pangoLayoutIndexToPos: pangoLayoutIndexToPos
In RGtk2: R Bindings for Gtk 2.8.0 and Above

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.

1	pangoLayoutIndexToPos(object, index, pos)

`object`	[`PangoLayout`] a `PangoLayout`
`index`	[integer] byte index within `layout`
`pos`	[`PangoRectangle`] rectangle in which to store the position of the grapheme