (hasRelativeHeight())
        intrinsicTileSize.setHeight(scaledTileSize.height());

    FloatSize scale(scaledTileSize.width() / intrinsicTileSize.width(),
                    scaledTileSize.height() / intrinsicTileSize.height());

    FloatSize actualTileSize(scaledTileSize.width() + repeatSpacing.width(), scaledTileSize.height() + repeatSpacing.height());
    FloatRect oneTileRect;
    oneTileRect.setX(destRect.x() + fmodf(fmodf(-srcPoint.x(), actualTileSize.width()) - actualTileSize.width(), actualTileSize.width()));
    oneTileRect.setY(destRect.y() + fmodf(fmodf(-srcPoint.y(), actualTileSize.height()) - actualTileSize.height(), actualTileSize.height()));
    oneTileRect.setSize(scaledTileSize);

    // Check and see if a single draw of the image can cover the entire area we are supposed to tile.
    if (oneTileRect.contains(destRect)) {
        FloatRect visibleSrcRect;
        visibleSrcRect.setX((destRect.x() - oneTileRect.x()) / scale.width());
        visibleSrcRect.setY((destRect.y() - oneTileRect.y()) / scale.height());
        visibleSrcRect.setWidth(destRect.width() / scale.width());
        visibleSrcRect.setHeight(destRect.height() / scale.height());
        draw(ctxt, destRect, visibleSrcRect, op, blendMode);
        return;
    }

    FloatRect tileRect(FloatPoint(), intrinsicTileSize);
    drawPattern(ctxt, tileRect, scale, oneTileRect.location(), op, destRect, blendMode, repeatSpacing);

    startAnimation();
}

// FIXME: Merge with the other drawTiled eventually, since we need a combination of both for some things.
void Image::drawTiled(GraphicsContext* ctxt, const FloatRect& dstRect, const FloatRect& srcRect,
    const FloatSize& providedTileScaleFactor, TileRule hRule, TileRule vRule, CompositeOperator op)
{
    if (mayFillWithSolidColor()) {
        fillWithSolidColor(ctxt, dstRect, solidColor(), op);
        return;
    }

    // FIXME: We do not support 'space' yet. For now just map it to 'repeat'.
    if (hRule == SpaceTile)
        hRule = RepeatTile;
    if (vRule == SpaceTile)
        vRule = RepeatTile;

    // FIXME: if this code is used for background-repeat: round (in addition to
    // border-image-repeat), then add logic to deal with the background-size: auto
    // special case. The aspect ratio should be maintained in this case.
    FloatSize tileScaleFactor = providedTileScaleFactor;
    bool useLowInterpolationQuality = false;
    if (hRule == RoundTile) {
        float hRepetitions = std::max(1.0f, roundf(dstRect.width() / (tileScaleFactor.width() * srcRect.width())));
        tileScaleFactor.setWidth(dstRect.width() / (srcRect.width() * hRepetitions));
    }
    if (vRule == RoundTile) {
        float vRepetitions = std::max(1.0f, roundf(dstRect.height() / (tileScaleFactor.height() * srcRect.height())));
        tileScaleFactor.setHeight(dstRect.height() / (srcRect.height() * vRepetitions));
    }
    if (hRule == RoundTile || vRule == RoundTile) {
        // High interpolation quality rounds the scaled tile to an integer size (see Image::drawPattern).
        // To avoid causing a visual problem, linear interpolation must be used instead.
        // FIXME: Allow using high-quality interpolation in this case, too.
        useLowInterpolationQuality = true;
    }

    // We want to construct the phase such that the pattern is centered (when stretch is not
    // set for a particular rule).
    float hPhase = tileScaleFactor.width() * srcRect.x();
    float vPhase = tileScaleFactor.height() * srcRect.y();
    float scaledTileWidth = tileScaleFactor.width() * srcRect.width();
    float scaledTileHeight = tileScaleFactor.height() * srcRect.height();
    if (hRule == Image::RepeatTile)
        hPhase -= (dstRect.width() - scaledTileWidth) / 2;
    if (vRule == Image::RepeatTile)
        vPhase -= (dstRect.height() - scaledTileHeight) / 2;
    FloatPoint patternPhase(dstRect.x() - hPhase, dstRect.y() - vPhase);

    if (useLowInterpolationQuality) {
        InterpolationQuality previousInterpolationQuality = ctxt->imageInterpolationQuality();
        ctxt->setImageInterpolationQuality(InterpolationLow);
        drawPattern(ctxt, srcRect, tileScaleFactor, patternPhase, op, dstRect);
        ctxt->setImageInterpolationQuality(previousInterpolationQuality);
    } else {
        drawPattern(ctxt, srcRect, tileScaleFactor, patternPhase, op, dstRect);
    }

    startAnimation();
}

void Image::drawPattern(GraphicsContext* context, const FloatRect& floatSrcRect, const FloatSize& scale,
    const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& destRect, blink::WebBlendMode blendMode, const IntSize& repeatSpacing)
{
    TRACE_EVENT0("skia", "Image::drawPattern");
    if (RefPtr<NativeImageSkia> bitmap = nativeImageForCurrentFrame())
        bitmap->drawPattern(context, adjustForNegativeSize(floatSrcRect), scale, phase, compositeOp, destRect, blendMode, repeatSpacing);
}

void Image::computeIntrinsicDimensions(Length& intrinsicWidth, Length& intrinsicHeight, FloatSize& intrinsicRatio)
{
    intrinsicRatio = size();
    intrinsicWidth = Length(intrinsicRatio.width(), Fixed);
    intrinsicHeight = Length(intrinsicRatio.height(), Fixed);
}

}
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root/Source/platform/graphics/Image.cpp

DEFINITIONS
