posn-actual-col-row

posn-actual-col-row is a compiled Lisp function in `subr.el'.

(posn-actual-col-row POSITION)

Return the window row number in POSITION and character number in that row.

Return nil if POSITION does not contain the actual position; in that case
`posn-col-row' can be used to get approximate values.
POSITION should be a list of the form returned by the `event-start'
and `event-end' functions.

This function does not account for the width on display, like the
number of visual columns taken by a TAB or image. If you need
the coordinates of POSITION in character units, you should use
`posn-col-row', not this function.