[HarfBuzz] Streamlining hb_font_t some more

[Werner LEMBERG]

> I am not a typographer, I just play one on the Internet, so I am not
> sure what someone who was actually typesetting a book would do in
> that situation.  My guess would be that they would, basically, do
> what SILE does right now (and what TeX does; perhaps Knuth knew what
> he was doing after all) - use consistent 14.4pt (or whatever) line
> spacing in situation (1) and use larger line spacing which fits in
> the descender in situation (2).  But I would have to ask a real
> typesetter to know.

Knuth knew *very well* what he was doing, and the TeX typesetting
model works just fine for almost all cases, even more than 30 years
later.

Given that the typographic values from the `OS/2' SFNT table are crap
in far too much fonts, and that Apple and MS differ on the right
approach, I would really not using it.  Your (1) and (2) are the way
to go, IMHO.


    Werner