/*
 * Copyright (C) 2003-2021 Apple Inc. All rights reserved.
 * Copyright (C) 2008-2009 Torch Mobile, Inc.
 *
 * 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.
 */

#pragma once

#include "DashArray.h"
#include "DestinationColorSpace.h"
#include "FloatRect.h"
#include "FontCascade.h"
#include "GraphicsTypes.h"
#include "Image.h"
#include "ImageOrientation.h"
#include "ImagePaintingOptions.h"
#include "IntRect.h"
#include "Pattern.h"
#include "RenderingMode.h"
#include <wtf/Function.h>
#include <wtf/Noncopyable.h>
#include <wtf/OptionSet.h>

#if USE(CG)
typedef struct CGContext PlatformGraphicsContext;
#elif USE(DIRECT2D)
interface ID2D1DCRenderTarget;
interface ID2D1RenderTarget;
interface ID2D1Factory;
interface ID2D1SolidColorBrush;
namespace WebCore {
class PlatformContextDirect2D;
}
typedef WebCore::PlatformContextDirect2D PlatformGraphicsContext;
#elif USE(CAIRO)
namespace WebCore {
class GraphicsContextCairo;
}
typedef WebCore::GraphicsContextCairo PlatformGraphicsContext;
#else
typedef void PlatformGraphicsContext;
#endif

#if PLATFORM(WIN)
#include "DIBPixelData.h"
typedef struct HDC__* HDC;
#if !USE(CG)
// UInt8 is defined in CoreFoundation/CFBase.h
typedef unsigned char UInt8;
#endif
#endif

// X11 headers define a bunch of macros with common terms, interfering with WebCore and WTF enum values.
// As a workaround, we explicitly undef them here.
#if defined(None)
#undef None
#endif
#if defined(Below)
#undef Below
#endif
#if defined(Success)
#undef Success
#endif

namespace WebCore {

class AffineTransform;
class FloatRoundedRect;
class Gradient;
class GraphicsContextPlatformPrivate;
class ImageBuffer;
class IntRect;
class MediaPlayer;
class RoundedRect;
class GraphicsContextGL;
class Path;
class TextRun;
class TransformationMatrix;

namespace DisplayList {
class Recorder;
}

enum class TextDrawingMode : uint8_t {
    Fill = 1 << 0,
    Stroke = 1 << 1,
};
using TextDrawingModeFlags = OptionSet<TextDrawingMode>;

// Legacy shadow blur radius is used for canvas, and -webkit-box-shadow.
// It has different treatment of radii > 8px.
enum class ShadowRadiusMode : bool {
    Default,
    Legacy
};

enum StrokeStyle {
    NoStroke,
    SolidStroke,
    DottedStroke,
    DashedStroke,
    DoubleStroke,
    WavyStroke,
};

struct DocumentMarkerLineStyle {
    enum class Mode : uint8_t {
        TextCheckingDictationPhraseWithAlternatives,
        Spelling,
        Grammar,
        AutocorrectionReplacement,
        DictationAlternatives
    } mode;
    bool shouldUseDarkAppearance { false };

    template<class Encoder> void encode(Encoder&) const;
    template<class Decoder> static std::optional<DocumentMarkerLineStyle> decode(Decoder&);
};

template<class Encoder>
void DocumentMarkerLineStyle::encode(Encoder& encoder) const
{
    encoder << mode;
    encoder << shouldUseDarkAppearance;
}

template<class Decoder>
std::optional<DocumentMarkerLineStyle> DocumentMarkerLineStyle::decode(Decoder& decoder)
{
    std::optional<Mode> mode;
    decoder >> mode;
    if (!mode)
        return std::nullopt;

    std::optional<bool> shouldUseDarkAppearance;
    decoder >> shouldUseDarkAppearance;
    if (!shouldUseDarkAppearance)
        return std::nullopt;

    return {{ *mode, *shouldUseDarkAppearance }};
}

struct GraphicsContextStateChange;

struct GraphicsContextState {
    WEBCORE_EXPORT GraphicsContextState();
    WEBCORE_EXPORT ~GraphicsContextState();

    GraphicsContextState(const GraphicsContextState&);
    WEBCORE_EXPORT GraphicsContextState(GraphicsContextState&&);

