1889 lines
42 KiB
Groff
1889 lines
42 KiB
Groff
'\" e
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.\" The above line should force the use of eqn as a preprocessor
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.ig
|
|
groff_out.5
|
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|
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Last update: 12 Sep 2002
|
|
|
|
This file is part of groff, the GNU roff type-setting system.
|
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|
|
Copyright (C) 1989, 2001, 2002 Free Software Foundation, Inc.
|
|
rewritten from scrach 2001 by Bernd Warken <bwarken@mayn.de>
|
|
|
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Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.1 or
|
|
any later version published by the Free Software Foundation; with the
|
|
Invariant Sections being this .ig-section and AUTHORS, with no
|
|
Front-Cover Texts, and with no Back-Cover Texts.
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|
|
|
A copy of the Free Documentation License is included as a file called
|
|
FDL in the main directory of the groff source package.
|
|
..
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.
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.\" --------------------------------------------------------------------
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.\" Setup
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.\" --------------------------------------------------------------------
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.
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.mso www.tmac
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.
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.if n \{\
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. mso tty-char.tmac
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. ftr CR R
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. ftr CI I
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. ftr CB B
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.\}
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.
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.if '\*[.T]'dvi' \
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. ftr CB CW
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.
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.if t \{\
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.EQ
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delim $$
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.EN
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.\}
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.
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.\" ----------------- Document configuration
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.
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.\" Number register to decide whether the commands `{' and `}' are used
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.\" 0: disable (actual default); 1: enable
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.nr @USE_ENV_STACK 0
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.
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.ig
|
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Unfortunately, old versions of groff used an illogical position change
|
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after some D\~commands (Dp, DP, Dt). If the number register
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@STUPID_DRAWING_POSITIONING is 1 (actual default) then change position
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after these commands, otherwise the position is not changed.
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..
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.nr @STUPID_DRAWING_POSITIONING 1
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.
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.\" ----------------- Syntactical definitions
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.
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.\" comments when escapes are switched off
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.de c
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..
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.\" Begin of macro definitions
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.eo
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.
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.de Text
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. nop \)\$*
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..
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.c follow-up line for a .TP header
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.de TP+
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. br
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. ns
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. TP \$1
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..
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.c a bulleted paragraph
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.de Topic
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. TP 2m
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. nop \[bu]
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..
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.de ShellCommand
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. br
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. IR "shell>" "\h'1m'\f[CB]\$*\f[]\/"
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..
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.ec
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.\" End of macro definitions
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.
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.c ----------------- Semantical definitions
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.
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.nr @maxcolor 65536
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.ds @backslash \[rs]\"
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.ds @linebreak \f[R]\[la]line_break\[ra]\f[]\"
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.
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.\" Begin of macro definitions
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.eo
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.
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.c format: .unit <letter> <punctuation>
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.de unit
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. BR \$@
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..
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.c argument in italic with punctuation
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.de argument
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. if (\n[.$] == 0) \
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. return
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. IR \$@
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..
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.c comma separated list of indexed variables
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.de list1..n
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. ds @arg1 \$1\"
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. nop \c
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. ie t \
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. nop $\*[@arg1] sub 1$, $\*[@arg1] sub 2$, .\|.\|., $\*[@arg1] sub n$ \c
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. el \{\
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. IR \*[@arg1]1 ,
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. IR \*[@arg1]2 ,
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. nop \&...,
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. I \*[@arg1]n
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. \}
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. rm @arg1
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..
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.de offset
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. if (\n[.$] < 2) \
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. ab `.offset' needs at least 2 arguments
|
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. ds @arg1 \$1\"
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. ds @arg2 \$2\"
|
|
. shift 2
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. nop (\f[I]\,\*[@arg1]\/\f[],\ \f[I]\,\*[@arg2]\/\f[])\$*
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. rm @arg1
|
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. rm @arg2
|
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..
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|
.de indexed_offset
|
|
. if (\n[.$] < 4) \
|
|
. ab `.indexed_offset' needs at least 4 arguments
|
|
. ds @arg1 \$1\"
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|
. ds @index1 \$2\"
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. ds @arg2 \$3\"
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. ds @index2 \$4\"
|
|
. shift 4
|
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. ie t \{\
|
|
. ie \B'\*[@index1]' \{\
|
|
. nop ($\*[@arg1] sub roman \*[@index1]$,\ \c
|
|
. \}
|
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. el \{\
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|
. nop ($\*[@arg1] sub \*[@index1]$,\ \c
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. \}
|
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. ie \B'\*[@index2]' \{\
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. nop $\*[@arg2] sub roman \*[@index2]$)\$* \c
|
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. \}
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. el \{\
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|
. nop $\*[@arg2] sub \*[@index2]$)\$* \c
|
|
. \}
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|
. \}
|
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. el \{\
|
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. nop (\f[I]\*[@arg1]\*[@index1]\f[],\ \c
|
|
. nop \f[I]\*[@arg2]\*[@index2]\f[])\$* \c
|
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. \}
|
|
. rm @arg1
|
|
. rm @arg2
|
|
. rm @index1
|
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. rm @index2
|
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..
|
|
.c format: .command <name> "<arguments>" <punctuation>
|
|
.de command
|
|
. ds @arg1 \$1\"
|
|
. ds @arg2 \$2\"
|
|
. shift 2
|
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. IP "\f[B]\*[@arg1]\f[]\ \f[I]\,\*[@arg2]\/\f[]\$*"
|
|
. rm @arg1
|
|
. rm @arg2
|
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..
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.c format: .command+ <name> "<arguments>" <punctuation>
|
|
.c continue previous .command heading
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|
.de command+
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. ds @arg1 \$1\"
|
|
. ds @arg2 \$2\"
|
|
. shift 2
|
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. TP+
|
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. Text "\f[B]\*[@arg1]\f[]\ \f[I]\,\*[@arg2]\/\f[]\$*"
|
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. rm @arg1
|
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. rm @arg2
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..
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|
.c format: .D-command <subcommand> "<arguments>"
|
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.de D-command
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. ds @sub \$1\"
|
|
. shift 1
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. IP "\f[B]D\*[@sub]\f[]\ \f[I]\,\$*\/\f[]\|\*[@linebreak]"
|
|
. rm @sub
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|
..
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.c format: .D-command+ <subcommand> "<arguments>"
|
|
.c continue previous .D-command heading
|
|
.de D-command+
|
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. ds @sub \$1\"
|
|
. shift 1
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|
. TP+
|
|
. Text "\f[B]D\*[@sub]\f[]\ \f[I]\,\$*\/\f[]\*[@linebreak]"
|
|
. rm @sub
|
|
..
