bd028579
 易尊强
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/**
* 正多边形
*/
import Path, { PathProps } from '../Path';
const PI = Math.PI;
const sin = Math.sin;
const cos = Math.cos;
export class IsogonShape {
x = 0
y = 0
r = 0
n = 0
}
export interface IsogonProps extends PathProps {
shape?: Partial<IsogonShape>
}
class Isogon extends Path<IsogonProps> {
shape: IsogonShape
constructor(opts?: IsogonProps) {
super(opts);
}
getDefaultShape() {
return new IsogonShape();
}
buildPath(ctx: CanvasRenderingContext2D, shape: IsogonShape) {
const n = shape.n;
if (!n || n < 2) {
return;
}
const x = shape.x;
const y = shape.y;
const r = shape.r;
const dStep = 2 * PI / n;
let deg = -PI / 2;
ctx.moveTo(x + r * cos(deg), y + r * sin(deg));
for (let i = 0, end = n - 1; i < end; i++) {
deg += dStep;
ctx.lineTo(x + r * cos(deg), y + r * sin(deg));
}
ctx.closePath();
return;
}
}
Isogon.prototype.type = 'isogon';
export default Isogon;
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