Metafont reads the program in the specified files
and outputs font rasters (in
gf
format) and font metrics (in
tfm
format). The Metafont
language is described in
The Metafontbook.
Like
TeX, Metafont
is normally used with a large body of precompiled macros, and font generation
in particular requires the support of several macro files. This
version of Metafont looks at its command line to see what name it was
called under. Both
inimf
and
virmf
are symlinks to the
mf
executable. When called as
inimf
(or when the
-ini
option is given) it can be used to precompile macros into a
.base
file. When called as
virmf
it will use the
plain
base. When called under any other name, Metafont will use that name as
the name of the base to use. For example, when called as
mf
the
mf
base is used, which is identical to the
plain
base. Other bases than
plain
are rarely used.
The
commands
given on the command line to the Metafont program are passed to it as the
first input line. (But it is often easier to type extended arguments
as the first input line, since UNIX shells tend to gobble up or
misinterpret Metafont's favorite symbols, like semicolons, unless you
quote them.) As described in
The Metafontbook,
that first line should begin with a filename, a
\controlsequence,
or a
&basename.
The normal usage is to say
-
mf '\mode=<printengine>; [mag=magstep(n);]' input font
to start processing
font.mf.
The single quotes are the best way of keeping the Unix
shell from misinterpreting the semicolons and
from removing the \ character, which is needed here to
keep Metafont from thinking that you want to produce a font called
mode.
(Or you can just say
mf
and give the other stuff on the next line, without quotes.) Other
control sequences, such as
batchmode
(for silent operation) can also appear.
The name
font
will be the ``jobname'', and is used in forming
output file names.
If Metafont doesn't get a file name in the first line,
the jobname is
mfput.
The default extension,
.mf,
can be overridden by specifying an extension explicitly.
A log of error messages goes into the file jobname.log.
The output files are jobname.tfm and
jobname.<number>gf, where <number> depends on
the resolution and magnification of the font. The
mode
in this
example is shown generically as <printengine>, a symbolic term for which
the name of an actual device or, most commonly, the name
localfont
(see below) must
be substituted. If the mode is not specified or is not valid for your
site, Metafont will default to
proof
mode which produces
large character images for use in font design and refinement. Proof
mode can be recognized by the suffix
.2602gf
after the jobname. Examples of proof mode output can be found
in
Computer Modern Typefaces
(Volume E of
Computers and Typesetting).
The system of
magsteps
is identical to the system used by
TeX,
with values generally in the range 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0.
A listing of
gf
numbers for 118-dpi, 240-dpi and 300-dpi fonts
is shown below.
| MAGSTEP | 118 dpi | 240 dpi | 300 dpi
|
| mag=magstep(0) | 118 | 240 | 300
|
| mag=magstep(0.5) | 129 | 263 | 329
|
| mag=magstep(1) | 142 | 288 | 360
|
| mag=magstep(2) | 170 | 346 | 432
|
| mag=magstep(3) | 204 | 415 | 518
|
| mag=magstep(4) | 245 | 498 | 622
|
| mag=magstep(5) | 294 | 597 | 746
|
Magnification can also be specified not as a magstep but as an
arbitrary value, such as 1.315, to create special character sizes.
Before font production can begin, it is necessary to set up the
appropriate base files. The minimum set of components for font
production for a given print-engine is the
plain.mf
macro file
and the local
mode_def
file. The macros in
plain.mf
can be
studied in an appendix to the
Metafontbook;
they were developed by Donald E. Knuth, and this file should never be
altered except when it is officially upgraded.
Each
mode_def
specification helps adapt fonts to a particular print-engine.
There is a regular discussion of
mode_defs
in
TUGboat,
the journal of the
TeX
Users Group.
The local ones in use on this computer should be in
modes.mf.
The
e
response to Metafont's error-recovery mode invokes the
system default
editor at the erroneous line of the source file.
There is an environment variable, MFEDIT,
that overrides the default editor.
It should contain a string with "%s" indicating where the
filename goes and "%d" indicating where the decimal linenumber (if any) goes.
For example, an MFEDIT string for the
vi
editor can be set with the
csh
command
-
setenv MFEDIT "vi +%d %s"
A convenient file in the library is
null.mf,
containing nothing.
When
mf
can't find the file it thinks you want to input, it keeps
asking you for another file name; responding `null' gets you out
of the loop if you don't want to input anything.