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|
.de Da-command
|
|
. shift 1
|
|
. ie t \
|
|
. ds @args $h sub 1$\~$v sub 1$ $h sub 2$\~$v sub 2$\"
|
|
. el \
|
|
. ds @args \f[I]h1\~v1 h2\~v2\f[]\"
|
|
. IP "\f[B]Da\f[]\ \*[@args]\|\*[@linebreak]"
|
|
. rm @args
|
|
..
|
|
.c graphics command .D with a variable number of arguments
|
|
.c format: .D-multiarg <subcommand>
|
|
.de D-multiarg
|
|
. ds @sub \$1\"
|
|
. shift 1
|
|
. ie t \{\
|
|
. ds @args "$h sub 1$\~$v sub 1$ $h sub 2$\~$v sub 2$ .\|.\|. \"
|
|
. as @args "$h sub n$\~$v sub n$\"
|
|
. \}
|
|
. el \
|
|
. ds @args \f[I]h1\~v1 h2\~v2\f[] ... \f[I]\,hn\~vn\f[]\"
|
|
. IP "\f[B]D\*[@sub]\f[]\ \*[@args]\|\*[@linebreak]"
|
|
. rm @args
|
|
. rm @sub
|
|
..
|
|
.c format: .x-command <subname> "<arguments>"
|
|
.de x-command
|
|
. ds @sub \$1\"
|
|
. shift 1
|
|
. ds @args
|
|
. if (\n[.$] > 0) \
|
|
. ds @args \ \f[I]\,\$*\/\f[]\"
|
|
. IP "\f[B]x\*[@sub]\f[]\*[@args]\f[]\|\*[@linebreak]"
|
|
. rm @sub
|
|
. rm @args
|
|
..
|
|
.de xsub
|
|
. RI "(" "\$1" " control command)"
|
|
. br
|
|
..
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|
.ec
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|
.\" End of macro definitions
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.\" Title
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
.TH GROFF_OUT @MAN5EXT@ "@MDATE@" "Groff Version @VERSION@"
|
|
.
|
|
.SH NAME
|
|
groff_out \- groff intermediate output format
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH DESCRIPTION
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
This manual page describes the intermediate output format of the GNU
|
|
.BR roff (@MAN7EXT@)
|
|
text processing system.
|
|
.
|
|
This output is produced by a run of the GNU
|
|
.BR troff (@MAN1EXT@)
|
|
program before it is fed into a device postprocessor program.
|
|
.
|
|
.P
|
|
As the GNU roff processor
|
|
.BR groff (@MAN1EXT@)
|
|
is a wrapper program around troff that automatically calls a
|
|
postprocessor, this output does not show up normally.
|
|
.
|
|
This is why it is called
|
|
.I intermediate
|
|
within the
|
|
.I groff
|
|
.IR system .
|
|
.
|
|
The
|
|
.B groff
|
|
program provides the option
|
|
.B -Z
|
|
to inhibit postprocessing, such that the produced intermediate output
|
|
is sent to standard output just like calling
|
|
.B troff
|
|
manually.
|
|
.
|
|
.P
|
|
In this document, the term
|
|
.I troff output
|
|
describes what is output by the GNU troff program, while
|
|
.I intermediate output
|
|
refers to the language that is accepted by the parser that prepares
|
|
this output for the postprocessors.
|
|
.
|
|
This parser is smarter on whitespace and implements obsolete elements
|
|
for compatibility, otherwise both formats are the same.
|
|
.
|
|
The pre-groff roff versions are denoted as
|
|
.I classical
|
|
.IR troff .
|
|
.
|
|
.P
|
|
The main purpose of the intermediate output concept is to facilitate
|
|
the development of postprocessors by providing a common programming
|
|
interface for all devices.
|
|
.
|
|
It has a language of its own that is completely different from the
|
|
.BR groff (@MAN7EXT@)
|
|
language.
|
|
.
|
|
While the
|
|
.I groff
|
|
language is a high-level programming language for text processing, the
|
|
intermediate output language is a kind of low-level assembler language
|
|
by specifying all positions on the page for writing and drawing.
|
|
.
|
|
.P
|
|
The intermediate output produced by
|
|
.I groff
|
|
is fairly readable, while
|
|
.I classical troff
|
|
output was hard to understand because of strange habits that are
|
|
still supported, but not used any longer by
|
|
.I GNU
|
|
.IR troff .
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "LANGUAGE CONCEPTS"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
During the run of
|
|
.BR troff ,
|
|
the roff input is cracked down to the information on what has to be
|
|
printed at what position on the intended device.
|
|
.
|
|
So the language of the intermediate output format can be quite small.
|
|
.
|
|
Its only elements are commands with or without arguments.
|
|
.
|
|
In this document, the term "command" always refers to the intermediate
|
|
output language, never to the roff language used for document
|
|
formatting.
|
|
.
|
|
There are commands for positioning and text writing, for drawing, and
|
|
for device controlling.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Separation"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
.I Classical troff output
|
|
had strange requirements on whitespace.
|
|
.
|
|
The
|
|
.I groff
|
|
output parser, however, is smart about whitespace by making it
|
|
maximally optional.
|
|
.
|
|
The whitespace characters, i.e.\& the
|
|
.IR tab ,
|
|
.IR space ,
|
|
and
|
|
.I newline
|
|
characters, always have a syntactical meaning.
|
|
.
|
|
They are never printable because spacing within the output is always
|
|
done by positioning commands.
|
|
.
|
|
.P
|
|
Any sequence of
|
|
.I space
|
|
or
|
|
.I tab
|
|
characters is treated as a single
|
|
.B syntactical
|
|
.BR space .
|
|
.
|
|
It separates commands and arguments, but is only required when there
|
|
would occur a clashing between the command code and the arguments
|
|
without the space.
|
|
.
|
|
Most often, this happens when variable length command names,
|
|
arguments, argument lists, or command clusters meet.
|
|
.
|
|
Commands and arguments with a known, fixed length need not be
|
|
separated by syntactical space.
|
|
.
|
|
.P
|
|
A line break is a syntactical element, too.
|
|
.
|
|
Every command argument can be followed by whitespace, a comment, or a
|
|
newline character.
|
|
.
|
|
Thus a
|
|
.B syntactical line break
|
|
is defined to consist of optional syntactical space that is optionally
|
|
followed by a comment, and a newline character.
|
|
.
|
|
.P
|
|
The normal commands, those for positioning and text, consist of a
|
|
single letter taking a fixed number of arguments.
|
|
.
|
|
For historical reasons, the parser allows to stack such commands on
|
|
the same line, but fortunately, in groff intermediate output, every
|
|
command with at least one argument is followed by a line break, thus
|
|
providing excellent readability.
|
|
.
|
|
.P
|
|
The other commands \[em] those for drawing and device controlling \[em]
|
|
have a more complicated structure; some recognize long command names,
|
|
and some take a variable number of arguments.
|
|
.
|
|
So all
|
|
.B D
|
|
and
|
|
.B x
|
|
commands were designed to request a
|
|
.I syntactical line break
|
|
after their last argument.
|
|
.
|
|
Only one command,
|
|
.RB ` x\ X '
|
|
has an argument that can stretch over several lines, all other
|
|
commands must have all of their arguments on the same line as the
|
|
command, i.e.\& the arguments may not be splitted by a line break.
|
|
.
|
|
.P
|
|
Empty lines, i.e.\& lines containing only space and/or a comment, can
|
|
occur everywhere.
|
|
.
