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Name | Description | Files | See also | COLOPHON |
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groff_font(5) File Formats Manual groff_font(5)
groff_font - GNU roff device and font description files
The groff font format is a rough superset of the AT&T device-
independent troff font format. In distinction to the AT&T
implementation, groff lacks a binary format; all files are text
files. (Plan 9 troff has also abandoned the binary format.} The
font files for device name are stored in a directory devname.
There are two types of file: a device description file called
DESC and for each font F, a font file called F. These are text
files; unlike the ditroff font format, there is no associated
binary format.
DESC file format
The DESC file can contain the following types of line as shown
below. Later entries in the file override previous values.
Empty lines are ignored.
charset
This line and everything following in the file are
ignored. It is allowed for the sake of backwards
compatibility.
family fam
The default font family is fam.
fonts n F1 F2 F3 ... Fn
Fonts F1, ..., Fn are mounted in the font positions m+1,
..., m+n where m is the number of styles. This command
may extend over more than one line. A font name of 0
causes no font to be mounted on the corresponding font
position.
hor n The horizontal resolution is n machine units.
image_generator string
Specify the program used to generate PNG images from
PostScript input; needed for grohtml only. Under
GNU/Linux this is usually gs(1) but under other systems
(notably Cygwin) it might be set to another name.
paperlength n
The physical vertical dimension of the output medium in
machine units. This isn't used by troff itself, but by
output devices. Deprecated. Use papersize instead.
papersize string
Select a paper size. Valid values for string are the ISO
paper types A0–A7, B0–B7, C0–C7, D0–D7, DL, and the U.S.
paper types letter, legal, tabloid, ledger, statement,
executive, com10, and monarch. Case is not significant
for string if it holds predefined paper types.
Alternatively, string can be a file name (e.g.,
/etc/papersize); if the file can be opened, groff reads
the first line and tests for the above paper sizes.
Finally, string can be a custom paper size in the format
length,width (no spaces before and after the comma). Both
length and width must have a unit appended; valid values
are ‘i’ for inches, ‘c’ for centimeters, ‘p’ for points,
and ‘P’ for picas. Example: 12c,235p. An argument which
starts with a digit is always treated as a custom paper
format. papersize sets both the vertical and horizontal
dimension of the output medium.
More than one argument can be specified; groff scans from
left to right and uses the first valid paper
specification.
paperwidth n
The physical horizontal dimension of the output medium in
machine units. Deprecated. Use papersize instead. This
isn't used by troff itself, but by output devices.
pass_filenames
Make troff tell the driver the source file name being
processed. This is achieved by another tcommand:
F filename.
postpro program
Use program as the postprocessor.
prepro program
Call program as a preprocessor.
print program
Use program as the spooler program for printing. If
omitted, the -l and -L options of groff are ignored.
res n There are n machine units per inch.
sizes s1 s2 ... sn 0
This means that the device has fonts at s1, s2, ..., sn
scaled points. The list of sizes must be terminated by a
0. Each si can also be a range of sizes m–n. The list
can extend over more than one line.
sizescale n
The scale factor for point sizes. By default this has a
value of 1. One scaled point is equal to one point/n.
The arguments to the unitwidth and sizes commands are
given in scaled points.
styles S1 S2 ... Sm
The first m font positions are associated with styles S1,
..., Sm.
tcommand
This means that the postprocessor can handle the t and u
output commands.
unicode
Indicate that the output device supports the complete
Unicode repertoire. Useful only for devices which produce
character entities instead of glyphs.
If unicode is present, no charset section is required in
the font description files since the Unicode handling
built into groff is used. However, if there are entries
in a charset section, they either override the default
mappings for those particular characters or add new
mappings (normally for composite characters).
This is used for -Tutf8, -Thtml, and -Txhtml.
unitwidth n
Quantities in the font files are given in machine units
for fonts whose point size is n scaled points.
unscaled_charwidths
Make the font handling module always return unscaled glyph
widths. Needed for the grohtml device.
use_charnames_in_special
This command indicates that troff should encode named
glyphs inside special commands.
vert n The vertical resolution is n machine units.
The res, unitwidth, fonts, and sizes lines are compulsory. Not
all commands in the DESC file are used by troff itself; some of
the keywords (or even additional ones) are used by postprocessors
to store arbitrary information about the device.
Here a list of obsolete keywords which are recognized by groff
but completely ignored: spare1, spare2, biggestfont.
Font file format
A font file has two sections; empty lines are ignored in both of
them.
The first section is a sequence of lines each containing a
sequence of blank delimited words; the first word in the line is
a key, and subsequent words give a value for that key.
ligatures lig1 lig2 ... lign [0]
Glyphs lig1, lig2, ..., lign are ligatures; possible
ligatures are ff, fi, fl, ffi, and ffl. For backwards
compatibility, the list of ligatures may be terminated
with a 0. The list of ligatures may not extend over more
than one line.
name F The name of the font is F.
slant n
The glyphs of the font have a slant of n degrees.
(Positive means forward.)
spacewidth n
The normal width of a space is n.
special
The font is special; this means that when a glyph is
requested that is not present in the current font, it is
searched for in any special fonts that are mounted.
Other commands are ignored by troff but may be used by
postprocessors to store arbitrary information about the font in
the font file.
The first section can contain comments which start with the #
character and extend to the end of a line.
