Any comments or suggestions to this Specification are welcome!!! ?BR Please openly discuss this on [http://lists.debian.org/debian-printing/ debian-printing mailing list].

PPD File Structure Specification

Created: 05/01/2006 by ?PascalDeVuyst ?BR Last update: 03/08/2006 ?BR Contributors: RogerLeigh, ?Hmh, ChrisLawrence and ?MartinPitt ?BR Packages affected: cupsys, foomatic-filters-ppds, hplip-ppds, cupsys-driver-gutenprint, linuxprinting.org-ppds and hp-ppd. ?BR When writing this specification the ?PrintingFilesystem Specification has been taken into consideration.

Introduction

There are several packages in Debian that provide Postscript Printer Descriptions (["PPD"]s) for PostScript and non-PostScript printers. These packages should cooperate to form a single database of unique PPDs. This allows GUI tools like the CUPS "Add Printer" web interface and gnome-cups-add to provide users a printer model list for adding printers.

Design

The main idea is to have the following file structure to make it possible for GUI tools to locate PPDs: ?BR common_directory/upstream_reference/manufacturer/filename.ppd

  1. The database of PPDs should be located in a common directory.
  2. To avoid possible filename clashes between different PPD providing packages and to easily seperate PPDs from different sources there should be a further classification refering to the "upstream project" where the PPDs come from and where they were created for.
  3. To seperate PPDs from different manufacturers a further classification by make/manufacturer of the printer under "upstream_reference" is necessary.
  4. The database is formed by several packages which provide PPD files inside this structure and it is not necessary to install all off these packages.
  5. Two seperate packages should not provide the same PPDs to avoid duplicate printer model entries in GUI tools.

Implementation

  1. PPDs should be located in /usr/share according to the Filesystem Hierarchy Standard because they contain static and arch-independent information.
  2. As common directory /usr/share/ppd should be used (this directory is currently used for this purpose).

  3. This ppd directory should contain subdirectories that refer to the name of the "upstream project" where the PPDs come from and where they were created for. I believe this to be the best classification:
    • /usr/share/ppd/cups-included for non-PostScript PPDs that come with cups;

    • /usr/share/ppd/linuxprinting.org-gs for non-PostScript PPDs from linuxprinting.org's foomatic-db project that can be used with binary printer drivers built into Ghostscript (GPL or ESP version) or with filters making use of Ghostscript to provide a printer independent raster format;

    • /usr/share/ppd/linuxprinting.org-postscript for real PPDs for PostScript printers from linuxprinting.org's foomatic-db project;

    • /usr/share/ppd/hpijs for non-PostScript PPDs from HPLIP project;

    • /usr/share/ppd/gutenprint for non-PostScript PPDs from gutenprint project;

  4. The above mentioned directory should contain subdirectories according to the *Manufacturer string as specified in the [http://partners.adobe.com/public/developer/en/ps/5003.PPD_Spec_v4.3.pdf PPD specification v4.3]. The *Manufacturer strings are case sensitive and must be noted literally as in the PPD specification. ?BR e.g. /usr/share/ppd/linuxprinting.org-gs/Lexmark, /usr/share/ppd/hpijs/HP, ...

  5. PPDs may be gzipped to reduce disk space usage. Gzipping the individual PPD files may increase the package size a lot. The decision is up to the package maintainer.
  6. Inside the PPDs a *Manufacturer string should be used as specified in the Adobe PPD specification v4.3. To summarize: the same *Manufacturer string must be used by a manufacturer in each of their PPD files. Also, the string must be unique among manufacturers; two or more manufacturers may not use the same string. ?BR Appendix D of the PPD specification provides a list of *Manufacturer strings that should be used! Not all known manufacturers are in this list. For manufacturers not listed in the PPD specification we agree to use the *Manufacturer string as found in PPDs on www.linuxprinting.org.?BR The use of a unique *Manufacturer string allows GUI tools to group printers of the same manufacturer together. The use of different *Manufacturer strings for the same manufacturer would cause a lot of confusion for users, if they look under the wrong Manufacturer name they may think their printers are not supported.

  7. Packages that need PPDs are responsible for symlinking to the PPDs in /usr/share/ppd. For example the cupsys package should simply include a symlink from /usr/share/cups/model/ppd to /usr/share/ppd.
  8. Packages that provide PPDs should NOT contain symlinks for other packages that need PPDs. The reason for this is that symlinks from different PPD providing packages can overlap each other resulting in duplicate drivers being seen by GUI tools.

Current PPD providing packages in Debian

Current issues