简单画图程序的实现，浮动工具栏，右键快捷菜单，状态栏，颜色对话框，设置对话框，文件保存与重现，橡皮筋技术实现，变换图标-The realization of a simple drawing program, a floating toolbar, context menu, status bar, color dialog, set the dialog box, save the file and reproduce, the rubber band technique.

001 - 获取屏幕角点坐标，002 - StartUndoMark EndUndoMark，003 - 搜索曲线上与一指定点最靠近的点，004 - 求图块内圆的圆心坐标(Matrix)，005 - 调用系统选择文件夹对话框，006 - AutoCAD索引颜色（ACI）与RGB颜色对照表，008 - 自定义Hatch，011 - 将AutoCAD数据转换成字符串(001 - Get screen corner coordinates, 002 - Start UndoMark End Undo