|
|
They are just ignored.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Argument Units"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
Some commands take integer arguments that are assumed to represent
|
|
values in a measurement unit, but the letter for the corresponding
|
|
.I scale indicator
|
|
is not written with the output command arguments; see
|
|
.BR groff (@MAN7EXT@)
|
|
and the groff info file for more on this topic.
|
|
.
|
|
Most commands assume the scale indicator\~\c
|
|
.unit u ,
|
|
the basic unit of the device, some use\~\c
|
|
.unit z ,
|
|
the
|
|
.I scaled point unit
|
|
of the device, while others, such as the color commands expect plain
|
|
integers.
|
|
.
|
|
Note that these scale indicators are relative to the chosen device.
|
|
.
|
|
They are defined by the parameters specified in the device's
|
|
.I DESC
|
|
file; see
|
|
.BR groff_font (@MAN5EXT@).
|
|
.
|
|
.P
|
|
Note that single characters can have the eighth bit set, as can the
|
|
names of fonts and special characters.
|
|
.
|
|
The names of characters and fonts can be of arbitrary length.
|
|
.
|
|
A character that is to be printed will always be in the current font.
|
|
.
|
|
.P
|
|
A string argument is always terminated by the next whitespace
|
|
character (space, tab, or newline); an embedded
|
|
.B #
|
|
character is regarded as part of the argument, not as the beginning of
|
|
a comment command.
|
|
.
|
|
An integer argument is already terminated by the next non-digit
|
|
character, which then is regarded as the first character of the next
|
|
argument or command.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Document Parts"
|
|
.\" --------------------------------------------------------------------
|
|
A correct intermediate output document consists of two parts, the
|
|
prologue and the body.
|
|
.
|
|
.P
|
|
The task of the
|
|
.I prologue
|
|
is to set the general device parameters using three exactly specified
|
|
commands.
|
|
.
|
|
The
|
|
.I groff prologue
|
|
is guaranteed to consist of the following three lines (in that order):
|
|
.RS
|
|
.P
|
|
.B x\ T
|
|
.I device
|
|
.br
|
|
.B x\ res
|
|
.I n\ h\ v
|
|
.br
|
|
.B x init
|
|
.RE
|
|
.P
|
|
with the arguments set as outlined in the section
|
|
.BR "Device Control Commands" .
|
|
.
|
|
But the parser for the intermediate output format is able to swallow
|
|
additional whitespace and comments as well.
|
|
.
|
|
.P
|
|
The
|
|
.I body
|
|
is the main section for processing the document data.
|
|
.
|
|
Syntactically, it is a sequence of any commands different from the
|
|
ones used in the prologue.
|
|
.
|
|
Processing is terminated as soon as the first
|
|
.B x\ stop
|
|
command is encountered; the last line of any groff intermediate output
|
|
always contains such a command.
|
|
.
|
|
.P
|
|
Semantically, the body is page oriented.
|
|
.
|
|
A new page is started by a
|
|
.BR p \~command.
|
|
.
|
|
Positioning, writing, and drawing commands are always done within the
|
|
current page, so they cannot occur before the first
|
|
.BR p \~command.
|
|
.
|
|
Absolute positioning (by the
|
|
.B H
|
|
and
|
|
.BR V \~commands)
|
|
is done relative to the current page, all other positioning
|
|
is done relative to the current location within this page.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "COMMAND REFERENCE"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
This section describes all intermediate output commands, the classical
|
|
commands as well as the
|
|
.I groff
|
|
extensions.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Comment Command"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
.TP
|
|
.BI # anything \[la]end_of_line\[ra]
|
|
A comment.
|
|
.
|
|
Ignore any characters from the
|
|
.BR # \~\c
|
|
character up to the next newline character.
|
|
.
|
|
.P
|
|
This command is the only possibility for commenting in the intermediate
|
|
output.
|
|
.
|
|
Each comment can be preceded by arbitrary
|
|
.I syntactical
|
|
.IR space ;
|
|
every command can be terminated by a comment.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Simple Commands"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
The commands in this subsection have a command code consisting of a
|
|
single character, taking a fixed number of arguments.
|
|
.
|
|
Most of them are commands for positioning and text writing.
|
|
.
|
|
These commands are smart about whitespace.
|
|
.
|
|
Optionally,
|
|
.I syntactical space
|
|
can be inserted before, after, and between the command letter and its
|
|
arguments.
|
|
.
|
|
All of these commands are stackable, i.e., they can be preceded by
|
|
other simple commands or followed by arbitrary other commands on the
|
|
same line.
|
|
.
|
|
A separating syntactical space is only necessary when two integer
|
|
arguments would clash or if the preceding argument ends with a string
|
|
argument.
|
|
.
|
|
.
|
|
.if (\n[@USE_ENV_STACK] == 1) \{\
|
|
.command {
|
|
Open a new environment by copying the actual device configuration data
|
|
to the environment stack.
|
|
.
|
|
The current environment is setup by the device specification and
|
|
manipulated by the setting commands.
|
|
.
|
|
.
|
|
.command }
|
|
Close the actual environment (opened by a preceding
|
|
.BR { \~command)
|
|
and restore the previous environment from the environment
|
|
stack as the actual device configuration data.
|
|
.
|
|
\} \" endif @USE_ENV_STACK
|
|
.
|
|
.
|
|
.command C xxx \[la]white_space\[ra]
|
|
Print a special groff character named
|
|
.argument xxx .
|
|
.
|
|
The trailing syntactical space or line break is necessary to allow
|
|
character names of arbitrary length.
|
|
.
|
|
The character is printed at the current print position;
|
|
the character's size is read from the font file.
|
|
.
|
|
The print position is not changed.
|
|
.
|
|
.
|
|
.command c c
|
|
Print character\~\c
|
|
.argument c
|
|
at the current print position;
|
|
the character's size is read from the font file.
|
|
.
|
|
The print position is not changed.
|
|
.
|
|
.
|
|
.command f n
|
|
Set font to font number\~\c
|
|
.argument n
|
|
(a non-negative integer).
|
|
.
|
|
.
|
|
.command H n
|
|
Move right to the absolute vertical position\~\c
|
|
.argument n
|
|
(a non-negative integer in basic units\~\c
|
|
.unit u )
|
|
relative to left edge of current page.
|
|
.
|
|
.
|
|
.command h n
|
|
Move
|
|
.argument n
|
|
(a non-negative integer) basic units\~\c
|
|
.unit u
|
|
horizontally to the right.
|
|
.
|
|
.I [54]
|
|
allows negative values for
|
|
.I n
|
|
also, but
|
|
.I groff
|
|
doesn't use this.
|
|
.
|
|
.
|
|
.command m "color_scheme \f[R][\f[]component .\|.\|.\f[R]]\f[]"
|
|
Set the color for text (glyphs), line drawing, and the outline of
|
|
graphic objects using different color schemes; the analoguous command
|
|
for the filling color of graphic objects is
|
|
.BR DF .
|
|
.
|
|
The color components are specified as integer arguments between 0 and
|
|
\n[@maxcolor].
|
|
.
