[Devel] Metric for hat (^) vertical offset?

[Gustavo J. A. M. Carneiro]

  I'm trying to do mathml rendering of a circumflex accent (^) on top of
an identifier.  However, the glyph as rendered by freetype2 is
vertically offset, leaving an empty space, like the screenshot in
attachment.  The same problem happens for other glyphs.

  Is there any metric in the font or glyph that can indicate that amount
of empty space?  Because in MathML I need tight bounding box.

  Thanks in advance.  Regards.

-- 
Gustavo João Alves Marques Carneiro
<address@hidden> <address@hidden>