/*
 * Copyright (C) 2003, 2004, 2005, 2006, 2009 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 INC. AND ITS 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 APPLE INC. OR ITS 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 "GraphicsContext.h"

#include "BidiResolver.h"
#include "BitmapImage.h"
#include "Generator.h"
#include "ImageBuffer.h"
#include "IntRect.h"
#include "RoundedRect.h"
#include "TextRun.h"

#include "stdio.h"

using namespace std;

namespace WebCore {

class TextRunIterator {
public:
    TextRunIterator()
        : m_textRun(0)
        , m_offset(0)
    {
    }

    TextRunIterator(const TextRun* textRun, unsigned offset)
        : m_textRun(textRun)
        , m_offset(offset)
    {
    }

    TextRunIterator(const TextRunIterator& other)
        : m_textRun(other.m_textRun)
        , m_offset(other.m_offset)
    {
    }

    unsigned offset() const { return m_offset; }
    void increment() { m_offset++; }
    bool atEnd() const { return !m_textRun || m_offset >= m_textRun->length(); }
    UChar current() const { return (*m_textRun)[m_offset]; }
    WTF::Unicode::Direction direction() const { return atEnd() ? WTF::Unicode::OtherNeutral : WTF::Unicode::direction(current()); }

    bool operator==(const TextRunIterator& other)
    {
        return m_offset == other.m_offset && m_textRun == other.m_textRun;
    }

    bool operator!=(const TextRunIterator& other) { return !operator==(other); }

private:
    const TextRun* m_textRun;
    int m_offset;
};

GraphicsContext::GraphicsContext(PlatformGraphicsContext* platformGraphicsContext)
    : m_updatingControlTints(false)
    , m_transparencyCount(0)
{
    platformInit(platformGraphicsContext);
}

GraphicsContext::~GraphicsContext()
{
    ASSERT(m_stack.isEmpty());
    ASSERT(!m_transparencyCount);
    platformDestroy();
}

void GraphicsContext::save()
{
    if (paintingDisabled())
        return;

    m_stack.append(m_state);

    savePlatformState();
}

void GraphicsContext::restore()
{
    if (paintingDisabled())
        return;

    if (m_stack.isEmpty()) {
        LOG_ERROR("ERROR void GraphicsContext::restore() stack is empty");
        return;
    }
    m_state = m_stack.last();
    m_stack.removeLast();

    restorePlatformState();
}

void GraphicsContext::setStrokeThickness(float thickness)
{
    m_state.strokeThickness = thickness;
    setPlatformStrokeThickness(thickness);
}

void GraphicsContext::setStrokeStyle(StrokeStyle style)
{
    m_state.strokeStyle = style;
    setPlatformStrokeStyle(style);
}

void GraphicsContext::setStrokeColor(const Color& color, ColorSpace colorSpace)
{
    m_state.strokeColor = color;
    m_state.strokeColorSpace = colorSpace;
    m_state.strokeGradient.clear();
    m_state.strokePattern.clear();
    setPlatformStrokeColor(color, colorSpace);
}

void GraphicsContext::setShadow(const FloatSize& offset, float blur, const Color& color, ColorSpace colorSpace)
{
    m_state.shadowOffset = offset;
    m_state.shadowBlur = blur;
    m_state.shadowColor = color;
    m_state.shadowColorSpace = colorSpace;
    setPlatformShadow(offset, blur, color, colorSpace);
}

void GraphicsContext::setLegacyShadow(const FloatSize& offset, float blur, const Color& color, ColorSpace colorSpace)
{
    m_state.shadowOffset = offset;
    m_state.shadowBlur = blur;
    m_state.shadowColor = color;
    m_state.shadowColorSpace = colorSpace;
#if USE(CG)
    m_state.shadowsUseLegacyRadius = true;
#endif
    setPlatformShadow(offset, blur, color, colorSpace);
}

void GraphicsContext::clearShadow()
{
    m_state.shadowOffset = FloatSize();
    m_state.shadowBlur = 0;
    m_state.shadowColor = Color();
    m_state.shadowColorSpace = ColorSpaceDeviceRGB;
    clearPlatformShadow();
}

