mouse-scroll-subr

mouse-scroll-subr is a compiled Lisp function in `mouse.el'.

(mouse-scroll-subr WINDOW JUMP &optional OVERLAY START)

Scroll the window WINDOW, JUMP lines at a time, until new input arrives.
If OVERLAY is an overlay, let it stretch from START to the far edge of
the newly visible text.
Upon exit, point is at the far edge of the newly visible text.