实现基本图形绘制和填充。能够更改图元绘制条件（改变线条颜色、线型、填充方式）和图元的保存功能。实现画笔和画刷风格认定功能等(Realize basic graphics and fill. Can change the drawing condition of the graph element (change the line color, line type, filling mode) and the preservation function of the graph element.