bool GraphicsContext::hasShadow() const
{
    return m_state.shadowColor.isValid() && m_state.shadowColor.alpha()
           && (m_state.shadowBlur || m_state.shadowOffset.width() || m_state.shadowOffset.height());
}

bool GraphicsContext::getShadow(FloatSize& offset, float& blur, Color& color, ColorSpace& colorSpace) const
{
    offset = m_state.shadowOffset;
    blur = m_state.shadowBlur;
    color = m_state.shadowColor;
    colorSpace = m_state.shadowColorSpace;

    return hasShadow();
}

float GraphicsContext::strokeThickness() const
{
    return m_state.strokeThickness;
}

StrokeStyle GraphicsContext::strokeStyle() const
{
    return m_state.strokeStyle;
}

Color GraphicsContext::strokeColor() const
{
    return m_state.strokeColor;
}

ColorSpace GraphicsContext::strokeColorSpace() const
{
    return m_state.strokeColorSpace;
}

WindRule GraphicsContext::fillRule() const
{
    return m_state.fillRule;
}

void GraphicsContext::setFillRule(WindRule fillRule)
{
    m_state.fillRule = fillRule;
}

void GraphicsContext::setFillColor(const Color& color, ColorSpace colorSpace)
{
    m_state.fillColor = color;
    m_state.fillColorSpace = colorSpace;
    m_state.fillGradient.clear();
    m_state.fillPattern.clear();
    setPlatformFillColor(color, colorSpace);
}

Color GraphicsContext::fillColor() const
{
    return m_state.fillColor;
}

ColorSpace GraphicsContext::fillColorSpace() const
{
    return m_state.fillColorSpace;
}

void GraphicsContext::setShouldAntialias(bool b)
{
    m_state.shouldAntialias = b;
    setPlatformShouldAntialias(b);
}

bool GraphicsContext::shouldAntialias() const
{
    return m_state.shouldAntialias;
}

void GraphicsContext::setShouldSmoothFonts(bool b)
{
    m_state.shouldSmoothFonts = b;
    setPlatformShouldSmoothFonts(b);
}

bool GraphicsContext::shouldSmoothFonts() const
{
    return m_state.shouldSmoothFonts;
}

void GraphicsContext::setShouldSubpixelQuantizeFonts(bool b)
{
    m_state.shouldSubpixelQuantizeFonts = b;
}

bool GraphicsContext::shouldSubpixelQuantizeFonts() const
{
    return m_state.shouldSubpixelQuantizeFonts;
}

const GraphicsContextState& GraphicsContext::state() const
{
    return m_state;
}

void GraphicsContext::setStrokePattern(PassRefPtr<Pattern> pattern)
{
    ASSERT(pattern);
    if (!pattern) {
        setStrokeColor(Color::black, ColorSpaceDeviceRGB);
        return;
    }
    m_state.strokeGradient.clear();
    m_state.strokePattern = pattern;
}

void GraphicsContext::setFillPattern(PassRefPtr<Pattern> pattern)
{
    ASSERT(pattern);
    if (!pattern) {
        setFillColor(Color::black, ColorSpaceDeviceRGB);
        return;
    }
    m_state.fillGradient.clear();
    m_state.fillPattern = pattern;
}

void GraphicsContext::setStrokeGradient(PassRefPtr<Gradient> gradient)
{
    ASSERT(gradient);
    if (!gradient) {
        setStrokeColor(Color::black, ColorSpaceDeviceRGB);
        return;
    }
    m_state.strokeGradient = gradient;
    m_state.strokePattern.clear();
}

void GraphicsContext::setFillGradient(PassRefPtr<Gradient> gradient)
{
    ASSERT(gradient);
    if (!gradient) {
        setFillColor(Color::black, ColorSpaceDeviceRGB);
        return;
    }
    m_state.fillGradient = gradient;
    m_state.fillPattern.clear();
}

