754 lines
16 KiB
Groff
754 lines
16 KiB
Groff
.ig \"-*- nroff -*-
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Copyright (C) 1989-1995 Free Software Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided that the
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entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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Permission is granted to copy and distribute translations of this
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manual into another language, under the above conditions for modified
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versions, except that this permission notice may be included in
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translations approved by the Free Software Foundation instead of in
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the original English.
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..
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.\" Like TP, but if specified indent is more than half
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.\" the current line-length - indent, use the default indent.
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.de Tp
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.ie \\n(.$=0:((0\\$1)*2u>(\\n(.lu-\\n(.iu)) .TP
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.el .TP "\\$1"
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..
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.ie t .ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
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.el .ds tx TeX
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.ie \n(.g .ds ic \/
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.el .ds ic \^
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.\" The BSD man macros can't handle " in arguments to font change macros,
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.\" so use \(ts instead of ".
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.tr \(ts"
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.TH @G@PIC @MAN1EXT@ "@MDATE@" "Groff Version @VERSION@"
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.SH NAME
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@g@pic \- compile pictures for troff or TeX
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.SH SYNOPSIS
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.B @g@pic
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[
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.B \-nvC
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]
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[
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.I filename
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\&.\|.\|.
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]
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.br
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.B @g@pic
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.B \-t
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[
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.B \-cvzC
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]
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[
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.I filename
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\&.\|.\|.
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]
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.SH DESCRIPTION
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.LP
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This manual page describes the GNU version of
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.BR pic ,
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which is part of the groff document formatting system.
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.B pic
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compiles descriptions of pictures embedded within
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.B troff
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or \*(tx input files into commands that are understood by \*(tx or
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.BR troff .
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Each picture starts with a line beginning with
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.B .PS
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and ends with a line beginning with
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.BR .PE .
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Anything outside of
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.B .PS
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and
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.B .PE
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is passed through without change.
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.LP
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It is the user's responsibility to provide appropriate definitions of the
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.B PS
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and
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.B PE
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macros.
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When the macro package being used does not supply such definitions
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(for example, old versions of \-ms),
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appropriate definitions can be obtained with
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.BR \-mpic :
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these will center each picture.
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.SH OPTIONS
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.LP
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Options that do not take arguments may be grouped behind a single
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.BR \- .
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The special option
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.B \-\^\-
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can be used to mark the end of the options.
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A filename of
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.B \-
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refers to the standard input.
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.TP
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.B \-C
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Recognize
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.B .PS
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and
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.B .PE
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even when followed by a character other than space or newline.
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.TP
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.B \-S
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Safer mode; do not execute
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.B sh
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commands.
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This can be useful when operating on untrustworthy input.
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.TP
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.B \-n
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Don't use the groff extensions to the troff drawing commands.
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You should use this if you are using a postprocessor that doesn't support
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these extensions.
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The extensions are described in
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.BR groff_out (@MAN5EXT@).
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The
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.B \-n
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option also causes pic
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not to use zero-length lines to draw dots in troff mode.
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.TP
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.B \-t
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\*(tx mode.
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.TP
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.B \-c
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Be more compatible with
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.BR tpic .
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Implies
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.BR \-t .
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Lines beginning with
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.B \e
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are not passed through transparently.
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Lines beginning with
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.B .
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are passed through with the initial
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.B .
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changed to
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.BR \e .
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A line beginning with
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.B .ps
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is given special treatment:
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it takes an optional integer argument specifying
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the line thickness (pen size) in milliinches;
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a missing argument restores the previous line thickness;
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the default line thickness is 8 milliinches.
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The line thickness thus specified takes effect only
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when a non-negative line thickness has not been
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specified by use of the
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.B thickness
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attribute or by setting the
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.B linethick
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variable.
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.TP
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.B \-v
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Print the version number.
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.TP
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.B \-z
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In \*(tx mode draw dots using zero-length lines.
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.LP
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The following options supported by other versions of
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.B pic
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are ignored:
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.TP
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.B \-D
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Draw all lines using the \eD escape sequence.
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.B pic
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always does this.
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.TP
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.BI \-T \ dev
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Generate output for the
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.B troff
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device
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.IR dev .
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This is unnecessary because the
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.B troff
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output generated by
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.B pic
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is device-independent.
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.SH USAGE
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This section describes only the differences between GNU pic and the original
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version of pic.
