GDI

GDI may refer to:

Organisations

Science and technology

Other uses

Graphics Device Interface

The Graphics Device Interface (GDI) is a Microsoft Windows application programming interface and core operating system component responsible for representing graphical objects and transmitting them to output devices such as monitors and printers.

GDI is responsible for tasks such as drawing lines and curves, rendering fonts and handling palettes. It is not directly responsible for drawing windows, menus, etc.; that task is reserved for the user subsystem, which resides in user32.dll and is built atop GDI. Other systems have components that are similar to GDI, for example Mac OS X's Quartz and X Window System's Xlib/XCB.

GDI's most significant advantages over more direct methods of accessing the hardware are perhaps its scaling capabilities and its abstract representation of target devices. Using GDI, it is very easy to draw on multiple devices, such as a screen and a printer, and expect proper reproduction in each case. This capability is at the center of most What You See Is What You Get applications for Microsoft Windows.

Microsoft Windows library files

The Microsoft Windows operating system supports a form of shared libraries known as "dynamic-link libraries", which are code libraries that can be used by multiple processes while only one copy is loaded into memory. This article provides an overview of the core libraries that are included with every modern Windows installation, on top of which most Windows applications are built.

Internal components

The library files in this section are not used directly by most programs; however, they are a dependency of other libraries that are used by programs.

Hal.dll

The Windows Hardware Abstraction Layer (HAL) is implemented in Hal.dll. The HAL implements a number of functions that are implemented in different ways by different hardware platforms, which in this context, refers mostly to the Chipset. Other components in the operating system can then call these functions in the same way on all platforms, without regard for the actual implementation.

For example, responding to an interrupt is quite different on a machine with an Advanced Programmable Interrupt Controller (APIC) than on one without. The HAL provides a single function for this purpose that works with all kinds of interrupts by various chipsets, so that other components need not be concerned with the differences.