    GraphicsContextState& operator=(const GraphicsContextState&);
    WEBCORE_EXPORT GraphicsContextState& operator=(GraphicsContextState&&);

    enum Change : uint32_t {
        StrokeGradientChange                    = 1 << 0,
        StrokePatternChange                     = 1 << 1,
        FillGradientChange                      = 1 << 2,
        FillPatternChange                       = 1 << 3,
        StrokeThicknessChange                   = 1 << 4,
        StrokeColorChange                       = 1 << 5,
        StrokeStyleChange                       = 1 << 6,
        FillColorChange                         = 1 << 7,
        FillRuleChange                          = 1 << 8,
        ShadowChange                            = 1 << 9,
        ShadowsIgnoreTransformsChange           = 1 << 10,
        AlphaChange                             = 1 << 11,
        CompositeOperationChange                = 1 << 12,
        BlendModeChange                         = 1 << 13,
        TextDrawingModeChange                   = 1 << 14,
        ShouldAntialiasChange                   = 1 << 15,
        ShouldSmoothFontsChange                 = 1 << 16,
        ShouldSubpixelQuantizeFontsChange       = 1 << 17,
        DrawLuminanceMaskChange                 = 1 << 18,
        ImageInterpolationQualityChange         = 1 << 19,
#if HAVE(OS_DARK_MODE_SUPPORT)
        UseDarkAppearanceChange                 = 1 << 20,
#endif
    };
    using StateChangeFlags = OptionSet<Change>;

    void mergeChanges(const GraphicsContextState&, GraphicsContextState::StateChangeFlags);

    RefPtr<Gradient> strokeGradient;
    RefPtr<Pattern> strokePattern;
    
    RefPtr<Gradient> fillGradient;
    RefPtr<Pattern> fillPattern;

    FloatSize shadowOffset;

    Color strokeColor { Color::black };
    Color fillColor { Color::black };
    Color shadowColor;

    AffineTransform strokeGradientSpaceTransform;
    AffineTransform fillGradientSpaceTransform;

    float strokeThickness { 0 };
    float shadowBlur { 0 };
    float alpha { 1 };

    StrokeStyle strokeStyle { SolidStroke };
    WindRule fillRule { WindRule::NonZero };

    TextDrawingModeFlags textDrawingMode { TextDrawingMode::Fill };
    CompositeOperator compositeOperator { CompositeOperator::SourceOver };
    BlendMode blendMode { BlendMode::Normal };
    InterpolationQuality imageInterpolationQuality { InterpolationQuality::Default };
    ShadowRadiusMode shadowRadiusMode { ShadowRadiusMode::Default };

    bool shouldAntialias : 1;
    bool shouldSmoothFonts : 1;
    bool shouldSubpixelQuantizeFonts : 1;
    bool shadowsIgnoreTransforms : 1;
    bool drawLuminanceMask : 1;
#if HAVE(OS_DARK_MODE_SUPPORT)
    bool useDarkAppearance : 1;
#endif
};

struct GraphicsContextStateChange {
    GraphicsContextStateChange() = default;
    GraphicsContextStateChange(const GraphicsContextState& state, GraphicsContextState::StateChangeFlags flags)
        : m_state(state)
        , m_changeFlags(flags)
    {
    }

    GraphicsContextState::StateChangeFlags changesFromState(const GraphicsContextState&) const;

    void accumulate(const GraphicsContextState&, GraphicsContextState::StateChangeFlags);
    void apply(GraphicsContext&) const;
    
    void dump(WTF::TextStream&) const;

    GraphicsContextState m_state;
    GraphicsContextState::StateChangeFlags m_changeFlags;
};

WTF::TextStream& operator<<(WTF::TextStream&, const GraphicsContextStateChange&);

class GraphicsContext {
    WTF_MAKE_NONCOPYABLE(GraphicsContext); WTF_MAKE_FAST_ALLOCATED;
public:   

    WEBCORE_EXPORT GraphicsContext() = default;
    WEBCORE_EXPORT virtual ~GraphicsContext();

#if USE(DIRECT2D)
    // FIXME: This should move to GraphicsContextDirect2D
    enum class BitmapRenderingContextType : uint8_t {
        CPUMemory,
        GPUMemory
    };
    WEBCORE_EXPORT GraphicsContext(PlatformGraphicsContext*, BitmapRenderingContextType);
#endif

    virtual bool hasPlatformContext() const { return false; }
    virtual PlatformGraphicsContext* platformContext() const { return nullptr; }

    virtual bool paintingDisabled() const { return false; }
    virtual bool performingPaintInvalidation() const { return false; }
    virtual bool invalidatingControlTints() const { return false; }
    virtual bool invalidatingImagesWithAsyncDecodes() const { return false; }
    virtual bool detectingContentfulPaint() const { return false; }

