[HarfBuzz] Streamlining hb_font_t some more

[Khaled Hosny]

On Mon, Oct 26, 2015 at 03:59:54PM +0100, Werner LEMBERG wrote:
> 
> > 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.

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

> 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.

Regards,
Khaled