Question -- not a bug

Lars Hellström Lars.Hellstrom@math.umu.se
Wed, 5 Apr 2000 08:39:47 -0400


At 23.08 +0200 0-04-04, Ravi and Vidhya Shanker wrote:
>Hi,
>
>I apologize for writing to this address, but I do not
>seem to find an address for asking questions.

The address for asking questions _is_ the one you have written to.
fontinst@cogs.susx.ac.uk is a list for general discussions about fontinst.
There is no formalized bug report procedure for fontinst, so this just
happens to be the best place to send bug reports to as well.

>My dilemma is as follows:
>
>I would like to create a virtual font based on a Sanskrit
>font developed by Charles Wikner (available under CTAN).
>Can I use fontinst to do this, or is fontinst limited to
>European characters?

If the font you want to generate can be constructed as a normal TeX virtual
font (for example fully ligatured arabic fonts generally can not, as you
need more than 256 characters for these; I don't know how many characters
are needed for sanskrit), then the fontinst program can generate the
necessary PL and VPL files. Thus fontinst is certainly not limited to
making virtual fonts consisting of only European characters.

>All the examples I have seen only deal with fontinst in terms
>of Times Roman or the Adobe Font Metrics.
>
>The problem I have is that every time I run fontinst, it creates
>a rather empty .vpl file with the "CODINGSCHEME UNKNOWN" message
>in it. If I try the examples (with .afm files and latin.mtx),
>I get a large .vpl file with all sorts of stuff in it. I think
>I'm missing something very small, but very important. Could
>someone help?

The main problem you face when using fontinst for fonts covering alphabets
other than the latin alphabet is that you need to tell fontinst what
encoding the virtual fonts should have. Encodings are specified in encoding
(.etx) files, and those .etx files that are in the distribution only covers
some latin alphabet encodings, math encodings, and text symbol encodings.
You most likely will have to create an .etx file yourself for whatever
sanskrit encoding you want your virtual font to have.

As the sanskrit fonts you want to use as base are originally Metafonts,
their metrics are in TFM format. You will have to convert these to PL
format using tftopl before fontinst can input them. You'll need an .etx
file describing the encoding used by these base fonts as well, and you need
to tell fontinst what codingscheme this encoding corresponds to using the
\declareencoding command.

The syntax of an .etx file is specified in the fontinst manual and
comparisions with the encoding files distributed with fontinst should also
help you on the way. I'm afraid however that there are several things about
TeX font encodings that aren't very well described anywhere that I know of.
Therefore don't hesitate to ask again if there is something you wonder
about.

In general (that is, leaving Ravi's immediate problem), I think the
fontinst distribution should be augmented by including encoding files that
cover non-latin alphabets. Surely someone on this list must have made such
a file!

Lars Hellström