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