    // Context State

    void setStrokeThickness(float thickness) { m_state.strokeThickness = thickness; didUpdateState(m_state, GraphicsContextState::StrokeThicknessChange); }
    float strokeThickness() const { return m_state.strokeThickness; }

    void setStrokeStyle(StrokeStyle style) { m_state.strokeStyle = style; didUpdateState(m_state, GraphicsContextState::StrokeStyleChange); }
    StrokeStyle strokeStyle() const { return m_state.strokeStyle; }

    WEBCORE_EXPORT void setStrokeColor(const Color&);
    const Color& strokeColor() const { return m_state.strokeColor; }

    WEBCORE_EXPORT void setStrokePattern(Ref<Pattern>&&);
    Pattern* strokePattern() const { return m_state.strokePattern.get(); }

    WEBCORE_EXPORT void setStrokeGradient(Ref<Gradient>&&, const AffineTransform& = { });
    Gradient* strokeGradient() const { return m_state.strokeGradient.get(); }

    void setFillRule(WindRule fillRule) { m_state.fillRule = fillRule; didUpdateState(m_state, GraphicsContextState::FillRuleChange); }
    WindRule fillRule() const { return m_state.fillRule; }

    WEBCORE_EXPORT void setFillColor(const Color&);
    const Color& fillColor() const { return m_state.fillColor; }

    WEBCORE_EXPORT void setFillPattern(Ref<Pattern>&&);
    Pattern* fillPattern() const { return m_state.fillPattern.get(); }

    WEBCORE_EXPORT void setFillGradient(Ref<Gradient>&&, const AffineTransform& = { });
    Gradient* fillGradient() const { return m_state.fillGradient.get(); }

    void setShadowsIgnoreTransforms(bool shadowsIgnoreTransforms) { m_state.shadowsIgnoreTransforms = shadowsIgnoreTransforms; didUpdateState(m_state, GraphicsContextState::ShadowsIgnoreTransformsChange); }
    bool shadowsIgnoreTransforms() const { return m_state.shadowsIgnoreTransforms; }

    void setShouldAntialias(bool shouldAntialias) { m_state.shouldAntialias = shouldAntialias; didUpdateState(m_state, GraphicsContextState::ShouldAntialiasChange); }
    bool shouldAntialias() const { return m_state.shouldAntialias; }

    void setShouldSmoothFonts(bool shouldSmoothFonts) { m_state.shouldSmoothFonts = shouldSmoothFonts; didUpdateState(m_state, GraphicsContextState::ShouldSmoothFontsChange); }
    bool shouldSmoothFonts() const { return m_state.shouldSmoothFonts; }

    // Normally CG enables subpixel-quantization because it improves the performance of aligning glyphs.
    // In some cases we have to disable to to ensure a high-quality output of the glyphs.
    void setShouldSubpixelQuantizeFonts(bool shouldSubpixelQuantizeFonts) { m_state.shouldSubpixelQuantizeFonts = shouldSubpixelQuantizeFonts; didUpdateState(m_state, GraphicsContextState::ShouldSubpixelQuantizeFontsChange); }
    bool shouldSubpixelQuantizeFonts() const { return m_state.shouldSubpixelQuantizeFonts; }

    void setImageInterpolationQuality(InterpolationQuality quality) { m_state.imageInterpolationQuality = quality; didUpdateState(m_state, GraphicsContextState::ImageInterpolationQualityChange); }
    InterpolationQuality imageInterpolationQuality() const { return m_state.imageInterpolationQuality; }

    void setAlpha(float alpha) { m_state.alpha = alpha; didUpdateState(m_state, GraphicsContextState::AlphaChange); }
    float alpha() const { return m_state.alpha; }

    WEBCORE_EXPORT void setCompositeOperation(CompositeOperator, BlendMode = BlendMode::Normal);
    CompositeOperator compositeOperation() const { return m_state.compositeOperator; }
    BlendMode blendModeOperation() const { return m_state.blendMode; }

    void setDrawLuminanceMask(bool drawLuminanceMask) { m_state.drawLuminanceMask = drawLuminanceMask; didUpdateState(m_state, GraphicsContextState::DrawLuminanceMaskChange); }
    bool drawLuminanceMask() const { return m_state.drawLuminanceMask; }

    void setTextDrawingMode(TextDrawingModeFlags mode) { m_state.textDrawingMode = mode; didUpdateState(m_state, GraphicsContextState::TextDrawingModeChange); }
    TextDrawingModeFlags textDrawingMode() const { return m_state.textDrawingMode; }