Gradient* GraphicsContext::fillGradient() const
{
    return m_state.fillGradient.get();
}

Gradient* GraphicsContext::strokeGradient() const
{
    return m_state.strokeGradient.get();
}

Pattern* GraphicsContext::fillPattern() const
{
    return m_state.fillPattern.get();
}

Pattern* GraphicsContext::strokePattern() const
{
    return m_state.strokePattern.get();
}

void GraphicsContext::setShadowsIgnoreTransforms(bool ignoreTransforms)
{
    m_state.shadowsIgnoreTransforms = ignoreTransforms;
}

bool GraphicsContext::shadowsIgnoreTransforms() const
{
    return m_state.shadowsIgnoreTransforms;
}

void GraphicsContext::beginTransparencyLayer(float opacity)
{
    beginPlatformTransparencyLayer(opacity);
    ++m_transparencyCount;
}

void GraphicsContext::endTransparencyLayer()
{
    endPlatformTransparencyLayer();
    ASSERT(m_transparencyCount > 0);
    --m_transparencyCount;
}

#if !PLATFORM(QT)
bool GraphicsContext::isInTransparencyLayer() const
{
    return (m_transparencyCount > 0) && supportsTransparencyLayers();
}
#endif

bool GraphicsContext::updatingControlTints() const
{
    return m_updatingControlTints;
}

void GraphicsContext::setUpdatingControlTints(bool b)
{
    setPaintingDisabled(b);
    m_updatingControlTints = b;
}

void GraphicsContext::setPaintingDisabled(bool f)
{
    m_state.paintingDisabled = f;
}

bool GraphicsContext::paintingDisabled() const
{
    return m_state.paintingDisabled;
}

#if !OS(WINCE) || PLATFORM(QT)
void GraphicsContext::drawText(const Font& font, const TextRun& run, const FloatPoint& point, int from, int to)
{
    if (paintingDisabled())
        return;

    font.drawText(this, run, point, from, to);
}
#endif

void GraphicsContext::drawEmphasisMarks(const Font& font, const TextRun& run, const AtomicString& mark, const FloatPoint& point, int from, int to)
{
    if (paintingDisabled())
        return;

    font.drawEmphasisMarks(this, run, mark, point, from, to);
}

void GraphicsContext::drawBidiText(const Font& font, const TextRun& run, const FloatPoint& point, Font::CustomFontNotReadyAction customFontNotReadyAction)
{
    if (paintingDisabled())
        return;

    BidiResolver<TextRunIterator, BidiCharacterRun> bidiResolver;
    bidiResolver.setStatus(BidiStatus(run.direction(), run.directionalOverride()));
    bidiResolver.setPositionIgnoringNestedIsolates(TextRunIterator(&run, 0));

    // FIXME: This ownership should be reversed. We should pass BidiRunList
    // to BidiResolver in createBidiRunsForLine.
    BidiRunList<BidiCharacterRun>& bidiRuns = bidiResolver.runs();
    bidiResolver.createBidiRunsForLine(TextRunIterator(&run, run.length()));
    if (!bidiRuns.runCount())
        return;

    FloatPoint currPoint = point;
    BidiCharacterRun* bidiRun = bidiRuns.firstRun();
    while (bidiRun) {
        TextRun subrun = run.subRun(bidiRun->start(), bidiRun->stop() - bidiRun->start());
        bool isRTL = bidiRun->level() % 2;
        subrun.setDirection(isRTL ? RTL : LTR);
        subrun.setDirectionalOverride(bidiRun->dirOverride(false));

        font.drawText(this, subrun, currPoint, 0, -1, customFontNotReadyAction);

        bidiRun = bidiRun->next();
        // FIXME: Have Font::drawText return the width of what it drew so that we don't have to re-measure here.
        if (bidiRun)
            currPoint.move(font.width(subrun), 0);
    }

    bidiRuns.deleteRuns();
}

void GraphicsContext::drawHighlightForText(const Font& font, const TextRun& run, const FloatPoint& point, int h, const Color& backgroundColor, ColorSpace colorSpace, int from, int to)
{
    if (paintingDisabled())
        return;

