/*
 * Copyright (C) 2006 Apple Inc.  All rights reserved.
 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
 * Copyright (C) 2008, 2009 Dirk Schulze <krit@webkit.org>
 * Copyright (C) 2008 Nuanti Ltd.
 * Copyright (C) 2009 Brent Fulgham <bfulgham@webkit.org>
 * Copyright (C) 2010, 2011 Igalia S.L.
 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
 * Copyright (C) 2012, Intel Corporation
 *
 * 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. ``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
 * 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"

#if USE(CAIRO)

#include "AffineTransform.h"
#include "CairoUtilities.h"
#include "DisplayListRecorder.h"
#include "DrawErrorUnderline.h"
#include "FloatConversion.h"
#include "FloatRect.h"
#include "FloatRoundedRect.h"
#include "Font.h"
#include "GraphicsContextPlatformPrivateCairo.h"
#include "ImageBuffer.h"
#include "IntRect.h"
#include "NotImplemented.h"
#include "Path.h"
#include "Pattern.h"
#include "PlatformContextCairo.h"
#include "PlatformPathCairo.h"
#include "RefPtrCairo.h"
#include "ShadowBlur.h"
#include "TransformationMatrix.h"
#include <cairo.h>
#include <math.h>
#include <stdio.h>
#include <wtf/MathExtras.h>

#if PLATFORM(WIN)
#include <cairo-win32.h>
#endif

using namespace std;

namespace WebCore {

// A helper which quickly fills a rectangle with a simple color fill.
static inline void fillRectWithColor(cairo_t* cr, const FloatRect& rect, const Color& color)
{
    if (!color.isVisible() && cairo_get_operator(cr) == CAIRO_OPERATOR_OVER)
        return;

    setSourceRGBAFromColor(cr, color);
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    cairo_fill(cr);
}

enum PathDrawingStyle { 
    Fill = 1,
    Stroke = 2,
    FillAndStroke = Fill + Stroke
};

static inline void drawPathShadow(GraphicsContext& context, PathDrawingStyle drawingStyle)
{
    ShadowBlur& shadow = context.platformContext()->shadowBlur();
    if (shadow.type() == ShadowBlur::NoShadow)
        return;

    // Calculate the extents of the rendered solid paths.
    cairo_t* cairoContext = context.platformContext()->cr();
    std::unique_ptr<cairo_path_t, void(*)(cairo_path_t*)> path(cairo_copy_path(cairoContext), [](cairo_path_t* path) {
        cairo_path_destroy(path);
    });

    FloatRect solidFigureExtents;
    double x0 = 0;
    double x1 = 0;
    double y0 = 0;
    double y1 = 0;
    if (drawingStyle & Stroke) {
        cairo_stroke_extents(cairoContext, &x0, &y0, &x1, &y1);
        solidFigureExtents = FloatRect(x0, y0, x1 - x0, y1 - y0);
    }
    if (drawingStyle & Fill) {
        cairo_fill_extents(cairoContext, &x0, &y0, &x1, &y1);
        FloatRect fillExtents(x0, y0, x1 - x0, y1 - y0);
        solidFigureExtents.unite(fillExtents);
    }

    GraphicsContext* shadowContext = shadow.beginShadowLayer(context, solidFigureExtents);
    if (!shadowContext)
        return;

    cairo_t* cairoShadowContext = shadowContext->platformContext()->cr();

    // It's important to copy the context properties to the new shadow
    // context to preserve things such as the fill rule and stroke width.
    copyContextProperties(cairoContext, cairoShadowContext);

    if (drawingStyle & Fill) {
        cairo_save(cairoShadowContext);
        cairo_append_path(cairoShadowContext, path.get());
        shadowContext->platformContext()->prepareForFilling(context.state(), PlatformContextCairo::NoAdjustment);
        cairo_fill(cairoShadowContext);
        cairo_restore(cairoShadowContext);
    }

    if (drawingStyle & Stroke) {
        cairo_append_path(cairoShadowContext, path.get());
        shadowContext->platformContext()->prepareForStroking(context.state(), PlatformContextCairo::DoNotPreserveAlpha);
        cairo_stroke(cairoShadowContext);
    }

