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PDQ and the OpenPrinting Database

We support PDQ through the PPD-O-Matic PPD generator and companion foomatic-filters backend filter package. What follows is quick-start information on setting up your printer with this pair, followed by some details on how it all works.

Note: PDQ computes the entire job before sending it to the printer. This means that large and/or computationally intensive jobs may involve a long delay before printing. This will mostly be of concern to color inkjet owners. For large format printers (A3/13x18inch and bigger) PDQ is not recommended, if you do not want to use one of the usual spoolers (CUPS, LPRng, PPR, …) for them, consider direct spooler-less printing.

Quick Start

This system should work with PDQ version 2.1.2 or newer. Check that you have this installed; see the PDQ website for details.

The foomatic-rip system does not only allow printing of PostScript files, but also printing of plain text, PDF, images, TeX/LaTeX, DVI, and perhaps other file formats. For plain text you must have one of the converters “a2ps”, “enscript”, or “mpage” installed on your machine, for the other formats both “a2ps” (to detect the format) and ImageMagick (for images), GhostScript 6.51 or newer (for PDF) and/or TeX and LaTeX (for TeX, LaTeX, and DVI) must be installed. Most distributions provide these programs, but not necessarily all of them are installed by default. foomatic-rip will auto-detect the installed converters and automatically choose the best one.

If you have a Postscript printer, you can make use of the PPD file provided by the printer's manufacturer. You can use also these PPDs with foomatic-rip, simply use them instead of the PPD-O-Matic PPD from this site. See the "Postscript" driver page and the instructions on how to use PPD files for more information.

More detailed instructions with examples and screenshots you will find in the tutorial chapter “Foomatic from the User's Point of View: Installing a Printer” (PDF). Note that the instructions in the tutorial are for the former Foomatic 2.0.x.

1.If your printer is not a native PostScript printer, you will need the driver that you wish to use installed (foomatic-rip and the PPD file only provide a way to connect PDQ to your driver). There are several styles of driver; the ones suitable for your printer will be referenced from your printer's page in the database:
* Ghostscript built-in
* Ghostscript is present on most free and many commercial Unix systems. It is not part of Mac OS X as shipped by Apple. Ghostscript contains many “compiled-in” drivers.
You can see the available Ghostscript drivers on your system by running 'gs -h'. If the driver you need is not listed, you need to obtain a new Ghostscript package which includes this driver, or compile Ghostscript yourself. GPL GhostScript includes all known free software built-in drivers and Linux distributions ship it with all drivers actually compiled. Currently such drivers are not developed any more by third parties, as adding these drivers is awkward and there are plenty of interfaces for modular drivers: CUPS Raster, IJS, OpenPrinting Vector, filters, ….
* CUPS Raster
* CUPS has a native driver style called “CUPS Raster”. These are executable programs, installed into CUPS' filter directory, which CUPS drives using a set of filters and Ghostscript. Such drivers are relatively easy to get going with CUPS, so are usually the best choice for CUPS users. With foomatic-rip one can use them also with other printing systems, though. You can see which CUPS Raster drivers are installed by examining the filters in /usr/lib/cups/filter; usually CUPS Raster drivers have names beginning with “rasterto”. Each CUPS Raster driver program will also have one or more PPD files in /usr/share/ppd or /usr/share/cups/model, each containing a reference to the proper CUPS Raster program.
* IJS is a plug-in interface to connect raster driver modules with Ghostscript (or a renderer in general) based on pipes. It was introduced for HP's HPIJS driver but currently it also used by several other drivers. The driver executables are usually installed into the standard search path for programs (/usr/bin or /usr/local/bin).
* OpenPrinting Vector
* This driver concept is developed by the Japanese members of the OpenPrinting project. It is a plugin interface for Ghostscript and other renderers which supports high-level (vector) graphics. This way modular drivers for printers with proprietary high-level page description languages can be created. Such printers are common on the Japanese market.
* Filter
* Some drivers are simply a filter into which generic bitmap output of Ghostscript is piped. This was one of the first solutions to make printer drivers without compiling them into Ghostscript. The filter executables are usually installed into the standard search path for programs (/usr/bin or /usr/local/bin).
* Uniprint
* A few drivers are Uniprint drivers. These consist simply of a upp file containing various parameters; most are included with Ghostscript. Others you will need to obtain and place in your ghostscript library directory (one of the directories listed under “Search path:” at the end of the “gs -h” output).
2.You will need a PPD file for your printer/driver, in case of a PostScript printer the one which came with the printer, for other printers running with a printer driver you should get one from the OpenPrinting database. To do this, you need to look up your printer's page in the database. When you want to use the driver which is recommended for your printer, click on the “download PPD” link in the summary box at the top of the page. For other drivers and some info about the drivers, go to the driver list at the bottom of the page. If a driver has no “download PPD” link, there is no info to generate a PPD in this driver entry, see the text of the driver entry, sometimes these drivers are covered by the PPD of another driver or the PPDs come with the driver.
3.Save the PPD file somewhere reasonable (create an /etc/foomatic/pdq/ directory for your PPD files for example). Do not save it in a directory which PDQ searches for configuration files. PDQ would assume that the PPD is a PDQ configuration file and stops with an error message. Make sure the PPD file is world-readable with 'chmod a+r <file>'.
4.Install the foomatic-filters package.

