[XeTeX] The future of XeTeX

Zdenek Wagner zdenek.wagner at gmail.com
Wed Aug 1 11:04:26 CEST 2012

2012/8/1 Simon Cozens <simon at simon-cozens.org>:
> On 01/08/2012 17:31, Zdenek Wagner wrote:
>> result with pure MF. Virtual fonts have to remedy the deficiencies of
>> encoding. The Latin alphabet for all languages (including Vietnamese)
>> contains 500+ characters but the non-Unicode encodings allow 256.
> NFSS/VF (and to some degree XeTeX) wasn't just about encoding, though. It
> was to also extend TeX beyond these strange "MetaFont" things that *nobody*
> was using to make it cope with these PS Fonts / TTF fonts that *everybody*
> was using.
You do not need virtual fonts in order to use PS fonts. There is a
cleaner postscript way. The problem is that afm2tfm does not copy
kernings to TFM if VPL is not generated. The remedy was to create a
virtual font with 1:1 mapping, copy the kernings to TFM and throw the
virtual font away. The PS font may contain more than 256 characters
but only 256 of them may have a numeric code that is assigned by
/Encoding inside the font. When loading the font to dvips or pdftex,
you may supply another /Encoding. Since the character names are
standardised, you can prepare *.enc files with the definition of
/Encoding (you find them in any TeX distribution). Then for each PFB
you need several TFM files, one for each encoding. This approach is
even better because e.g. "ccaron" shape was optimised by the font
designer but in the virtual font you can only build it of the base
character and an accent. However, such simplistic approach is
typographically undesirable, thus use of virtual fonts for this
purpose is not only unnecessary but even the wrong solution.

One off topic remark: when Latin Modern fonts were being developed,
they were extensively tested even for use in the Czech and Slovak
languages and verified that our requirements will not break French,
Danish, Swedish and Norvegian. As a result accents in Latin Modern are
done the right way.

> TeX is a collection of technologies that didn't catch on.
> --------------------------------------------------
> Subscriptions, Archive, and List information, etc.:
>  http://tug.org/mailman/listinfo/xetex

Zdeněk Wagner

More information about the XeTeX mailing list