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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 "Medi-aType", "MediaType",
       aType",  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 userselected
       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 val-ues values
       ues 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-com-pleted job-media-sheets-completed
            pleted 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)