实现简单图形的绘制，放大缩小移动，鼠标操作交互，图形数据的保存以及打开-Drawing simple graphics, Zoom mobile, mouse interaction, graphics data, as well as the preservation of open

代码.采用面向对象的思想设计绘图工具.其中运用了动态库的知识。-Code using the object-oriented design ideas drawing tools which use a dynamic library of knowledge.