Converts from an index within a PangoLayout to the onscreen position
corresponding to the grapheme at that index, which is represented
as rectangle. Note that pos->x is always the leading
edge of the grapheme and pos->x + pos->width the trailing
edge of the grapheme. If the directionality of the grapheme is right-to-left,
then pos->width will be negative.
Converts from an index within a PangoLayout to the onscreen position corresponding to the grapheme at that index, which is represented as rectangle. Note that pos->x is always the leading edge of the grapheme and pos->x + pos->width the trailing edge of the grapheme. If the directionality of the grapheme is right-to-left, then pos->width will be negative.