win32下windows应用程序，简单的写屏幕程序。该demo实现获取整个屏幕的上下文设备，并实现画一个正方形的小方块，用绿色填充。-under win32 windows application, simply write the program of the screen. The demo is to achieve access to the equipment of the context of the entire screen, and draw a small square b

一个进行画图的小程序，可以简单明了的画出所要图形。(A small program for drawing, you can simply and easily draw the desired graphics.)