NAME
grn - groff preprocessor for gremlin files
SYNOPSIS
grn [ -Cv ] [ -Tdev ]
[ -Mdir ] [ -Fdir ] [ file... ]
It is possible to have whitespace between a command line option
and its parameter.
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.
The following command-line options are understood:
- -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/1.18.1.1/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/1.18.1.1/font, and /usr/lib/font.
- -C
- Recognize .GS and .GE (resp. .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 (resp. 16, 24, and 36).
- 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 (resp. I, B, and S).
- 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 (resp. medium and
thick) lines to N times 0.15pt (this value can be changed at
compile time). The default is 1.0 (resp. 3.0 and 5.0), which
corresponds to 0.15pt (resp. 0.45pt and 0.75pt). 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
legal in a single line of troff input is legal 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 to the 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
| B['e]zier
|
| 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 legal 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 legal. 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
u+3n
-
/usr/share/groff/1.18.1.1/font/devname/DESC
Device description file for device name.
SEE ALSO
gremlin(1),
groff(1),
pic(1),
ideal(1)
HISTORY
David Slattengren and Barry Roitblat wrote the original Berkeley
grn.
Daniel Senderowicz and Werner Lemberg modified it for
groff.