    WEBCORE_EXPORT void setShadow(const FloatSize&, float blur, const Color&, ShadowRadiusMode = ShadowRadiusMode::Default);
    WEBCORE_EXPORT virtual void clearShadow();
    WEBCORE_EXPORT bool getShadow(FloatSize&, float&, Color&) const;

    bool hasVisibleShadow() const { return m_state.shadowColor.isVisible(); }
    bool hasShadow() const { return hasVisibleShadow() && (m_state.shadowBlur || m_state.shadowOffset.width() || m_state.shadowOffset.height()); }
    bool hasBlurredShadow() const { return hasVisibleShadow() && m_state.shadowBlur; }

#if HAVE(OS_DARK_MODE_SUPPORT)
    void setUseDarkAppearance(bool useDarkAppearance) { m_state.useDarkAppearance = useDarkAppearance; didUpdateState(m_state, GraphicsContextState::UseDarkAppearanceChange); }
    bool useDarkAppearance() const { return m_state.useDarkAppearance; }
#endif

    virtual const GraphicsContextState& state() const { return m_state; }

    void updateState(const GraphicsContextState&, GraphicsContextState::StateChangeFlags);

    // Called *after* any change to GraphicsContextState; generally used to propagate changes
    // to the platform context's state.
    virtual void didUpdateState(const GraphicsContextState&, GraphicsContextState::StateChangeFlags) = 0;

    WEBCORE_EXPORT virtual void save();
    WEBCORE_EXPORT virtual void restore();
    
    unsigned stackSize() const { return m_stack.size(); }

#if USE(CG) || USE(DIRECT2D)
    // FIXME: Should these really be public GraphicsContext methods?
    virtual void applyStrokePattern() = 0;
    virtual void applyFillPattern() = 0;

    // FIXME: Can we make this a why instead of a what, and then have it exist cross-platform?
    virtual void setIsCALayerContext(bool) = 0;
    virtual bool isCALayerContext() const = 0;

    // FIXME: Can this be a GraphicsContextCG constructor parameter? Or just be read off the context?
    virtual void setIsAcceleratedContext(bool) = 0;
#endif

    virtual RenderingMode renderingMode() const { return RenderingMode::Unaccelerated; }

    // Pixel Snapping

    enum RoundingMode {
        RoundAllSides,
        RoundOriginAndDimensions
    };
    virtual FloatRect roundToDevicePixels(const FloatRect&, RoundingMode = RoundAllSides) = 0;
    WEBCORE_EXPORT static void adjustLineToPixelBoundaries(FloatPoint& p1, FloatPoint& p2, float strokeWidth, StrokeStyle);

    // Shapes

    // These draw methods will do both stroking and filling.
    // FIXME: ...except drawRect(), which fills properly but always strokes
    // using a 1-pixel stroke inset from the rect borders (of the correct
    // stroke color).
    virtual void drawRect(const FloatRect&, float borderThickness = 1) = 0;
    virtual void drawLine(const FloatPoint&, const FloatPoint&) = 0;

    virtual void drawEllipse(const FloatRect&) = 0;
    WEBCORE_EXPORT virtual void drawRaisedEllipse(const FloatRect&, const Color& ellipseColor, const Color& shadowColor);

    virtual void fillPath(const Path&) = 0;
    virtual void strokePath(const Path&) = 0;
    WEBCORE_EXPORT virtual void drawPath(const Path&);

    virtual void fillEllipse(const FloatRect& ellipse) { fillEllipseAsPath(ellipse); }
    virtual void strokeEllipse(const FloatRect& ellipse) { strokeEllipseAsPath(ellipse); }

    virtual void fillRect(const FloatRect&) = 0;
    virtual void fillRect(const FloatRect&, const Color&) = 0;
    virtual void fillRect(const FloatRect&, Gradient&);
    WEBCORE_EXPORT virtual void fillRect(const FloatRect&, const Color&, CompositeOperator, BlendMode = BlendMode::Normal);
    virtual void fillRoundedRectImpl(const FloatRoundedRect&, const Color&) = 0;
    WEBCORE_EXPORT virtual void fillRoundedRect(const FloatRoundedRect&, const Color&, BlendMode = BlendMode::Normal);
    WEBCORE_EXPORT virtual void fillRectWithRoundedHole(const FloatRect&, const FloatRoundedRect& roundedHoleRect, const Color&);

    virtual void clearRect(const FloatRect&) = 0;

    virtual void strokeRect(const FloatRect&, float lineWidth) = 0;

    virtual void setLineCap(LineCap) = 0;
    virtual void setLineDash(const DashArray&, float dashOffset) = 0;
    virtual void setLineJoin(LineJoin) = 0;
    virtual void setMiterLimit(float) = 0;