    // The original path may still be hanging around on the context and endShadowLayer
    // will take care of properly creating a path to draw the result shadow. We remove the path
    // temporarily and then restore it.
    // See: https://bugs.webkit.org/show_bug.cgi?id=108897
    cairo_new_path(cairoContext);
    shadow.endShadowLayer(context);
    cairo_append_path(cairoContext, path.get());
}

static inline void fillCurrentCairoPath(GraphicsContext& context)
{
    cairo_t* cr = context.platformContext()->cr();
    cairo_save(cr);

    context.platformContext()->prepareForFilling(context.state(), PlatformContextCairo::AdjustPatternForGlobalAlpha);
    cairo_fill(cr);

    cairo_restore(cr);
}

static inline void shadowAndFillCurrentCairoPath(GraphicsContext& context)
{
    drawPathShadow(context, Fill);
    fillCurrentCairoPath(context);
}

static inline void shadowAndStrokeCurrentCairoPath(GraphicsContext& context)
{
    drawPathShadow(context, Stroke);
    context.platformContext()->prepareForStroking(context.state());
    cairo_stroke(context.platformContext()->cr());
}

GraphicsContext::GraphicsContext(cairo_t* cr)
{
    if (!cr)
        return;

    m_data = new GraphicsContextPlatformPrivateToplevel(new PlatformContextCairo(cr));
}

void GraphicsContext::platformInit(PlatformContextCairo* platformContext)
{
    if (!platformContext)
        return;

    m_data = new GraphicsContextPlatformPrivate(platformContext);
    m_data->syncContext(platformContext->cr());
}

void GraphicsContext::platformDestroy()
{
    delete m_data;
}

AffineTransform GraphicsContext::getCTM(IncludeDeviceScale) const
{
    if (paintingDisabled())
        return AffineTransform();

    if (isRecording()) {
        WTFLogAlways("GraphicsContext::getCTM() is not yet compatible with recording contexts.");
        return AffineTransform();
    }

    cairo_t* cr = platformContext()->cr();
    cairo_matrix_t m;
    cairo_get_matrix(cr, &m);
    return AffineTransform(m.xx, m.yx, m.xy, m.yy, m.x0, m.y0);
}

PlatformContextCairo* GraphicsContext::platformContext() const
{
    return m_data->platformContext;
}

void GraphicsContext::savePlatformState()
{
    ASSERT(!isRecording());
    platformContext()->save();
    m_data->save();
}

void GraphicsContext::restorePlatformState()
{
    ASSERT(!isRecording());
    platformContext()->restore();
    m_data->restore();

    platformContext()->shadowBlur().setShadowValues(FloatSize(m_state.shadowBlur, m_state.shadowBlur),
                                                    m_state.shadowOffset,
                                                    m_state.shadowColor,
                                                    m_state.shadowsIgnoreTransforms);
}

// Draws a filled rectangle with a stroked border.
void GraphicsContext::drawRect(const FloatRect& rect, float borderThickness)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->drawRect(rect, borderThickness);
        return;
    }

    ASSERT(!rect.isEmpty());

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);

    fillRectWithColor(cr, rect, fillColor());

    if (strokeStyle() != NoStroke) {
        setSourceRGBAFromColor(cr, strokeColor());
        FloatRect r(rect);
        r.inflate(-.5f);
        cairo_rectangle(cr, r.x(), r.y(), r.width(), r.height());
        cairo_set_line_width(cr, 1.0); // borderThickness?
        cairo_stroke(cr);
    }

    cairo_restore(cr);
}

void GraphicsContext::drawNativeImage(const NativeImagePtr& image, const FloatSize& imageSize, const FloatRect& destRect, const FloatRect& srcRect, CompositeOperator op, BlendMode blendMode, ImageOrientation orientation)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->drawNativeImage(image, imageSize, destRect, srcRect, op, blendMode, orientation);
        return;
    }

    platformContext()->save();

    // Set the compositing operation.
    if (op == CompositeSourceOver && blendMode == BlendModeNormal)
        setCompositeOperation(CompositeCopy);
    else
        setCompositeOperation(op, blendMode);

