应用可种算法绘制直线，椭圆，矩形的各种图形，可以作为GIS开发的原型。-Application of straight-line drawing algorithms, oval, rectangular variety of graphics, GIS can be used as the prototype development.

主要介绍的是直线圆椭圆的绘制以及其裁剪算法-Describes the straight line drawn round the ellipse and its cutting algorithm