filter(7)                         Apple Inc.                         filter(7)



NAME
       filter - cups file conversion filter interface

SYNOPSIS
       filter job user title num-copies options [ filename ]

DESCRIPTION
       The CUPS filter interface provides a standard method for adding support
       for new document types to CUPS. Each filter is capable of converting
       from one or more input formats to another format that can either be
       printed directly or piped into another filter to get it to a printable
       format.

       Filters must be capable of reading from a filename on the command-line
       or from the standard input, copying the standard input to a temporary
       file as required by the file format. All output must be sent to the
       standard output.

       The command name (argv[0]) is set to the name of the destination
       printer but is also available in the PRINTER environment variable.


OPTIONS
       Options passed on the command-line typically do not include the default
       choices the printer's PPD file. In addition, some options may be
       specified in multiple ways - "landscape" is a synonym for "orientation-
       requested=4", "media" is a synonym for "PageSize", "PageRegion",
       "InputSlot", and "MediaType", and "sides" is a synonym for the various
       "Duplex" options. Non-raster filters must support both explicit and
       implicit specification of PPD options - use the ppdMarkDefaults and
       cupsMarkOptions functions in the CUPS library to use the correct
       mapping, and ppdFindMarkedChoice to get the user-selected choice.

       Raster filters should use option choices set through the raster page
       header, as those reflect the options in effect for a given page.
       Options specified on the command-line determine the default values for
       the entire job, which can be overridden on a per-page basis.


LOG MESSAGES
       Messages sent to stderr are generally logged to printer-state-message
       attribute and the current ErrorLog.  Each line begins with a standard
       prefix:


       ALERT: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "alert" log level.


       ATTR: attribute=value [attribute=value]
            Sets the named job attribute(s). Typically this will be used to
            set the job-remote-id attribute.


       CRIT: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "critical" log level.


       DEBUG: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "debug" log level.


       DEBUG2: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "debug2" log level.


       EMERG: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "emergency" log level.


       ERROR: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "error" log level.


       INFO: message
            Sets the printer-state-message attribute. If the current LogLevel
            is set to "debug2", also adds the specified message to the current
            ErrorLog using the "info" log level.


       NOTICE: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "notice" log level.


       PAGE: page-number #-copies

       PAGE: total #-pages
            Adds an entry to the current PageLog. The first form adds #-copies
            to the job-media-sheets-completed attribute. The second form sets
            the job-media-sheets-completed attribute to #-pages.


       PPD: Keyword=Value ... KeywordN=Value
            Sets the named keywords in the printer's PPD file. This is
            typically used to update default option keywords such as
            DefaultPageSize and the various installable options in the PPD
            file.


       STATE: printer-state-reason [printer-state-reason ...]

       STATE: + printer-state-reason [printer-state-reason ...]

       STATE: - printer-state-reason [printer-state-reason ...]
            Sets, adds, or removes printer-state-reason keywords to the
            current queue. Typically this is used to indicate media, ink, and
            toner conditions on a printer.


       WARNING: message
            Sets the printer-state-message attribute and adds the specified
            message to the current ErrorLog using the "warning" log level.


ENVIRONMENT VARIABLES
       The following environment variables are defined by the CUPS server when
       executing the filter:


       CHARSET
            The default text character set, typically utf-8.


       CLASS
            When a job is submitted to a printer class, contains the name of
            the destination printer class. Otherwise this environment variable
            will not be set.


       CONTENT_TYPE
            The MIME type associated with the file (e.g.
            application/postscript).


       CUPS_CACHEDIR
            The directory for semi-persistent cache files can be found.


       CUPS_DATADIR
            The directory where data files can be found.


       CUPS_FILETYPE
            The type of file being printed: "job-sheet" for a banner page and
            "document" for a regular print file.


       CUPS_SERVERROOT
            The root directory of the server.


       DEVICE_URI
            The device-uri associated with the printer.


       FINAL_CONTENT_TYPE
            The MIME type associated with the printer (e.g.
            application/vnd.cups-postscript).


       LANG
            The default language locale (typically C or en).


       PATH
            The standard execution path for external programs that may be run
            by the filter.


       PPD
            The full pathname of the PostScript Printer Description (PPD) file
            for this printer.


       PRINTER
            The name of the printer.


       RIP_CACHE
            The recommended amount of memory to use for Raster Image
            Processors (RIPs).


       SOFTWARE
            The name and version number of the server (typically CUPS/1.2).


       TZ
            The timezone of the server.


       USER
            The user executing the filter, typically "lp" or "root"; consult
            the cupsd.conf(5) file for the current setting.


COMPATIBILITY
       While the filter interface is compatible with System V interface
       scripts, it will only work with the System V interface script as the
       only filter.  Typically the interface script will be provided via the
       lpadmin(8) command using the -i option.

SEE ALSO
       backend(7), cupsd(8),
       http://localhost:631/help

COPYRIGHT
       Copyright 2007-2009 by Apple Inc.



13 May 2009                          CUPS                            filter(7)