    FloatRect dst = destRect;

    if (orientation != DefaultImageOrientation) {
        // ImageOrientation expects the origin to be at (0, 0).
        translate(dst.x(), dst.y());
        dst.setLocation(FloatPoint());
        concatCTM(orientation.transformFromDefault(dst.size()));
        if (orientation.usesWidthAsHeight()) {
            // The destination rectangle will have its width and height already reversed for the orientation of
            // the image, as it was needed for page layout, so we need to reverse it back here.
            dst = FloatRect(dst.x(), dst.y(), dst.height(), dst.width());
        }
    }

    platformContext()->drawSurfaceToContext(image.get(), dst, srcRect, *this);
    platformContext()->restore();
}

// This is only used to draw borders, so we should not draw shadows.
void GraphicsContext::drawLine(const FloatPoint& point1, const FloatPoint& point2)
{
    if (paintingDisabled())
        return;

    if (strokeStyle() == NoStroke)
        return;

    if (isRecording()) {
        m_displayListRecorder->drawLine(point1, point2);
        return;
    }

    const Color& strokeColor = this->strokeColor();
    float thickness = strokeThickness();
    bool isVerticalLine = (point1.x() + thickness == point2.x());
    float strokeWidth = isVerticalLine ? point2.y() - point1.y() : point2.x() - point1.x();
    if (!thickness || !strokeWidth)
        return;

    cairo_t* cairoContext = platformContext()->cr();
    StrokeStyle strokeStyle = this->strokeStyle();
    float cornerWidth = 0;
    bool drawsDashedLine = strokeStyle == DottedStroke || strokeStyle == DashedStroke;

    if (drawsDashedLine) {
        cairo_save(cairoContext);
        // Figure out end points to ensure we always paint corners.
        cornerWidth = dashedLineCornerWidthForStrokeWidth(strokeWidth);
        if (isVerticalLine) {
            fillRectWithColor(cairoContext, FloatRect(point1.x(), point1.y(), thickness, cornerWidth), strokeColor);
            fillRectWithColor(cairoContext, FloatRect(point1.x(), point2.y() - cornerWidth, thickness, cornerWidth), strokeColor);
        } else {
            fillRectWithColor(cairoContext, FloatRect(point1.x(), point1.y(), cornerWidth, thickness), strokeColor);
            fillRectWithColor(cairoContext, FloatRect(point2.x() - cornerWidth, point1.y(), cornerWidth, thickness), strokeColor);
        }
        strokeWidth -= 2 * cornerWidth;
        float patternWidth = dashedLinePatternWidthForStrokeWidth(strokeWidth);
        // Check if corner drawing sufficiently covers the line.
        if (strokeWidth <= patternWidth + 1) {
            cairo_restore(cairoContext);
            return;
        }

        float patternOffset = dashedLinePatternOffsetForPatternAndStrokeWidth(patternWidth, strokeWidth);
        const double dashedLine[2] = { static_cast<double>(patternWidth), static_cast<double>(patternWidth) };
        cairo_set_dash(cairoContext, dashedLine, 2, patternOffset);
    } else {
        setSourceRGBAFromColor(cairoContext, strokeColor);
        if (thickness < 1)
            cairo_set_line_width(cairoContext, 1);
    }


    auto centeredPoints = centerLineAndCutOffCorners(isVerticalLine, cornerWidth, point1, point2);
    auto p1 = centeredPoints[0];
    auto p2 = centeredPoints[1];

    if (shouldAntialias())
        cairo_set_antialias(cairoContext, CAIRO_ANTIALIAS_NONE);

    cairo_new_path(cairoContext);
    cairo_move_to(cairoContext, p1.x(), p1.y());
    cairo_line_to(cairoContext, p2.x(), p2.y());
    cairo_stroke(cairoContext);
    if (drawsDashedLine)
        cairo_restore(cairoContext);
    if (shouldAntialias())
        cairo_set_antialias(cairoContext, CAIRO_ANTIALIAS_DEFAULT);
}