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Many of these differences also apply to newer versions of Unix pic.
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.SS \*(tx mode
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.LP
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\*(tx mode is enabled by the
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.B \-t
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option.
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In \*(tx mode, pic will define a vbox called
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.B \egraph
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for each picture.
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You must yourself print that vbox using, for example, the command
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.RS
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.LP
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.B
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\ecenterline{\ebox\egraph}
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.RE
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.LP
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Actually, since the vbox has a height of zero this will produce
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slightly more vertical space above the picture than below it;
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.RS
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.LP
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.B
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\ecenterline{\eraise 1em\ebox\egraph}
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.RE
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.LP
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would avoid this.
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.LP
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You must use a \*(tx driver that supports the
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.B tpic
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specials, version 2.
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.LP
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Lines beginning with
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.B \e
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are passed through transparently; a
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.B %
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is added to the end of the line to avoid unwanted spaces.
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You can safely use this feature to change fonts or to
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change the value of
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.BR \ebaselineskip .
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Anything else may well produce undesirable results; use at your own risk.
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Lines beginning with a period are not given any special treatment.
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.SS Commands
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.TP
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\fBfor\fR \fIvariable\fR \fB=\fR \fIexpr1\fR \fBto\fR \fIexpr2\fR \
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[\fBby\fR [\fB*\fR]\fIexpr3\fR] \fBdo\fR \fIX\fR \fIbody\fR \fIX\fR
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Set
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.I variable
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to
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.IR expr1 .
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While the value of
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.I variable
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is less than or equal to
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.IR expr2 ,
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do
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.I body
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and increment
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.I variable
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by
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.IR expr3 ;
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if
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.B by
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is not given, increment
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.I variable
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by 1.
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If
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.I expr3
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is prefixed by
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.B *
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then
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.I variable
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will instead be multiplied by
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.IR expr3 .
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.I X
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can be any character not occurring in
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.IR body .
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.TP
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\fBif\fR \fIexpr\fR \fBthen\fR \fIX\fR \fIif-true\fR \fIX\fR \
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[\fBelse\fR \fIY\fR \fIif-false\fR \fIY\fR]
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Evaluate
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.IR expr ;
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if it is non-zero then do
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.IR if-true ,
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otherwise do
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.IR if-false .
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.I X
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can be any character not occurring in
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.IR if-true .
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.I Y
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can be any character not occurring in
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.IR if-false .
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.TP
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\fBprint\fR \fIarg\fR\|.\|.\|.
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Concatenate the arguments and print as a line on stderr.
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Each
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.I arg
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must be an expression, a position, or text.
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This is useful for debugging.
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.TP
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\fBcommand\fR \fIarg\fR\|.\|.\|.
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Concatenate the arguments
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and pass them through as a line to troff or\*(tx.
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Each
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.I arg
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must be an expression, a position, or text.
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This has a similar effect to a line beginning with
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.B .
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or
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.BR \e ,
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but allows the values of variables to be passed through.
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.TP
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\fBsh\fR \fIX\fR \fIcommand\fR \fIX\fR
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Pass
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.I command
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to a shell.
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.I X
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can be any character not occurring in
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.IR command .
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.TP
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\fBcopy\fR \fB"\fIfilename\fB"\fR
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Include
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.I filename
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at this point in the file.
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.TP
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\fBcopy\fR [\fB"\fIfilename\fB"\fR] \fBthru\fR \fIX\fR \fIbody\fR \fIX\fR \
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[\fBuntil\fR \fB"\fIword\*(ic\fB"\fR]
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.ns
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.TP
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\fBcopy\fR [\fB"\fIfilename\fB"\fR] \fBthru\fR \fImacro\fR \
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[\fBuntil\fR \fB"\fIword\*(ic\fB"\fR]
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This construct does
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.I body
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once for each line of
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.IR filename ;
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the line is split into blank-delimited words,
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and occurrences of
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.BI $ i
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in
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.IR body ,
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for
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.I i
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between 1 and 9,
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are replaced by the
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.IR i -th
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word of the line.
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If
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.I filename
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is not given, lines are taken from the current input up to
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.BR .PE .
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If an
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.B until
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clause is specified,
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lines will be read only until a line the first word of which is
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.IR word ;
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that line will then be discarded.
