国外网站下载的比较有名的大牛编写的代码可以实现，基本的操作功能。-Large cattle written code to download more famous foreign websites can achieve the basic operating functions.

在国外网站上找到的计算任意凸多边形的形心的源代码，基本算法是叠加各个三角形的形心。-the source code to calculate arbitrary convex polygon centroid found on foreign websites , the basic algorithm is superimposed on each triangle.