１）给出系统框架。

２）调用画点的函数，分别用DDA、中点Bresenham算法和改进Bresenham算法绘制直线和中点算法绘制直线、用不同的算法绘制圆和椭圆 ，并各自比较算法精度与效率的差别 。

３）实现二维图形的变换。（包括平移，放缩，旋转，错切以及复合变换）

４）运用所学的区域填充算法实现区域填充。

５）运用所学算法实现线段裁剪以及多边形裁剪（多边形裁剪为可选）。

６）自己实现其它附加以及需要完善的功能。

-1) give system fr a mework.

2) calls the function, some painting separately in DDA, midpoint Bresenham algorithm and improve Bresenham algorithm draws lines and the midpoint algorithm with different beeline, drawing algorithm, and each round and elliptic comparison algorithm accuracy and efficiency difference.

3) to realize the transformation of 2 d graphics. (including translation, rotation, zooming, shear and composite transform)

4) by using their area filling area filling algorithm.

5) by using their algorithm line cutting and cutting (poly cut for polygon optional).

6) in realizing additional and need to perfect function.