    // Images, Patterns, and Media

    virtual void drawNativeImage(NativeImage&, const FloatSize& selfSize, const FloatRect& destRect, const FloatRect& srcRect, const ImagePaintingOptions& = { }) = 0;

    WEBCORE_EXPORT ImageDrawResult drawImage(Image&, const FloatPoint& destination, const ImagePaintingOptions& = { ImageOrientation::FromImage });
    WEBCORE_EXPORT ImageDrawResult drawImage(Image&, const FloatRect& destination, const ImagePaintingOptions& = { ImageOrientation::FromImage });
    WEBCORE_EXPORT virtual ImageDrawResult drawImage(Image&, const FloatRect& destination, const FloatRect& source, const ImagePaintingOptions& = { ImageOrientation::FromImage });

    WEBCORE_EXPORT virtual ImageDrawResult drawImageForCanvas(Image&, const FloatRect& destination, const FloatRect& source, const ImagePaintingOptions&, DestinationColorSpace canvasColorSpace);

    WEBCORE_EXPORT virtual ImageDrawResult drawTiledImage(Image&, const FloatRect& destination, const FloatPoint& source, const FloatSize& tileSize, const FloatSize& spacing, const ImagePaintingOptions& = { });
    WEBCORE_EXPORT virtual ImageDrawResult drawTiledImage(Image&, const FloatRect& destination, const FloatRect& source, const FloatSize& tileScaleFactor, Image::TileRule, Image::TileRule, const ImagePaintingOptions& = { });

    WEBCORE_EXPORT void drawImageBuffer(ImageBuffer&, const FloatPoint& destination, const ImagePaintingOptions& = { });
    WEBCORE_EXPORT void drawImageBuffer(ImageBuffer&, const FloatRect& destination, const ImagePaintingOptions& = { });
    WEBCORE_EXPORT virtual void drawImageBuffer(ImageBuffer&, const FloatRect& destination, const FloatRect& source, const ImagePaintingOptions& = { });

    WEBCORE_EXPORT void drawConsumingImageBuffer(RefPtr<ImageBuffer>, const FloatPoint& destination, const ImagePaintingOptions& = { });
    WEBCORE_EXPORT void drawConsumingImageBuffer(RefPtr<ImageBuffer>, const FloatRect& destination, const ImagePaintingOptions& = { });
    WEBCORE_EXPORT virtual void drawConsumingImageBuffer(RefPtr<ImageBuffer>, const FloatRect& destination, const FloatRect& source, const ImagePaintingOptions& = { });

    virtual void drawPattern(NativeImage&, const FloatSize& imageSize, const FloatRect& destRect, const FloatRect& tileRect, const AffineTransform& patternTransform, const FloatPoint& phase, const FloatSize& spacing, const ImagePaintingOptions& = { }) = 0;

#if ENABLE(VIDEO)
    WEBCORE_EXPORT virtual void paintFrameForMedia(MediaPlayer&, const FloatRect& destination);
#endif

    // Clipping

    virtual void clip(const FloatRect&) = 0;
    WEBCORE_EXPORT virtual void clipRoundedRect(const FloatRoundedRect&);

    virtual void clipOut(const FloatRect&) = 0;
    virtual void clipOut(const Path&) = 0;
    WEBCORE_EXPORT virtual void clipOutRoundedRect(const FloatRoundedRect&);
    virtual void clipPath(const Path&, WindRule = WindRule::EvenOdd) = 0;
    WEBCORE_EXPORT virtual void clipToImageBuffer(ImageBuffer&, const FloatRect&);

    enum class ClipToDrawingCommandsResult : bool { Success, FailedToCreateImageBuffer };
    WEBCORE_EXPORT virtual ClipToDrawingCommandsResult clipToDrawingCommands(const FloatRect& destination, const DestinationColorSpace&, Function<void(GraphicsContext&)>&&);

    WEBCORE_EXPORT virtual IntRect clipBounds() const;