(If you are using a PostScript printer with a PPD from your printer vendor, you probably do not need Foomatic and should skip this step). Usually, your Linux distribution ships the foomatic-filters package (you have /usr/bin/foomatic-rip then). If not, get the foomatic-filters package from here. You need a C compiler and the Ghostscript shared library to build it. See the USAGE file in the foomatic-filters package for more information.
5.If you do not have a text(and other files)-to-PostScript converter installed (see above), install one. This is used to print option documentation for your printer or non-PostScript files, so it's nice to have it right. If you have more than one converter installed and the one automatically chosen by foomatic-rip is not the desired one, edit the “textfilter:” line in the /etc/foomatic/filter.conf file inserting the name of one of the supported converters (“a2ps”, “enscript”, “mpage”) after the colon. Do not forget to remove the “#” in the beginning of the line.
6.Generate the PDQ driver description file with
foomatic-rip --ppd /path/to/your/ppdfile --genpdq myprinter.pdq

Move the PDQ driver file into one of the subdirectories of /usr/lib/pdq/drivers/ (Can be also /usr/local/lib/pdq/drivers/, check also the “try_include” lines in /etc/pdq/printrc for suitable directories). You could name the file after the PPD file from which you have it generated (example: HP-LaserJet_2200-pxlmono.ppd –> HP-LaserJet_2200-pxlmono.pdq). Make sure that the file is world-readable (“chmod a+r <file>”)

7.Run the printer setup wizard in xpdq, either as root to define a system-wide printer, or as a normal user to define a printer in your personal ~/.printrc.
8.To get your printouts well-centered and to be able to make use of the full imageable area (the area of the page where the printer can print, most printers cannot print up to the borders of the paper) of your printer, you should adjust the printout. With a driver made especially for your printer this is usually not necessary, but som printers, as for example PCL laser printers from other manufacturers than HP since need this adjustment since the GhostScript PCL drivers are mainly tested on HP printers.
Download the alignment page '''' (when you click on the link, the page will be displayed, please choose “File”
“Save As…” in your browser's menues to write the file to your disk) and print it. Follow the instructions on the page to do the adjustment.
9.If you want to print out of PPD-aware applications as Star Office, Open Office, GIMP, … or from a client (Windows, MacOS), use the same PPD file as you already have used for setting up your printer queue and follow the appropriate instructions.

Printing with PDQ-O-Matic

To actually use this now that you've set it up, you use the pdq(1) command. For example the command line

$ pdq -P foo1 -oPageSize_Letter -aGamma=1.4

would print the file on letter paper with a gmma correction of 1.4.

With some printer/driver combos it is also possible to use arbitrary, custom page sizes (as long as they fit into the printer). Then you have a “-oPageSize_Custom” option which you can use as follows:

$ pdq -P foo1 -oPageSize_Custom -aPageWidth=20 -aPageHeight=30

You give always the width with “-aPageWidth=XX”, the height with “-aPageHeight=YY”, and also the unit with “-oPageSizeUnit_ZZ”, where “ZZ” can be “pt” (PostScript points, 1/72 inch), “in” (inches), “cm” (centimeters), or “mm” (millimeters). If you leave out the unit, “pt” will be used as default. The numbers do not need to be integers, something like “-aPageWidth=25.5” is allowed.

To get a list of the available options for your setup, either issue the command

$ pdq -P foo1 -h

to see the options for the printer “foo1” on the screen or

$ pdq -P foo1 -odocs ~/.bashrc

to get a printed option overview page. Note that the file ~/.bashrc is not actually printed, the “-odocs” option makes the help page being printes instead of the sent document.

You can also print with the “Print” commands in the “File” menu of “xpdq”. Use the “Driver Options” button then to adjust the option settings and to save default settings.

For more information on using PDQ and defining printers, consult the PDQ webpage. If it doesn't work, click on the entry of the failed job in “xpdq” to mark it, then click with the right button and choose “Show details” to see what happened. And feel free to contact us for help.

How does it work?

There are four parts to the Foomatic scheme:

  • The Database
  • The database contains a number of XML files which detail exactly how to execute a given printer driver. There are two front-ends which use these files: the human-readable one generates the information shown on all “Execution Details” pages, the PPD-O-Matic PPD generator computes an Adobe-compliant PPD file which you need to configure your print queue and PPD-aware applications/clients.
  • The PPD File
  • The PPD file generated by the database contains all information about important printer capabilities, available options and how to build the renderer's (usually Ghostscript's) command line depending on the user's choices for the options. foomatic-rip reads it to know how to execute the print job. GUI frontends read it to build dialog boxes in which the user can adjust the options. Besides the usual stuff the PPD file contains various extra lines beginning with “*Foomatic…”. These contain details of the driver command line, the information whether an option accepts arbitrary numbers and not only the choices listed in the PPD file, and more. frontends and application programs ignore these extra lines.
  • The backend filter
  • The filter 'foomatic-rip' is called by PDQ with various inputs, including both the PPD filename and the various options selected by the user. foomatic-rip opens the PPD, extracts all options and their possible settings and also the command line to execute Ghostscript with the appropriate driver. It parses the PostScript input for option settings which were stuffed in by application programs and it also stuffs in PostScript code by itself, if needed.
  • The PDQ driver declaration
  • The PDQ file generated by 'foomatic-rip' contains option declarations for the various options supported by the driver (or the PostScript printer PPD file), and it contains a bit of Bourne shell code to generate and execute the proper 'foomatic-rip' command line.

PDQ supports all the option types defined in the database. Boolean values are somewhat awkwardly handled as a choice rather than a single checkbox, but they work fine.

openprinting/database/pdqdocumentation.txt · Last modified: 2016/07/19 01:20 (external edit)