38 lines
1.1 KiB
JavaScript
38 lines
1.1 KiB
JavaScript
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const epsilon = 1e-6;
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export default class Path {
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constructor() {
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this._x0 = this._y0 = // start of current subpath
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this._x1 = this._y1 = null; // end of current subpath
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this._ = "";
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}
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moveTo(x, y) {
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this._ += `M${this._x0 = this._x1 = +x},${this._y0 = this._y1 = +y}`;
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}
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closePath() {
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if (this._x1 !== null) {
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this._x1 = this._x0, this._y1 = this._y0;
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this._ += "Z";
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}
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}
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lineTo(x, y) {
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this._ += `L${this._x1 = +x},${this._y1 = +y}`;
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}
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arc(x, y, r) {
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x = +x, y = +y, r = +r;
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const x0 = x + r;
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const y0 = y;
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if (r < 0) throw new Error("negative radius");
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if (this._x1 === null) this._ += `M${x0},${y0}`;
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else if (Math.abs(this._x1 - x0) > epsilon || Math.abs(this._y1 - y0) > epsilon) this._ += "L" + x0 + "," + y0;
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if (!r) return;
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this._ += `A${r},${r},0,1,1,${x - r},${y}A${r},${r},0,1,1,${this._x1 = x0},${this._y1 = y0}`;
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}
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rect(x, y, w, h) {
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this._ += `M${this._x0 = this._x1 = +x},${this._y0 = this._y1 = +y}h${+w}v${+h}h${-w}Z`;
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}
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value() {
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return this._ || null;
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}
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}
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