Copyright 2007 TeX Users Group.
You may freely use, modify and/or distribute this file.

Naming of TFM and PFM metric files:
==================================

It is useful to be able to distinguish between metric files created using
different encoding vectors.  When naming a font metric file, tagging the
letter `x' on to the end of a font name to indicate that it is remapped is
helpful, but not entirely unambiguous.  The main problem is that Windows
reencodes a font that uses StandardEncoding to Windows ANSI.  So the 
`normal' encoding is StandardEncoding when such a font is used with
non-Windows applications, but it is Windows ANSI when used with Windows.
There is not much of a problem if DVIPSONE or DVIWindo are used alone.  But
when they are used together then there is a confusion about what encoding
should apply when the name does not have the `x' tagged on at the end.

It is hard to come up with a consistent scheme that will satisfy everyone and
is suitable for use with both DVIPSONE and DVIWindo.  To reduce confusion, we
recommend the following slightly more refined scheme (which is now used for
TFM and PFM files supplied with DVIPSONE and DVIWindo): 

(*) `n' is tagged on to the end of the name for the font's `native' encoding.
(*) `w' is tagged on to the end of the name for Windows ANSI encoding.
(*) `t' is tagged on to the end of the name for TeX text encoding.
(*) `a' is tagged on to the end of the name for `TeX ANSI' encoding.

The `native' encoding for most commercial text fonts is Adobe
StandardEncoding, while for Computer Modern text fonts it is `TeX text'.
So most TFM files that come with TeX would strictly speaking have a `t'
tagged on at the end it the above scheme was followed consistently.

Similarly, the PFM files that come with ATM (which have no letter tagged on)
would have the letter `w' tagged on according to the above scheme. And the
metric files previously supplied with DVIPSONE and DVIWindo without a letter
tagged on, now have an `n'.

Of course, you are free to rename these files to best suit your own system
setup.  However, the font file name used in TeX (used to find the metric
file) must be connected to the name of the actual outline font file itself
(accesses by DVIPSONE and DVIWindo).  

In DVIPSONE, if the font is not remapped, then the metric file and the
outline file should use the same name.  If the font is remapped, then the
font substitution file has an entry indicating the required remapping, and
making the connection between the metric file name (with the tagged on
letter) and the name of the outline font itself (presumably without a letter
tagged on).  Note that because of this arrangement, the same outline font can
be used with several different encodings if required.

For use with DVIWindo, the names of the TFM, PFM and PFB files should match.
Because of limitations of Windows and ATM, it is not possible to reencode a
font on-the-fly and so the outline font itself has to be reencoded ahead of
time if required.  Also, there can be only one outline font associated with a
particular Windows font face name, so it is not possible to access one font
with several different encodings. 

This may all seem a bit confusing, but most users end up standardizing on
one particular encoding scheme and use the same font names from then on.