计算机图形学实验： 实现Bresenham算法绘制线段，并利用“橡皮筋”功能绘制折线。 可将绘制的折线连接成多边形，并选择种子填充法或扫描线填充法进行填充。-Computer Graphics Lab: Bresenham algorithm for drawing line segments to achieve, and to use " rubber band" line drawing functions. Line connection can be draw