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.I X
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can be any character not occurring in
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.IR body .
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For example,
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.RS
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.IP
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.ft B
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.nf
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\&.PS
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copy thru % circle at ($1,$2) % until "END"
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1 2
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3 4
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5 6
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END
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box
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\&.PE
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.ft
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.fi
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.RE
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.IP
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is equivalent to
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.RS
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.IP
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.ft B
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.nf
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\&.PS
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circle at (1,2)
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circle at (3,4)
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circle at (5,6)
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box
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\&.PE
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.ft
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.fi
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.RE
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.IP
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The commands to be performed for each line can also be taken
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from a macro defined earlier by giving the name of the macro
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as the argument to
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.BR thru .
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.LP
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.B reset
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.br
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.ns
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.TP
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\fBreset\fI variable1\fB,\fI variable2 .\^.\^.
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Reset pre-defined variables
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.IR variable1 ,
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.I variable2
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\&.\^.\^. to their default values.
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If no arguments are given, reset all pre-defined variables
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to their default values.
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Note that assigning a value to
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.B scale
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also causes all pre-defined variables that control dimensions
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to be reset to their default values times the new value of scale.
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.TP
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\fBplot\fR \fIexpr\fR [\fB"\fItext\*(ic\fB"\fR]
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This is a text object which is constructed by using
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.I text
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as a format string for sprintf
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with an argument of
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.IR expr .
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If
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.I text
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is omitted a format string of
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.B "\(ts%g\(ts"
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is used.
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Attributes can be specified in the same way as for a normal text
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object.
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Be very careful that you specify an appropriate format string;
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pic does only very limited checking of the string.
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This is deprecated in favour of
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.BR sprintf .
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.TP
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.IB variable := expr
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This is similar to
|
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.B =
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except
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.I variable
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must already be defined,
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and the value of
|
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.I variable
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will be changed only in the innermost block in which it is defined.
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(By contrast,
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.B =
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defines the variable in the current block if it is not already defined there,
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and then changes the value in the current block.)
|
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.LP
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Arguments of the form
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.IP
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.IR X\ anything\ X
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.LP
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are also allowed to be of the form
|
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.IP
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.BI {\ anything\ }
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.LP
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In this case
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.I anything
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can contain balanced occurrences of
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.B {
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and
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.BR } .
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Strings may contain
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.I X
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or imbalanced occurrences of
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.B {
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and
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.BR } .
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.SS Expressions
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The syntax for expressions has been significantly extended:
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.LP
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.IB x\ ^\ y
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(exponentiation)
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.br
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.BI sin( x )
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.br
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.BI cos( x )
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.br
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.BI atan2( y , \ x )
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.br
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.BI log( x )
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(base 10)
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.br
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.BI exp( x )
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(base 10, ie 10\v'-.4m'\fIx\*(ic\fR\v'.4m')
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.br
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.BI sqrt( x )
|
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.br
|
|
.BI int( x )
|
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.br
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|
.B rand()
|
|
(return a random number between 0 and 1)
|
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.br
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|
.BI rand( x )
|
|
(return a random number between 1 and
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.IR x ;
|
|
deprecated)
|
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.br
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|
.BI max( e1 , \ e2 )
|
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.br
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|
.BI min( e1 , \ e2 )
|
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.br
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|
.BI ! e
|
|
.br
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|
\fIe1\fB && \fIe2\fR
|
|
.br
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|
\fIe1\fB || \fIe2\fR
|
|
.br
|
|
\fIe1\fB == \fIe2\fR
|
|
.br
|
|
\fIe1\fB != \fIe2\fR
|
|
.br
|
|
\fIe1\fB >= \fIe2\fR
|
|
.br
|
|
\fIe1\fB > \fIe2\fR
|
|
.br
|
|
\fIe1\fB <= \fIe2\fR
|
|
.br
|
|
\fIe1\fB < \fIe2\fR
|
|
.br
|
|
\fB"\fIstr1\*(ic\fB" == "\fIstr2\*(ic\fB"\fR
|
|
.br
|
|
\fB"\fIstr1\*(ic\fB" != "\fIstr2\*(ic\fB"\fR
|
|
.br
|
|
.LP
|
|
String comparison expressions must be parenthesised in some contexts
|
|
to avoid ambiguity.
