[XeTeX] Microtypography?

[Ralf Stubner]

Ralf Stubner <ralf.stubner at physik.uni-erlangen.de> writes:

> Would that also be true for OpenType fonts with the (equally named)
> 'opbd' feature? Or would that require additional coding in ICU(?) first?
> I don't have a font that supports this feature, but I could build one,
> once I really understand how the OT specs are to be interpreted wrt to
> 'opbd' and its relation to 'rtbd' and 'ltbd'.

Some success: I have build an OpenType TT font in which the advance
width of the hyphen might be reduced (by an insanely large amount ;-)
via an 'opbd' feature and (separately) via an 'rtbd' feature. Switching
on one of these feature in XeTeX does indeed make the hyphen go into the
margin. However, the change in advance width is also applied in normal
text, which is of course not what I want.

I have no idea if this in an error in the font, in XeTeX, in ICU, or
somewhere else.

cheerio
ralf