21.6.8 Motion Events

Emacs sometimes generates mouse motion events to describe motion of the mouse without any button activity. Mouse motion events are represented by lists that look like this:

(mouse-movement (window buffer-pos (x . y) timestamp))

The second element of the list describes the current position of the mouse, just as in a click event (see section 21.6.4 Click Events).

The special form track-mouse enables generation of motion events within its body. Outside of track-mouse forms, Emacs does not generate events for mere motion of the mouse, and these events do not appear. See section 29.13 Mouse Tracking.