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CanvasRenderingContext2D.idl
typedef (HTMLImageElement or
HTMLVideoElement or
HTMLCanvasElement) CanvasImageSource;
interface CanvasRenderingContext2D {
// back-reference to the canvas
readonly attribute HTMLCanvasElement canvas;
void drawFocusIfNeeded(Element element);
// hit regions
void addHitRegion(HitRegionOptions options);
void removeHitRegion(DOMString id);
void clearHitRegions();
};
CanvasRenderingContext2D implements CanvasDrawingStyles;
CanvasRenderingContext2D implements CanvasImageDataMethods;
CanvasRenderingContext2D implements CanvasMethods;
CanvasRenderingContext2D implements CanvasPathMethods;
// TODO bikeshed name.
interface OffscreenCanvasRenderingContext2D {
};
OffscreenCanvasRenderingContext2D implements CanvasDrawingStyles;
OffscreenCanvasRenderingContext2D implements CanvasImageDataMethods;
OffscreenCanvasRenderingContext2D implements CanvasMethods;
OffscreenCanvasRenderingContext2D implements CanvasPathMethods;
// TODO bikeshed name.
interface HoudiniCanvasRenderingContext2D {
};
HoudiniCanvasRenderingContext2D implements CanvasDrawingStyles;
HoudiniCanvasRenderingContext2D implements CanvasMethods;
HoudiniCanvasRenderingContext2D implements CanvasPathMethods;
[NoInterfaceObject]
interface CanvasImageDataMethods {
ImageData createImageData(unrestricted double sw, unrestricted double sh);
ImageData createImageData(ImageData imagedata);
ImageData getImageData(double sx, double sy, double sw, double sh); // NOTE arguably only getImageData should be here.
void putImageData(ImageData imagedata, double dx, double dy);
void putImageData(ImageData imagedata, double dx, double dy, double dirtyX, double dirtyY, double dirtyWidth, double dirtyHeight);
};
// "write-only" methods should go here, i.e. no methods which would force a raster.
[NoInterfaceObject]
interface CanvasMethods {
// state
void save(); // push state on state stack
void restore(); // pop state stack and restore state
// transforms (default: transform is the identity matrix)
void scale(unrestricted double x, unrestricted double y);
void rotate(unrestricted double angle);
void translate(unrestricted double x, unrestricted double y);
void transform(unrestricted double a, unrestricted double b, unrestricted double c, unrestricted double d, unrestricted double e, unrestricted double f);
void setTransform(unrestricted double a, unrestricted double b, unrestricted double c, unrestricted double d, unrestricted double e, unrestricted double f);
// compositing
attribute unrestricted double globalAlpha; // (default: 1.0)
attribute DOMString globalCompositeOperation; // (default: "source-over")
// colors and styles (see also the CanvasDrawingStyles interface)
attribute (DOMString or CanvasGradient or CanvasPattern) strokeStyle; // (default: "black")
attribute (DOMString or CanvasGradient or CanvasPattern) fillStyle; // (default: "black")
CanvasGradient createLinearGradient(double x0, double y0, double x1, double y1);
CanvasGradient createRadialGradient(double x0, double y0, double r0, double x1, double y1, double r1);
CanvasPattern createPattern(CanvasImageSource image, [TreatNullAs=EmptyString] DOMString repetition);
// shadows
attribute unrestricted double shadowOffsetX; // (default: 0)
attribute unrestricted double shadowOffsetY; // (default: 0)
attribute unrestricted double shadowBlur; // (default: 0)
attribute DOMString shadowColor; // (default: "transparent black")
// rects
void clearRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
void fillRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
void strokeRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
// path API (see also CanvasPathMethods)
void beginPath();
void fill();
void stroke();
void clip();
boolean isPointInPath(unrestricted double x, unrestricted double y);
// text (see also the CanvasDrawingStyles interface)
void fillText(DOMString text, unrestricted double x, unrestricted double y, optional unrestricted double maxWidth);
void strokeText(DOMString text, unrestricted double x, unrestricted double y, optional unrestricted double maxWidth);
TextMetrics measureText(DOMString text);
// drawing images
void drawImage(CanvasImageSource image, unrestricted double dx, unrestricted double dy);
void drawImage(CanvasImageSource image, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
void drawImage(CanvasImageSource image, unrestricted double sx, unrestricted double sy, unrestricted double sw, unrestricted double sh, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
};
[NoInterfaceObject]
interface CanvasDrawingStyles {
// line caps/joins
attribute unrestricted double lineWidth; // (default: 1)
attribute DOMString lineCap; // "butt", "round", "square" (default: "butt")
attribute DOMString lineJoin; // "round", "bevel", "miter" (default: "miter")
attribute unrestricted double miterLimit; // (default: 10)
// dashed lines
void setLineDash(sequence<unrestricted double> segments); // (default: empty)
sequence<unrestricted double> getLineDash();
attribute unrestricted double lineDashOffset;
// text
attribute DOMString font; // (default: "10px sans-serif")
attribute DOMString textAlign; // "start", "end", "left", "right", "center" (default: "start")
attribute DOMString textBaseline; // "top", "hanging", "middle", "alphabetic", "ideographic", "bottom" (default: "alphabetic")
};
[NoInterfaceObject]
interface CanvasPathMethods {
// shared path API methods
void closePath();
void moveTo(unrestricted double x, unrestricted double y);
void lineTo(unrestricted double x, unrestricted double y);
void quadraticCurveTo(unrestricted double cpx, unrestricted double cpy, unrestricted double x, unrestricted double y);
void bezierCurveTo(unrestricted double cp1x, unrestricted double cp1y, unrestricted double cp2x, unrestricted double cp2y, unrestricted double x, unrestricted double y);
void arcTo(unrestricted double x1, unrestricted double y1, unrestricted double x2, unrestricted double y2, unrestricted double radius);
void rect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
void arc(unrestricted double x, unrestricted double y, unrestricted double radius, unrestricted double startAngle, unrestricted double endAngle, optional boolean counterclockwise = false);
};
interface CanvasGradient {
// opaque object
void addColorStop(double offset, DOMString color);
};
interface CanvasPattern {
// opaque object
};
interface TextMetrics {
readonly attribute double width;
};
dictionary HitRegionOptions {
// dictionary to allow expansion on Hit Regions in Canvas Context 2D Level 2
DOMString id = "";
// for control-backed regions:
Element? control = null;
};
interface ImageData {
readonly attribute unsigned long width;
readonly attribute unsigned long height;
readonly attribute Uint8ClampedArray data;
};
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