[HarfBuzz] Streamlining hb_font_t some more

[Werner LEMBERG]

>> 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.
> 
> That is such a big claim, judging by the amount of people strugling with
> TeX line spacing on tex.stackexchange.com:
> http://tex.stackexchange.com/questions/tagged/line-spacing

Hehe :-) Actually, I've meant the simple idea of using glyph boxes
glued together to form a line, where lines normally have a fixed
baseline-to-baseline distance.  And yes, the fine details of line
spacing can be overwhelming.

>> 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.
> 
> I have only seen a handful of utterly broken fonts, the rest of the
> world are doing just fine.

OK.  I'm certainly biased as the FreeType maintainer, seeing far too
much broken fonts...


    Werner