|
|
The number of color components and their meaning vary for the
|
|
different color schemes.
|
|
.
|
|
These commands are generated by the groff escape sequence
|
|
.BR \*[@backslash]m .
|
|
.
|
|
No position changing.
|
|
.
|
|
These commands are a groff extension.
|
|
.
|
|
.
|
|
.RS
|
|
.
|
|
.command mc "cyan magenta yellow"
|
|
Set color using the CMY color scheme, having the 3\~color components
|
|
cyan, magenta, and yellow.
|
|
.
|
|
.
|
|
.command md
|
|
Set color to the default color value
|
|
(black in most cases).
|
|
.
|
|
No component arguments.
|
|
.
|
|
.
|
|
.command mg "gray"
|
|
Set color to the shade of gray given by the argument, an integer
|
|
between 0 (black) and \n[@maxcolor] (white).
|
|
.
|
|
.
|
|
.command mk "cyan magenta yellow black"
|
|
Set color using the CMYK color scheme, having the 4\~color components
|
|
cyan, magenta, yellow, and black.
|
|
.
|
|
.command mr "red green blue"
|
|
Set color using the RGB color scheme, having the 3\~color components
|
|
red, green, and blue.
|
|
.
|
|
.RE
|
|
.
|
|
.
|
|
.command N n
|
|
Print character with index\~\c
|
|
.argument n
|
|
(a non-negative integer) of the current font.
|
|
.
|
|
The print position is not changed.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.command n b\ a
|
|
Inform the device about a line break, but no positioning is done by
|
|
this command.
|
|
.
|
|
In classical troff, the integer arguments
|
|
.argument b
|
|
and\~\c
|
|
.argument a
|
|
informed about the space before and after the current line to
|
|
make the intermediate output more human readable without performing
|
|
any action.
|
|
.
|
|
In groff, they are just ignored, but they must be provided for
|
|
compatibility reasons.
|
|
.
|
|
.
|
|
.command p n
|
|
Begin a new page in the outprint.
|
|
.
|
|
The page number is set to\~\c
|
|
.argument n .
|
|
.
|
|
This page is completely independent of pages formerly processed even
|
|
if those have the same page number.
|
|
.
|
|
The vertical position on the outprint is automatically set to\~0.
|
|
.
|
|
All positioning, writing, and drawing is always done relative to a
|
|
page, so a
|
|
.BR p \~command
|
|
must be issued before any of these commands.
|
|
.
|
|
.
|
|
.command s n
|
|
Set point size to
|
|
.argument n
|
|
scaled points
|
|
(this is unit\~\c
|
|
.unit z
|
|
in GNU
|
|
.BR troff ).
|
|
.
|
|
Classical troff used the unit
|
|
.I points
|
|
(\c
|
|
.unit p )
|
|
instead; see section
|
|
.BR COMPATIBILITY .
|
|
.
|
|
.
|
|
.command t xxx \[la]white_space\[ra]
|
|
.command+ t "xxx dummy_arg" \[la]white_space\[ra]
|
|
Print a word, i.e.\& a sequence of characters
|
|
.argument xxx
|
|
terminated by a space character or a line break; an optional second
|
|
integer argument is ignored (this allows the formatter to generate
|
|
an even number of arguments).
|
|
.
|
|
The first character should be printed at the current position, the
|
|
current horizontal position should then be increased by the width of
|
|
the first character, and so on for each character.
|
|
.
|
|
The widths of the characters are read from the font file, scaled for the
|
|
current point size, and rounded to a multiple of the horizontal
|
|
resolution.
|
|
.
|
|
Special characters cannot be printed using this command (use the
|
|
.B C
|
|
command for named characters).
|
|
.
|
|
This command is a groff extension; it is only used for devices whose
|
|
.I DESC
|
|
file contains the
|
|
.B tcommand
|
|
keyword; see
|
|
.BR groff_font (@MAN5EXT@).
|
|
.
|
|
.
|
|
.command u "n xxx" \[la]white_space\[ra]
|
|
Print word with track kerning.
|
|
.
|
|
This is the same as the
|
|
.B t
|
|
command except that after printing each character, the current
|
|
horizontal position is increased by the sum of the width of that
|
|
character and\~\c
|
|
.argument n
|
|
(an integer in
|
|
basic units\~\c
|
|
.unit u ).
|
|
This command is a groff extension; it is only used for devices whose
|
|
.I DESC
|
|
file contains the
|
|
.B tcommand
|
|
keyword; see
|
|
.BR groff_font (@MAN5EXT@).
|
|
.
|
|
.
|
|
.command V n
|
|
Move down to the absolute vertical position\~\c
|
|
.argument n
|
|
(a non-negative integer in basic units\~\c
|
|
.unit u )
|
|
relative to upper edge of current page.
|
|
.
|
|
.
|
|
.command v n
|
|
Move
|
|
.argument n
|
|
basic units\~\c
|
|
.unit u
|
|
down
|
|
.RI ( n
|
|
is a non-negative integer).
|
|
.
|
|
.I [54]
|
|
allows negative values for
|
|
.I n
|
|
also, but
|
|
.I groff
|
|
doesn't use this.
|
|
.
|
|
.
|
|
.command w
|
|
Informs about a paddable whitespace to increase readability.
|
|
.
|
|
The spacing itself must be performed explicitly by a move command.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Graphics Commands"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
Each graphics or drawing command in the intermediate output starts
|
|
with the letter\~\c
|
|
.B D
|
|
followed by one or two characters that specify a subcommand; this
|
|
is followed by a fixed or variable number of integer arguments that
|
|
are separated by a single space character.
|
|
.
|
|
A
|
|
.BR D \ command
|
|
may not be followed by another command on the same line
|
|
(apart from a comment), so each
|
|
.BR D \ command
|
|
is terminated by a syntactical line break.
|
|
.
|
|
.P
|
|
.I troff
|
|
output follows the classical spacing rules (no space between command
|
|
and subcommand, all arguments are preceded by a single space
|
|
character), but the parser allows optional space between the command
|
|
letters and makes the space before the first argument optional.
|
|
.
|
|
As usual, each space can be any sequence of tab and space characters.
|
|
.
|
|
.P
|
|
Some graphics commands can take a variable number of arguments.
|
|
.
|
|
In this case, they are integers representing a size measured in basic
|
|
units\~\c
|
|
.unit u .
|
|
.
|
|
The arguments called
|
|
.list1..n h
|
|
stand for horizontal distances where positive means right, negative
|
|
left.
|
|
.
|
|
The arguments called
|
|
.list1..n v
|
|
stand for vertical distances where positive means down, negative up.
|
|
.
|
|
All these distances are offsets relative to the current location.
|
|
.
|
|
.P
|
|
Unless indicated otherwise, each graphics command directly corresponds
|
|
to a similar
|
|
.I groff
|
|
.B \*[@backslash]D
|
|
escape sequence; see
|
|
.BR groff (@MAN7EXT@).
|
|
.
|
|
.P
|
|
Unknown D\~commands are assumed to be device-specific.
|
|
.
|
|
Its arguments are parsed as strings; the whole information is then
|
|
sent to the postprocessor.