    // Text

    WEBCORE_EXPORT virtual FloatSize drawText(const FontCascade&, const TextRun&, const FloatPoint&, unsigned from = 0, std::optional<unsigned> to = std::nullopt);
    WEBCORE_EXPORT virtual void drawGlyphs(const Font&, const GlyphBufferGlyph*, const GlyphBufferAdvance*, unsigned numGlyphs, const FloatPoint&, FontSmoothingMode);
    WEBCORE_EXPORT virtual void drawEmphasisMarks(const FontCascade&, const TextRun&, const AtomString& mark, const FloatPoint&, unsigned from = 0, std::optional<unsigned> to = std::nullopt);
    WEBCORE_EXPORT virtual void drawBidiText(const FontCascade&, const TextRun&, const FloatPoint&, FontCascade::CustomFontNotReadyAction = FontCascade::DoNotPaintIfFontNotReady);

    virtual void drawGlyphsAndCacheFont(const Font& font, const GlyphBufferGlyph* glyphs, const GlyphBufferAdvance* advances, unsigned numGlyphs, const FloatPoint& point, FontSmoothingMode fontSmoothingMode)
    {
        drawGlyphs(font, glyphs, advances, numGlyphs, point, fontSmoothingMode);
    }

    WEBCORE_EXPORT FloatRect computeUnderlineBoundsForText(const FloatRect&, bool printing);
    WEBCORE_EXPORT virtual void drawLineForText(const FloatRect&, bool printing, bool doubleLines = false, StrokeStyle = SolidStroke);
    virtual void drawLinesForText(const FloatPoint&, float thickness, const DashArray& widths, bool printing, bool doubleLines = false, StrokeStyle = SolidStroke) = 0;
    virtual void drawDotsForDocumentMarker(const FloatRect&, DocumentMarkerLineStyle) = 0;

    // Transparency Layers

    WEBCORE_EXPORT virtual void beginTransparencyLayer(float opacity);
    WEBCORE_EXPORT virtual void endTransparencyLayer();
    bool isInTransparencyLayer() const { return (m_transparencyLayerCount > 0) && supportsTransparencyLayers(); }

    // Focus Rings

    virtual void drawFocusRing(const Vector<FloatRect>&, float width, float offset, const Color&) = 0;
    virtual void drawFocusRing(const Path&, float width, float offset, const Color&) = 0;
    // FIXME: Can we hide these in the CG implementation? Or elsewhere?
#if PLATFORM(MAC)
    virtual void drawFocusRing(const Path&, double timeOffset, bool& needsRedraw, const Color&) = 0;
    virtual void drawFocusRing(const Vector<FloatRect>&, double timeOffset, bool& needsRedraw, const Color&) = 0;
#endif

    // Transforms

    void scale(float s) { scale({ s, s }); }
    virtual void scale(const FloatSize&) = 0;
    virtual void rotate(float angleInRadians) = 0;
    void translate(const FloatSize& size) { translate(size.width(), size.height()); }
    void translate(const FloatPoint& p) { translate(p.x(), p.y()); }
    virtual void translate(float x, float y) = 0;

    virtual void concatCTM(const AffineTransform&) = 0;
    virtual void setCTM(const AffineTransform&) = 0;

    enum IncludeDeviceScale { DefinitelyIncludeDeviceScale, PossiblyIncludeDeviceScale };
    virtual AffineTransform getCTM(IncludeDeviceScale = PossiblyIncludeDeviceScale) const = 0;

    // This function applies the device scale factor to the context, making the context capable of
    // acting as a base-level context for a HiDPI environment.
    virtual void applyDeviceScaleFactor(float factor) { scale(factor); }
    WEBCORE_EXPORT FloatSize scaleFactor() const;
    WEBCORE_EXPORT FloatSize scaleFactorForDrawing(const FloatRect& destRect, const FloatRect& srcRect) const;

    // Links

    virtual void setURLForRect(const URL&, const FloatRect&) { }

    virtual void setDestinationForRect(const String&, const FloatRect&) { }
    virtual void addDestinationAtPoint(const String&, const FloatPoint&) { }

    virtual bool supportsInternalLinks() const { return false; }

    // Contentful Paint Detection

    void setContentfulPaintDetected() { m_contentfulPaintDetected = true; }
    bool contenfulPaintDetected() const { return m_contentfulPaintDetected; }

    // FIXME: Nothing in this section belongs here, and should be moved elsewhere.
#if OS(WINDOWS)
    HDC getWindowsContext(const IntRect&, bool supportAlphaBlend); // The passed in rect is used to create a bitmap for compositing inside transparency layers.
    void releaseWindowsContext(HDC, const IntRect&, bool supportAlphaBlend); // The passed in HDC should be the one handed back by getWindowsContext.
#endif

#if OS(WINDOWS) && !USE(CAIRO)
    // FIXME: This should not exist; we need a different place to
    // put code shared between Windows CG and Windows Cairo backends.
    virtual GraphicsContextPlatformPrivate* deprecatedPrivateContext() const { return nullptr; }
#endif

#if USE(DIRECT2D)
    GraphicsContext(HDC, ID2D1DCRenderTarget**, RECT, bool hasAlpha = false); // FIXME: To be removed.

