@node Fonts, , Mongo, Appendices
@appendixsec SM's Fonts
@findex fonts, available characters
@findex fonts, choice
@findex fonts, hardware character sets
These are a sub-set of the well-known Hershey fonts@footnote{created by
Dr. A. V. Hershey at the U. S. National
Bureau of Standards and illustrated in National Bureau of Standards
publication NBS SP-24. The format used in the hershey_oc.dat file was
originally due to James Hurt at Cognition, Inc., 900 Technology Park Drive,
Billerica, MA 01821. It may be converted to any format @emph{except}
the format distributed by the U. S. NTIS (whatever it may be). We have
to tell you all this for copyright reasons, but as distributed the
fonts are in the public domain.}
and the available characters are listed in the following table, which
were generated from within SM by saying @code{load fonts fonts}.

For details on SM's implementation of @TeX{} and the `traditional' style
see the section in the
main body of this manual (@pxref{Labels}).

The characters in a font are specified using a programme @code{read_fonts}
which you can use to make binary font files from the list of
Hershey characters, using an index file to specify what character
should go where. The binary fonts file also specifies which @TeX{}
`definitions' are available (e.g. @code{\alpha}). The first 4 bytes
of the file are an integer (in binary) that specifies the format of
the file; when the format is changed in an incompatible way this number
if changed and you will have to rebuild your font files (`make fonts').

The default font table is
illustrated at the end of this appendix. Which font file you want to
use is specified as the @code{fonts} entry in your
@file{.sm} file.@footnote{It's possible to resurrect the font table used by
pre-2.0 versions of SM, using the index file
@file{old_font_index}}. 
@findex fonts, .sm
@findex .sm, fonts
The @code{fonts.bin} fonts have been cleaned up a bit for version 2.0
of SM, although the
order of characters in the greek and roman fonts is unchanged. There
is a new font, `Old English' or \o or \oe, and a good number of new
characters are provided. Neither of these fonts supports the `private'
fonts, that is there in case users desperately need something,
when they can make their own binary font file. For example, there is a
set of Hershey oriental fonts that can be used to help SM write Japanese
(@pxref{Japanese}).

The complete list of (occidental) Hershey
characters is given in a file called @code{hershey_oc.dat}, and is in
the public domain. Each character is specified by a number in the
first 5 columns, then a number of strokes in the next 3, then pairs of
letters in the remaining columns up to 72, and in as many 72 character
lines as are needed. (Annoyingly, if a line consists of exactly 72
characters, the next must be left blank).
Each pair of characters consists of a coordinate,
with the origin at (R,R), and the y axis pointing @emph{down}.
A ` ' indicates that the next point is a move, otherwise just
connect the dots. The very first pair is different, as it specifies
the left and right spacing for the character. If this isn't clear, try
drawing a few characters on graph paper, character 2001 (roman A) for example.
There are a few characters that have
traditionally been available in Mongo that are not in the Hershey set,
these have been added to the end of the @file{hershey_oc.dat} file, plus a
few that we thought deserved adding.

If you want to create your own characters, the macro @code{make_char} in
@file{fonts} (i.e. @code{load fonts make_char}) might help. It uses the
cursor to make a string that is (nearly) in the correct form for
inclusion in @file{hershey_oc.dat}

The programme @code{read_fonts} reads this file,
@findex read_fonts
an `index' file that specifies the characters to be put into the
fonts, and a list of @TeX{} definitions. The index file consists of
character numbers, or ranges 
consisting of two numbers separated by a minus sign. Comments go from
the character # to end of line. Each font consists of 96 characters
in ascii order, and fonts appear in the index in the order
rm, gr, sc, ti, oe, and then the various private fonts (privateA, privateB,
@dots{}, privateG.).
@findex cat_fonts
You can also use @code{cat_fonts} to concatenate
binary font files prepared with @code{read_fonts}.

The format of the @TeX{} definition file
is that each definition has a line to itself, lines starting with a
# are comments. A line consists of a name, some whitespace, the number
of arguments (optional, defaults to zero), the name
of the font to use, a single white-space character, and the value of
the definition to the end of the line; you can continue onto another line
by putting a @code{\} at the end of the line. You can use any of the normal
font specifications, or @code{cu} which means use the current font.

For example
@example
alpha        gr a
alsoalpha  0 cu \gr a
alphatoo   1 gr \#1a
@end example
@noindent
defines @code{\alpha} the conventional way as the character @code{a}
in the greek font, then defines @code{alsoalpha} in a less efficient
way (by specifying the current font, then explicitly switching to
greek), then defines @code{alphatoo} as a large
@tex
$\alpha$
@end tex
@ifinfo
alpha
@end ifinfo
, used as @code{\alphatoo5}. There's no reason
why your definitions can't be reasonably complicated, see for example
the definition of @code{\TeX}.

If the
number of arguments is given as -1 the @TeX{} symbol will be interpreted as
an alias for the specified font, for example the @TeX{} definition file begins
@example
katakana -1 privateA
hiragana -1 privateB
@end example
@noindent
to make @code{\katakana} change to the @code{privateA} font.

The main Makefile prepares your binary font file for you. There is also
a programme @code{cat_fonts} that can be used to concatenate two or more
binary fonts files; an example is given in the section on Japanese fonts
(@ref{Japanese}).
@tex
\vfill\eject
\centerline\file{%
Select a device and say `load fonts TeX\_defs' to make this page}
\vfill\eject
\centerline\file{%
Select a device and say `load fonts fonts' to make this page}
@end tex
@ifinfo
If you want to see the @TeX{} definitions that SM knows about, start SM,
then say
@example
load fonts
TeX_defs
@end example
@noindent
you can see the raw font tables with 
@example
load fonts
fonts
@end example
@noindent
but why would you want to do that?
@end ifinfo


It is also possible to
build SM fonts for other languages:
@menu
* Japanese::		Using SM to write Japanese
@end menu

@node Japanese, , , Fonts
@appendixsec Using SM to write Japanese 

SM is currently able to use either katakana or hiragana fonts, but no kanji
are yet supported. The order of characters in the fonts is likely to change,
based on the desires of the users. Please let me know what you want.

As distributed, the Japanese font tables aren't built. To make them, say
@code{make jfonts.bin} in the toplevel SM directory, and ensure that your
@file{.sm} file sets @code{fonts} correctly. The Japanese characters are
available as @code{\hiragana} and @code{\katakana}. You can list the characters
available with @code{load fonts jTeX_fonts}.

One question is whether @code{\katakana 2} should print an Arabic (western)
or a Japanese two; I am open to suggestions.

There are a variety of kanji characters present, but no easy way to
select them. If someone would like to donate a table of the
correspondence between some accepted ascii encoding and the available
characters, I will ensure that the character encoded as @code{AB} os
available as (say) @code{\kanjiAB}, and provide a programme to
generate such codes from the output of at least one popular word
processor, expecting the user to cut-and-paste the result.  Of course,
it'd be quicker if you did it for me!