|
|
.
|
|
.P
|
|
In the following command reference, the syntax element
|
|
.I \[la]line_break\[ra]
|
|
means a
|
|
.I syntactical line break
|
|
as defined in section
|
|
.BR Separation .
|
|
.
|
|
.
|
|
.D-multiarg ~
|
|
Draw B-spline from current position to offset
|
|
.indexed_offset h 1 v 1 ,
|
|
then to offset
|
|
.indexed_offset h 2 v 2
|
|
if given, etc.\& up to
|
|
.indexed_offset h n v n .
|
|
This command takes a variable number of argument pairs;
|
|
the current position is moved to the terminal point of the drawn curve.
|
|
.
|
|
.
|
|
.Da-command
|
|
Draw arc from current position to
|
|
.indexed_offset h 1 v 1 \|+\|\c
|
|
.indexed_offset h 2 v 2
|
|
with center at
|
|
.indexed_offset h 1 v 1 ;
|
|
then move the current position to the final point of the arc.
|
|
.
|
|
.
|
|
.D-command C d
|
|
.D-command+ C d dummy_arg
|
|
Draw a solid circle using the current fill color with diameter\~\c
|
|
.argument d
|
|
(integer in basic units\~\c
|
|
.unit u )
|
|
with leftmost point at the current position; then move the current
|
|
position to the rightmost point of the circle.
|
|
.
|
|
An optional second integer argument is ignored (this allows to the
|
|
formatter to generate an even number of arguments).
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.D-command c d
|
|
Draw circle line with diameter\~\c
|
|
.argument d
|
|
(integer in basic units\~\c
|
|
.unit u )
|
|
with leftmost point at the current position; then move the current
|
|
position to the rightmost point of the circle.
|
|
.
|
|
.
|
|
.D-command E "h v"
|
|
Draw a solid ellipse in the current fill color with a horizontal
|
|
diameter of\~\c
|
|
.argument h
|
|
and a vertical diameter of\~\c
|
|
.argument v
|
|
(both integers in basic units\~\c
|
|
.unit u )
|
|
with the leftmost point at the current position; then move to the
|
|
rightmost point of the ellipse.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.D-command e "h v"
|
|
Draw an outlined ellipse with a horizontal diameter of\~\c
|
|
.argument h
|
|
and a vertical diameter of\~\c
|
|
.argument v
|
|
(both integers in basic units\~\c
|
|
.unit u )
|
|
with the leftmost point at current position; then move to the
|
|
rightmost point of the ellipse.
|
|
.
|
|
.
|
|
.D-command F "color_scheme \f[R][\f[]component .\|.\|.\f[R]]\f[]"
|
|
Set fill color for solid drawing objects using different color
|
|
schemes; the analoguous command for setting the color of text, line
|
|
graphics, and the outline of graphic objects is
|
|
.BR m .
|
|
.
|
|
The color components are specified as integer arguments between 0 and
|
|
\n[@maxcolor].
|
|
.
|
|
The number of color components and their meaning vary for the
|
|
different color schemes.
|
|
.
|
|
These commands are generated by the groff escape sequences
|
|
.B \*[@backslash]D'F\ .\|.\|.'
|
|
and
|
|
.B \*[@backslash]M
|
|
(with no other corresponding graphics commands).
|
|
.
|
|
No position changing.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.RS
|
|
.
|
|
.D-command Fc "cyan magenta yellow"
|
|
Set fill color for solid drawing objects using the CMY color scheme,
|
|
having the 3\~color components cyan, magenta, and yellow.
|
|
.
|
|
.
|
|
.D-command Fd
|
|
Set fill color for solid drawing objects to the default fill color value
|
|
(black in most cases).
|
|
.
|
|
No component arguments.
|
|
.
|
|
.
|
|
.D-command Fg "gray"
|
|
Set fill color for solid drawing objects to the shade of gray given by
|
|
the argument, an integer between 0 (black) and \n[@maxcolor] (white).
|
|
.
|
|
.
|
|
.D-command Fk "cyan magenta yellow black"
|
|
Set fill color for solid drawing objects using the CMYK color scheme,
|
|
having the 4\~color components cyan, magenta, yellow, and black.
|
|
.
|
|
.D-command Fr "red green blue"
|
|
Set fill color for solid drawing objects using the RGB color scheme,
|
|
having the 3\~color components red, green, and blue.
|
|
.
|
|
.RE
|
|
.
|
|
.
|
|
.D-command f n
|
|
The argument
|
|
.argument n
|
|
must be an integer in the range -32767 to 32767.
|
|
.
|
|
.RS
|
|
.TP
|
|
.RI "0 \[<=] " n " \[<=] 1000"
|
|
Set the color for filling solid drawing objects to a shade of gray,
|
|
where 0 corresponds to solid white, 1000 (the default) to solid black,
|
|
and values in between to intermediate shades of gray; this is
|
|
obsoleted by command
|
|
.BR DFg .
|
|
.
|
|
.TP
|
|
.IR n " < 0 or " n " > 1000"
|
|
Set the filling color to the color that is currently being used for
|
|
the text and the outline, see command
|
|
.BR m .
|
|
For example, the command sequence
|
|
.
|
|
.nf
|
|
.ft CB
|
|
.RS
|
|
.RS
|
|
mg 0 0 \n[@maxcolor]
|
|
Df -1
|
|
.RE
|
|
.ft
|
|
.fi
|
|
.
|
|
sets all colors to blue.
|
|
.RE
|
|
.
|
|
.P
|
|
No position changing.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.RE
|
|
.
|
|
.
|
|
.D-command l "h v"
|
|
Draw line from current position to offset
|
|
.offset h v
|
|
(integers in basic units\~\c
|
|
.unit u );
|
|
then set current position to the end of the drawn line.
|
|
.
|
|
.
|
|
.D-multiarg p
|
|
Draw a polygon line from current position to offset
|
|
.offset h1 v1 ,
|
|
from there to offset
|
|
.offset h2 v2 ,
|
|
etc.\& up to offset
|
|
.offset hn vn ,
|
|
and from there back to the starting position.
|
|
.
|
|
.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
|
|
For historical reasons, the position is changed by adding the sum of
|
|
all arguments with odd index to the actual horizontal position and the
|
|
even ones to the vertical position.
|
|
.
|
|
Although this doesn't make sense it is kept for compatibility.
|
|
.
|
|
\}
|
|
.el \{\
|
|
As the polygon is closed, the end of drawing is the starting point, so
|
|
the position doesn't change.
|
|
\}
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.D-multiarg P
|
|
The same macro as the corresponding
|
|
.B Dp
|
|
command with the same arguments, but draws a solid polygon in the
|
|
current fill color rather than an outlined polygon.
|
|
.
|
|
.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
|
|
The position is changed in the same way as with
|
|
.BR Dp .
