1GRN(1)                      General Commands Manual                     GRN(1)
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NAME

6       grn - groff preprocessor for gremlin files
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SYNOPSIS

9       grn [ -Cv ] [ -Tdev ] [ -Mdir ] [ -Fdir ] [ file... ]
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11       It is possible to have whitespace between a command line option and its
12       parameter.
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DESCRIPTION

15       grn is a preprocessor for including gremlin pictures  in  groff  input.
16       grn  writes to standard output, processing only input lines between two
17       that start with .GS and .GE.  Those lines  must  contain  grn  commands
18       (see below).  These commands request a gremlin file, and the picture in
19       that file is converted and placed in the troff input stream.   The  .GS
20       request  may be followed by a C, L, or R to center, left, or right jus‐
21       tify the whole gremlin picture (default justification is  center).   If
22       no  file  is  mentioned, the standard input is read.  At the end of the
23       picture, the position on the page is the bottom of the gremlin picture.
24       If the grn entry is ended with .GF instead of .GE, the position is left
25       at the top of the picture.
26
27       Please note that currently only the -me macro package has  support  for
28       .GS, .GE, and .GF.
29
30       The following command-line options are understood:
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32       -Tdev  Prepare  output for printer dev.  The default device is ps.  See
33              groff(1) for acceptable devices.
34
35       -Mdir  Prepend dir to the default search path for gremlin  files.   The
36              default  path is (in that order) the current directory, the home
37              directory,  /usr/lib64/groff/site-tmac,   /usr/share/groff/site-
38              tmac, and /usr/share/groff/1.18.1.4/tmac.
39
40       -Fdir  Search  dir  for subdirectories devname (name is the name of the
41              device) for the DESC file before the  default  font  directories
42              /usr/share/groff/site-font,  /usr/share/groff/1.18.1.4/font, and
43              /usr/lib/font.
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45       -C     Recognize .GS and .GE (and .GF) even when followed by a  charac‐
46              ter other than space or newline.
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48       -v     Print the version number.
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GRN COMMANDS

51       Each input line between .GS and .GE may have one grn command.  Commands
52       consist of one or two strings  separated  by  white  space,  the  first
53       string  being  the command and the second its operand.  Commands may be
54       upper or lower case and abbreviated down to one character.
55
56       Commands that affect  a  picture's  environment  (those  listed  before
57       default,  see  below)  are  only in effect for the current picture: The
58       environment is reinitialized to the defaults at the start of  the  next
59       picture.  The commands are as follows:
60
61       1 N
62       2 N
63       3 N
64       4 N    Set  gremlin's text size number 1 (2, 3, or 4) to N points.  The
65              default is 12 (16, 24, and 36, respectively).
66
67       roman f
68       italics f
69       bold f
70       special f
71              Set the roman (italics, bold, or special) font to troff's font f
72              (either  a  name  or  number).   The  default is R (I, B, and S,
73              respectively).
74
75       l f
76       stipple f
77              Set the stipple font to troff's stipple font f (name or number).
78              The  command  stipple may be abbreviated down as far as `st' (to
79              avoid confusion with special).  There is no default for stipples
80              (unless one is set by the default command), and it is invalid to
81              include a gremlin picture with  polygons  without  specifying  a
82              stipple font.
83
84       x N
85       scale N
86              Magnify  the  picture (in addition to any default magnification)
87              by N, a floating point number larger  than  zero.   The  command
88              scale may be abbreviated down to `sc'.
89
90       narrow N
91       medium N
92       thick N
93              Set the thickness of gremlin's narrow (medium and thick, respec‐
94              tively) lines to N times 0.15pt (this value can  be  changed  at
95              compile  time).  The default is 1.0 (3.0 and 5.0, respectively),
96              which corresponds to 0.15pt (0.45pt and  0.75pt,  respectively).
97              A  thickness  value  of zero selects the smallest available line
98              thickness.  Negative values cause the line thickness to be  pro‐
99              portional to the current point size.
100
101       pointscale <off/on>
102              Scale  text  to  match  the  picture.   Gremlin  text is usually
103              printed in the point size specified with the commands 1,  2,  3,
104              or 4, regardless of any scaling factors in the picture.  Setting
105              pointscale will cause the point sizes to scale with the  picture
106              (within troff's limitations, of course).  An operand of anything
107              but off will turn text scaling on.
108
109       default
110              Reset the picture environment defaults to the  settings  in  the
111              current picture.  This is meant to be used as a global parameter
112              setting mechanism at the beginning of the troff input file,  but
113              can be used at any time to reset the default settings.
114
115       width N
116              Forces  the  picture  to  be  N inches wide.  This overrides any
117              scaling factors present in  the  same  picture.   `width  0'  is
118              ignored.
119
120       height N
121              Forces  picture  to  be  N inches high, overriding other scaling
122              factors.  If both `width' and `height' are specified the tighter
123              constraint  will determine the scale of the picture.  Height and
124              width commands are not saved with a default command.  They will,
125              however, affect point size scaling if that option is set.
126
127       file name
128              Get picture from gremlin file name located the current directory
129              (or in the library directory; see the -M option above).  If  two
130              file commands are given, the second one overrides the first.  If
131              name doesn't exist, an error message is reported and  processing
132              continues from the .GE line.
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NOTES ABOUT GROFF

