On Mon, 16 Jul 2001, Tony Duell wrote:
> > So here's a trick question .. what happens when a person holds
> > a lightpen to a dark section of the screen. Is the lightpen
>
> Nothing happens (literally). The light pen never sees any light, so it
> can't send a signal to the video card, so the CRT controller can never
> report the position.
>
> > completely blind unless come pixel is lit up?
>
> Yes.
Ok, my mind is still blown. How does a light-pen drawing program work
then? (Or is a light-pen drawing program not possible?)
Sellam Ismail Vintage Computer Festival
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Received on Mon Jul 16 2001 - 16:01:06 BST