关于VC和windows 的绘图机制,使用GDI(图形设备接口)对象，通常使用CDC 类，CPaintDC也一样（device-context）设备上下文 Windows下的MFC编程机制，消息驱动，事件等待.-On the VC and the windows of the drawing mechanism, the use of GDI (Graphics Device Interface) objects, used by CDC category, CPaintDC same (dev