135       Since  grn  is  a  preprocessor, it doesn't know about current indents,
136       point sizes, margins, number registers, etc.   Consequently,  no  troff
137       input can be placed between the .GS and .GE requests.  However, gremlin
138       text is now processed by troff, so anything valid in a single  line  of
139       troff  input is valid in a line of gremlin text (barring `.' directives
140       at the beginning of a line).  Thus, it is possible  to  have  equations
141       within  a  gremlin  figure by including in the gremlin file eqn expres‐
142       sions enclosed by previously defined delimiters (e.g.  $$).
143
144       When using grn along with other preprocessors, it is best  to  run  tbl
145       before  grn,  pic,  and/or  ideal to avoid overworking tbl.  Eqn should
146       always be run last.
147
148       A picture is considered an entity, but that  doesn't  stop  troff  from
149       trying  to  break it up if it falls off the end of a page.  Placing the
150       picture between `keeps' in -me macros will ensure proper placement.
151
152       grn uses troff's number registers g1 through g9 and sets  registers  g1
153       and  g2 to the width and height of the gremlin figure (in device units)
154       before entering the .GS request (this is for those who want to  rewrite
155       these macros).
156

GREMLIN FILE FORMAT

158       There exist two distinct gremlin file formats, the original format from
159       the AED graphic terminal version, and  the  SUN  or  X11  version.   An
160       extension  to  the SUN/X11 version allowing reference points with nega‐
161       tive coordinates is not compatible with the AED version.  As long as  a
162       gremlin  file does not contain negative coordinates, either format will
163       be read correctly by either version of gremlin or grn.  The other  dif‐
164       ference  to  the SUN/X11 format is the use of names for picture objects
165       (e.g., POLYGON, CURVE) instead of numbers.  Files representing the same
166       picture are shown in Table 1 in each format.
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168
169                        sungremlinfile        gremlinfile
170                        0 240.00 128.00       0 240.00 128.00
171                        CENTCENT              2
172                        240.00 128.00         240.00 128.00
173                        185.00 120.00         185.00 120.00
174                        240.00 120.00         240.00 120.00
175                        296.00 120.00         296.00 120.00
176                        *                     -1.00 -1.00
177                        2 3                   2 3
178                        10 A Triangle         10 A Triangle
179                        POLYGON               6
180                        224.00 416.00         224.00 416.00
181                        96.00 160.00          96.00 160.00
182                        384.00 160.00         384.00 160.00
183                        *                     -1.00 -1.00
184                        5 1                   5 1
185                        0                     0
186                        -1                    -1
187
188                               Table 1. File examples
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190
191       ·      The  first  line of each gremlin file contains either the string
192              gremlinfile (AED version) or sungremlinfile (SUN/X11)
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194       ·      The second line of the file contains an orientation, and x and y
195              values for a positioning point, separated by spaces.  The orien‐
196              tation, either 0 or 1, is ignored by  the  SUN/X11  version.   0
197              means  that  gremlin  will  display  things in horizontal format
198              (drawing area wider than it is tall, with menu across  top).   1
199              means that gremlin will display things in vertical format (draw‐
200              ing area taller than it is wide, with menu on left side).  x and
201              y  are  floating  point  values giving a positioning point to be
202              used when this file is read into another  file.   The  stuff  on
203              this  line  really isn't all that important; a value of ``1 0.00
204              0.00'' is suggested.
205
206       ·      The rest of the file consists of zero or more element specifica‐
207              tions.   After the last element specification is a line contain‐
208              ing the string ``-1''.
209
210       ·      Lines longer than 127 characters are chopped to this limit.
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ELEMENT SPECIFICATIONS