    fillRect(font.selectionRectForText(run, point, h, from, to), backgroundColor, colorSpace);
}

void GraphicsContext::drawImage(Image* image, ColorSpace styleColorSpace, const IntPoint& p, CompositeOperator op, RespectImageOrientationEnum shouldRespectImageOrientation)
{
    if (!image)
        return;
    drawImage(image, styleColorSpace, FloatRect(IntRect(p, image->size())), FloatRect(FloatPoint(), FloatSize(image->size())), op, shouldRespectImageOrientation);
}

void GraphicsContext::drawImage(Image* image, ColorSpace styleColorSpace, const IntRect& r, CompositeOperator op, RespectImageOrientationEnum shouldRespectImageOrientation, bool useLowQualityScale)
{
    if (!image)
        return;
    drawImage(image, styleColorSpace, FloatRect(r), FloatRect(FloatPoint(), FloatSize(image->size())), op, shouldRespectImageOrientation, useLowQualityScale);
}

void GraphicsContext::drawImage(Image* image, ColorSpace styleColorSpace, const IntPoint& dest, const IntRect& srcRect, CompositeOperator op, RespectImageOrientationEnum shouldRespectImageOrientation)
{
    drawImage(image, styleColorSpace, FloatRect(IntRect(dest, srcRect.size())), FloatRect(srcRect), op, shouldRespectImageOrientation);
}

void GraphicsContext::drawImage(Image* image, ColorSpace styleColorSpace, const FloatRect& dest, const FloatRect& src, CompositeOperator op, RespectImageOrientationEnum shouldRespectImageOrientation, bool useLowQualityScale)
{
    drawImage(image, styleColorSpace, dest, src, op, BlendModeNormal, shouldRespectImageOrientation, useLowQualityScale);
}

void GraphicsContext::drawImage(Image* image, ColorSpace styleColorSpace, const FloatRect& dest)
{
    if (!image)
        return;
    drawImage(image, styleColorSpace, dest, FloatRect(IntRect(IntPoint(), image->size())));
}

void GraphicsContext::drawImage(Image* image, ColorSpace styleColorSpace, const FloatRect& dest, const FloatRect& src, CompositeOperator op, BlendMode blendMode, RespectImageOrientationEnum shouldRespectImageOrientation, bool useLowQualityScale)
{    if (paintingDisabled() || !image)
        return;

    InterpolationQuality previousInterpolationQuality = InterpolationDefault;

    if (useLowQualityScale) {
        previousInterpolationQuality = imageInterpolationQuality();
#if PLATFORM(CHROMIUM)
        setImageInterpolationQuality(InterpolationLow);
#else
        // FIXME (49002): Should be InterpolationLow
        setImageInterpolationQuality(InterpolationNone);
#endif
    }

    image->draw(this, dest, src, styleColorSpace, op, blendMode, shouldRespectImageOrientation);

    if (useLowQualityScale)
        setImageInterpolationQuality(previousInterpolationQuality);
}

void GraphicsContext::drawTiledImage(Image* image, ColorSpace styleColorSpace, const IntRect& destRect, const IntPoint& srcPoint, const IntSize& tileSize, CompositeOperator op, bool useLowQualityScale, BlendMode blendMode)
{
    if (paintingDisabled() || !image)
        return;

    if (useLowQualityScale) {
        InterpolationQuality previousInterpolationQuality = imageInterpolationQuality();
        setImageInterpolationQuality(InterpolationLow);
        image->drawTiled(this, destRect, srcPoint, tileSize, styleColorSpace, op, blendMode);
        setImageInterpolationQuality(previousInterpolationQuality);
    } else
        image->drawTiled(this, destRect, srcPoint, tileSize, styleColorSpace, op, blendMode);
}

void GraphicsContext::drawTiledImage(Image* image, ColorSpace styleColorSpace, const IntRect& dest, const IntRect& srcRect,
    const FloatPoint& patternPhase, const AffineTransform& patternTransform, CompositeOperator op, bool useLowQualityScale)
{
    if (paintingDisabled() || !image)
        return;

