Windows中负责图形输出的是GDI(即Graphic Device Interface，图形设备接口)。这是Windows与硬件无关的图形输出模式的体现。GDI建立在硬件抽象层(HAL)之上,屏蔽了不同输出设备之间的差异,从而为用户提供了一个统一的“标准输出设备”。但是，与DOS不同，Windows是多任务、进程独立的，每一个窗口都应该有一个独立的输出通道。这样，GDI又使用了一种简单的机制来保证在窗口中画图的不同程序之间能共享“设备”而又互不干扰。这个机制就是DC(Device Context，设备描述表)。-Windows in charge of graphics output is GDI (ie Graphic Device Interface, Graphics Device Interface). This is not related to Windows and hardware graphics output mode of the embodiment. GDI based on hardware abstraction layer (HAL) on top of different shielding difference between the output device, providing users with a unified　standard output device.　However, with the DOS different, Windows is a multi-task, the process of independence, each window should have an independent output channels. This, GDI also uses a simple mechanism to ensure the drawing in the window between the different procedures to share the　equipment　and non-interfering. This mechanism is the DC (Device Context, device descr iption table).