[ft] Loading FT_Face without having access to the font as whole

[Khaled Hosny]

Hi all,

I’ve been using FreeType with Core Text fonts on Mac, and one of the
issues I had is that Core Text does not provide an API to get face index
from multi-font files (TTC, dfont, etc.) so I had to resort to some
hacks to guess the face index[1], but this fails for at least one
Apple-shipped font.

I was wondering if there is a way or if it is possible to added a new
way to create FT_Face with callback function(s) for returning individual
font tables and other info that FreeType might need, similar to
HarfBuzz’s hb_face_create_for_tables(), so that I can just hook it with
the API for getting font tables and not have to worry about face index.
Or may be I should just do like LibreOffice and "fake" a font in memory
from the individual tables[2] (not for FreeType, but I don't think the
approach will be much different)?

Regards,
Khaled

[1] 
https://github.com/khaledhosny/xetex/blob/master/source/texk/web2c/xetexdir/XeTeX_mac.c#L443
[2] 
https://gerrit.libreoffice.org/gitweb?p=core.git;a=blob;f=vcl/coretext/salgdi2.cxx#l532