绘图 可以绘制椭圆和方形的图案一个图形绘制程序。它具有画线段、画矩形、画椭圆、清屏四个功能。实现了对线段、矩形、椭圆的动态绘制-Graphics can draw a pattern of oval and square graphic drawing program. It has a painted line, draw rectangle, painted oval, clear the screen of four functions. Realize the line, rectangle, ellipse dynamic rendering