public do(){
egret.Tween.get(t, { loop: true }).to({ fa: 180 }, 2000);
}
 public get fa(): number {
        return -180;
    }
    public set fa(s) {
        let chang = 50;
        let duan = 20;//长短一样时就是圆周运动
        let xx = chang;
        let yy = 0;
        this.x = xx + Math.cos(s * Math.PI / 180) * chang;
        this.y = yy + Math.sin(s * Math.PI / 180) * duan;
    }
原文:https://www.cnblogs.com/jiajunjie/p/12486650.html