【python】两线段的交点

参考：https://en.wikipedia.org/wiki/Line–line_intersection

坐标参考：

 def findIntersection(x1,y1,x2,y2,x3,y3,x4,y4):
        px= ( (x1*y2-y1*x2)*(x3-x4)-(x1-x2)*(x3*y4-y3*x4) ) / ( (x1-x2)*(y3-y4)-(y1-y2)*(x3-x4) ) 
        py= ( (x1*y2-y1*x2)*(y3-y4)-(y1-y2)*(x3*y4-y3*x4) ) / ( (x1-x2)*(y3-y4)-(y1-y2)*(x3-x4) )
        return [px, py]