CanvasRenderingContext2D.h   [plain text]

/*
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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#ifndef CanvasRenderingContext2D_h
#define CanvasRenderingContext2D_h

#include "AffineTransform.h"
#include "CanvasPathMethods.h"
#include "CanvasRenderingContext.h"
#include "CanvasStyle.h"
#include "Color.h"
#include "ColorSpace.h"
#include "DashArray.h"
#include "FloatSize.h"
#include "Font.h"
#include "GraphicsTypes.h"
#include "ImageBuffer.h"
#include "Path.h"
#include <wtf/Vector.h>
#include <wtf/text/WTFString.h>

#if USE(ACCELERATED_COMPOSITING)
#include "PlatformLayer.h"
#endif

namespace WebCore {

class CanvasGradient;
class CanvasPattern;
#if ENABLE(CANVAS_PATH)
class DOMPath;
#endif
class FloatRect;
class GraphicsContext;
class HTMLCanvasElement;
class HTMLImageElement;
class HTMLVideoElement;
class ImageData;
class TextMetrics;

typedef int ExceptionCode;

class CanvasRenderingContext2D : public CanvasRenderingContext, public CanvasPathMethods {
public:
    static PassOwnPtr<CanvasRenderingContext2D> create(HTMLCanvasElement* canvas, bool usesCSSCompatibilityParseMode, bool usesDashboardCompatibilityMode)
    {
        return adoptPtr(new CanvasRenderingContext2D(canvas, usesCSSCompatibilityParseMode, usesDashboardCompatibilityMode));
    }
    virtual ~CanvasRenderingContext2D();

    const CanvasStyle& strokeStyle() const { return state().m_strokeStyle; }
    void setStrokeStyle(CanvasStyle);

    const CanvasStyle& fillStyle() const { return state().m_fillStyle; }
    void setFillStyle(CanvasStyle);

    float lineWidth() const;
    void setLineWidth(float);

    String lineCap() const;
    void setLineCap(const String&);

    String lineJoin() const;
    void setLineJoin(const String&);

    float miterLimit() const;
    void setMiterLimit(float);

    const Vector<float>& getLineDash() const;
    void setLineDash(const Vector<float>&);
    void setWebkitLineDash(const Vector<float>&);

    float lineDashOffset() const;
    void setLineDashOffset(float);
    float webkitLineDashOffset() const;
    void setWebkitLineDashOffset(float);

    float shadowOffsetX() const;
    void setShadowOffsetX(float);

    float shadowOffsetY() const;
    void setShadowOffsetY(float);

    float shadowBlur() const;
    void setShadowBlur(float);

    String shadowColor() const;
    void setShadowColor(const String&);

    float globalAlpha() const;
    void setGlobalAlpha(float);

    String globalCompositeOperation() const;
    void setGlobalCompositeOperation(const String&);

    void save() { ++m_unrealizedSaveCount; }
    void restore();

    void scale(float sx, float sy);
    void rotate(float angleInRadians);
    void translate(float tx, float ty);
    void transform(float m11, float m12, float m21, float m22, float dx, float dy);
    void setTransform(float m11, float m12, float m21, float m22, float dx, float dy);

    void setStrokeColor(const String& color);
    void setStrokeColor(float grayLevel);
    void setStrokeColor(const String& color, float alpha);
    void setStrokeColor(float grayLevel, float alpha);
    void setStrokeColor(float r, float g, float b, float a);
    void setStrokeColor(float c, float m, float y, float k, float a);

    void setFillColor(const String& color);
    void setFillColor(float grayLevel);
    void setFillColor(const String& color, float alpha);
    void setFillColor(float grayLevel, float alpha);
    void setFillColor(float r, float g, float b, float a);
    void setFillColor(float c, float m, float y, float k, float a);

    void beginPath();

#if ENABLE(CANVAS_PATH)
    PassRefPtr<DOMPath> currentPath();
    void setCurrentPath(DOMPath*);
#endif
    void fill(const String& winding = "nonzero");
    void stroke();
    void clip(const String& winding = "nonzero");

    bool isPointInPath(const float x, const float y, const String& winding = "nonzero");
    bool isPointInStroke(const float x, const float y);

    void clearRect(float x, float y, float width, float height);
    void fillRect(float x, float y, float width, float height);
    void strokeRect(float x, float y, float width, float height);