    if (useLowQualityScale) {
        InterpolationQuality previousInterpolationQuality = imageInterpolationQuality();
        setImageInterpolationQuality(InterpolationLow);
        image->drawTiled(this, dest, srcRect, patternPhase, patternTransform, styleColorSpace, op);
        setImageInterpolationQuality(previousInterpolationQuality);
    } else
        image->drawTiled(this, dest, srcRect, patternPhase, patternTransform, styleColorSpace, op);
}

void GraphicsContext::drawImageBuffer(ImageBuffer* image, ColorSpace styleColorSpace, const IntPoint& p, CompositeOperator op, BlendMode blendMode)
{
    if (!image)
        return;
    drawImageBuffer(image, styleColorSpace, FloatRect(IntRect(p, image->logicalSize())), FloatRect(FloatPoint(), FloatSize(image->logicalSize())), op, blendMode);
}

void GraphicsContext::drawImageBuffer(ImageBuffer* image, ColorSpace styleColorSpace, const IntRect& r, CompositeOperator op, BlendMode blendMode, bool useLowQualityScale)
{
    if (!image)
        return;
    drawImageBuffer(image, styleColorSpace, FloatRect(r), FloatRect(FloatPoint(), FloatSize(image->logicalSize())), op, blendMode, useLowQualityScale);
}

void GraphicsContext::drawImageBuffer(ImageBuffer* image, ColorSpace styleColorSpace, const IntPoint& dest, const IntRect& srcRect, CompositeOperator op, BlendMode blendMode)
{
    drawImageBuffer(image, styleColorSpace, FloatRect(IntRect(dest, srcRect.size())), FloatRect(srcRect), op, blendMode);
}

void GraphicsContext::drawImageBuffer(ImageBuffer* image, ColorSpace styleColorSpace, const IntRect& dest, const IntRect& srcRect, CompositeOperator op, BlendMode blendMode, bool useLowQualityScale)
{
    drawImageBuffer(image, styleColorSpace, FloatRect(dest), FloatRect(srcRect), op, blendMode, useLowQualityScale);
}

void GraphicsContext::drawImageBuffer(ImageBuffer* image, ColorSpace styleColorSpace, const FloatRect& dest)
{
    if (!image)
        return;
    drawImageBuffer(image, styleColorSpace, dest, FloatRect(IntRect(IntPoint(), image->logicalSize())));
}

void GraphicsContext::drawImageBuffer(ImageBuffer* image, ColorSpace styleColorSpace, const FloatRect& dest, const FloatRect& src, CompositeOperator op, BlendMode blendMode, bool useLowQualityScale)
{
    if (paintingDisabled() || !image)
        return;

    if (useLowQualityScale) {
        InterpolationQuality previousInterpolationQuality = imageInterpolationQuality();
#if PLATFORM(CHROMIUM)
        setImageInterpolationQuality(InterpolationLow);
#else
        // FIXME (49002): Should be InterpolationLow
        setImageInterpolationQuality(InterpolationNone);
#endif
        image->draw(this, styleColorSpace, dest, src, op, blendMode, useLowQualityScale);
        setImageInterpolationQuality(previousInterpolationQuality);
    } else
        image->draw(this, styleColorSpace, dest, src, op, blendMode, useLowQualityScale);
}

#if !PLATFORM(QT)
void GraphicsContext::clip(const IntRect& rect)
{
    clip(FloatRect(rect));
}
#endif

#if !USE(SKIA)
void GraphicsContext::clipRoundedRect(const RoundedRect& rect)
{
    if (paintingDisabled())
        return;

    if (!rect.isRounded()) {
        clip(rect.rect());
        return;
    }

    Path path;
    path.addRoundedRect(rect);
    clip(path);
}
#endif

void GraphicsContext::clipOutRoundedRect(const RoundedRect& rect)
{
    if (paintingDisabled())
        return;

    if (!rect.isRounded()) {
        clipOut(rect.rect());
        return;
    }

    Path path;
    path.addRoundedRect(rect);
    clipOut(path);
}

void GraphicsContext::clipToImageBuffer(ImageBuffer* buffer, const FloatRect& rect)
{
    if (paintingDisabled())
        return;
    buffer->clip(this, rect);
}