    WEBCORE_EXPORT static ID2D1Factory* systemFactory();
    WEBCORE_EXPORT static ID2D1RenderTarget* defaultRenderTarget();

    WEBCORE_EXPORT void beginDraw();
    D2D1_COLOR_F colorWithGlobalAlpha(const Color&) const;
    WEBCORE_EXPORT void endDraw();
    void flush();

    ID2D1Brush* solidStrokeBrush() const;
    ID2D1Brush* solidFillBrush() const;
    ID2D1Brush* patternStrokeBrush() const;
    ID2D1Brush* patternFillBrush() const;
    ID2D1StrokeStyle* platformStrokeStyle() const;

    ID2D1SolidColorBrush* brushWithColor(const Color&);
#endif

private:
    virtual bool supportsTransparencyLayers() const { return true; }

protected:
    void fillEllipseAsPath(const FloatRect&);
    void strokeEllipseAsPath(const FloatRect&);

    FloatRect computeLineBoundsAndAntialiasingModeForText(const FloatRect&, bool printing, Color&);

    float dashedLineCornerWidthForStrokeWidth(float) const;
    float dashedLinePatternWidthForStrokeWidth(float) const;
    float dashedLinePatternOffsetForPatternAndStrokeWidth(float patternWidth, float strokeWidth) const;
    Vector<FloatPoint> centerLineAndCutOffCorners(bool isVerticalLine, float cornerWidth, FloatPoint point1, FloatPoint point2) const;

    GraphicsContextState m_state;

private:
    Vector<GraphicsContextState, 1> m_stack;

    unsigned m_transparencyLayerCount { 0 };
    bool m_contentfulPaintDetected { false };
};

class GraphicsContextStateSaver {
    WTF_MAKE_FAST_ALLOCATED;
public:
    GraphicsContextStateSaver(GraphicsContext& context, bool saveAndRestore = true)
    : m_context(context)
    , m_saveAndRestore(saveAndRestore)
    {
        if (m_saveAndRestore)
            m_context.save();
    }
    
    ~GraphicsContextStateSaver()
    {
        if (m_saveAndRestore)
            m_context.restore();
    }
    
    void save()
    {
        ASSERT(!m_saveAndRestore);
        m_context.save();
        m_saveAndRestore = true;
    }

    void restore()
    {
        ASSERT(m_saveAndRestore);
        m_context.restore();
        m_saveAndRestore = false;
    }
    
    GraphicsContext* context() const { return &m_context; }

private:
    GraphicsContext& m_context;
    bool m_saveAndRestore;
};

class TransparencyLayerScope {
public:
    TransparencyLayerScope(GraphicsContext& context, float alpha, bool beginLayer = true)
        : m_context(context)
        , m_alpha(alpha)
        , m_beganLayer(beginLayer)
    {
        if (beginLayer)
            m_context.beginTransparencyLayer(m_alpha);
    }
    
    void beginLayer(float alpha)
    {
        m_alpha = alpha;
        m_context.beginTransparencyLayer(m_alpha);
        m_beganLayer = true;
    }
    
    ~TransparencyLayerScope()
    {
        if (m_beganLayer)
            m_context.endTransparencyLayer();
    }

private:
    GraphicsContext& m_context;
    float m_alpha;
    bool m_beganLayer;
};

class GraphicsContextStateStackChecker {
public:
    GraphicsContextStateStackChecker(GraphicsContext& context)
        : m_context(context)
        , m_stackSize(context.stackSize())
    { }
    