213       ·      The first line of each element contains a single decimal  number
214              giving  the  type of the element (AED version) or its ASCII name
215              (SUN/X11 version).  See Table 2.
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217
218                      gremlin File Format − Object Type Specification
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220                  AED Number   SUN/X11 Name           Description
221                       0       BOTLEFT        bottom-left-justified text
222                       1       BOTRIGHT       bottom-right-justified text
223                       2       CENTCENT       center-justified text
224                       3       VECTOR         vector
225                       4       ARC            arc
226                       5       CURVE          curve
227                       6       POLYGON        polygon
228                       7       BSPLINE        b-spline
229                       8       BEZIER         Bézier
230                      10       TOPLEFT        top-left-justified text
231                      11       TOPCENT        top-center-justified text
232                      12       TOPRIGHT       top-right-justified text
233                      13       CENTLEFT       left-center-justified text
234                      14       CENTRIGHT      right-center-justified text
235                      15       BOTCENT        bottom-center-justified text
236
237                                          Table 2.
238                            Type Specifications in gremlin Files
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240
241       ·      After the object type comes a variable  number  of  lines,  each
242              specifying  a point used to display the element.  Each line con‐
243              tains an x-coordinate and a y-coordinate in floating point  for‐
244              mat, separated by spaces.  The list of points is terminated by a
245              line containing the string ``-1.0 -1.0'' (AED version) or a sin‐
246              gle asterisk, ``*'' (SUN/X11 version).
247
248       ·      After  the  points  comes  a line containing two decimal values,
249              giving the brush and size for the element.  The brush determines
250              the  style  in  which  things are drawn.  For vectors, arcs, and
251              curves there are six valid brush values:
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253
254                              1 −       thin dotted lines
255                              2 −       thin dot-dashed lines
256                              3 −       thick solid lines
257                              4 −       thin dashed lines
258                              5 −       thin solid lines
259                              6 −       medium solid lines
260
261              For polygons, one more value, 0, is valid.  It specifies a poly‐
262              gon  with  an  invisible  border.  For text, the brush selects a
263              font as follows:
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265
266                            1 −       roman (R font in groff)
267                            2 −       italics (I font in groff)
268                            3 −       bold (B font in groff)
269                            4 −       special (S font in groff)
270
271              If you're using grn to run your pictures through groff, the font
272              is really just a starting font: The text string can contain for‐
273              matting sequences like ``\fI'' or ``\d'' which  may  change  the
274              font  (as  well  as  do  many other things).  For text, the size
275              field is a decimal value between 1 and 4.  It selects  the  size
276              of the font in which the text will be drawn.  For polygons, this
277              size field is interpreted as a stipple number to fill the  poly‐
278              gon  with.   The  number is used to index into a stipple font at
279              print time.
280
281       ·      The last line of each element contains a decimal  number  and  a
282              string  of  characters, separated by a single space.  The number
283              is a count of the number of  characters  in  the  string.   This
284              information  is  only  used  for text elements, and contains the
285              text string.  There can be spaces inside the  text.   For  arcs,
286              curves,  and  vectors,  this  line  of  the element contains the
287              string ``0''.
288

NOTES ON COORDINATES

290       gremlin was designed for AEDs, and  its  coordinates  reflect  the  AED
291       coordinate  space.   For  vertical pictures, x-values range 116 to 511,
292       and y-values from 0 to 483.  For horizontal  pictures,  x-values  range
293       from  0  to 511 and y-values range from 0 to 367.  Although you needn't
294       absolutely stick to this range, you'll get best results if you at least
295       stay  in this vicinity.  Also, point lists are terminated by a point of
296       (-1, -1), so you shouldn't  ever  use  negative  coordinates.   gremlin
297       writes  out  coordinates  using  format ``%f1.2''; it's probably a good
298       idea to use the same format if you want to modify the grn code.
299

NOTES ON SUN/X11 COORDINATES

301       There is no longer a restriction on the range of  coordinates  used  to
302       create  objects in the SUN/X11 version of gremlin.  However, files with
303       negative coordinates will cause problems if displayed on the AED.
304

FILES

306       /usr/share/groff/1.18.1.4/font/devname/DESC
307              Device description file for device name.
308

SEE ALSO

310       gremlin(1), groff(1), pic(1), ideal(1)
311

HISTORY

313       David Slattengren and Barry Roitblat wrote the original Berkeley grn.
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315       Daniel Senderowicz and Werner Lemberg modified it for groff.
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319Groff Version 1.18.1.4         24 February 2006                         GRN(1)
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