#if !USE(CG) && !PLATFORM(QT) && !USE(CAIRO)
IntRect GraphicsContext::clipBounds() const
{
    ASSERT_NOT_REACHED();
    return IntRect();
}
#endif

TextDrawingModeFlags GraphicsContext::textDrawingMode() const
{
    return m_state.textDrawingMode;
}

void GraphicsContext::setTextDrawingMode(TextDrawingModeFlags mode)
{
    m_state.textDrawingMode = mode;
    if (paintingDisabled())
        return;
    setPlatformTextDrawingMode(mode);
}

void GraphicsContext::fillRect(const FloatRect& rect, Generator& generator)
{
    if (paintingDisabled())
        return;
    generator.fill(this, rect);
}

void GraphicsContext::fillRect(const FloatRect& rect, const Color& color, ColorSpace styleColorSpace, CompositeOperator op)
{
    if (paintingDisabled())
        return;

    CompositeOperator previousOperator = compositeOperation();
    setCompositeOperation(op);
    fillRect(rect, color, styleColorSpace);
    setCompositeOperation(previousOperator);
}

void GraphicsContext::fillRoundedRect(const RoundedRect& rect, const Color& color, ColorSpace colorSpace)
{
    if (rect.isRounded())
        fillRoundedRect(rect.rect(), rect.radii().topLeft(), rect.radii().topRight(), rect.radii().bottomLeft(), rect.radii().bottomRight(), color, colorSpace);
    else
        fillRect(rect.rect(), color, colorSpace);
}

#if !USE(CG)
void GraphicsContext::fillRectWithRoundedHole(const IntRect& rect, const RoundedRect& roundedHoleRect, const Color& color, ColorSpace colorSpace)
{
    if (paintingDisabled())
        return;

    Path path;
    path.addRect(rect);

    if (!roundedHoleRect.radii().isZero())
        path.addRoundedRect(roundedHoleRect);
    else
        path.addRect(roundedHoleRect.rect());

    WindRule oldFillRule = fillRule();
    Color oldFillColor = fillColor();
    ColorSpace oldFillColorSpace = fillColorSpace();
    
    setFillRule(RULE_EVENODD);
    setFillColor(color, colorSpace);

    fillPath(path);
    
    setFillRule(oldFillRule);
    setFillColor(oldFillColor, oldFillColorSpace);
}
#endif

void GraphicsContext::setCompositeOperation(CompositeOperator compositeOperation, BlendMode blendMode)
{
    m_state.compositeOperator = compositeOperation;
    m_state.blendMode = blendMode;
    setPlatformCompositeOperation(compositeOperation, blendMode);
}

CompositeOperator GraphicsContext::compositeOperation() const
{
    return m_state.compositeOperator;
}

BlendMode GraphicsContext::blendModeOperation() const
{
    return m_state.blendMode;
}

#if !USE(CG) && !USE(SKIA)
// Implement this if you want to go ahead and push the drawing mode into your native context
// immediately.
void GraphicsContext::setPlatformTextDrawingMode(TextDrawingModeFlags)
{
}
#endif

#if !PLATFORM(QT) && !USE(CAIRO) && !USE(SKIA) && !PLATFORM(OPENVG)
void GraphicsContext::setPlatformStrokeStyle(StrokeStyle)
{
}
#endif

