Provided by: groff_1.22.3-7_amd64 bug

NAME

       grn - groff preprocessor for gremlin files

SYNOPSIS

       grn [ -Cv ] [ -Tdev ] [ -Mdir ] [ -Fdir ] [ file... ]

DESCRIPTION

       grn  is  a  preprocessor  for  including  gremlin  pictures in groff input.  grn writes to
       standard output, processing only input lines between two that  start  with  .GS  and  .GE.
       Those lines must contain grn commands (see below).  These commands request a gremlin file,
       and the picture in that file is converted and placed in the troff input stream.   The  .GS
       request  may  be  followed  by  a  C,  L, or R to center, left, or right justify the whole
       gremlin picture (default justification is center).  If no file is mentioned, the  standard
       input  is  read.  At the end of the picture, the position on the page is the bottom of the
       gremlin picture.  If the grn entry is ended with .GF instead of .GE, the position is  left
       at the top of the picture.

       Please note that currently only the -me macro package has support for .GS, .GE, and .GF.

       The following command-line options are understood:

       -Tdev  Prepare  output  for  printer  dev.   The  default  device is ps.  See groff(1) for
              acceptable devices.

       -Mdir  Prepend dir to the default search path for gremlin files.  The default path is  (in
              that  order)  the  current directory, the home directory, /usr/lib/groff/site-tmac,
              /usr/share/groff/site-tmac, and /usr/share/groff/1.22.3/tmac.

       -Fdir  Search dir for subdirectories devname (name is the name of the device) for the DESC
              file    before    the    default   font   directories   /usr/share/groff/site-font,
              /usr/share/groff/1.22.3/font, and /usr/lib/font.

       -C     Recognize .GS and .GE (and .GF) even when followed by a character other than  space
              or newline.

       -v     Print the version number.

       It is possible to have whitespace between a command line option and its parameter.

GRN COMMANDS

       Each  input line between .GS and .GE may have one grn command.  Commands consist of one or
       two strings separated by white space, the first string being the command  and  the  second
       its operand.  Commands may be upper or lower case and abbreviated down to one character.

       Commands  that affect a picture's environment (those listed before default, see below) are
       only in effect for the current picture: The environment is reinitialized to  the  defaults
       at the start of the next picture.  The commands are as follows:

       1 N
       2 N
       3 N
       4 N    Set  gremlin's text size number 1 (2, 3, or 4) to N points.  The default is 12 (16,
              24, and 36, respectively).

       roman f
       italics f
       bold f
       special f
              Set the roman (italics, bold, or special) font to troff's font f (either a name  or
              number).  The default is R (I, B, and S, respectively).

       l f
       stipple f
              Set  the  stipple  font  to  troff's  stipple font f (name or number).  The command
              stipple may be abbreviated down as far as ‘st’ (to avoid confusion  with  special).
              There is no default for stipples (unless one is set by the default command), and it
              is invalid to include a gremlin picture with polygons without specifying a  stipple
              font.

       x N
       scale N
              Magnify  the  picture  (in  addition to any default magnification) by N, a floating
              point number larger than zero.  The command scale may be abbreviated down to ‘sc’.

       narrow N
       medium N
       thick N
              Set the thickness of gremlin's narrow (medium and thick, respectively) lines  to  N
              times  0.15pt (this value can be changed at compile time).  The default is 1.0 (3.0
              and  5.0,  respectively),  which  corresponds  to  0.15pt   (0.45pt   and   0.75pt,
              respectively).   A  thickness  value  of  zero  selects the smallest available line
              thickness.  Negative values cause the line thickness  to  be  proportional  to  the
              current point size.

       pointscale <off/on>
              Scale text to match the picture.  Gremlin text is usually printed in the point size
              specified with the commands 1, 2, 3, or 4, regardless of any scaling factors in the
              picture.   Setting  pointscale will cause the point sizes to scale with the picture
              (within troff's limitations, of course).  An operand of anything but off will  turn
              text scaling on.

       default
              Reset  the  picture  environment  defaults  to the settings in the current picture.
              This is meant to be used as a global parameter setting mechanism at  the  beginning
              of the troff input file, but can be used at any time to reset the default settings.

       width N
              Forces the picture to be N inches wide.  This overrides any scaling factors present
              in the same picture.  ‘width 0’ is ignored.

       height N
              Forces picture to be N inches high, overriding  other  scaling  factors.   If  both
              ‘width’  and ‘height’ are specified the tighter constraint will determine the scale
              of the picture.  Height and width commands are not saved with  a  default  command.
              They will, however, affect point size scaling if that option is set.

       file name
              Get picture from gremlin file name located the current directory (or in the library
              directory; see the -M option above).  If two file commands are  given,  the  second
              one  overrides  the first.  If name doesn't exist, an error message is reported and
              processing continues from the .GE line.

