bouncing balls改良

draw() {
      var MyColor=this.color;
            var MyX=this.x;
            var MyY=this.y;
            var MyRad=this.size;
            var InitCx=MyX+MyRad*(204-175)/100;
            var InitCy=MyY+MyRad*(50-100)/100;
            var InitCr=0.1*MyRad;
            var EndCx=MyX+0.25*MyRad;
            var EndCy=MyY-0.25*MyRad;
            var EndCr=0.75*MyRad;
      ctx.beginPath();
      //ctx.fillStyle = this.color;
      ctx.arc(this.x, this.y, this.size, 0, 2 * Math.PI);
      var gradient2=ctx.createRadialGradient(InitCx,InitCy,InitCr,EndCx,EndCy,EndCr);
            gradient2.addColorStop(0.0,"#FFFFFF");
            gradient2.addColorStop(1.0,MyColor);
            ctx.fillStyle = gradient2; 
            ctx.fill();
   }