[plt-scheme] Using a canvas% and its dc<%>

At Sun, 2 Mar 2003 15:16:45 +0100, Jens_Axel_Søgaard wrote:
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> 
> Akiva Kleiman wrote:
> 
> > Little window, with a canvas in it, and it draws a red circle, filled
> > with white; less then a second later, though, the entire window is
> > filled with white, and my circle is nowhere to be found.
> > What could be the problem?
> 
> Deja vu. I had the same problem until Robby showed me the solution:
> 
> http://www.cs.utah.edu/plt/mailarch/plt-scheme-2002/msg00288.html

I wonder if that was in the days before the paint-callback as init-arg
to canvas%. In any case, the above is a more general solution that
you'd need if you wanted to catch mouse or keyboard events in the
canvas in addition to drawing in it.

Robby