画图板

代码说明：

说明：  类似Windows画图板的小程序，功能和界面全部模仿于Windows自带的画图板，界面如截图。功能主要有： 手绘线、简单图形、文字输入、图块拖放、重复撤销、画面缩放、打开保存图片文件(Small programs similar to the Windows drawing board, all functions and interfaces imitate the drawing board that comes with Windows. The interface is like a screenshot. The main functions are: hand-drawn lines, simple graphics, text input, block drag and drop, repeated undo, screen zoom, open and save picture files)