Components of a Printer Driver

A Windows NT printer driver consists of the following components:

• The printer graphics driver DLL implements the DDI to the degree necessary to support printer rendering features and capabilities that cannot be adequately handled by the graphics engine.

• The printer interface driver DLL creates an interface that allows users to set the physical properties of the printer and the logical properties of the document. This interface is also responsible for interacting with the Common Property Sheet User Interface to provide device- and document-specific property sheet page(s) in response to an application request.

• The printer device data file supplies printer-specific information to both the printer graphics and interface components. The file type (and contents) depends on the printer with which it is associated.

A printer driver is specific to a particular type of printer or family of printers. Three types of printer drivers shipped with Windows NT are the raster device driver (RasDD), PostScript driver, and plotter driver. The components that comprise each of these drivers are shown in the following table.

Type of Printer Driver	Printer Graphics Driver DLL	Printer UI DLL	Data File
RasDD	rasdd.dll	rasddui.dll	Raster minidriver .DLL
PostScript	pscript.dll	psui.dll	.PPD
Plotter	plotter.dll	plotui.dll	.PCD

For example, the three components that comprise the printer driver for an HP IIIsi PostScript printer are:

• pscript.dll

• PSUI.dll

• HP3SI<ver>.PPD

Printer driver files are installed on a Windows NT system when the corresponding printer is installed.

These three driver types provide support for many of the printing devices on the market today. You need only write a printer driver if your printing device is not compatible with the appropriate system-supplied one.