计算机图形学画圆，画线段，画多边形，填充-Computer graphics circle, draw the line, polygon drawing, filling

计算机图形学的简单实验，完成了基本图形的绘制，以及图形的颜色填充处理，对于刚刚入门的同学可以参考-Simple experimental computer graphics to complete the basic graphics rendering, and color graphics filling treatment, just for introductory students can reference