Unidrv
Encyclopedia
UniDrv is a GDI
Graphics Device Interface
The Graphics Device Interface 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....

-based Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 universal printer
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...

 driver
Printer driver
In computers, a printer driver or a print processor is a piece of software that converts the data to be printed to the form specific to a printer...

 and architecture for non-PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...

 printers. It is used to simplify driver development of non-PostScript printers (also called Winprinters) for printer manufacturers. Unidrv allows the creation of a printer-specific minidriver in the form of a GPD (Generic Printer Description) file, similar to a PPD
PostScript Printer Description
PostScript Printer Description files are created by vendors to describe the entire set of features and capabilities available for their PostScript printers.A PPD also contains the PostScript code used to invoke features for the print job...

 file, which is much simpler than kernel mode driver development. Unidrv was introduced in Windows 2000
Windows 2000
Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...

 and replaced the Raster Device Driver (RASDD) interface used in Windows NT 4.0
Windows NT 4.0
Windows NT 4.0 is a preemptive, graphical and business-oriented operating system designed to work with either uniprocessor or symmetric multi-processor computers. It was the next release of Microsoft's Windows NT line of operating systems and was released to manufacturing on 31 July 1996...

 and earlier versions.

Overview

The concept behind Unidrv is that a complete printer driver need not be written by the hardware manufacturer; only a device-specific minidriver is required that uses the core printing functionality of the Unidrv engine. A minidriver can be a customization file, or a plug-in, that allows special rendering functions or customized UI options. Unidrv supports non-PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...

 printers driven by PCL
Printer Command Language
Printer Command Language, more commonly referred to as PCL, is a page description language developed by Hewlett-Packard as a printer protocol and has become a de facto industry standard. Originally developed for early inkjet printers in 1984, PCL has been released in varying levels for thermal,...

 and PCL-like page description language
Page description language
A page description language is a language that describes the appearance of a printed page in a higher level than an actual output bitmap. An overlapping term is printer control language, but it should not be confused as referring solely to Hewlett-Packard's PCL...

s.

Driver file details

The Unidriver is implemented as a set of DLL
Dynamic-link library
Dynamic-link library , or DLL, is Microsoft's implementation of the shared library concept in the Microsoft Windows and OS/2 operating systems...

 and GPD files along with other printer-specific support files:
  • UniDrv.dll is the printer graphics driver file for printer languages based on raster images, including most inkjet and dot-matrix printer languages.
  • UniDrvUI.dll is the configuration file. It displays the user interface for UniDrv.dll.
  • UniRes.dll, StdNames.gpd, TtfSub.gpd and some other support files.
  • Raster minidriver, which has the file name extension .GPD, is the data file, and is also called the characterization file. The file name depends on the printer or printer family.


Newer Unidrv-based printer driver
Printer driver
In computers, a printer driver or a print processor is a piece of software that converts the data to be printed to the form specific to a printer...

s from some printer vendors, e.g. Hewlett Packard, may contain many other support files to allow support for more printer-specific options.

Unidrv capabilities

The Unidriver is also called the raster driver because it supports raster (bitmap) graphics printing and is compatible with many printers. This driver supports the following features:
  • Color printing at various depths, such as 4 bits per pixel (bpp), 8 bpp, and 24 bpp.
  • Scalable TrueType
    TrueType
    TrueType is an outline font standard originally developed by Apple Computer in the late 1980s as a competitor to Adobe's Type 1 fonts used in PostScript...

     and OpenType
    OpenType
    OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior...

     fonts, device fonts (including double-byte), grayscale printing, font substitution
    Font substitution
    Font substitution is the process of using one font in place of another when the intended font either is not available or does not contain glyphs for the required characters.Font substitution can be aided by:...

    , run length encoding (RLE), Tag Image File Format (TIFF) version 4.0, and Delta Row Compression (DRC).
  • An extension interface that allows printer manufacturers to extend and customize the driver for specific models.
  • Vector graphics languages HP-GL/2 and PCL-XL, monochrome, and color.

Determining if the printer driver is Unidrv-based

To determine whether a driver is Unidrv-based, the following steps need to be taken on Windows:
  1. Click the Start button, and then open the Printers folder.
  2. From the File menu, click Server Properties.
  3. Click the Drivers tab.
  4. Select a driver, and then click Properties.
  5. Observe the driver list in the Driver Properties dialog box. If UniDrv.dll appears on the list of files, the driver is Unidrv-based.

Future

Starting with Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...

, Unidrv is intended to be succeeded by XPSDrv. The XPSDrv printer driver extends Microsoft's GDI-based, printer driver architecture to support consuming XML Paper Specification
XML Paper Specification
Open XML Paper Specification , is an open specification for a page description language and a fixed-document format originally developed by Microsoft as XML Paper Specification that was later standardized by Ecma International as international standard ECMA-388...

(XPS) documents and is more modular and extensible. With an XPSDrv printer driver, the XPS Document format is used as a spool file format and as a document file format.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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