|
|
\}
|
|
.el \
|
|
No position changing.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.D-command t n
|
|
Set the current line thickness to\~\c
|
|
.argument n
|
|
(an integer in basic units\~\c
|
|
.unit u )
|
|
if
|
|
.argument n >0;
|
|
if
|
|
.argument n =0
|
|
select the smallest available line thickness; if
|
|
.argument n <0
|
|
set the line thickness proportional to the point size (this is the
|
|
default before the first
|
|
.B Dt
|
|
command was specified).
|
|
.
|
|
.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
|
|
For historical reasons, the horizontal position is changed by adding
|
|
the argument to the actual horizontal position, while the vertical
|
|
position is not changed.
|
|
.
|
|
Although this doesn't make sense it is kept for compatibility.
|
|
.
|
|
\}
|
|
.el \
|
|
No position changing.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Device Control Commands"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
Each device control command starts with the letter
|
|
.B x
|
|
followed by a space character (optional or arbitrary space/\:tab in
|
|
groff) and a subcommand letter or word; each argument (if any) must be
|
|
preceded by a syntactical space.
|
|
.
|
|
All
|
|
.B x
|
|
commands are terminated by a
|
|
.IR "syntactical line break" ;
|
|
no device control command can be followed by another command on the same
|
|
line (except a comment).
|
|
.
|
|
.P
|
|
The subcommand is basically a single letter, but to increase
|
|
readability, it can be written as a word, i.e.\& an arbitrary sequence
|
|
of characters terminated by the next tab, space, or newline character.
|
|
.
|
|
All characters of the subcommand word but the first are simply ignored.
|
|
.
|
|
For example,
|
|
.I troff
|
|
outputs the initialization command
|
|
.B x\ i
|
|
as
|
|
.B x\ init
|
|
and the resolution command
|
|
.B x\ r
|
|
as
|
|
.BR "x\ res" .
|
|
.
|
|
But writings like
|
|
.B x\ i_like_groff
|
|
and
|
|
.B x\ roff_is_groff
|
|
resp.\& are accepted as well to mean the same commands.
|
|
.
|
|
.P
|
|
In the following, the syntax element
|
|
.I \[la]line_break\[ra]
|
|
means a
|
|
.I syntactical line break
|
|
as defined in section
|
|
.BR Separation .
|
|
.
|
|
.x-command F name
|
|
.xsub Filename
|
|
Use
|
|
.argument name
|
|
as the intended name for the current file in error reports.
|
|
.
|
|
This is useful for remembering the original file name when groff uses
|
|
an internal piping mechanism.
|
|
.
|
|
The input file is not changed by this command.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.x-command f "n\ s"
|
|
.xsub font
|
|
Mount font position\~\c
|
|
.argument n
|
|
(a non-negative integer) with font named\~\c
|
|
.argument s
|
|
(a text word),
|
|
cf.
|
|
.BR groff_font (@MAN5EXT@).
|
|
.
|
|
.
|
|
.x-command H n
|
|
.xsub Height
|
|
Set character height to\~\c
|
|
.argument n
|
|
(a positive integer in scaled points\~\c
|
|
.unit z ).
|
|
.
|
|
Classical troff used the unit
|
|
points (\c
|
|
.unit p )
|
|
instead; see section
|
|
.BR COMPATIBILITY .
|
|
.
|
|
.
|
|
.x-command i
|
|
.xsub init
|
|
Initialize device.
|
|
.
|
|
This is the third command of the prologue.
|
|
.
|
|
.
|
|
.x-command p
|
|
.xsub pause
|
|
Parsed but ignored.
|
|
.
|
|
The classical documentation reads
|
|
.I pause device, can be
|
|
.IR restarted .
|
|
.
|
|
.
|
|
.x-command r "n\ h\ v"
|
|
.xsub resolution
|
|
Resolution is\~\c
|
|
.argument n ,
|
|
while
|
|
.argument h
|
|
is the minimal horizontal motion, and
|
|
.argument v
|
|
the minimal vertical motion possible with this device; all arguments
|
|
are positive integers in basic units\~\c
|
|
.unit u
|
|
per inch.
|
|
.
|
|
This is the second command of the prologue.
|
|
.
|
|
.
|
|
.x-command S n
|
|
.xsub Slant
|
|
Set slant to\~\c
|
|
.argument n
|
|
(an integer in basic units\~\c
|
|
.unit u ).
|
|
.
|
|
.
|
|
.x-command s
|
|
.xsub stop
|
|
Terminates the processing of the current file; issued as the last
|
|
command of any intermediate troff output.
|
|
.
|
|
.
|
|
.x-command t
|
|
.xsub trailer
|
|
Generate trailer information, if any.
|
|
.
|
|
In
|
|
.IR groff ,
|
|
this is actually just ignored.
|
|
.
|
|
.
|
|
.x-command T xxx
|
|
.xsub Typesetter
|
|
Set name of device to word
|
|
.argument xxx ,
|
|
a sequence of characters ended by the next whitespace character.
|
|
.
|
|
The possible device names coincide with those from the groff
|
|
.B -T
|
|
option.
|
|
.
|
|
This is the first command of the prologue.
|
|
.
|
|
.
|
|
.x-command u n
|
|
.xsub underline
|
|
Configure underlining of spaces.
|
|
.
|
|
If
|
|
.argument n
|
|
is\~1, start underlining of spaces;
|
|
if
|
|
.argument n
|
|
is\~0, stop underlining of spaces.
|
|
.
|
|
This is needed for the
|
|
.B cu
|
|
request in
|
|
.I nroff
|
|
mode and is ignored otherwise.
|
|
.
|
|
This command is a groff extension.
|
|
.
|
|
.
|
|
.x-command X anything
|
|
.xsub X-escape
|
|
Send string
|
|
.argument anything
|
|
uninterpreted to the device.
|
|
.
|
|
If the line following this command starts with a
|
|
.B +
|
|
character this line is interpreted as a continuation line in the
|
|
following sense.
|
|
.
|
|
The
|
|
.B +
|
|
is ignored, but a newline character is sent instead to the device, the
|
|
rest of the line is sent uninterpreted.
|
|
.
|
|
The same applies to all following lines until the first character of a
|
|
line is not a
|
|
.B +
|
|
character.
|
|
.
|
|
This command is generated by the
|
|
.I groff
|
|
escape sequence
|
|
.BR \*[@backslash]X .
|
|
.
|
|
The line-continuing feature is a groff extension.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SS "Obsolete Command"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
In
|
|
.I classical troff
|
|
output, the writing of a single character was mostly done by a very
|
|
strange command that combined a horizontal move and the printing of a
|
|
character.
|
|
.
|
|
It didn't have a command code, but is represented by a 3-character
|
|
argument consisting of exactly 2\~digits and a character.
|
|
.
|
|
.TP
|
|
.argument ddc
|
|
Move right
|
|
.argument dd
|
|
(exactly two decimal digits) basic units\~\c
|
|
.unit u ,
|
|
then print character\~\c
|
|
.argument c .
|
|
.
|
|
.RS
|
|
.P
|
|
In groff, arbitrary syntactical space around and within this command
|
|
is allowed to be added.
|
|
.
|
|
Only when a preceding command on the same line ends with an argument
|
|
of variable length a separating space is obligatory.
|
|
.
