Developing a Minidriver with Unitool

The Windows NT Unitool is a development tool that allows driver writers to easily create a minidriver for their raster printer. It permits GPC data to be organized and defined into a minidriver for a single raster printer or a group of similar raster printers. Unitool automatically combines the printer description file with a layer of RasDD interface code to create a minidriver. The GPC data that Unitool creates in the minidriver provides the resources that RasDD requires to run a printing device. This eliminates the need to create a complex driver for every printer within a family of similar printing devices.

Unitool, sample GPC data, and other related files and information required to build a minidriver are provided in the Windows NT DDK. Sample GPC data, used to create actual Windows NT minidrivers, is provided for the following printer drivers:

• Digital Equipment Corporation driver for DEClaser 3200 printers

• Epson 9-pin driver

• Epson 24-pin driver

• Hewlett Packard driver for printers that use HPPCL

• HP PaintJet driver

• A text-only base driver

To save development time, driver writers can start with the supplied GPC data set that most closely resembles the characteristics of their raster printer, and customize it to fit their device.

The GPC resource data in Unitool enables you to collect comprehensive information about the related printer driver in the minidriver. Each minidriver supports RasDD and the RasDD user interface. For the user interface, the minidriver data defines general information about the printer, such as the number of available paper trays, and what form is contained in which tray.

The subsequent topics:

• Contain information related to using Unitool.

• Describe the general procedure for building a Windows NT minidriver.

Subsequent topics provide detailed descriptions of each type of information contained in Unitool, including:

• Character-translation table used to remap characters from the printer’s native character and symbol set to the Windows ANSI set.

• Minidriver data and the specification for master units.

• Control information, including the page-control and cursor-movement commands.

• Paper information, including the paper size, paper source and paper destination commands.

• Graphics information, including the printer resolution, compression, color and rectangle fill commands

• Font information, including text font cartridge, font simulation and downloadable fonts

• Printer model data, including model-specific data for the concerned minidriver.

• Minidriver callback functions.

• Unitool error messages.

Note  Unitool creates data files (including PFM and CTT) that are compatible with Windows 95 and Windows 3.1. You must convert these files to the necessary format to work on Windows NT. For more information, see Converting a Minidriver to Windows NT.

Many topics contain examples of minidriver data for the following printer types:

• Kodak Diconix 150 Plus

• Hewlett-Packard LaserJet IIP

• Hewlett-Packard PaintJet

The Kodak Diconix printer is an ink-jet printer that uses a command set similar to the Epson and IBM dot-matrix printer command set. The HP LaserJet IIP printer is a laser printer that uses HPPCL. The HP PaintJet is an ink-jet color printer that is used as an example to describe color support for the minidriver.