// This method is only used to draw the little circles used in lists.
void GraphicsContext::drawEllipse(const FloatRect& rect)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->drawEllipse(rect);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);
    float yRadius = .5 * rect.height();
    float xRadius = .5 * rect.width();
    cairo_translate(cr, rect.x() + xRadius, rect.y() + yRadius);
    cairo_scale(cr, xRadius, yRadius);
    cairo_arc(cr, 0., 0., 1., 0., 2 * piFloat);
    cairo_restore(cr);

    if (fillColor().isVisible()) {
        setSourceRGBAFromColor(cr, fillColor());
        cairo_fill_preserve(cr);
    }

    if (strokeStyle() != NoStroke) {
        setSourceRGBAFromColor(cr, strokeColor());
        cairo_set_line_width(cr, strokeThickness());
        cairo_stroke(cr);
    } else
        cairo_new_path(cr);
}

void GraphicsContext::fillPath(const Path& path)
{
    if (paintingDisabled() || path.isEmpty())
        return;

    if (isRecording()) {
        m_displayListRecorder->fillPath(path);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    setPathOnCairoContext(cr, path.platformPath()->context());
    shadowAndFillCurrentCairoPath(*this);
}

void GraphicsContext::strokePath(const Path& path)
{
    if (paintingDisabled() || path.isEmpty())
        return;

    if (isRecording()) {
        m_displayListRecorder->strokePath(path);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    setPathOnCairoContext(cr, path.platformPath()->context());
    shadowAndStrokeCurrentCairoPath(*this);
}

void GraphicsContext::fillRect(const FloatRect& rect)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->fillRect(rect);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    shadowAndFillCurrentCairoPath(*this);
}

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

    if (isRecording()) {
        m_displayListRecorder->fillRect(rect, color);
        return;
    }

    if (hasShadow())
        platformContext()->shadowBlur().drawRectShadow(*this, FloatRoundedRect(rect));

    fillRectWithColor(platformContext()->cr(), rect, color);
}

void GraphicsContext::clip(const FloatRect& rect)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->clip(rect);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
    // The rectangular clip function is traditionally not expected to
    // antialias. If we don't force antialiased clipping here,
    // edge fringe artifacts may occur at the layer edges
    // when a transformation is applied to the GraphicsContext
    // while drawing the transformed layer.
    cairo_antialias_t savedAntialiasRule = cairo_get_antialias(cr);
    cairo_set_antialias(cr, CAIRO_ANTIALIAS_NONE);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
    cairo_set_antialias(cr, savedAntialiasRule);
    m_data->clip(rect);
}

void GraphicsContext::clipPath(const Path& path, WindRule clipRule)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->clipPath(path, clipRule);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    if (!path.isNull())
        setPathOnCairoContext(cr, path.platformPath()->context());

    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, clipRule == RULE_EVENODD ? CAIRO_FILL_RULE_EVEN_ODD : CAIRO_FILL_RULE_WINDING);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);

    m_data->clip(path);
}

void GraphicsContext::clipToImageBuffer(ImageBuffer& buffer, const FloatRect& destRect)
{
    if (paintingDisabled())
        return;

    RefPtr<Image> image = buffer.copyImage(DontCopyBackingStore);
    RefPtr<cairo_surface_t> surface = image->nativeImageForCurrentFrame();
    if (surface)
        platformContext()->pushImageMask(surface.get(), destRect);
}

IntRect GraphicsContext::clipBounds() const
{
    if (paintingDisabled())
        return IntRect();

    if (isRecording()) {
        WTFLogAlways("Getting the clip bounds not yet supported with display lists");
        return IntRect(-2048, -2048, 4096, 4096); // FIXME: display lists.
    }

    double x1, x2, y1, y2;
    cairo_clip_extents(platformContext()->cr(), &x1, &y1, &x2, &y2);
    return enclosingIntRect(FloatRect(x1, y1, x2 - x1, y2 - y1));
}

static inline void adjustFocusRingColor(Color& color)
{
#if !PLATFORM(GTK)
    // Force the alpha to 50%.  This matches what the Mac does with outline rings.
    color = Color(makeRGBA(color.red(), color.green(), color.blue(), 127));
#else
    UNUSED_PARAM(color);
#endif
}

static inline void adjustFocusRingLineWidth(float& width)
{
#if PLATFORM(GTK)
    width = 2;
#else
    UNUSED_PARAM(width);
#endif
}

static inline StrokeStyle focusRingStrokeStyle()
{
#if PLATFORM(GTK)
    return DottedStroke;
#else
    return SolidStroke;
#endif
}

void GraphicsContext::drawFocusRing(const Path& path, float width, float /* offset */, const Color& color)
{
    if (paintingDisabled())
        return;