The second section contains one or two subsections. It must
contain a charset subsection and it may also contain a kernpairs
subsection. These subsections can appear in any order. Each
subsection starts with a word on a line by itself.
The word charset starts the charset subsection. The charset line
is followed by a sequence of lines. Each line gives information
for one glyph. A line comprises a number of fields separated by
blanks or tabs. The format is
name metrics type code [entity_name] [-- comment]
name identifies the glyph: if name is a single glyph c then it
corresponds to the groff input character c; if it is of the form
\c where c is a single character, then it corresponds to the
special character \[c]; otherwise it corresponds to the groff
input character \[name]. If it is exactly two characters xx it
can be entered as \(xx. Note that single-letter special
characters can't be accessed as \c; the only exception is ‘\-’
which is identical to ‘\[-]’. The name --- is special and
indicates that the glyph is unnamed; such glyphs can only be used
by means of the \N escape sequence in troff.
The type field gives the glyph type:
1 means the glyph has a descender, for example, ‘p’;
2 means the glyph has an ascender, for example, ‘b’;
3 means the glyph has both an ascender and a descender, for
example, ‘(’.
The code field gives the code which the postprocessor uses to
print the glyph. The glyph can also be input to groff using this
code by means of the \N escape sequence. The code can be any
integer. If it starts with a 0 it is interpreted as octal; if it
starts with 0x or 0X it is interpreted as hexadecimal. Note,
however, that the \N escape sequence only accepts a decimal
integer.
The entity_name field defines a string identifying the glyph
which the postprocessor uses to print that glyph. This field is
optional and is used by grops to build sub-encoding arrays for
PostScript fonts containing more than 256 glyphs. (It was
formerly used for grohtml's entity names, but for efficiency
reasons these data are now compiled directly into grohtml.)
Anything on the line after the encoding field or ‘--’ are
ignored.
The metrics field has the form (on one line; it may be broken
here for the sake of readability):
width[,height[,depth[,italic-correction[,
left-italic-correction[,subscript-correction]]]]]
There must not be any spaces between these subfields. Missing
subfields are assumed to be 0. The subfields are all decimal
integers. Since there is no associated binary format, these
values are not required to fit into a variable of type char as
they are in ditroff. The width subfields gives the width of the
glyph. The height subfield gives the height of the glyph
(upwards is positive); if a glyph does not extend above the
baseline, it should be given a zero height, rather than a
negative height. The depth subfield gives the depth of the
glyph, that is, the distance below the baseline to which the
glyph extends (downwards is positive); if a glyph does not extend
below the baseline, it should be given a zero depth, rather than
a negative depth. The italic-correction subfield gives the
amount of space that should be added after the glyph when it is
immediately to be followed by a glyph from a roman font. The
left-italic-correction subfield gives the amount of space that
should be added before the glyph when it is immediately to be
preceded by a glyph from a roman font. The subscript-correction
gives the amount of space that should be added after a glyph
before adding a subscript. This should be less than the italic
correction.
A line in the charset section can also have the format
name "
This indicates that name is just another name for the glyph
mentioned in the preceding line.
The word kernpairs starts the kernpairs section. This contains a
sequence of lines of the form:
c1 c2 n
This means that when glyph c1 appears next to glyph c2 the space
between them should be increased by n. Most entries in kernpairs
section have a negative value for n.
/usr/local/share/groff/1.23.0/font/devname/DESC
Device description file for device name.
/usr/local/share/groff/1.23.0/font/devname/F
Font file for font F of device name.
Groff: The GNU Implementation of troff, by Trent A. Fisher and
Werner Lemberg, is the primary groff manual. You can browse it
interactively with “info groff”.
“Troff User's Manual” by Joseph F. Ossanna, 1976 (revised by
Brian W. Kernighan, 1992), AT&T Bell Laboratories Computing
Science Techical Report No. 54, widely called simply “CSTR #54”,
documents the language, device and font description file formats,
and device-independent output format referred to collectively in
groff documentation as “AT&T troff”.
“A Typesetter-independent TROFF” by Brian W. Kernighan, 1982,
AT&T Bell Laboratories Computing Science Techical Report No. 97,
provides additional insights into the device and font description
file formats and device-independent output format.
Section “See Also” of groff(1) lists utilities available for
preparing font files in a variety of formats for use with groff
output drivers.
groff_out(5), troff(1), addftinfo(1), afmtodit(1)
This page is part of the groff (GNU troff) project. Information
about the project can be found at
⟨http://www.gnu.org/software/groff/⟩. If you have a bug report
for this manual page, see ⟨http://www.gnu.org/software/groff/⟩.
This page was obtained from the project's upstream Git repository
⟨https://git.savannah.gnu.org/git/groff.git⟩ on 2020-12-18. (At
that time, the date of the most recent commit that was found in
the repository was 2020-12-09.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
groff 1.23.0.rc1.56-5346-dirt1y3 November 2020 groff_font(5)
Pages that refer to this page: addftinfo(1), afmtodit(1), eqn(1), grodvi(1), groff(1), grohtml(1), grolbp(1), grolj4(1), gropdf(1), grops(1), grotty(1), hpftodit(1), tfmtodit(1), groff_out(5), groff_tmac(5), lj4_font(5), groff(7), groff_char(7), groff_diff(7)
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