|
|
.SS Other Changes
|
|
.LP
|
|
A bare expression,
|
|
.IR expr ,
|
|
is acceptable as an attribute;
|
|
it is equivalent to
|
|
.IR dir\ expr ,
|
|
where
|
|
.I dir
|
|
is the current direction.
|
|
For example
|
|
.IP
|
|
.B line 2i
|
|
.LP
|
|
means draw a line 2 inches long in the current direction.
|
|
.LP
|
|
The maximum width and height of the picture are taken from the variables
|
|
.B maxpswid
|
|
and
|
|
.BR maxpsht .
|
|
Initially these have values 8.5 and 11.
|
|
.LP
|
|
Scientific notation is allowed for numbers.
|
|
For example
|
|
.RS
|
|
.B
|
|
x = 5e\-2
|
|
.RE
|
|
.LP
|
|
Text attributes can be compounded.
|
|
For example,
|
|
.RS
|
|
.B
|
|
"foo" above ljust
|
|
.RE
|
|
is legal.
|
|
.LP
|
|
There is no limit to the depth to which blocks can be examined.
|
|
For example,
|
|
.RS
|
|
.B
|
|
[A: [B: [C: box ]]] with .A.B.C.sw at 1,2
|
|
.br
|
|
.B
|
|
circle at last [\^].A.B.C
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|
.RE
|
|
is acceptable.
|
|
.LP
|
|
Arcs now have compass points
|
|
determined by the circle of which the arc is a part.
|
|
.LP
|
|
Circles and arcs can be dotted or dashed.
|
|
In \*(tx mode splines can be dotted or dashed.
|
|
.LP
|
|
Boxes can have rounded corners.
|
|
The
|
|
.B rad
|
|
attribute specifies the radius of the quarter-circles at each corner.
|
|
If no
|
|
.B rad
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|
or
|
|
.B diam
|
|
attribute is given, a radius of
|
|
.B boxrad
|
|
is used.
|
|
Initially,
|
|
.B boxrad
|
|
has a value of 0.
|
|
A box with rounded corners can be dotted or dashed.
|
|
.LP
|
|
The
|
|
.B .PS
|
|
line can have a second argument specifying a maximum height for
|
|
the picture.
|
|
If the width of zero is specified the width will be ignored in computing
|
|
the scaling factor for the picture.
|
|
Note that GNU pic will always scale a picture by the same amount
|
|
vertically as horizontally.
|
|
This is different from the
|
|
.SM DWB
|
|
2.0 pic which may scale a picture by a
|
|
different amount vertically than horizontally if a height is
|
|
specified.
|
|
.LP
|
|
Each text object has an invisible box associated with it.
|
|
The compass points of a text object are determined by this box.
|
|
The implicit motion associated with the object is also determined
|
|
by this box.
|
|
The dimensions of this box are taken from the width and height attributes;
|
|
if the width attribute is not supplied then the width will be taken to be
|
|
.BR textwid ;
|
|
if the height attribute is not supplied then the height will be taken to be
|
|
the number of text strings associated with the object
|
|
times
|
|
.BR textht .
|
|
Initially
|
|
.B textwid
|
|
and
|
|
.B textht
|
|
have a value of 0.
|
|
.LP
|
|
In places where a quoted text string can be used,
|
|
an expression of the form
|
|
.IP
|
|
.BI sprintf(\(ts format \(ts,\ arg ,\fR.\|.\|.\fB)
|
|
.LP
|
|
can also be used;
|
|
this will produce the arguments formatted according to
|
|
.IR format ,
|
|
which should be a string as described in
|
|
.BR printf (3)
|
|
appropriate for the number of arguments supplied,
|
|
using only the
|
|
.BR e ,
|
|
.BR f ,
|
|
.B g
|
|
or
|
|
.B %
|
|
format characters.
|
|
.LP
|
|
The thickness of the lines used to draw objects is controlled by the
|
|
.B linethick
|
|
variable.
|
|
This gives the thickness of lines in points.
|
|
A negative value means use the default thickness:
|
|
in \*(tx output mode, this means use a thickness of 8 milliinches;
|
|
in \*(tx output mode with the
|
|
.B -c
|
|
option, this means use the line thickness specified by
|
|
.B .ps
|
|
lines;
|
|
in troff output mode, this means use a thickness proportional
|
|
to the pointsize.
|
|
A zero value means draw the thinnest possible line supported by
|
|
the output device.