|
|
In
|
|
.I classical
|
|
.IR troff ,
|
|
large clusters of these and other commands were used, mostly without
|
|
spaces; this made such output almost unreadable.
|
|
.
|
|
.RE
|
|
.
|
|
.P
|
|
For modern high-resolution devices, this command does not make sense
|
|
because the width of the characters can become much larger than two
|
|
decimal digits.
|
|
.
|
|
In groff, this is only used for the devices
|
|
.BR X75 ,
|
|
.BR X75-12 ,
|
|
.BR X100 ,
|
|
and
|
|
.BR X100-12 .
|
|
.
|
|
For other devices,
|
|
the commands
|
|
.B t
|
|
and\~\c
|
|
.B u
|
|
provide a better functionality.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "POSTPROCESSING"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
The
|
|
.I roff
|
|
postprocessors are programs that have the task to translate the
|
|
intermediate output into actions that are sent to a device.
|
|
.
|
|
A device can be some piece of hardware such as a printer, or a software
|
|
file format suitable for graphical or text processing.
|
|
.
|
|
The
|
|
.I groff
|
|
system provides powerful means that make the programming of such
|
|
postprocessors an easy task.
|
|
.P
|
|
There is a library function that parses the intermediate output and
|
|
sends the information obtained to the device via methods of a class
|
|
with a common interface for each device.
|
|
.
|
|
So a
|
|
.I groff
|
|
postprocessor must only redefine the methods of this class.
|
|
.
|
|
For details, see the reference in section
|
|
.BR FILES .
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "EXAMPLES"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
This section presents the intermediate output generated from the same
|
|
input for three different devices.
|
|
.
|
|
The input is the sentence
|
|
.I hell world
|
|
fed into groff on the command line.
|
|
.
|
|
.Topic
|
|
High-resolution device
|
|
.I ps
|
|
.
|
|
.RS
|
|
.
|
|
.P
|
|
.ShellCommand echo "hell world" | groff -Z -T ps
|
|
.
|
|
.P
|
|
.nf
|
|
.ft CB
|
|
x T ps
|
|
x res 72000 1 1
|
|
x init
|
|
p1
|
|
x font 5 TR
|
|
f5
|
|
s10000
|
|
V12000
|
|
H72000
|
|
thell
|
|
wh2500
|
|
tw
|
|
H96620
|
|
torld
|
|
n12000 0
|
|
x trailer
|
|
V792000
|
|
x stop
|
|
.ft P
|
|
.fi
|
|
.RE
|
|
.
|
|
.P
|
|
This output can be fed into the postprocessor
|
|
.BR grops (@MAN1EXT@)
|
|
to get its representation as a PostScript file.
|
|
.
|
|
.
|
|
.Topic
|
|
Low-resolution device
|
|
.I latin1
|
|
.
|
|
.RS
|
|
.
|
|
.P
|
|
This is similar to the high-resolution device except that the
|
|
positioning is done at a minor scale.
|
|
.
|
|
Some comments (lines starting with
|
|
.IR # )
|
|
were added for clarification; they were not generated by the
|
|
formatter.
|
|
.
|
|
.P
|
|
.ShellCommand echo "hell world" | groff -Z -T latin1
|
|
.
|
|
.P
|
|
.nf
|
|
.I # prologue
|
|
.ft CB
|
|
x T latin1
|
|
x res 240 24 40
|
|
x init
|
|
.I # begin a new page
|
|
.ft CB
|
|
p1
|
|
.I # font setup
|
|
.ft CB
|
|
x font 1 R
|
|
f1
|
|
s10
|
|
.I # initial positioning on the page
|
|
.ft CB
|
|
V40
|
|
H0
|
|
.I # write text `hell'
|
|
.ft CB
|
|
thell
|
|
.I # inform about a space, and do it by a horizontal jump
|
|
.ft CB
|
|
wh24
|
|
.I # write text `world'
|
|
.ft CB
|
|
tworld
|
|
.I # announce line break, but do nothing because ...
|
|
.ft CB
|
|
n40 0
|
|
.I # ... the end of the document has been reached
|
|
.ft CB
|
|
x trailer
|
|
V2640
|
|
x stop
|
|
.ft P
|
|
.fi
|
|
.RE
|
|
.
|
|
.P
|
|
This output can be fed into the postprocessor
|
|
.BR grotty (@MAN1EXT@)
|
|
to get a formatted text document.
|
|
.
|
|
.
|
|
.Topic
|
|
Classical style output
|
|
.
|
|
.RS
|
|
.
|
|
.P
|
|
As a computer monitor has a very low resolution compared to modern
|
|
printers the intermediate output for the X\~devices can use the
|
|
jump-and-write command with its 2-digit displacements.
|
|
.
|
|
.P
|
|
.ShellCommand echo "hell world" | groff -Z -T X100
|
|
.
|
|
.P
|
|
.nf
|
|
.ft CB
|
|
x T X100
|
|
x res 100 1 1
|
|
x init
|
|
p1
|
|
x font 5 TR
|
|
f5
|
|
s10
|
|
V16
|
|
H100
|
|
.I # write text with old-style jump-and-write command
|
|
.ft CB
|
|
ch07e07l03lw06w11o07r05l03dh7
|
|
n16 0
|
|
x trailer
|
|
V1100
|
|
x stop
|
|
.ft P
|
|
.fi
|
|
.RE
|
|
.
|
|
.P
|
|
This output can be fed into the postprocessor
|
|
.BR xditview (1x)
|
|
or
|
|
.BR gxditview (@MAN1EXT@)
|
|
for displaying in\~X.
|
|
.
|
|
.P
|
|
Due to the obsolete jump-and-write command, the text clusters in the
|
|
classical output are almost unreadable.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "COMPATIBILITY"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
The intermediate output language of the
|
|
.I classical troff
|
|
was first documented in
|
|
.IR [97] .
|
|
.
|
|
The
|
|
.I groff
|
|
intermediate output format is compatible with this specification
|
|
except for the following features.
|
|
.Topic
|
|
The classical quasi device independence is not yet implemented.
|
|
.
|
|
.Topic
|
|
The old hardware was very different from what we use today.
|
|
.
|
|
So the groff devices are also fundamentally different from the ones in
|
|
classical troff.
|
|
.
|
|
For example, the classical PostScript device was called
|
|
.I post
|
|
and had a resolution of 720 units per inch,
|
|
while groff's
|
|
.I ps
|
|
device has a resolution of 72000 units per inch.
|
|
.
|
|
Maybe, by implementing some rescaling mechanism similar to the
|
|
classical quasi device independence, these could be integrated into
|
|
modern groff.
|
|
.
|
|
.Topic
|
|
The B-spline command
|
|
.B D~
|
|
is correctly handled by the intermediate output parser, but the
|
|
drawing routines aren't implemented in some of the postprocessor
|
|
programs.
|
|
.Topic
|
|
The argument of the commands
|
|
.B s
|
|
and
|
|
.B x H
|
|
has the implicit unit scaled point\~\c
|
|
.unit z
|
|
in groff, while classical troff had point (\c
|
|
.unit p ).
