HoughLnDetectInGraphics

代码说明：

  根据图像处理中hough转换的原理，从实际能运行的代码中修改得到能检测出图形中可共直线的点，并可改为显示2、3、4...点共线。 (hough transform for straight lines detect on graphic,the straight lines do not exist,but can formed by the multi points,maybe 2,3,4,...)