js拆分曲线

function splitBezierCurve(points, t) {
    let x = (1 - t) * points[0].x + t * points[1].x;
    let y = (1 - t) * points[0].y + t * points[1].y;
    let x1 = (1 - t) * points[1].x + t * points[2].x;
    let y1 = (1 - t) * points[1].y + t * points[2].y;
    let x2 = (1 - t) * points[2].x + t * points[3].x;
    let y2 = (1 - t) * points[2].y + t * points[3].y;

    let x1_ = (1 - t) * x + t * x1;
    let y1_ = (1 - t) * y + t * y1;
    let x2_ = (1 - t) * x1 + t * x2;
    let y2_ = (1 - t) * y1 + t * y2;

    let x_ = (1 - t) * x1_ + t * x2_;
    let y_ = (1 - t) * y1_ + t * y2_;

    return [
        { x: points[0].x, y: points[0].y },
        { x: x, y: y },
        { x: x1_, y: y1_ },
        { x: x_, y: y_ },
        { x: x2_, y: y2_ },
        { x: x2, y: y2 },
        { x: points[3].x, y: points[3].y }
    ];
}