    // FIXME: We should draw paths that describe a rectangle with rounded corners
    // so as to be consistent with how we draw rectangular focus rings.
    Color ringColor = color;
    adjustFocusRingColor(ringColor);
    adjustFocusRingLineWidth(width);

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);
    cairo_push_group(cr);
    appendWebCorePathToCairoContext(cr, path);
    setSourceRGBAFromColor(cr, ringColor);
    cairo_set_line_width(cr, width);
    setPlatformStrokeStyle(focusRingStrokeStyle());
    cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
    cairo_stroke_preserve(cr);

    cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
    cairo_fill(cr);

    cairo_pop_group_to_source(cr);
    cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
    cairo_paint(cr);
    cairo_restore(cr);
}

void GraphicsContext::drawFocusRing(const Vector<FloatRect>& rects, float width, float /* offset */, const Color& color)
{
    if (paintingDisabled())
        return;

    Path path;
#if PLATFORM(GTK)
    for (const auto& rect : rects)
        path.addRect(rect);
#else
    unsigned rectCount = rects.size();
    int radius = (width - 1) / 2;
    Path subPath;
    for (unsigned i = 0; i < rectCount; ++i) {
        if (i > 0)
            subPath.clear();
        subPath.addRoundedRect(rects[i], FloatSize(radius, radius));
        path.addPath(subPath, AffineTransform());
    }
#endif
    drawFocusRing(path, width, 0, color);
}

void GraphicsContext::drawLineForText(const FloatPoint& origin, float width, bool printing, bool doubleUnderlines, StrokeStyle)
{
    DashArray widths;
    widths.append(width);
    widths.append(0);
    drawLinesForText(origin, widths, printing, doubleUnderlines);
}

void GraphicsContext::drawLinesForText(const FloatPoint& point, const DashArray& widths, bool printing, bool doubleUnderlines, StrokeStyle)
{
    if (paintingDisabled())
        return;

    if (widths.size() <= 0)
        return;

    if (isRecording()) {
        m_displayListRecorder->drawLinesForText(point, widths, printing, doubleUnderlines, strokeThickness());
        return;
    }

    Color localStrokeColor(strokeColor());

    FloatRect bounds = computeLineBoundsAndAntialiasingModeForText(point, widths.last(), printing, localStrokeColor);

    Vector<FloatRect, 4> dashBounds;
    ASSERT(!(widths.size() % 2));
    dashBounds.reserveInitialCapacity(dashBounds.size() / 2);
    for (size_t i = 0; i < widths.size(); i += 2)
        dashBounds.append(FloatRect(FloatPoint(bounds.x() + widths[i], bounds.y()), FloatSize(widths[i+1] - widths[i], bounds.height())));

    if (doubleUnderlines) {
        // The space between double underlines is equal to the height of the underline
        for (size_t i = 0; i < widths.size(); i += 2)
            dashBounds.append(FloatRect(FloatPoint(bounds.x() + widths[i], bounds.y() + 2 * bounds.height()), FloatSize(widths[i+1] - widths[i], bounds.height())));
    }

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);

    for (auto& dash : dashBounds)
        fillRectWithColor(cr, dash, localStrokeColor);

    cairo_restore(cr);
}

void GraphicsContext::updateDocumentMarkerResources()
{
    // Unnecessary, since our document markers don't use resources.
}

void GraphicsContext::drawLineForDocumentMarker(const FloatPoint& origin, float width, DocumentMarkerLineStyle style)
{
    if (paintingDisabled())
        return;

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);

    switch (style) {
    case DocumentMarkerSpellingLineStyle:
        cairo_set_source_rgb(cr, 1, 0, 0);
        break;
    case DocumentMarkerGrammarLineStyle:
        cairo_set_source_rgb(cr, 0, 1, 0);
        break;
    default:
        cairo_restore(cr);
        return;
    }

    drawErrorUnderline(cr, origin.x(), origin.y(), width, cMisspellingLineThickness);

    cairo_restore(cr);
}

FloatRect GraphicsContext::roundToDevicePixels(const FloatRect& frect, RoundingMode)
{
    if (paintingDisabled())
        return frect;

    if (isRecording()) {
        WTFLogAlways("GraphicsContext::roundToDevicePixels() is not yet compatible with recording contexts.");
        return frect;
    }

