Mouse position: Difference between revisions

=={{header|Common Lisp}}==

With the ltk library.

<lang lisp>

(ql:quickload "ltk")

(in-package :ltk-user)

(defun motion (event)

(format t "~a x position is ~a~&" event (event-x event)))

(with-ltk ()

;; create a small window. Enter the mouse to see lots of events.

(bind *tk* "<Motion>" #'motion))

</lang>

This prints a lot of events of the form

#S(EVENT

:X 0

:Y 85

:KEYCODE ??

:CHAR ??

:WIDTH ??

:HEIGHT ??

:ROOT-X 700

:ROOT-Y 433

:MOUSE-BUTTON ??)

The <code>#S</code> indicates we get a structure, so we can access the x position with <code>(event-x event)</code>.