n次贝塞尔曲线及三次b样条曲线的绘制，使用自己编写的curve类，实现曲线上点坐标的计算与绘制，曲线点坐标的计算使用递归算法。点击左键设定控制点，之后点击右件绘制曲线。-n Bessel curve and three b-spline curve mapping, prepared to use their own type of curve, curve coordinates of the point on the calculation and drawing, curve coordi