MF(1)

NAME
mf, inimf, virmf - Metafont, a language for alphabet design

SYNOPSIS
mf [ first line ]

inimf [ first line ]

virmf [ first line ]

DESCRIPTION
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. The basic program as compiled is called inimf; it can be used to precompile macros into a .base file. The virmf variant is used to reload the .base files quickly. Typically, virmf has links to it by the names of the various base files. For example, if you link virmf to foo and then execute the program foo, you get the base file foo.base. You can load a different base by saying, e.g., virmf \\&mybase.

As described in The Metafontbook, the command line (or first input line) should otherwise begin with a file name or a \controlsequence. 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.

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 @MFINPUTDIR@/@LOCALMODES@.mf. With only plain.mf and the modes file loaded it is possible to create fonts of simple characters, such as those used for the Metafont logo, and those used for the LaTeX line and circle fonts, but the production of Computer Modern fonts would be facilitated by making a cmmf.base file (which includes the macros in cmbase.mf as well as those in plain.mf).

Several environment variables can be used to set up directory paths to search when Metafont opens a file for input. For example, the csh command
    setenv MFINPUTS .:~me/mylib:@MFINPUTDIR@
or the sh command sequence
    MFINPUTS=.:~me/mylib:@MFINPUTDIR@
    export MFINPUTS
would cause all invocations of Metafont and its derivatives to look for \input files first in the current directory, then in a hypothetical user's mylib, and finally in the system library. Normally, the user will place the command sequence which sets up the MFINPUTS environment variable in his or her .login or .profile file.

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 "/usr/ucb/vi +%d %s"
The ENVIRONMENT section below lists the relevant environment variables, and their defaults.

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.

ONLINE GRAPHICS OUTPUT
Metafont can use most modern displays, so you can see its output without printing. Chapter 23 of The Metafontbook describes what you can do. This implementation of Metafont uses environment variables to determine which display device you want to use. First it looks for a variable MFTERM, and then for TERM. If it can't find either, you get no online output. Otherwise, the value of the variable determines the device to use: hp2627, sun (for SunView), tek, uniterm (for an Atari ST Tek 4014 emulator), xterm (for either X10 or X11). Some of these devices may not be supported in all Metafont executables; the choice is made at compilation time.

ENVIRONMENT
The default values for all environment variables are set at the time of compilation in a file site.h. See tex(1) for the details of the searching. If the environment variable TEXMFOUTPUT is set, Metafont attempts to put its output files in it, if they cannot be put in the current directory. Again, see tex(1).

MFINPUTS
    Search path for input and openin files. Default:
    @MFINPUTS@

MFBASES
    Search path for base files. Default: @MFBASES@

MFPOOL
    Search path for Metafont internal strings. (Used by inimf only.) Default: @MFPOOL@

MFEDIT
    Command template for switching to editor. Default: @EDITOR@

DISPLAY, MFTERM, TERM
    Determines the online graphics display. If DISPLAY is set, it's assumed to be the name of an X window system server.

FONT UTILITIES
A number of utility programs are available. The following is a partial list of available utilities and their purpose. Consult your local Metafont guru for details.

gftopk
    Takes a gf file and produces a more tightly packed pk font file.

gftodvi
    Produces proof sheets for fonts.

gftype
    Displays the contents of a gf file in mnemonics and/or images.

pktype
    Mnemonically displays the contents of a pk file.

mft Formats a source file as shown in Computer Modern Typefaces.

FILES

@MFLIBDIR@
    Metafont's library areas

@MFPOOLDIR@/mf.pool
    Encoded text of Metafont's messages

@BASEDIR@/*.base
    Metafont base files

@MFINPUTDIR@/plain.mf
    The ``standard'' macro package

@MFINPUTDIR@/@LOCALMODES@.mf
    The file of mode_defs for your site's various printers

@CMSOURCES@/mf
    Metafont sources for Computer Modern

SUGGESTED READING
Donald E. Knuth, The Metafontbook (Volume C of Computers and Typesetting), Addison-Wesley, 1986, ISBN 0-201-13445-4.
Donald E. Knuth, Metafont: The Program (Volume D of Computers and Typesetting), Addison-Wesley, 1986, ISBN 0-201-13438-1.
Donald E. Knuth, Computer Modern Typefaces (Volume E of Computers and Typesetting), Addison-Wesley, 1986, ISBN 0-201-13446-2.
TUGboat (the journal of the TeX Users Group).

COMMENTS
Warning: ``Type design can be hazardous to your other interests. Once you get hooked, you will develop intense feelings about letterforms; the medium will intrude on the messages that you read. And you will perpetually be thinking of improvements to the fonts that you see everywhere, especially those of your own design.''

SEE ALSO
gftopk(1), gftodvi(1), gftype(1), mft(1), pltotf(1), tftopl(1).

BUGS
On January 4, 1986 the ``final'' bug in Metafont was discovered and removed. If an error still lurks in the code, Donald E. Knuth promises to pay a finder's fee which doubles every year to the first person who finds it. Happy hunting.

AUTHORS
Metafont was designed by Donald E. Knuth, who implemented it using his Web system for Pascal programs. It was originally ported to UNIX by Paul Richards at the University of Illinois at Urbana-Champaign. This page was mostly written by Pierre MacKay.