NOTES ABOUT GROFF

       Since grn is a preprocessor, it doesn't know about current indents, point sizes,  margins,
       number registers, etc.  Consequently, no troff input can be placed between the .GS and .GE
       requests.  However, gremlin text is now processed by troff, so anything valid in a  single
       line  of  troff  input  is  valid in a line of gremlin text (barring ‘.’ directives at the
       beginning of a line).  Thus, it is possible to have equations within a gremlin  figure  by
       including  in  the  gremlin file eqn expressions enclosed by previously defined delimiters
       (e.g. $$).

       When using grn along with other preprocessors, it is best to  run  tbl  before  grn,  pic,
       and/or ideal to avoid overworking tbl.  Eqn should always be run last.

       A  picture is considered an entity, but that doesn't stop troff from trying to break it up
       if it falls off the end of a page.  Placing the picture between ‘keeps’ in -me macros will
       ensure proper placement.

       grn  uses troff's number registers g1 through g9 and sets registers g1 and g2 to the width
       and height of the gremlin figure (in device units) before entering the .GS  request  (this
       is for those who want to rewrite these macros).

GREMLIN FILE FORMAT

       There  exist  two  distinct gremlin file formats, the original format from the AED graphic
       terminal version, and the SUN or  X11  version.   An  extension  to  the  SUN/X11  version
       allowing  reference  points  with  negative  coordinates  is  not  compatible with the AED
       version.  As long as a gremlin file does not contain negative coordinates,  either  format
       will  be  read correctly by either version of gremlin or grn.  The other difference to the
       SUN/X11 format is the use of names for picture objects (e.g., POLYGON, CURVE)  instead  of
       numbers.  Files representing the same picture are shown in Table 1 in each format.

                                 sungremlinfile        gremlinfile
                                 0 240.00 128.00       0 240.00 128.00
                                 CENTCENT              2
                                 240.00 128.00         240.00 128.00
                                 185.00 120.00         185.00 120.00
                                 240.00 120.00         240.00 120.00
                                 296.00 120.00         296.00 120.00
                                 *                     -1.00 -1.00
                                 2 3                   2 3
                                 10 A Triangle         10 A Triangle
                                 POLYGON               6
                                 224.00 416.00         224.00 416.00
                                 96.00 160.00          96.00 160.00
                                 384.00 160.00         384.00 160.00
                                 *                     -1.00 -1.00
                                 5 1                   5 1
                                 0                     0
                                 -1                    -1

                                        Table 1.  File examples

       ·      The  first  line  of  each gremlin file contains either the string gremlinfile (AED
              version) or sungremlinfile (SUN/X11)

       ·      The second line of the file contains an orientation, and  x  and  y  values  for  a
              positioning point, separated by spaces.  The orientation, either 0 or 1, is ignored
              by the SUN/X11 version.  0 means that gremlin will  display  things  in  horizontal
              format  (drawing  area  wider than it is tall, with menu across top).  1 means that
              gremlin will display things in vertical format (drawing  area  taller  than  it  is
              wide,  with  menu  on  left  side).   x  and  y  are floating point values giving a
              positioning point to be used when this file is read into another file.   The  stuff
              on  this  line  really  isn't  all  that  important;  a  value  of “1 0.00 0.00” is
              suggested.

       ·      The rest of the file consists of zero or more element  specifications.   After  the
              last element specification is a line containing the string “-1”.

       ·      Lines longer than 127 characters are chopped to this limit.

ELEMENT SPECIFICATIONS

       ·      The  first line of each element contains a single decimal number giving the type of
              the element (AED version) or its ASCII name (SUN/X11 version).  See Table 2.

