is a subclass of pinboard-object which is drawn by a supplied function, and is provided as a means of the user creating their own pinboard objects.
Called to display the object.
is called with the output pane to draw on, the
itself, and the
of the object, and it is expected to redraw that section.
An alternative way of doing this is to create a subclass of pinboard-object and to provide a method for
(output-pane self x y width height)
(let ((x-radius (floor width 2))
(y-radius (floor height 2)))
(+ x x-radius) (+ y y-radius)
LispWorks CAPI Reference Manual - 21 Dec 2009