贝塞尔曲线本身，程式还从第一个控制点向左边的第一个端点（也叫做开始点）画一条直线，并从第二个控制点向右边的端点画一条直线。-Bezier curve itself, the program also from the first control point to the left of the first endpoint (also called the starting point) Draw a straight line, and from the second control poin