Gdi ( graphical device interface ) is the kernel module of graphics subsystem in gui and it insulates gui application program from difference among output hardwares . detailed design and implementation of gdi with dc ( device context ) mechanism is studied from the point of view of 00 Gdi作为嵌入式gui的图形子系统核心模块,通过引入设备上下文机制,运用面向对象技术,隔离上层应用程序和不同特性的输出设备,从而达到与设备无关图形操作的设计目标。