中点画椭圆法的扫描转换程序，算法描述：考虑圆心不在原点，设圆心坐标为（x0,y0）。通过平移坐标原点到圆心。-Stipple Ellipsometry in the scan conversion process, the algorithm descr iption: consider the center of a circle is not the origin, set up the center coordinates (x0, y0). Through shifting the or