由于之前的一个竞赛需求，对bresenham作了一些完善，就是可以根据圆上的任意一个点，取出该点的下一个点坐标（顺时针逆时针均可）-As a contest before the demand for bresenham made some improvement, that is, according to an arbitrary point on the circle, take out the next point of the point coordinates (both clock