贝塞尔曲线路径类（TypeScript）

export type pos = {
  x: number; 
  y: number;
}

export class BezierPath {
  /**
  * 创建几个选定坐标点沿着贝塞尔曲线的坐标集
  * @param anchorpoints 关键坐标点（比如开始点，最高峰值点，结束点）
  * @param pointsAmount 需要沿着曲线创建的坐标点数量（数字越大，则运动轨迹越精确）
  */
  private static CreateBezierPoints(anchorpoints: pos[], pointsAmount: number): Array<pos> {
    const points = new Array<pos>();
    let point: pos;
    for (let i = 0; i < pointsAmount; ++i) {
      point = this.MultiPointBezier(anchorpoints, i / pointsAmount);
      points.push(point);
    }
    return points;
  }

  private static MultiPointBezier(points: pos[], t: number): pos {
    let x = 0;
    let y = 0;
    let point: pos;
    const len = points.length;
    for (let i = 0; i < len; ++i) {
      point = points[i];
      x += point.x * Math.pow(1 - t, len - 1 - i) * Math.pow(t, i) * this.erxiangshi(len - 1, i);
      y += point.y * Math.pow(1 - t, len - 1 - i) * Math.pow(t, i) * this.erxiangshi(len - 1, i);
    }
    return { x: x, y: y };
  }

  private static erxiangshi(start: number, end: number): number {
    let cs = 1;
    let bcs = 1;
    while (end > 0) {
      cs *= start;
      bcs *= end;
      start--;
      end--;
    }
    return cs / bcs;
  }
}