通过鼠标绘制各种图形，包括 直线，矩形，圆及多边形。同时还可以对多边形进行裁剪，区域填色。实现多种曲线，插值及逼近-Through a variety of mouse drawn graphics, including a straight line, rectangle, circle and polygon. At the same time can also be carried out on the polygon clipping, regional coloring. To ach