Provided by: groff_1.23.0-3build2_amd64 bug

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
       standard 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 picture 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 default 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  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
              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
              continues from the .GE line.

   Usage with groff
       Since  grn  is  a  preprocessor,  it has no access to elements of formatter state, such as
       indentation, 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 expressions 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 automatically 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 gremlin file does not contain negative coordinates, either format will  be  read
       correctly  by either 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
         “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 (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
         element 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
         element (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
         border.  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,
         separated  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 absolutely stick to this range, you'll get better 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 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
       displayed 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
              current 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)