Font glyphs get clipped on the top

When running the attached sample application on the harmattan device the top of the font glyphs gets slightly clipped for some ranges of the font size:

• The problems start around a size of 60 pixels
• It is only reproducible on the harmattan device that uses the MeeGo graphicssystem. When starting the sample application with "-graphicssystem raster" everything is fine.
• It seems to be unrelated to the used font.

See https://projects.maemo.org/bugzilla/attachment.cgi?id=143221 for a screenshot showing the issue (is part of bug https://projects.maemo.org/bugzilla/show_bug.cgi?id=214636 )