Path: utzoo!attcan!uunet!husc6!think!ephraim
From: ephraim@think.COM (ephraim vishniac)
Newsgroups: comp.sys.mac.programmer
Subject: Re: The Last Screensaver
Message-ID: <20706@think.UUCP>
Date: 12 May 88 14:44:50 GMT
References: <900003@zaphod> <5241@cup.portal.com> <310@piring.cwi.nl> <52703@sun.uucp> <313@piring.cwi.nl>
Sender: usenet@think.UUCP
Reply-To: ephraim@vidar.think.com.UUCP (ephraim vishniac)
Organization: Thinking Machines Corporation, Cambridge, MA
Lines: 45

In article <313@piring.cwi.nl> guido@cwi.nl (Guido van Rossum) writes:
>>And even more fun, it comes with Pyro, which is as close to the perfect
>>screensaver as you'll find, as an added bonus. Solving both discussions at
>>once.

>I have seen Pyro.  It's far too busy when it's in the same room as me
>and I am not using my Mac.  My ideal screensaver would do something like
>the good old Dali clock: slowly move a picture around on the screen.  Of
>course the Dali clock (besides being an applicataion) needn't apply for
>the job: it also changes every second :-(.

I'll happily send the complete source code for Dali Clock to anyone
who wants to build it into a screensaver.  (Or to anyone who just
wants to play with it, for that matter.)  You can trivially modify it
to change by minutes instead of seconds, if that's what you want.  

In case anyone hasn't noticed, Dali Clock avoids screen burn-in by
moving the image down one scan line every sixteen seconds until it's
shifted down slightly more than the original height of the figures.
Then, of course, it changes direction.

If anyone just wants to update Dali Clock, here are its current
problems:

	1. It's not multi-finder compatible.  It draws directly onto
	   the screen and also uses the desktop port.  So, the desktop
	   stays black when you exit.

	2. It doesn't work in color because of drawing directly to the
	   screen and ignoring the screen depth.  This should be
	   trivially fixable by use of an off-screen bitmap and
	   copybits.

Apart from those little details, it seems to work fine on all sorts of
Macs.  It is fastidious about *not* using hard-coded values for screen
size or location.

>Guido van Rossum, Centre for Mathematics and Computer Science (CWI), Amsterdam
>guido@piring.cwi.nl or mcvax!piring!guido or guido%piring.cwi.nl@uunet.uu.net

Ephraim Vishniac					  ephraim@think.com
Thinking Machines Corporation / 245 First Street / Cambridge, MA 02142-1214

     On two occasions I have been asked, "Pray, Mr. Babbage, if you put
     into the machine wrong figures, will the right answers come out?"