实现了一个简单的绘工具，该绘图工具具有打开，关闭，保存，另存文件的功能；它能够对直线，矩形等几种图元进行绘制和操作。-Implements a simple drawing tool, the drawing tools with open, close, save, save the file functions that it will be a straight line, rectangle, etc. to draw some primitives and operations.