    FloatRect result;
    double x = frect.x();
    double y = frect.y();
    cairo_t* cr = platformContext()->cr();
    cairo_user_to_device(cr, &x, &y);
    x = round(x);
    y = round(y);
    cairo_device_to_user(cr, &x, &y);
    result.setX(narrowPrecisionToFloat(x));
    result.setY(narrowPrecisionToFloat(y));

    // We must ensure width and height are at least 1 (or -1) when
    // we're given float values in the range between 0 and 1 (or -1 and 0).
    double width = frect.width();
    double height = frect.height();
    cairo_user_to_device_distance(cr, &width, &height);
    if (width > -1 && width < 0)
        width = -1;
    else if (width > 0 && width < 1)
        width = 1;
    else
        width = round(width);
    if (height > -1 && height < 0)
        height = -1;
    else if (height > 0 && height < 1)
        height = 1;
    else
        height = round(height);
    cairo_device_to_user_distance(cr, &width, &height);
    result.setWidth(narrowPrecisionToFloat(width));
    result.setHeight(narrowPrecisionToFloat(height));

    return result;
}

void GraphicsContext::translate(float x, float y)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->translate(x, y);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    cairo_translate(cr, x, y);
    m_data->translate(x, y);
}

void GraphicsContext::setPlatformFillColor(const Color&)
{
    // Cairo contexts can't hold separate fill and stroke colors
    // so we set them just before we actually fill or stroke
}

void GraphicsContext::setPlatformStrokeColor(const Color&)
{
    // Cairo contexts can't hold separate fill and stroke colors
    // so we set them just before we actually fill or stroke
}

void GraphicsContext::setPlatformStrokeThickness(float strokeThickness)
{
    if (paintingDisabled())
        return;

    ASSERT(!isRecording());

    cairo_set_line_width(platformContext()->cr(), strokeThickness);
}

void GraphicsContext::setPlatformStrokeStyle(StrokeStyle strokeStyle)
{
    static const double dashPattern[] = { 5.0, 5.0 };
    static const double dotPattern[] = { 1.0, 1.0 };

    if (paintingDisabled())
        return;

    ASSERT(!isRecording());

    switch (strokeStyle) {
    case NoStroke:
        // FIXME: is it the right way to emulate NoStroke?
        cairo_set_line_width(platformContext()->cr(), 0);
        break;
    case SolidStroke:
    case DoubleStroke:
    case WavyStroke: // FIXME: https://bugs.webkit.org/show_bug.cgi?id=94110 - Needs platform support.
        cairo_set_dash(platformContext()->cr(), 0, 0, 0);
        break;
    case DottedStroke:
        cairo_set_dash(platformContext()->cr(), dotPattern, 2, 0);
        break;
    case DashedStroke:
        cairo_set_dash(platformContext()->cr(), dashPattern, 2, 0);
        break;
    }
}

void GraphicsContext::setURLForRect(const URL&, const FloatRect&)
{
    notImplemented();
}

void GraphicsContext::concatCTM(const AffineTransform& transform)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->concatCTM(transform);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    const cairo_matrix_t matrix = cairo_matrix_t(transform);
    cairo_transform(cr, &matrix);
    m_data->concatCTM(transform);
}

void GraphicsContext::setCTM(const AffineTransform& transform)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        WTFLogAlways("GraphicsContext::setCTM() is not compatible with recording contexts.");
        return;
    }

    cairo_t* cr = platformContext()->cr();
    const cairo_matrix_t matrix = cairo_matrix_t(transform);
    cairo_set_matrix(cr, &matrix);
    m_data->setCTM(transform);
}

void GraphicsContext::setPlatformShadow(FloatSize const& size, float, Color const&)
{
    if (paintingDisabled())
        return;

    if (m_state.shadowsIgnoreTransforms) {
        // Meaning that this graphics context is associated with a CanvasRenderingContext
        // We flip the height since CG and HTML5 Canvas have opposite Y axis
        m_state.shadowOffset = FloatSize(size.width(), -size.height());
    }

    // Cairo doesn't support shadows natively, they are drawn manually in the draw* functions using ShadowBlur.
    platformContext()->shadowBlur().setShadowValues(FloatSize(m_state.shadowBlur, m_state.shadowBlur),
                                                    m_state.shadowOffset,
                                                    m_state.shadowColor,
                                                    m_state.shadowsIgnoreTransforms);
}