    ~GraphicsContextStateStackChecker()
    {
        if (m_context.stackSize() != m_stackSize)
            WTFLogAlways("GraphicsContext %p stack changed by %d", &m_context, (int)m_context.stackSize() - (int)m_stackSize);
    }

private:
    GraphicsContext& m_context;
    unsigned m_stackSize;
};

class InterpolationQualityMaintainer {
public:
    explicit InterpolationQualityMaintainer(GraphicsContext& graphicsContext, InterpolationQuality interpolationQualityToUse)
        : m_graphicsContext(graphicsContext)
        , m_currentInterpolationQuality(graphicsContext.imageInterpolationQuality())
        , m_interpolationQualityChanged(interpolationQualityToUse != InterpolationQuality::Default && m_currentInterpolationQuality != interpolationQualityToUse)
    {
        if (m_interpolationQualityChanged)
            m_graphicsContext.setImageInterpolationQuality(interpolationQualityToUse);
    }

    explicit InterpolationQualityMaintainer(GraphicsContext& graphicsContext, std::optional<InterpolationQuality> interpolationQuality)
        : InterpolationQualityMaintainer(graphicsContext, interpolationQuality ? interpolationQuality.value() : graphicsContext.imageInterpolationQuality())
    {
    }

    ~InterpolationQualityMaintainer()
    {
        if (m_interpolationQualityChanged)
            m_graphicsContext.setImageInterpolationQuality(m_currentInterpolationQuality);
    }

private:
    GraphicsContext& m_graphicsContext;
    InterpolationQuality m_currentInterpolationQuality;
    bool m_interpolationQualityChanged;
};

} // namespace WebCore

namespace WTF {

template<> struct EnumTraits<WebCore::DocumentMarkerLineStyle::Mode> {
    using values = EnumValues<
    WebCore::DocumentMarkerLineStyle::Mode,
    WebCore::DocumentMarkerLineStyle::Mode::TextCheckingDictationPhraseWithAlternatives,
    WebCore::DocumentMarkerLineStyle::Mode::Spelling,
    WebCore::DocumentMarkerLineStyle::Mode::Grammar,
    WebCore::DocumentMarkerLineStyle::Mode::AutocorrectionReplacement,
    WebCore::DocumentMarkerLineStyle::Mode::DictationAlternatives
    >;
};

template<> struct EnumTraits<WebCore::GraphicsContextState::Change> {
    using values = EnumValues<
        WebCore::GraphicsContextState::Change,
        WebCore::GraphicsContextState::Change::StrokeGradientChange,
        WebCore::GraphicsContextState::Change::StrokePatternChange,
        WebCore::GraphicsContextState::Change::FillGradientChange,
        WebCore::GraphicsContextState::Change::FillPatternChange,
        WebCore::GraphicsContextState::Change::StrokeThicknessChange,
        WebCore::GraphicsContextState::Change::StrokeColorChange,
        WebCore::GraphicsContextState::Change::StrokeStyleChange,
        WebCore::GraphicsContextState::Change::FillColorChange,
        WebCore::GraphicsContextState::Change::FillRuleChange,
        WebCore::GraphicsContextState::Change::ShadowChange,
        WebCore::GraphicsContextState::Change::ShadowsIgnoreTransformsChange,
        WebCore::GraphicsContextState::Change::AlphaChange,
        WebCore::GraphicsContextState::Change::CompositeOperationChange,
        WebCore::GraphicsContextState::Change::BlendModeChange,
        WebCore::GraphicsContextState::Change::TextDrawingModeChange,
        WebCore::GraphicsContextState::Change::ShouldAntialiasChange,
        WebCore::GraphicsContextState::Change::ShouldSmoothFontsChange,
        WebCore::GraphicsContextState::Change::ShouldSubpixelQuantizeFontsChange,
        WebCore::GraphicsContextState::Change::DrawLuminanceMaskChange,
        WebCore::GraphicsContextState::Change::ImageInterpolationQualityChange
#if HAVE(OS_DARK_MODE_SUPPORT)
        , WebCore::GraphicsContextState::Change::UseDarkAppearanceChange
#endif
    >;
};

template<> struct EnumTraits<WebCore::StrokeStyle> {
    using values = EnumValues<
    WebCore::StrokeStyle,
    WebCore::StrokeStyle::NoStroke,
    WebCore::StrokeStyle::SolidStroke,
    WebCore::StrokeStyle::DottedStroke,
    WebCore::StrokeStyle::DashedStroke,
    WebCore::StrokeStyle::DoubleStroke,
    WebCore::StrokeStyle::WavyStroke
    >;
};

template<> struct EnumTraits<WebCore::TextDrawingMode> {
    using values = EnumValues<
        WebCore::TextDrawingMode,
        WebCore::TextDrawingMode::Fill,
        WebCore::TextDrawingMode::Stroke
    >;
};

} // namespace WTF
