[HarfBuzz] Units of members of hb_glyph_position_t

[Eli Zaretskii]

I cannot figure out in what units are these values reported, or how to
control those units (if they are under the client program's control).
In particular, I get a huge value of x_advance for the letter U+05EA
HEBREW LETTER TAV when it is followed by U+05BB HEBREW POINT QUBUTS.
The value of x_advance I get is 1229, which is too large even after
dividing by 64 (which, btw, I still am not sure is TRT in my case,
because I don't understand the source of the 64 value).

Can someone please help me figure out what am I doing wrong?

TIA