    void setShadow(float width, float height, float blur);
    void setShadow(float width, float height, float blur, const String& color);
    void setShadow(float width, float height, float blur, float grayLevel);
    void setShadow(float width, float height, float blur, const String& color, float alpha);
    void setShadow(float width, float height, float blur, float grayLevel, float alpha);
    void setShadow(float width, float height, float blur, float r, float g, float b, float a);
    void setShadow(float width, float height, float blur, float c, float m, float y, float k, float a);

    void clearShadow();

    void drawImage(HTMLImageElement*, float x, float y, ExceptionCode&);
    void drawImage(HTMLImageElement*, float x, float y, float width, float height, ExceptionCode&);
    void drawImage(HTMLImageElement*, float sx, float sy, float sw, float sh, float dx, float dy, float dw, float dh, ExceptionCode&);
    void drawImage(HTMLImageElement*, const FloatRect& srcRect, const FloatRect& dstRect, ExceptionCode&);
    void drawImage(HTMLCanvasElement*, float x, float y, ExceptionCode&);
    void drawImage(HTMLCanvasElement*, float x, float y, float width, float height, ExceptionCode&);
    void drawImage(HTMLCanvasElement*, float sx, float sy, float sw, float sh, float dx, float dy, float dw, float dh, ExceptionCode&);
    void drawImage(HTMLCanvasElement*, const FloatRect& srcRect, const FloatRect& dstRect, ExceptionCode&);
    void drawImage(HTMLImageElement*, const FloatRect& srcRect, const FloatRect& dstRect, const CompositeOperator&, const BlendMode&, ExceptionCode&);
#if ENABLE(VIDEO)
    void drawImage(HTMLVideoElement*, float x, float y, ExceptionCode&);
    void drawImage(HTMLVideoElement*, float x, float y, float width, float height, ExceptionCode&);
    void drawImage(HTMLVideoElement*, float sx, float sy, float sw, float sh, float dx, float dy, float dw, float dh, ExceptionCode&);
    void drawImage(HTMLVideoElement*, const FloatRect& srcRect, const FloatRect& dstRect, ExceptionCode&);
#endif

    void drawImageFromRect(HTMLImageElement*, float sx = 0, float sy = 0, float sw = 0, float sh = 0,
                           float dx = 0, float dy = 0, float dw = 0, float dh = 0, const String& compositeOperation = emptyString());

    void setAlpha(float);

    void setCompositeOperation(const String&);

    PassRefPtr<CanvasGradient> createLinearGradient(float x0, float y0, float x1, float y1, ExceptionCode&);
    PassRefPtr<CanvasGradient> createRadialGradient(float x0, float y0, float r0, float x1, float y1, float r1, ExceptionCode&);
    PassRefPtr<CanvasPattern> createPattern(HTMLImageElement*, const String& repetitionType, ExceptionCode&);
    PassRefPtr<CanvasPattern> createPattern(HTMLCanvasElement*, const String& repetitionType, ExceptionCode&);

    PassRefPtr<ImageData> createImageData(PassRefPtr<ImageData>, ExceptionCode&) const;
    PassRefPtr<ImageData> createImageData(float width, float height, ExceptionCode&) const;
    PassRefPtr<ImageData> getImageData(float sx, float sy, float sw, float sh, ExceptionCode&) const;
    PassRefPtr<ImageData> webkitGetImageDataHD(float sx, float sy, float sw, float sh, ExceptionCode&) const;
    void putImageData(ImageData*, float dx, float dy, ExceptionCode&);
    void putImageData(ImageData*, float dx, float dy, float dirtyX, float dirtyY, float dirtyWidth, float dirtyHeight, ExceptionCode&);
    void webkitPutImageDataHD(ImageData*, float dx, float dy, ExceptionCode&);
    void webkitPutImageDataHD(ImageData*, float dx, float dy, float dirtyX, float dirtyY, float dirtyWidth, float dirtyHeight, ExceptionCode&);

    float webkitBackingStorePixelRatio() const { return canvas()->deviceScaleFactor(); }

    void reset();

    String font() const;
    void setFont(const String&);

    String textAlign() const;
    void setTextAlign(const String&);

    String textBaseline() const;
    void setTextBaseline(const String&);

    void fillText(const String& text, float x, float y);
    void fillText(const String& text, float x, float y, float maxWidth);
    void strokeText(const String& text, float x, float y);
    void strokeText(const String& text, float x, float y, float maxWidth);
    PassRefPtr<TextMetrics> measureText(const String& text);

    LineCap getLineCap() const { return state().m_lineCap; }
    LineJoin getLineJoin() const { return state().m_lineJoin; }

    bool webkitImageSmoothingEnabled() const;
    void setWebkitImageSmoothingEnabled(bool);

private:
    struct State : FontSelectorClient {
        State();
        virtual ~State();

