[XeTeX] UniMath fonts

[Jonathan Kew]

On 21 Jun 2004, at 4:08 pm, Jon Breitenbucher wrote:

> Sorry for all the recent questions. Has anyone tried to set up the 
> UniMath font by Selwyn Hollis as the math font for XeTeX. Is such 
> possible? Would it require a significant amount of work? I don't have 
> the font, but if it would be possible to implement it and go 100% open 
> type, I might consider it.
>

I don't know anything about this font, but my instinctive feeling is 
that it will be a lot of work at best, and perhaps not possible at this 
point.

The trouble is that for math typesetting, TeX requires a lot of extra 
information about metrics and other properties of the characters (or 
glyphs) in the math fonts. This is provided via the .tfm files; it's 
not available to XeTeX when using OpenType or AAT fonts "natively". In 
principle, you could create a suitable .tfm file for a new math symbol 
font; but .tfm files are tied to the old 8-bit world, so I suspect you 
wouldn't be able to take advantage of a full Unicode math font.

What is probably needed is a Unicode extension of the .tfm format. I 
guess Omega has something along these lines, but currently XeTeX 
doesn't. The focus of the XeTeX project has been text typesetting (and 
in particular, multilingual text), rather than math; the fact that 
legacy TeX math stuff can be made to work at all is a bonus, given that 
it's entirely based on non-standard 8-bit encodings and XeTeX wants to 
be a purely Unicode system. :-)

Besides needing full .tfm metrics in order to use fonts in math mode, 
there would also be a lot of Plain TeX definitions to re-write; there 
are long lists of codes there which are heavily dependent on the 
particular font encoding of the various TeX math/symbol fonts. It's not 
just a case of switching fonts!

Jonathan