                               gremlin File Format − Object Type Specification

                           AED Number   SUN/X11 Name           Description
                                0       BOTLEFT        bottom-left-justified text
                                1       BOTRIGHT       bottom-right-justified text
                                2       CENTCENT       center-justified text
                                3       VECTOR         vector
                                4       ARC            arc
                                5       CURVE          curve
                                6       POLYGON        polygon
                                7       BSPLINE        b-spline
                                8       BEZIER         Bézier
                               10       TOPLEFT        top-left-justified text
                               11       TOPCENT        top-center-justified text
                               12       TOPRIGHT       top-right-justified text
                               13       CENTLEFT       left-center-justified text
                               14       CENTRIGHT      right-center-justified text

                               15       BOTCENT        bottom-center-justified text

                                                   Table 2.
                                     Type Specifications in gremlin Files

       ·      After the object type comes a variable number of lines,  each  specifying  a  point
              used to display the element.  Each line contains an x-coordinate and a y-coordinate
              in floating point format, separated by spaces.  The list of points is terminated by
              a  line  containing  the string “-1.0 -1.0” (AED version) or a single asterisk, “*”
              (SUN/X11 version).

       ·      After the points comes a line containing two decimal values, giving the  brush  and
              size  for  the  element.  The brush determines the style in which things are drawn.
              For vectors, arcs, and curves there are six valid brush values:

                                        1 −       thin dotted lines
                                        2 −       thin dot-dashed lines
                                        3 −       thick solid lines
                                        4 −       thin dashed lines
                                        5 −       thin solid lines
                                        6 −       medium solid lines

              For polygons, one more value,  0,  is  valid.   It  specifies  a  polygon  with  an
              invisible border.  For text, the brush selects a font as follows:

                                      1 −       roman (R font in groff)
                                      2 −       italics (I font in groff)
                                      3 −       bold (B font in groff)
                                      4 −       special (S font in groff)

              If  you're  using grn to run your pictures through groff, the font is really just a
              starting font: The text string can contain formatting sequences like “\fI” or  “\d”
              which  may  change  the font (as well as do many other things).  For text, the size
              field is a decimal value between 1 and 4.  It selects the size of the font in which
              the  text will be drawn.  For polygons, this size field is interpreted as a stipple
              number to fill the polygon with.  The number is used to index into a  stipple  font
              at print time.

       ·      The last line of each element contains a decimal number and a string of characters,
              separated by a single space.  The number is a count of the number of characters  in
              the string.  This information is only used for text elements, and contains the text
              string.  There can be spaces inside the text.  For arcs, curves, and vectors,  this
              line of the element contains the string “0”.

NOTES ON COORDINATES

       gremlin  was designed for AEDs, and its coordinates reflect the AED coordinate space.  For
       vertical pictures, x-values range 116 to 511, and y-values from 0 to 483.  For  horizontal
       pictures,  x-values  range  from  0 to 511 and y-values range from 0 to 367.  Although you
       needn't absolutely stick to this range, you'get best results if you at least stay in  this
       vicinity.   Also, point lists are terminated by a point of (-1, -1), so you shouldn't ever
       use negative coordinates.  gremlin writes  out  coordinates  using  format  “%f1.2”;  it's
       probably a good idea to use the same format if you want to modify the grn code.

NOTES ON SUN/X11 COORDINATES

       There is no longer a restriction on the range of coordinates used to create objects in the
       SUN/X11 version of gremlin.  However, files with negative coordinates will cause  problems
       if displayed on the AED.

FILES

       /usr/share/groff/1.22.3/font/devname/DESC   Device description file for device name.

SEE ALSO

       gremlin(1), groff(1), pic(1), ideal(1)

COPYING

       Copyright © 2000-2014 Free Software Foundation, Inc.

       Permission  is  granted to make and distribute verbatim copies of this manual provided the
       copyright notice and this permission notice are preserved on all copies.

       Permission is granted to copy and distribute modified versions of this  manual  under  the
       conditions  for  verbatim  copying,  provided  that  the  entire resulting derived work is
       distributed under the terms of a permission notice identical to this one.

       Permission is granted to copy and distribute translations  of  this  manual  into  another
       language,  under  the  above conditions for modified versions, except that this permission
       notice may be included in translations approved by the Free Software Foundation instead of
       in the original English.

AUTHORS

       David Slattengren and Barry Roitblat wrote the original Berkeley grn.

       Daniel Senderowicz and Werner Lemberg modified it for groff.