#if !USE(CG)
void GraphicsContext::setPlatformShouldSmoothFonts(bool)
{
}
#endif

#if !USE(SKIA) && !USE(CG)
bool GraphicsContext::isAcceleratedContext() const
{
    return false;
}
#endif

void GraphicsContext::adjustLineToPixelBoundaries(FloatPoint& p1, FloatPoint& p2, float strokeWidth, StrokeStyle penStyle)
{
    // For odd widths, we add in 0.5 to the appropriate x/y so that the float arithmetic
    // works out.  For example, with a border width of 3, WebKit will pass us (y1+y2)/2, e.g.,
    // (50+53)/2 = 103/2 = 51 when we want 51.5.  It is always true that an even width gave
    // us a perfect position, but an odd width gave us a position that is off by exactly 0.5.
    if (penStyle == DottedStroke || penStyle == DashedStroke) {
        if (p1.x() == p2.x()) {
            p1.setY(p1.y() + strokeWidth);
            p2.setY(p2.y() - strokeWidth);
        } else {
            p1.setX(p1.x() + strokeWidth);
            p2.setX(p2.x() - strokeWidth);
        }
    }

    if (static_cast<int>(strokeWidth) % 2) { //odd
        if (p1.x() == p2.x()) {
            // We're a vertical line.  Adjust our x.
            p1.setX(p1.x() + 0.5f);
            p2.setX(p2.x() + 0.5f);
        } else {
            // We're a horizontal line. Adjust our y.
            p1.setY(p1.y() + 0.5f);
            p2.setY(p2.y() + 0.5f);
        }
    }
}

static bool scalesMatch(AffineTransform a, AffineTransform b)
{
    return a.xScale() == b.xScale() && a.yScale() == b.yScale();
}

PassOwnPtr<ImageBuffer> GraphicsContext::createCompatibleBuffer(const IntSize& size, bool hasAlpha) const
{
    // Make the buffer larger if the context's transform is scaling it so we need a higher
    // resolution than one pixel per unit. Also set up a corresponding scale factor on the
    // graphics context.

    AffineTransform transform = getCTM(DefinitelyIncludeDeviceScale);
    IntSize scaledSize(static_cast<int>(ceil(size.width() * transform.xScale())), static_cast<int>(ceil(size.height() * transform.yScale())));

    OwnPtr<ImageBuffer> buffer = ImageBuffer::createCompatibleBuffer(scaledSize, 1, ColorSpaceDeviceRGB, this, hasAlpha);
    if (!buffer)
        return nullptr;

    buffer->context()->scale(FloatSize(static_cast<float>(scaledSize.width()) / size.width(),
        static_cast<float>(scaledSize.height()) / size.height()));

    return buffer.release();
}

bool GraphicsContext::isCompatibleWithBuffer(ImageBuffer* buffer) const
{
    GraphicsContext* bufferContext = buffer->context();

    return scalesMatch(getCTM(), bufferContext->getCTM()) && isAcceleratedContext() == bufferContext->isAcceleratedContext();
}

#if !USE(CG)
void GraphicsContext::platformApplyDeviceScaleFactor(float)
{
}
#endif

void GraphicsContext::applyDeviceScaleFactor(float deviceScaleFactor)
{
    scale(FloatSize(deviceScaleFactor, deviceScaleFactor));
    platformApplyDeviceScaleFactor(deviceScaleFactor);
}

void GraphicsContext::fillEllipse(const FloatRect& ellipse)
{
    platformFillEllipse(ellipse);
}

void GraphicsContext::strokeEllipse(const FloatRect& ellipse)
{
    platformStrokeEllipse(ellipse);
}

void GraphicsContext::fillEllipseAsPath(const FloatRect& ellipse)
{
    Path path;
    path.addEllipse(ellipse);
    fillPath(path);
}

void GraphicsContext::strokeEllipseAsPath(const FloatRect& ellipse)
{
    Path path;
    path.addEllipse(ellipse);
    strokePath(path);
}

#if !USE(CG) && !USE(SKIA) // append && !USE(MYPLATFORM) here to optimize ellipses on your platform.
void GraphicsContext::platformFillEllipse(const FloatRect& ellipse)
{
    if (paintingDisabled())
        return;

    fillEllipseAsPath(ellipse);
}

void GraphicsContext::platformStrokeEllipse(const FloatRect& ellipse)
{
    if (paintingDisabled())
        return;

    strokeEllipseAsPath(ellipse);
}
#endif

}