|
|
.
|
|
This isn't an incompatibility, but a compatible extension,
|
|
for both units coincide for all devices without a
|
|
.I sizescale
|
|
parameter, including all classical and the groff text devices.
|
|
.
|
|
The few groff devices with a sizescale parameter either did
|
|
not exist, had a different name, or seem to have had a different
|
|
resolution.
|
|
.
|
|
So conflicts with classical devices are very unlikely.
|
|
.
|
|
.ie (\n[@STUPID_DRAWING_POSITIONING] == 1) \{\
|
|
.Topic
|
|
The position changing after the commands
|
|
.BR Dp ,
|
|
.BR DP ,
|
|
and
|
|
.B Dt
|
|
is illogical, but as old versions of groff used this feature it is
|
|
kept for compatibility reasons.
|
|
.\} \" @STUPID_DRAWING_POSITIONING
|
|
.el \{\
|
|
.Topic
|
|
Temporarily, there existed some confusion on the positioning after the
|
|
.B D
|
|
commands that are groff extensions.
|
|
.
|
|
This has been clarified by establishing the classical rule for all
|
|
groff drawing commands:
|
|
.
|
|
.RS
|
|
.P
|
|
.I The position after a graphic object has been drawn is at its end;
|
|
.I for circles and ellipses, the "end" is at the right side.
|
|
.RE
|
|
.
|
|
.P
|
|
From this, the positionings specified for the drawing commands above
|
|
follow quite naturally.
|
|
.\} \" @STUPID_DRAWING_POSITIONING
|
|
.
|
|
.P
|
|
The differences between groff and classical troff are documented in
|
|
.BR groff_diff (@MAN7EXT@).
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "FILES"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
.TP
|
|
.BI @FONTDIR@/dev name /DESC
|
|
Device description file for device
|
|
.IR name .
|
|
.
|
|
.TP
|
|
.IB \[la]groff_source_dir\[ra] /src/libs/libdriver/input.cc
|
|
Defines the parser and postprocessor for the intermediate output.
|
|
.
|
|
It is located relative to the top directory of the
|
|
.I groff
|
|
source tree, e.g.
|
|
.IR @GROFFSRCDIR@ .
|
|
.
|
|
This parser is the definitive specification of the
|
|
.I groff
|
|
intermediate output format.
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "SEE ALSO"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
A reference like
|
|
.BR groff (@MAN7EXT@)
|
|
refers to a manual page; here
|
|
.I groff
|
|
in section\~\c
|
|
.I @MAN7EXT@
|
|
of the man-page documentation system.
|
|
.
|
|
To read the example, look up section\~@MAN7EXT@ in your desktop help
|
|
system or call from the shell prompt
|
|
.
|
|
.RS
|
|
.P
|
|
.ShellCommand man @MAN7EXT@ groff
|
|
.RE
|
|
.
|
|
.P
|
|
For more details, see
|
|
.BR man (1).
|
|
.
|
|
.TP
|
|
.BR groff (@MAN1EXT@)
|
|
option
|
|
.B -Z
|
|
and further readings on groff.
|
|
.
|
|
.TP
|
|
.BR groff (@MAN7EXT@)
|
|
for details of the
|
|
.I groff
|
|
language such as numerical units and escape sequences.
|
|
.
|
|
.TP
|
|
.BR groff_font (@MAN5EXT@)
|
|
for details on the device scaling parameters of the
|
|
.B DESC
|
|
file.
|
|
.
|
|
.TP
|
|
.BR troff (@MAN1EXT@)
|
|
generates the device-independent intermediate output.
|
|
.
|
|
.TP
|
|
.BR roff (@MAN7EXT@)
|
|
for historical aspects and the general structure of roff systems.
|
|
.
|
|
.TP
|
|
.BR groff_diff (@MAN7EXT@)
|
|
The differences between the intermediate output in groff and classical
|
|
troff.
|
|
.
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.P
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.BR \%grodvi (@MAN1EXT@),
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.BR \%grohtml (@MAN1EXT@),
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.BR \%grolbp (@MAN1EXT@),
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|
.BR \%grolj4 (@MAN1EXT@),
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|
.BR \%grops (@MAN1EXT@),
|
|
.BR \%grotty (@MAN1EXT@)
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|
.br
|
|
.RS
|
|
the groff postprocessor programs.
|
|
.RE
|
|
.
|
|
.P
|
|
For a treatment of all aspects of the groff system within a single
|
|
document, see the
|
|
.I groff info
|
|
.IR file .
|
|
.
|
|
It can be read within the integrated help systems, within
|
|
.BR emacs (1)
|
|
or from the shell prompt by
|
|
.
|
|
.RS
|
|
.ShellCommand info groff
|
|
.RE
|
|
.
|
|
.P
|
|
The
|
|
.I classical troff output language
|
|
is described in two AT&T Bell Labs CSTR documents available on-line at
|
|
.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr.html \
|
|
"Bell Labs CSTR site" .
|
|
.
|
|
.TP
|
|
.I [CSTR #97]
|
|
.I A Typesetter-independent TROFF
|
|
by
|
|
.I Brian Kernighan
|
|
is the original and most concise documentation on the output language;
|
|
see
|
|
.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:97.ps.gz CSTR\~#97 .
|
|
.
|
|
.TP
|
|
.I [CSTR\~#54]
|
|
The 1992 revision of the
|
|
.I Nroff/\:Troff User's Manual
|
|
by
|
|
.I J.\& F.\& Osanna
|
|
and
|
|
.I Brian Kernighan
|
|
isn't as concise as
|
|
.I [CSTR\~#97]
|
|
regarding the output language;
|
|
see
|
|
.URL http://\:cm.bell-labs.com/\:cm/\:cs/\:cstr/\:54.ps.gz CSTR\~#54 .
|
|
.
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.SH "AUTHORS"
|
|
.\" --------------------------------------------------------------------
|
|
.
|
|
Copyright (C) 1989, 2001, 2002 Free Software Foundation, Inc.
|
|
.P
|
|
This document is distributed under the terms of the FDL (GNU Free
|
|
Documentation License) version 1.1 or later.
|
|
.
|
|
You should have received a copy of the FDL with this package; it is also
|
|
available on-line at the
|
|
.URL http://\:www.gnu.org/\:copyleft/\:fdl.html "GNU copyleft site" .
|
|
.
|
|
.P
|
|
This document is part of
|
|
.IR groff ,
|
|
the GNU roff distribution.
|
|
.
|
|
It is based on a former version \- published under the GPL \- that
|
|
described only parts of the
|
|
.I groff
|
|
extensions of the output language.
|
|
.
|
|
It has been rewritten 2002 by
|
|
.MTO bwarken@mayn.de "Bernd Warken"
|
|
and is maintained by
|
|
.MTO wl@gnu.org "Werner Lemberg" .
|
|
.
|
|
.\" --------------------------------------------------------------------
|
|
.\" Emacs settings
|
|
.\" --------------------------------------------------------------------
|
|
.\"
|
|
.\" Local Variables:
|
|
.\" mode: nroff
|
|
.\" End:
|