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

    platformContext()->shadowBlur().clear();
}

void GraphicsContext::beginPlatformTransparencyLayer(float opacity)
{
    if (paintingDisabled())
        return;

    ASSERT(!isRecording());

    cairo_t* cr = platformContext()->cr();
    cairo_push_group(cr);
    m_data->layers.append(opacity);
}

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

    ASSERT(!isRecording());

    cairo_t* cr = platformContext()->cr();

    cairo_pop_group_to_source(cr);
    cairo_paint_with_alpha(cr, m_data->layers.last());
    m_data->layers.removeLast();
}

bool GraphicsContext::supportsTransparencyLayers()
{
    return true;
}

void GraphicsContext::clearRect(const FloatRect& rect)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->clearRect(rect);
        return;
    }

    cairo_t* cr = platformContext()->cr();

    cairo_save(cr);
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
    cairo_fill(cr);
    cairo_restore(cr);
}

void GraphicsContext::strokeRect(const FloatRect& rect, float width)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->strokeRect(rect, width);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);
    cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
    cairo_set_line_width(cr, width);
    shadowAndStrokeCurrentCairoPath(*this);
    cairo_restore(cr);
}

void GraphicsContext::setLineCap(LineCap lineCap)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->setLineCap(lineCap);
        return;
    }

    cairo_line_cap_t cairoCap = CAIRO_LINE_CAP_BUTT;
    switch (lineCap) {
    case ButtCap:
        // no-op
        break;
    case RoundCap:
        cairoCap = CAIRO_LINE_CAP_ROUND;
        break;
    case SquareCap:
        cairoCap = CAIRO_LINE_CAP_SQUARE;
        break;
    }
    cairo_set_line_cap(platformContext()->cr(), cairoCap);
}

static inline bool isDashArrayAllZero(const DashArray& dashes)
{
    for (auto& dash : dashes) {
        if (dash)
            return false;
    }
    return true;
}

void GraphicsContext::setLineDash(const DashArray& dashes, float dashOffset)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->setLineDash(dashes, dashOffset);
        return;
    }

    if (isDashArrayAllZero(dashes))
        cairo_set_dash(platformContext()->cr(), 0, 0, 0);
    else
        cairo_set_dash(platformContext()->cr(), dashes.data(), dashes.size(), dashOffset);
}

void GraphicsContext::setLineJoin(LineJoin lineJoin)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->setLineJoin(lineJoin);
        return;
    }

    cairo_line_join_t cairoJoin = CAIRO_LINE_JOIN_MITER;
    switch (lineJoin) {
    case MiterJoin:
        // no-op
        break;
    case RoundJoin:
        cairoJoin = CAIRO_LINE_JOIN_ROUND;
        break;
    case BevelJoin:
        cairoJoin = CAIRO_LINE_JOIN_BEVEL;
        break;
    }
    cairo_set_line_join(platformContext()->cr(), cairoJoin);
}

void GraphicsContext::setMiterLimit(float miter)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        // Maybe this should be part of the state.
        m_displayListRecorder->setMiterLimit(miter);
        return;
    }

    cairo_set_miter_limit(platformContext()->cr(), miter);
}

void GraphicsContext::setPlatformAlpha(float alpha)
{
    platformContext()->setGlobalAlpha(alpha);
}

void GraphicsContext::setPlatformCompositeOperation(CompositeOperator op, BlendMode blendOp)
{
    if (paintingDisabled())
        return;

    cairo_set_operator(platformContext()->cr(), toCairoOperator(op, blendOp));
}

void GraphicsContext::canvasClip(const Path& path, WindRule windRule)
{
    clipPath(path, windRule);
}

void GraphicsContext::clipOut(const Path& path)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->clipOut(path);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    double x1, y1, x2, y2;
    cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
    cairo_rectangle(cr, x1, y1, x2 - x1, y2 - y1);
    appendWebCorePathToCairoContext(cr, path);

