实现全屏绘图，主界面为工具条。跟商用电子白板软件界面一样，实现基本绘图功能。界面可以用做开发参考。有详细中文注解。-To achieve full-screen graphics, the main interface for the toolbar. Whiteboard software interface with business, like the realization of the basic drawing functions. Interface can be used for