PangoGlyphGeometry and y_offset

[dov imagic weizmann ac il]

I have been trying to change the y_offset of the accent glyphs in the
Hebrew pango-ft2 rendering module that I am writing in order to better
place the accents. But it seems that doing so changes the line
height. I.e. if I increase the y_offset by e.g. DY, then the line
height is increased by the same DY. Is there any way of preventing this
line height increase?

Should I file it as a bug?

Regards,
Dov