grn - groff preprocessor for gremlin files
[
-Cv] [
-T
dev] [
-M dir]
[
-F dir] [
file ...]
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.
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.
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.
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).
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.
- •
- 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”.
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.
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.
-
/usr/share/groff/1.22.4/font/devname/DESC
- Device description file for device name.
David Slattengren and Barry Roitblat wrote the original Berkeley
grn.
Daniel Senderowicz and Werner Lemberg modified it for
groff.
gremlin(1),
groff(1),
pic(1),
ideal(1)