Provided by: groff_1.22.4-8build1_amd64 bug

NAME

       grn - groff preprocessor for gremlin files

SYNOPSIS

       grn [-Cv] [-T dev] [-M dir] [-F dir] [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.

OPTIONS

       Whitespace is permitted between a command-line option and its argument.

       -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/1.22.4/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/1.22.4/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.

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 from 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'll  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/1.22.4/font/devname/DESC
              Device description file for device name.

AUTHORS

       David  Slattengren  and  Barry  Roitblat  wrote the original Berkeley grn.  Daniel Senderowicz and Werner
       Lemberg modified it for groff.

SEE ALSO

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