.\"
.\" "$Id: filter.man 11022 2013-06-06 22:14:09Z msweet $"
.\"
.\"   filter man page for CUPS.
.\"
.\"   Copyright 2007-2013 by Apple Inc.
.\"   Copyright 1997-2007 by Easy Software Products.
.\"
.\"   These coded instructions, statements, and computer programs are the
.\"   property of Apple Inc. and are protected by Federal copyright
.\"   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
.\"   which should have been included with this file.  If this file is
.\"   file is missing or damaged, see the license at "http://www.cups.org/".
.\"
.TH filter 7 "CUPS" "18 May 2012" "Apple Inc."
.SH NAME
filter \- cups file conversion filter interface
.SH SYNOPSIS
.B filter
job user title num-copies options [
.I filename
]
.SH 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.
.LP
Filters \fBmust\fR 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 \fBmust\fR be sent to the
standard output.
.LP
The command name (argv[0]) is set to the name of the destination printer but is
also available in the PRINTER environment variable.
.SH WARNING
CUPS filters are not meant to be run directly by the user. Aside from the legacy
System V interface issues (argv[0] is the printer name), CUPS filters also
expect specific environment variables and file descriptors, and typically run in
a user session that (on OS X) has additional restrictions that affect how it
runs. Unless you are a developer and know what you are doing, please do not run
filters directly. Instead, use the \fIcupsfilter(8)\fR program to use the
appropriate filters to do the conversions you need.
.SH 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 \fBmust\fR
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.
.LP
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.
.SH LOG MESSAGES
Messages sent to stderr are generally logged to
printer-state-message attribute and the current \fIErrorLog\fR.
Each line begins with a standard prefix:
.TP 5
ALERT: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "alert" log level.
.TP 5
ATTR: attribute=value [attribute=value]
.br
Sets the named job or printer attribute(s). The following job attributes can be
set: "job-media-progress". The following printer attributes can be set:
"auth-info-required", "marker-colors", "marker-high-levels", "marker-levels",
"marker-low-levels", "marker-message", "marker-names", "marker-types",
"printer-alert", and "printer-alert-description".
.TP 5
CRIT: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "critical" log level.
.TP 5
DEBUG: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "debug" log level.
.TP 5
DEBUG2: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "debug2" log level.
.TP 5
EMERG: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "emergency" log level.
.TP 5
ERROR: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "error" log level.
.TP 5
INFO: message
.br
Sets the printer-state-message attribute. If the current \fILogLevel\fR
is set to "debug2", also adds the specified message to the
current \fIErrorLog\fR using the "info" log level.
.TP 5
NOTICE: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "notice" log level.
.TP 5
PAGE: page-number #-copies
.TP 5
PAGE: total #-pages
.br
Adds an entry to the current \fIPageLog\fR. The first form adds
#-copies to the job-media-sheets-completed attribute. The second
form sets the job-media-sheets-completed attribute to #-pages.
.TP 5
PPD: Keyword=Value ... KeywordN=Value
.br
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.
.TP 5
STATE: printer-state-reason [printer-state-reason ...]
.TP 5
STATE: + printer-state-reason [printer-state-reason ...]
.TP 5
STATE: \- printer-state-reason [printer-state-reason ...]
.br
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.
.TP 5
WARNING: message
.br
Sets the printer-state-message attribute and adds the specified
message to the current \fIErrorLog\fR using the "warning" log level.
.SH ENVIRONMENT VARIABLES
The following environment variables are defined by the CUPS
server when executing the filter:
.TP 5
CHARSET
.br
The default text character set, typically utf-8.
.TP 5
CLASS
.br
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.
.TP 5
CONTENT_TYPE
.br
The MIME type associated with the file (e.g.
application/postscript).
.TP 5
CUPS_CACHEDIR
.br
The directory for semi-persistent cache files can be found.
.TP 5
CUPS_DATADIR
.br
The directory where data files can be found.
.TP 5
CUPS_FILETYPE
.br
The type of file being printed: "job-sheet" for a banner page and "document"
for a regular print file.
.TP 5
CUPS_MAX_MESSAGE
.br
The maximum size of a message sent to stderr, including any leading prefix and
the trailing newline.
.TP 5
CUPS_SERVERROOT
.br
The root directory of the server.
.TP 5
DEVICE_URI
.br
The device-uri associated with the printer.
.TP 5
FINAL_CONTENT_TYPE
.br
The MIME type associated with the printer (e.g.
application/vnd.cups-postscript).
.TP 5
LANG
.br
The default language locale (typically C or en).
.TP 5
PATH
.br
The standard execution path for external programs that may be run by
the filter.
.TP 5
PPD
.br
The full pathname of the PostScript Printer Description (PPD)
file for this printer.
.TP 5
PRINTER
.br
The name of the printer.
.TP 5
RIP_CACHE
.br
The recommended amount of memory to use for Raster Image
Processors (RIPs).
.TP 5
SOFTWARE
.br
The name and version number of the server (typically CUPS/1.2).
.TP 5
TZ
.br
The timezone of the server.
.TP 5
USER
.br
The user executing the filter, typically "lp" or "root"; consult the
\fIcupsd.conf(5)\fR file for the current setting.
.SH 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
\fIlpadmin(8)\fR command using the \fI-i\fR option.
.SH SEE ALSO
\fIbackend(7)\fR, \fIcupsd(8)\fR, \fIcupsfilter(8)\fR,
.br
http://localhost:631/help
.SH COPYRIGHT
Copyright 2007-2013 by Apple Inc.
.\"
.\" End of "$Id: filter.man 11022 2013-06-06 22:14:09Z msweet $".
.\"