[ft] Prevent synthesis of Unicode charmap?

[Antony Lee]

Hi all,
Is there a way to prevent FreeType from synthesizing a Unicode charmap, or
at least clearly identifying the synthesized charmap as such?
In the Python plotting library Matplotlib (of which I am a developer),
there is an option to use TeX for text rendering; when outputting to vector
formats the dvi file produced by TeX is then parsed (more or less) into a
list of (font path, glyph index) pairs, where the font path maps to some
TeX-supported font (typically single-charmap, e.g. pfb) and the glyph index
uses that "single" charmap.  So we then want to get retrieve glyphs
according to that charmap.
In practice, right now we just look up a charmap with either
TT_ADOBE_ID_STANDARD or TT_ADOBE_ID_CUSTOM encoding, which essentially
works, but having a way to distinguish the actual font-provided charmap
from the FreeType-synthesized one seems cleaner.
Thanks in advance,
Antony Lee