[Devel] The problem of display fonts in multiple vertical levels

[stephenfung]

I found that freetype is great enough to display many kinds of 
characters,
like thai, which may consist of multiple level per characters.
Say, for using unicode, 0x0e23 + 0x0e47 will spend 1 space of character,
instead of 2.

Can anybody give me hints of the implementation of this function?

I need to modify this function.

THX A LOT!