19 Mar
2005
19 Mar
'05
8:39 a.m.
On Mar 19 2005, 11:19, GManuel \(GMC\) wrote:
It must be able to somehow. I have used a light pen on
a Commodore 64
with a
Graphics Program called Picasso's Revenge and have
drawn on the
screen with
it even on a completely black background. Not sure how
it does it
though.
It's just a question of sensitivity. The black portions of the screen
are rarely quite black, because the electron beam is not quite turned
off. Thus a suficciently sensitive lightpen can still detect the spot
as it scans past the pen's location.
--
Pete Peter Turnbull
Network Manager
University of York