From: fj05+@andrew.cmu.edu (Faisal Nameer Jawdat)
Newsgroups: comp.sys.mac.misc,comp.sys.mac.advocacy,comp.sys.mac.system,comp.sys.mac.hardware
Subject: Re: Mac & IBM Info (added Info)
Date: 13 Dec 92 20:16:15 GMT
Article-I.D.: andrew.gf=2Oje00WB7QK0Jg0
	<1gg9hlINN3qb@pith.uoregon.edu>
Distribution: na
Organization: Sophomore, Physics, Carnegie Mellon, Pittsburgh, PA

rtaylor@cie.uoregon.edu (Russ Taylor) writes:
> Not exactly.  All 68020+ Macs have the 32-bit color quickdraw routines in
> ROM.  So they are capable of handling 32-bit graphics routines EVEN IF THE
> MONITOR DOES NOT DISPLAY THEM.  It will be dithered to whatever pixel depth
> you are using, I believe.   I don't think PCs have there graphics codes in
> ROM, do they?
> 
> This built-in quickdraw becomes important with games like Lemmings and 
> Out of this World, some color printers, and quicktime.

Then you're saying that the pc can't support 24 bit graphics at all?
Damn near nothing is in the pc's rom.  It all depends on what you add
to it.  If you take a basic mac and a basic pc, neither one of them
will show you 24 bit graphics on screen.  If stick a 24 bit graphics
expansion in either one, it will display 24 bit graphics on screen,
where an application has need for that many colours.  From the user
standpoint, they're the same.  In terms of internal mechanics, you
make different calls to do the same thing.  Telling people that macs
support 24 (32 bit) graphics and pc's don't is deceptive unless you
explain what you're talking about.  To most people, saying 'machine x'
supports 24 bit colour graphics, that means that you can turn it on
and start displaying 24 bit images.

Better phrasing would be:
Macs have built in definition of how the operating system interacts
with the video hardware, including up to 32 bit video.  PC's  have no
internal definition of how the operating system interacts with the
video hardware, and leave it up to the os and video hardware in
question.  Most macs have 8 or 16 bit display capability built in, and
most of those can be expanded to display 24 bit colour.  Most pc's
come with cards that display 8 bit (or occasionally 16 bit) images,
and similarly, can be upgraded to a 24 bit display card.  Software
such as Windows and OS/2 will have to support your specific display
card (currently levels of support vary, but support is constantly
growin - check with your vendor to see what runs what with what), or
if you're running dos or certain Windows apps that write directly to
the display hardware, the specific application will have to support
your display hardware.

As for dithering to whatever your card display, have you ever gotten a
box that says "Application X requires the monitor to be set in Y
colors mode.  Sorry"?  Happens all the time.  Is that the application
refusing to run because the programmer didn't want it to, or the
application refusing to run because it wants colour support the mac
won't give it.


-- faisal jawdat                  | "Certainly the game is rigged.
email: fj05+@andrew.cmu.edu       | Don't let that stop you;
if mail handler barfs             | if you don't bet, you can't win." 
fj05@andrew.cmu.edu               |        -Lazarus Long