Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!umich!samsung!brutus.cs.uiuc.edu!lll-winken!decwrl!adobe!gelphman
From: gelphman@adobe.COM (David Gelphman)
Newsgroups: comp.sys.mac
Subject: Re: A call for "3D look" (a la Next) interface guidelines from Apple
Message-ID: <1716@adobe.UUCP>
Date: 1 Feb 90 04:55:06 GMT
References: <7334@tank.uchicago.edu> <38207@apple.Apple.COM> <18971@dartvax.Dartmouth.EDU> <6443@internal.Apple.COM>
Reply-To: gelphman@adobe.UUCP (David Gelphman)
Organization: Adobe Systems Incorporated, Mountain View
Lines: 52

In article <6443@internal.Apple.COM> lsr@Apple.COM (Larry Rosenstein) writes:
>In article <18971@dartvax.Dartmouth.EDU> erics@eleazar.dartmouth.edu (Eric 
>Schlegel) writes:
>> The NeXT has 2 bits per pixel, allowing white, black, lt gray and dk 
>gray.
>> If Apple would reserve ltGray and dkGray slots in the standard system 
>palette,
>> in addition to white and black, we could easily write CDEFs that produced
>
>I think the point was that only Mac II class machines have the ability to 
>do even 2-bit displays.  (The Mac SE/30 can do it also, although not on 
>its built-in display.)  You can experiment with using 4 grays, but the 
>results will only be usable on those machines.
>
>One question is whether you should have 2 interfaces one designed for 2 
>bits and the other for 1 bit.  Another question is whether it even makes 
>sense to design for 2 bits.  I think any users that has 2 bits available 
>has at least 4 (ie, there aren't any cards that provide only 2 bits per 
>pixel).  Perhaps we should design for 4 bits.  Finally, you will notice 
>that NeXT punts on these issues because it only supports one kind of 
>display.

The only 2 bit display card that I'm aware of are the ones Apple sells
for their portrait and 2 page monitors. Both support 4 bits if you add
memory but they come as 2 bit monitors.

One of the advantages of the NeXT machine's use of the Display PostScript
systems is that colors which are not directly available throught the
'system palette' are produced by dithering with the available colors.
If there were a 1 bit per pixel display available for the NeXT machine then
instead of having the light gray and dark gray map into white and black
the way they do with QuickDraw, they would map into dithered dark gray
and light gray. The interface would still look like gray levels, albeit
it not quite as nice and clean as it does today. Application writers who
specify rgb values for their drawing colors will get appropriate gray
values. If a color monitor is available for the NeXT machine then those
applications would get color on the display without any changes to them.
That is one of the goals of the Display PostScript system.

I think there is a pretty good argument that NeXT is in an excellent
position to add new monitors to their system. Because the whole system
is based on the device independence of the  PostScript language, they
could change the resolution of the display and add more color/graylevels
and applications could immediately take advantage of those capabilities.
Because QuickDraw is pixel based, using a high resolution monitor on
the Macintosh is not an attractive solution for most applications.

David Gelphman
Adobe Systems Incorporated

Disclaimer: These views are my own and do not necessarily reflect those
of my employer.