    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
}

void GraphicsContext::rotate(float radians)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->rotate(radians);
        return;
    }

    cairo_rotate(platformContext()->cr(), radians);
    m_data->rotate(radians);
}

void GraphicsContext::scale(const FloatSize& size)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->scale(size);
        return;
    }

    cairo_scale(platformContext()->cr(), size.width(), size.height());
    m_data->scale(size);
}

void GraphicsContext::clipOut(const FloatRect& r)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->clipOut(r);
        return;
    }

    cairo_t* cr = platformContext()->cr();
    double x1, y1, x2, y2;
    cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
    cairo_rectangle(cr, x1, y1, x2 - x1, y2 - y1);
    cairo_rectangle(cr, r.x(), r.y(), r.width(), r.height());
    cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
    cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
    cairo_clip(cr);
    cairo_set_fill_rule(cr, savedFillRule);
}

void GraphicsContext::platformFillRoundedRect(const FloatRoundedRect& rect, const Color& color)
{
    if (paintingDisabled())
        return;

    ASSERT(!isRecording());

    if (hasShadow())
        platformContext()->shadowBlur().drawRectShadow(*this, rect);

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);
    Path path;
    path.addRoundedRect(rect);
    appendWebCorePathToCairoContext(cr, path);
    setSourceRGBAFromColor(cr, color);
    cairo_fill(cr);
    cairo_restore(cr);
}

void GraphicsContext::fillRectWithRoundedHole(const FloatRect& rect, const FloatRoundedRect& roundedHoleRect, const Color& color)
{
    if (paintingDisabled() || !color.isValid())
        return;

    if (isRecording()) {
        m_displayListRecorder->fillRectWithRoundedHole(rect, roundedHoleRect, color);
        return;
    }

    if (this->mustUseShadowBlur())
        platformContext()->shadowBlur().drawInsetShadow(*this, rect, roundedHoleRect);

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

    cairo_t* cr = platformContext()->cr();
    cairo_save(cr);
    setPathOnCairoContext(platformContext()->cr(), path.platformPath()->context());
    fillCurrentCairoPath(*this);
    cairo_restore(cr);
}

void GraphicsContext::drawPattern(Image& image, const FloatRect& destRect, const FloatRect& tileRect, const AffineTransform& patternTransform, const FloatPoint& phase, const FloatSize& spacing, CompositeOperator op, BlendMode blendMode)
{
    if (paintingDisabled())
        return;

    if (isRecording()) {
        m_displayListRecorder->drawPattern(image, destRect, tileRect, patternTransform, phase, spacing, op, blendMode);
        return;
    }

    RefPtr<cairo_surface_t> surface = image.nativeImageForCurrentFrame();
    if (!surface) // If it's too early we won't have an image yet.
        return;

    cairo_t* cr = platformContext()->cr();
    drawPatternToCairoContext(cr, surface.get(), IntSize(image.size()), tileRect, patternTransform, phase, toCairoOperator(op, blendMode), destRect);
}

void GraphicsContext::setPlatformShouldAntialias(bool enable)
{
    if (paintingDisabled())
        return;

    ASSERT(!isRecording());

    // When true, use the default Cairo backend antialias mode (usually this
    // enables standard 'grayscale' antialiasing); false to explicitly disable
    // antialiasing.
    cairo_set_antialias(platformContext()->cr(), enable ? CAIRO_ANTIALIAS_DEFAULT : CAIRO_ANTIALIAS_NONE);
}

void GraphicsContext::setPlatformImageInterpolationQuality(InterpolationQuality quality)
{
    ASSERT(!isRecording());

    platformContext()->setImageInterpolationQuality(quality);
}

bool GraphicsContext::isAcceleratedContext() const
{
    if (isRecording())
        return false;

    return cairo_surface_get_type(cairo_get_target(platformContext()->cr())) == CAIRO_SURFACE_TYPE_GL;
}

#if ENABLE(3D_TRANSFORMS) && USE(TEXTURE_MAPPER)
TransformationMatrix GraphicsContext::get3DTransform() const
{
    // FIXME: Can we approximate the transformation better than this?
    return getCTM().toTransformationMatrix();
}

void GraphicsContext::concat3DTransform(const TransformationMatrix& transform)
{
    concatCTM(transform.toAffineTransform());
}

void GraphicsContext::set3DTransform(const TransformationMatrix& transform)
{
    setCTM(transform.toAffineTransform());
}
#endif // ENABLE(3D_TRANSFORMS) && USE(TEXTURE_MAPPER)

} // namespace WebCore

#endif // USE(CAIRO)