        State(const State&);
        State& operator=(const State&);

        virtual void fontsNeedUpdate(FontSelector*) OVERRIDE;

        String m_unparsedStrokeColor;
        String m_unparsedFillColor;
        CanvasStyle m_strokeStyle;
        CanvasStyle m_fillStyle;
        float m_lineWidth;
        LineCap m_lineCap;
        LineJoin m_lineJoin;
        float m_miterLimit;
        FloatSize m_shadowOffset;
        float m_shadowBlur;
        RGBA32 m_shadowColor;
        float m_globalAlpha;
        CompositeOperator m_globalComposite;
        BlendMode m_globalBlend;
        AffineTransform m_transform;
        bool m_invertibleCTM;
        Vector<float> m_lineDash;
        float m_lineDashOffset;
        bool m_imageSmoothingEnabled;

        // Text state.
        TextAlign m_textAlign;
        TextBaseline m_textBaseline;

        String m_unparsedFont;
        Font m_font;
        bool m_realizedFont;
    };

    enum CanvasDidDrawOption {
        CanvasDidDrawApplyNone = 0,
        CanvasDidDrawApplyTransform = 1,
        CanvasDidDrawApplyShadow = 1 << 1,
        CanvasDidDrawApplyClip = 1 << 2,
        CanvasDidDrawApplyAll = 0xffffffff
    };

    CanvasRenderingContext2D(HTMLCanvasElement*, bool usesCSSCompatibilityParseMode, bool usesDashboardCompatibilityMode);

    State& modifiableState() { ASSERT(!m_unrealizedSaveCount); return m_stateStack.last(); }
    const State& state() const { return m_stateStack.last(); }

    void applyLineDash() const;
    void setShadow(const FloatSize& offset, float blur, RGBA32 color);
    void applyShadow();
    bool shouldDrawShadows() const;

    void didDraw(const FloatRect&, unsigned options = CanvasDidDrawApplyAll);
    void didDrawEntireCanvas();

    GraphicsContext* drawingContext() const;

    void unwindStateStack();
    void realizeSaves()
    {
        if (m_unrealizedSaveCount)
            realizeSavesLoop();
    }
    void realizeSavesLoop();

    void applyStrokePattern();
    void applyFillPattern();

    void drawTextInternal(const String& text, float x, float y, bool fill, float maxWidth = 0, bool useMaxWidth = false);

    const Font& accessFont();

#if ENABLE(DASHBOARD_SUPPORT)
    void clearPathForDashboardBackwardCompatibilityMode();
#endif

    void clearCanvas();
    Path transformAreaToDevice(const Path&) const;
    Path transformAreaToDevice(const FloatRect&) const;
    bool rectContainsCanvas(const FloatRect&) const;

    template<class T> IntRect calculateCompositingBufferRect(const T&, IntSize*);
    PassOwnPtr<ImageBuffer> createCompositingBuffer(const IntRect&);
    void compositeBuffer(ImageBuffer*, const IntRect&, CompositeOperator);

    void inflateStrokeRect(FloatRect&) const;

    template<class T> void fullCanvasCompositedFill(const T&);
    template<class T> void fullCanvasCompositedDrawImage(T*, ColorSpace, const FloatRect&, const FloatRect&, CompositeOperator);

    void prepareGradientForDashboard(CanvasGradient* gradient) const;

    PassRefPtr<ImageData> getImageData(ImageBuffer::CoordinateSystem, float sx, float sy, float sw, float sh, ExceptionCode&) const;
    void putImageData(ImageData*, ImageBuffer::CoordinateSystem, float dx, float dy, float dirtyX, float dirtyY, float dirtyWidth, float dirtyHeight, ExceptionCode&);

    virtual bool is2d() const OVERRIDE { return true; }
    virtual bool isAccelerated() const OVERRIDE;

    virtual bool isTransformInvertible() const { return state().m_invertibleCTM; }

#if ENABLE(ACCELERATED_2D_CANVAS) && USE(ACCELERATED_COMPOSITING)
    virtual PlatformLayer* platformLayer() const OVERRIDE;
#endif

    Vector<State, 1> m_stateStack;
    unsigned m_unrealizedSaveCount;
    bool m_usesCSSCompatibilityParseMode;
#if ENABLE(DASHBOARD_SUPPORT)
    bool m_usesDashboardCompatibilityMode;
#endif
};

} // namespace WebCore

#endif