[luatex] luatextra font system

[Will Robertson]

On 2009-03-15 00:04:15 +1030, Ulrike Fischer 
<luatex at nililand.de> said:

> But only for the latin
> modern fonts there are eu1*.fd-files. As far as I know Will used
> this special way for the latin modern fonts because there are the
> default fonts and should always work.

Yes, although these days it would be possible to load the fonts with 
purely fontspec commands; back when I wrote the eu1*.fd files, fontspec 
wasn't sophisticated enough to get the fine-grained control that is 
possble in the .fd files.

* * *

If you want to load the LM fonts by default in LuaTeX and use a 
different font-loading syntax than XeTeX, but all means go with an EU2 
font encoding. I'd argue fairly strongly that the CM fonts should *not* 
be used and the LM fonts made the default as soon as possible.

* * *

Back to the connection between fontenc and LuaTeX. Assuming that LuaTeX 
will always use UTF8 for new documents, there needs to be some way of 
mapping unicode input characters to their appropriate glyph slots in 
the font being used. LaTeX uses inputenc and fontenc to do this, and 
while its LICRs are still being used they're an effective way to solve 
the problem.

It's possible there'd be some value in constructing virtual unicode 
fonts on-the-fly from T1+TS1 (+whatever else exists) so unicode input 
characters can be directly mapped to their output glyphs (i.e., without 
going through the LICR abstraction layer), but the main appeal of XeTeX 
and LuaTeX is that you can use *new* fonts.

So, especially due to the TeX Gyre project, I don't see much need for 
extensive support for old font encodings. As above, much of the current 
system should still work, and OpenType fonts just have so much more 
going for them.

Will