If you have a negative value in the bbox, this is the amount below
the baseline.
I'm not getting negative values in the bounding box.
Hmm. You should indeed write a small FreeType test program which
uses the FreeType API directly. Then you can compare the results.
It's easily possible that the glyph `E' descends slightly (due to
serifs, for example).
In that case, the descent was definitely not from a serif. It was a
value much larger than you'd expect. I drew the "E", then drew a
cross-hair at the output positionn and there was really no descent.
Which font? You might use, say, FontForge to check the glyph's
dimensions.
Werner