设计一个简单的单文档界面绘图程序,实现绘制线条、矩形、椭圆以及更改线条颜色、线型,程序界面包含菜单、工具栏和状态栏-Design a simple single document interface drawing program, draw lines, rectangles, ellipses, and change the line color, line styles, the program interface contains the menu, toolbar and status