所有的与软件环境无关的函数：

1、点在线上判断

2、确定两条线段是否相交,包括端点

3、求两条线的交点

4、 判断点q是否在多边形Polygon内

等多个函数-All has nothing to do with the software environment of the function: 1, 2-point line on the judge to determine whether two line segments intersect, including the endpoint 3, the point of intersection for two lines 4, to determine whether q points Polygon polygon with a number of functions, such as