[Dev-luatex] Q: Can LuaTeX produce xdv?

Barry Schwartz chemoelectric at chemoelectric.org
Thu Jan 1 22:17:12 CET 2009

Jonathan Fine <jfine at pytex.org> skribis:
> I'm looking for a what might be called a Unicode savvy Device Independent 
> binary format.  And I'm looking for XeTeX and LuTeX to share code and 
> ideas, when possible.

Glyph indexes plus a ToUnicode map. That's how Unicode-savviness is
done in a PDF: each glyph index is mapped to a Unicode string.

For my own hobby-work I have a slightly hacked xdvipdfmx that reads in
pre-computed ToUnicode maps (made with a FontForge script and put
side-by-side with the font files) in spots where xdvipdfmx wasn't
generating them. Really xdvipdfmx should be doing that on the fly. I
think all the necessary code is there--it already reads my
pre-computed maps and then generates a more efficient version,
magically--the code just needs to be called at the right times, but I
wasn't interested in working on it. (I'm disabled and have to ration
my keyboard time.)

However, LuaTeX should be perfectly capable of doing its own ToUnicode

Otherwise AFAIK the advantages of xdvipdfmx are that it's already
written, supports various specials, and can use the list of fonts that
is known to fontconfig (which isn't a big deal, and which LuaTeX could
just as easily do).

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