Xerox Parc

From: Eric Smith <eric_at_brouhaha.com>
Date: Fri Nov 8 14:15:01 2002

nerdware_at_ctgonline.org wrote:
> Jef Raskin (I think) developed ways to render
> the hidden parts of windows that even blew away the PARC people,
> since they'd been trying to figure it out for years.

No, the trick to get decent performance is to NOT render the parts that
are hidden. It's a completely trivial problem if you do render them,
but it wastes time. The clever thing that Bill Atkinson came up with was
the region data structure and related algorithms; Apple patented it.
This allows for an efficient representation of an arbitrary area of the
screen, for instance, the portion of a window that is partially obscured
by other windows.

This work was done for the Lisa; later Bill Atkinson was recruited away
to the Macintosh team, where he refined the concepts and produced a
hand-optimized assembler version to meet the limited memory requirements
of the Macintosh.

"Sean 'Captain Napalm' Conner" <spc_at_conman.org> wrote:
> The engineer in question had been on the tour of Xerox PARC and had
> thought that the engineers there (at PARC) *had* overlapping windows and
> proceeded to reverse engineer their design.

Apple didn't reverse-engineer any of it. They built their own.

> It was only *after* the
> Apple engineer had it working did he find out that PARC engineers never
> implemented overlapping windows (and I think they were still trying to
> figure out how to do that).

Xerox had overlapping windows well before that time. I'm not sure
exactly when they appeared, but they definitely existed by the time
of the Apple visit.
Received on Fri Nov 08 2002 - 14:15:01 GMT