[HarfBuzz] Streamlining hb_font_t some more

[Simon Cozens]

On 27/10/2015 00:37, Nikolay Sivov wrote:
> But probably more important is that this functionality doesn't seem 
> to belong to harfbuzz in a first place, as it never needs global 
> metrics internally (or does it?).

No, it doesn't need these metrics internally. If Harfbuzz just sticks to
text shaping, then I agree that global font metric functions shouldn't
be there. On the other hand, if Harfbuzz wants to be providing the
information that layout engines need, then it absolutely should be able
to tell you about global font metrics. But in that sense, the recent
work on OT font functions isn't necessary either, because other
libraries easily provide this.

> If you only need a couple of fields it's easy to get them manually 
> from font blob.

Eh, I don't know you about you but the reason I use libraries is to
abstract away this kind of low-level grubbing around... But yeah,
Freetype already does this. I just left it was a shame that something
already had my font open and already had an OpenType parser ready to go,
and it couldn't tell me what I wanted.