Cursor with any size

[jipan@gmuvax2.gmu.edu (Jiqian Pan)]

Hi, MCL experts:

Because the size of a cursor is limited by the Macintosh O/S,
I used the following way to simulate a cursor with any size:

  * Set a regular cursor to nothing, that is, we can't see it
    in a window,

  * Display an object such as a big hand on a window,

  * Move the object as mouse moves.

Moreover, other events such as keystroke should be done while
mouse moves.  Here is some code about the job:

;;; Detect an object, erase it and redraw it in a new position.
;;; item is an object with bitmap-dialog-item.
(defun my-cursor (position)
    (let* ((last-pos position) c-pos (tolerance 3)
           (mypos (view-position item))
           (delta (subtract-points last-pos mypos)))
           (setq c-pos (view-mouse-position (view-container item)))
           (when (or (>= (abs (- (point-h c-pos) (point-h last-pos))) tolerance)
                     (>= (abs (- (point-v c-pos) (point-v last-pos))) tolerance))
                 (setq last-pos c-pos)
                 (let* ((mypos (view-position item))
                        (mybotright (add-points mypos (view-size item))))
                        (erase-rect (view-container item) 
                                    (point-h mypos)(point-v mypos)
                                    (point-h mybotright)(point-v mybotright))
                        (set-view-position item (subtract-points c-pos delta))
                        (view-draw-contents item)))))

;;; Move a cursor looply.
(defun run ( )
      (do ((pt (view-position item)(view-position item))) (( ))
           (my-cursor pt)))

;;; Process key event, just seeing whether the method works.
(defmethod view-key-event-handler ((toy my-window) char)
           (print "key"))

;;; New cursor is called when the object is clicked.
(defmethod view-click-event-handler ((item bitmap-dialog-item) position)
          (run))

;;; New cursor.
(run)

The interesting thing is that the method view-key-event-handler does
not work, that is, the word "key" can't be seen in Listener, when the 
function RUN is called inside the method view-click-event-handler.
But the method works when the function RUN is run directly in Listener.
Does anyone know the problem, and other good ways to simulate a cursor
with any size?  Thanks.

-J. Pan