说明：  本算法是个B样条曲线拟合算法，包括2D的和3D的两种曲线拟合算法。用户可以自己设定拟合的点数，也可以让算法根据拟合效果自动确定。
(This algorithm is a B-spline curve fitting algorithms, including 2D and 3D two curve fitting algorithm. Users can set their own fitting points, but also allows the algorithm automatically determined according to the fitting effect.)