scroll-bar-event-ratio

scroll-bar-event-ratio is a compiled Lisp function in `scroll-bar.el'.

(scroll-bar-event-ratio EVENT)

Given a scroll bar event EVENT, return the scroll bar position as a ratio.
The value is a cons cell (PORTION . WHOLE) containing two integers
whose ratio gives the event's vertical position in the scroll bar, with 0
referring to the top and 1 to the bottom.