|
|
Initially it has a value of -1.
|
|
There is also a
|
|
.BR thick [ ness ]
|
|
attribute.
|
|
For example,
|
|
.RS
|
|
.LP
|
|
.B circle thickness 1.5
|
|
.RE
|
|
.LP
|
|
would draw a circle using a line with a thickness of 1.5 points.
|
|
The thickness of lines is not affected by the
|
|
value of the
|
|
.B scale
|
|
variable, nor by the width or height given in the
|
|
.B .PS
|
|
line.
|
|
.LP
|
|
Boxes (including boxes with rounded corners),
|
|
circles and ellipses can be filled by giving then an attribute of
|
|
.BR fill [ ed ].
|
|
This takes an optional argument of an expression with a value between
|
|
0 and 1; 0 will fill it with white, 1 with black, values in between
|
|
with a proportionally gray shade.
|
|
A value greater than 1 can also be used:
|
|
this means fill with the
|
|
shade of gray that is currently being used for text and lines.
|
|
Normally this will be black, but output devices may provide
|
|
a mechanism for changing this.
|
|
Without an argument, then the value of the variable
|
|
.B fillval
|
|
will be used.
|
|
Initially this has a value of 0.5.
|
|
The invisible attribute does not affect the filling of objects.
|
|
Any text associated with a filled object will be added after the
|
|
object has been filled, so that the text will not be obscured
|
|
by the filling.
|
|
.LP
|
|
Arrow heads will be drawn as solid triangles if the variable
|
|
.B arrowhead
|
|
is non-zero and either \*(tx mode is enabled or
|
|
the
|
|
.B \-x
|
|
option has been given.
|
|
Initially
|
|
.B arrowhead
|
|
has a value of 1.
|
|
.LP
|
|
The troff output of pic is device-independent.
|
|
The
|
|
.B \-T
|
|
option is therefore redundant.
|
|
All numbers are taken to be in inches; numbers are never interpreted
|
|
to be in troff machine units.
|
|
.LP
|
|
Objects can have an
|
|
.B aligned
|
|
attribute.
|
|
This will only work when the postprocessor is
|
|
.BR grops .
|
|
Any text associated with an object having the
|
|
.B aligned
|
|
attribute will be rotated about the center of the object
|
|
so that it is aligned in the direction from the start point
|
|
to the end point of the object.
|
|
Note that this attribute will have no effect for objects whose start and
|
|
end points are coincident.
|
|
.LP
|
|
In places where
|
|
.IB n th
|
|
is allowed
|
|
.BI ` expr 'th
|
|
is also allowed.
|
|
Note that
|
|
.B 'th
|
|
is a single token: no space is allowed between the
|
|
.B '
|
|
and the
|
|
.BR th .
|
|
For example,
|
|
.IP
|
|
.B
|
|
.nf
|
|
for i = 1 to 4 do {
|
|
line from `i'th box.nw to `i+1'th box.se
|
|
}
|
|
.fi
|
|
.SH FILES
|
|
.Tp \w'\fB@MACRODIR@/tmac.pic'u+3n
|
|
.B
|
|
@MACRODIR@/tmac.pic
|
|
Example definitions of the
|
|
.B PS
|
|
and
|
|
.B PE
|
|
macros.
|
|
.SH "SEE ALSO"
|
|
.BR @g@troff (@MAN1EXT@),
|
|
.BR groff_out (@MAN5EXT@),
|
|
.BR tex (1)
|
|
.br
|
|
Tpic: Pic for \*(tx
|
|
.br
|
|
AT&T Bell Laboratories, Computing Science Technical Report No.\ 116,
|
|
PIC \(em A Graphics Language for Typesetting.
|
|
(This can be obtained by sending a mail message to netlib@research.att.com
|
|
with a body of `send\ 116\ from\ research/cstr'.)
|
|
.SH BUGS
|
|
.LP
|
|
Input characters that are illegal for
|
|
.B groff
|
|
(ie those with
|
|
.SM ASCII
|
|
code 0 or between 013 and 037 octal or between 0200 and 0237 octal)
|
|
are rejected even in \*(tx mode.
|
|
.LP
|
|
The interpretation of
|
|
.B fillval
|
|
is incompatible with the pic in 10th edition Unix,
|
|
which interprets 0 as black and 1 as white.
|