man > grn(1)

grn(1)                                 General Commands Manual                                grn(1)

Name
       grn - embed Gremlin images in groff documents

Synopsis
       grn [-C] [-T dev] [-M dir] [-F dir] [file ...]

       grn -?
       grn --help

       grn -v
       grn --version

Description
       grn  is a preprocessor for including gremlin pictures in troff(1) input.  grn writes to stan‐
       dard output, processing only input lines between two that start  with  .GS  and  .GE.   Those
       lines  must  contain grn commands (see below).  These macros request a gremlin file; the pic‐
       ture in that file is converted and placed in the troff input stream.  .GS may be called  with
       a  C,  L, or R argument to center, left-, or right-justify the whole gremlin picture (the de‐
       fault is to 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.

       Currently only the me macro package has support for .GS, .GE, and .GF.

       grn  produces  drawing  escape sequences that use groff's color scheme extension (\D'F ...'),
       and thus may not work with other troffs.

   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 lowercase 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  in‐
              valid 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  val‐
              ues 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
              Force  the picture to be N inches wide.  This overrides any scaling factors present in
              the same picture.  “width 0” is ignored.

       height N
              Force the 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 multiple file commands are given, the last
              one controls.  If name doesn't exist, an error message is reported and processing con‐
              tinues from the .GE line.

   Usage with groff
       Since grn is a preprocessor, it has no access to elements of formatter state, such as  inden‐
       tation,  line  length,  type  size,  or register values.  Consequently, no troff input can be
       placed between the .GS and .GE macros.   However,  gremlin  text  elements  are  subsequently
       processed  by  troff, so anything valid in a single line of troff input is valid in a line of
       gremlin text (barring the dot control character “.” at the beginning of a line).  Thus, it is
       possible to have equations within a gremlin figure by including in the gremlin file  eqn  ex‐
       pressions enclosed by previously defined delimiters (e.g., “$$”).

       When  using  grn along with other preprocessors, it is best to run tbl(1) before grn, pic(1),
       and/or ideal to avoid overworking tbl.  eqn(1) should always be run last.  groff(1) will  au‐
       tomatically run preprocessors in the correct order.

       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 the  me  macros  will
       ensure proper placement.

       grn uses troff's 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 macro (this is for those who
       want to rewrite these macros).

   Gremlin file format
       There exist two distinct gremlin file formats: the original format for AED graphic terminals,
       and the Sun or X11 version.  An extension used by  the  Sun/X11  version  allowing  reference
       points  with negative coordinates is not compatible with the AED version.  As long as a grem‐
       lin file does not contain negative coordinates, either format will be read correctly  by  ei‐
       ther  version  of gremlin or grn.  The other difference in 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 below.

                                   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

       • The first line of each gremlin file contains either the string “gremlinfile” (AED) or “sun‐
         gremlinfile” (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 ver‐
         sion.  0 means that gremlin will display things in horizontal format (a drawing area  wider
         than  it is tall, with a menu across the top).  1 means that gremlin will display things in
         vertical format (a drawing area taller than it is wide, with a menu on the 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  ele‐
         ment specification is a line containing the string “-1”.

       • Lines longer than 127 characters are truncated to that length.

   Element specifications
       • The first line of each element contains a single decimal number giving the type of the ele‐
         ment (AED) or its name (Sun/X11).

                               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

       • 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) or a single asterisk, “*” (Sun/X11).

       • 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 bor‐
         der.  For text, the brush selects a font as follows.

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

         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, sepa‐
         rated by a single space.  The number is a count of the number of characters in the  string.
         This  information  is used only for text elements, and contains the text string.  There can
         be spaces inside the text.  For arcs, curves, and vectors, the character count is zero (0),
         followed by exactly one space before the newline.

   Coordinates
       gremlin was designed for AED terminals, 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 from 0 to 367.  Although you needn't ab‐
       solutely stick to this range, you'll get better results if you at least stay in  this  vicin‐
       ity.  Also, point lists are terminated by a point of (-1, -1), so you shouldn't ever use neg‐
       ative  coordinates.   gremlin writes out coordinates using the printf(3) format “%f1.2”; it's
       probably a good idea to use the same format if you want to modify the grn code.

   Sun/X11 coordinates
       There is no 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 dis‐
       played on the AED.

Options
       -? and --help display a usage message, while -v and --version show version  information;  all
       exit afterward.

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

       -F dir Search dir for subdirectories devname (name is the name of the output driver) for  the
              DESC  file before the default font directories /usr/share/groff/site-font, /usr/share/
              groff/1.23.0/font, and /usr/lib/font.

       -M dir Prepend dir to the search path for gremlin files.  The default search path is the cur‐
              rent directory, the home directory, /usr/share/groff/site-tmac, and  /usr/share/groff/
              1.23.0/tmac, in that order.

       -T dev Prepare device output using output driver dev.  The default is ps.  See groff(1) for a
              list of valid devices.

Files
       /usr/share/groff/1.23.0/font/devname/DESC
              describes the output 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)

groff 1.23.0                                31 March 2024                                     grn(1)
grn(1) □✕
Name Synopsis
grn -? grn --help grn -v grn --version
Description
default Usage with groff Gremlin file format Element specifications Coordinates Sun/X11 coordinates
Options
-C Recognize .GS and .GE (and .GF) even when followed by a character other than space or -F dir Search dir for subdirectories devname (name is the name of the output driver) for the -M dir Prepend dir to the search path for gremlin files. The default search path is the cur‐ -T dev Prepare device output using output driver dev. The default is ps. See groff(1) for a
Files Authors

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