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filter

cups file conversion filter interfaces

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1. filter.1.man

Manpage of filter

filter

Section: Easy Software Products (1)
Updated: Common UNIX Printing System
Index Return to Main Contents

NAME

filter - cups file conversion filter interfaces

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.

ENVIRONMENT VARIABLES

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

CHARSET: The default text character set (typically us-ascii or iso-8859-1).
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_DATADIR: The directory where data files can be found.
CUPS_SERVERROOT: The root directory of the server.
DEVICE_URI: The device-uri associated with the printer.
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; this is provided for shell scripts which may not be able to get the passed argv[0] string.
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/1.1).
TZ: The timezone of the server.
USER: The user executing the filter, typically lp; consult the cupsd.conf 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.

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This document was created by man2html using the manual pages.
Time: 07:35:33 GMT, May 02, 2010

2. filter.3.man

Manpage of curs_util

curs_util

Section: Miscellaneous Library Functions (3X)
Updated:
Index Return to Main Contents

NAME

delay_output, filter, flushinp, getwin, key_name, keyname, nofilter, putwin, unctrl, use_env, wunctrl - miscellaneous curses utility routines

SYNOPSIS

#include <curses.h>

char *unctrl(chtype c);
wchar_t *wunctrl(cchar_t *c);
char *keyname(int c);
char *key_name(wchar_t w);
void filter(void);
void nofilter(void);
void use_env(bool f);
int putwin(WINDOW *win, FILE *filep);
WINDOW *getwin(FILE *filep);
int delay_output(int ms);
int flushinp(void);

DESCRIPTION

The unctrl routine returns a character string which is a printable representation of the character c, ignoring attributes. Control characters are displayed in the ^X notation. Printing characters are displayed as is. The corresponding wunctrl returns a printable representation of a wide-character.

The keyname routine returns a character string corresponding to the key c:

-: Printable characters are displayed as themselves, e.g., a one-character string containing the key.
-: Control characters are displayed in the ^X notation.
-: DEL (character 127) is displayed as ^?.
-: Values above 128 are either meta characters (if the screen has not been initialized, or if meta has been called with a TRUE parameter), shown in the M-X notation, or are displayed as themselves. In the latter case, the values may not be printable; this follows the X/Open specification.
-: Values above 256 may be the names of the names of function keys.
-: Otherwise (if there is no corresponding name) the function returns null, to denote an error. X/Open also lists an "UNKNOWN KEY" return value, which some implementations return rather than null.

The corresponding key_name returns a character string corresponding to the wide-character value w. The two functions do not return the same set of strings; the latter returns null where the former would display a meta character.

The filter routine, if used, must be called before initscr or newterm are called. The effect is that, during those calls, LINES is set to 1; the capabilities clear, cup, cud, cud1, cuu1, cuu, vpa are disabled; and the home string is set to the value of cr.

The nofilter routine cancels the effect of a preceding filter call. That allows the caller to initialize a screen on a different device, using a different value of $TERM. The limitation arises because the filter routine modifies the in-memory copy of the terminal information.

The use_env routine, if used, is called before initscr or newterm are called. When called with FALSE as an argument, the values of lines and columns specified in the terminfo database will be used, even if environment variables LINES and COLUMNS (used by default) are set, or if curses is running in a window (in which case default behavior would be to use the window size if LINES and COLUMNS are not set). Note that setting LINES or COLUMNS overrides the corresponding size which may be obtained from the operating system.

The putwin routine writes all data associated with window win into the file to which filep points. This information can be later retrieved using the getwin function.

The getwin routine reads window related data stored in the file by putwin. The routine then creates and initializes a new window using that data. It returns a pointer to the new window.

The delay_output routine inserts an ms millisecond pause in output. This routine should not be used extensively because padding characters are used rather than a CPU pause. If no padding character is specified, this uses napms to perform the delay.

The flushinp routine throws away any typeahead that has been typed by the user and has not yet been read by the program.

