[HarfBuzz] How to override Harfbuzz's freetype functions?

[Tom Hacohen]

Dear all,

I ran a test application in callgrind and noticed that the calls to
FT_Load_Glyph are what slows everything down. We already have glyph
cache in EFL and I would really like to be able to use it with harfbuzz.
At first glance, it seems like I can't override harfbuzz's
hb_ft_get_glyph_advance from the outside, but I have to implement my own
class and put it in harfbuzz, which is less than convinient.

I'd very much like to be able to do that, because using my cache will
make everything a lot faster.

Are my observations correct?

How do you guys (that use harfbuzz in other projects) solve it?

Thanks,
Tom.