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ligatures lig1 lig2...lign [0] |
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Characters
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.
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name F |
The name of the font is
F.
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slant n |
The characters of the font have a slant of
n degrees.
(Positive means forward.)
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spacewidth n |
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The normal width of a space is
n.
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special |
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The font is
special; this means that when a character is requested that is not present in
the current font, it will be searched for in any special fonts that
are mounted.
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Other commands are ignored by
troff but may be used by postprocessors to store arbitrary information
about the font in the font file.
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The first section can contain comments which start with the
# character and extend to the end of a line.
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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.
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The word
charset starts the charset subsection.
The
charset line is followed by a sequence of lines.
Each line gives information for one character.
A line comprises a number of fields separated
by blanks or tabs.
The format is
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name metrics type code
[entity_name]
[--
comment]
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name identifies the character:
if
name is a single character
c then it corresponds to the groff input character
c; if it is of the form
[rs]c where c is a single character, then it
corresponds to the special character
[rs][c]; otherwise it corresponds to the groff input character
[rs][name].
If it is exactly two characters
xx it can be entered as
[rs](xx.
Note that single-letter special characters can’t be accessed as
[rs]c; the only exception is ‘[rs]-’ which is identical to ‘[rs][-]’.
The name
--- is special and indicates that the character is unnamed;
such characters can only be used by means of the
[rs]N escape sequence in
troff.
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Groff supports eight-bit characters; however some utilities
have difficulties with eight-bit characters.
For this reason, there is a convention that the name
charn is equivalent to the single character whose code is
n.
For example,
char163 would be equivalent to the character with code 163
which is the pounds sterling sign in ISO Latin-1.
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The
type field gives the character type:
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1
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means the character has a descender, for example, p;
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2
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means the character has an ascender, for example, b;
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3
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means the character has both an ascender and a descender, for example,
(.
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The
code field gives the code which the postprocessor uses to print the character.
The character can also be input to groff using this code by means of the
[rs]N escape sequence.
The code can be any integer.
If it starts with a
0 it will be interpreted as octal;
if it starts with
0x or
0X it will be intepreted as hexadecimal.
Note, however, that the
[rs]N escape sequence only accepts a decimal integer.
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The
entity_name field gives an ascii string identifying the glyph which the postprocessor
uses to print the character.
This field is optional and has been introduced so that the html device driver
can encode its character set.
For example, the character ‘[rs][Po]’ is represented as ‘£’ in
html~4.0.
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Anything on the line after the encoding field resp. after ‘--’ will
be ignored.
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The
metrics field has the form (in one line; it is broken here for the sake of
readability):
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width[,height[,depth[,italic-correction
[,left-italic-correction[,subscript-correction]]]]]
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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 character.
The
height subfield gives the height of the character (upwards is positive);
if a character 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 character, that is, the distance
below the lowest point below the baseline to which the
character extends (downwards is positive);
if a character does not extend below above 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
character when it is immediately to be followed by a character
from a roman font.
The
left-italic-correction subfield gives the amount of space that should be added before the
character when it is immediately to be preceded by a character
from a roman font.
The
subscript-correction gives the amount of space that should be added after a character
before adding a subscript.
This should be less than the italic correction.
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A line in the charset section can also have the format
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name "
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This indicates that
name is just another name for the character mentioned in the
preceding line.
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The word
kernpairs starts the kernpairs section.
This contains a sequence of lines of the form:
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c1 c2 n
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This means that when character