RETURN VALUE

Except for flushinp, routines that return an integer return ERR upon failure and OK (SVr4 specifies only "an integer value other than ERR") upon successful completion.

Routines that return pointers return NULL on error.

X/Open does not define any error conditions. In this implementation

flushinp: returns an error if the terminal was not initialized.
meta: returns an error if the terminal was not initialized.
putwin: returns an error if the associated fwrite calls return an error.

PORTABILITY

The XSI Curses standard, Issue 4 describes these functions. It states that unctrl and wunctrl will return a null pointer if unsuccessful, but does not define any error conditions. This implementation checks for three cases:

-: the parameter is a 7-bit US-ASCII code. This is the case that X/Open Curses documented.
-: the parameter is in the range 128-159, i.e., a C1 control code. If use_legacy_coding has been called with a 2 parameter, unctrl returns the parameter, i.e., a one-character string with the parameter as the first character. Otherwise, it returns ``~@'', ``~A'', etc., analogous to ``^@'', ``^A'', C0 controls.
: X/Open Curses does not document whether unctrl can be called before initializing curses. This implementation permits that, and returns the ``~@'', etc., values in that case.
-: parameter values outside the 0 to 255 range. unctrl returns a null pointer.

The SVr4 documentation describes the action of filter only in the vaguest terms. The description here is adapted from the XSI Curses standard (which erroneously fails to describe the disabling of cuu).

The strings returned by unctrl in this implementation are determined at compile time, showing C1 controls from the upper-128 codes with a `~' prefix rather than `^'. Other implementations have different conventions. For example, they may show both sets of control characters with `^', and strip the parameter to 7 bits. Or they may ignore C1 controls and treat all of the upper-128 codes as printable. This implementation uses 8 bits but does not modify the string to reflect locale. The use_legacy_coding function allows the caller to change the output of unctrl.

Likewise, the meta function allows the caller to change the output of keyname, i.e., it determines whether to use the `M-' prefix for ``meta'' keys (codes in the range 128 to 255). Both use_legacy_coding and meta succeed only after curses is initialized. X/Open Curses does not document the treatment of codes 128 to 159. When treating them as ``meta'' keys (or if keyname is called before initializing curses), this implementation returns strings ``M-^@'', ``M-^A'', etc.

The keyname function may return the names of user-defined string capabilities which are defined in the terminfo entry via the -x option of tic. This implementation automatically assigns at run-time keycodes to user-defined strings which begin with "k". The keycodes start at KEY_MAX, but are not guaranteed to be the same value for different runs because user-defined codes are merged from all terminal descriptions which have been loaded. The use_extended_names function controls whether this data is loaded when the terminal description is read by the library.

The nofilter routine is specific to ncurses. It was not supported on Version 7, BSD or System V implementations. It is recommended that any code depending on ncurses extensions be conditioned using NCURSES_VERSION.

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
PORTABILITY
SEE ALSO

This document was created by man2html using the manual pages.
Time: 07:35:33 GMT, May 02, 2010

3. filter.7.man

Manpage of filter

filter

Section: Apple Inc. (7)
Updated: CUPS
Index Return to Main Contents

NAME

filter - cups file conversion filter interface

SYNOPSIS

filter job user title num-copies options [ filename ]

DESCRIPTION

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

COPYRIGHT

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
LOG MESSAGES
ENVIRONMENT VARIABLES
COMPATIBILITY
SEE ALSO
COPYRIGHT

This document was created by man2html using the manual pages.
Time: 07:35:33 GMT, May 02, 2010

filter

1. filter.1.man

Manpage of filter

filter

NAME

SYNOPSIS

DESCRIPTION

ENVIRONMENT VARIABLES

COMPATIBILITY

SEE ALSO

COPYRIGHT

Index

2. filter.3.man

Manpage of curs_util

curs_util

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

PORTABILITY

SEE ALSO

Index

3. filter.7.man

Manpage of filter

filter

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

LOG MESSAGES

ENVIRONMENT VARIABLES

COMPATIBILITY

SEE ALSO

COPYRIGHT

Index

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