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animated color fading


I'd like to be able to let individual words in a text gradually disappear.
I could of course 'turn off' pixels, but I was hoping for a nicer solution,
in which the intensity gradually decays (if you have a copy of Think
Reference, you can watch a good example of what I mean: the information in
about dialog gradually darkens; I need this process reversed).

The best I could come up with was to increase the color components with
#'make-color in a loop, and overwrite as below...

(defun test ()
  (let ((win (make-instance 'window
               :view-position (make-point 380 225)
               :view-font '("Helvetica" 48)
               :view-size (make-point 250 250)
               :color-p t)))
    (with-focused-view win
      (dotimes (n 650)
        (#_MoveTo 50 125)
        (with-fore-color (make-color (* 100 n) (* 100 n) (* 100 n))
          (grafport-write-string "bye" 0 3))))))

I suspect that the palette manager bothers me, for the (black) color
'faints' stepwise. Perhaps I need to poke the palette with #_AnimateEntry?
Anyway, I appreciate anyone's comment on how this is supposed to be done.

Thanks, Arnoud.

Arnoud Verdwaald,
Dept. of Special Education 
University of Nijmegen,                    e-mail:     arnoudv@ped.kun.nl
Postbus 9104,                              telephone:  +31 80 612691
6500 HE  Nijmegen,                         fax:        +31 80 615938