Path: utzoo!attcan!uunet!seismo!dimacs.rutgers.edu!rutgers!netnews.upenn.edu!grad1.cis.upenn.edu!meuchen
From: meuchen@grad1.cis.upenn.edu (Paul Eric Menchen)
Newsgroups: comp.graphics
Subject: Why no 32 bit QuickDraw on Mac Plus
Summary: Was Re: Mac PICT2 specs, a trade secret?
Message-ID: <27190@netnews.upenn.edu>
Date: 18 Jul 90 03:13:27 GMT
Sender: news@netnews.upenn.edu
Reply-To: meuchen@grad1.cis.upenn.edu (Paul Eric Menchen)
Organization: University of Pennsylvania
Lines: 21

In article <1990Jul16.173822.6405@cs.swarthmore.edu> jackiw@cs.swarthmore.edu (Nick Jackiw) writes:
>dan@sics.se (Dan Sahlin) writes:
>> PS.  Does anyone have any ideas how the dithering is performed in 32-bit
>> Color Quickdraw?  It seems to work very well, and I can display a dithered
>> version of color pictures even on a black and white Mac SE/30.
>> Unfortunately this feature is for some reason disabled on a Mac Plus.
>
>Color QuickDraw, and its 32-bit superset, are written in 68030 code.  The
>Mac plus is a 68000.  The feature is not disabled; it is nonexistent.

Not quite. 32 bit QuickDraw and Color QuickDraw run fine on my 68020
Mac II. When 32 bit QuickDraw attempts to load, it checks for Color
QuickDraw first, which isn't in the Mac Plus ROMs. I think you can
patch Color QuickDraw on the Plus and SE. This is my impression from
Inside Mac V which discusses the "features of Color QuickDraw
implemented for the Macintosh Plus, the Macintosh SE, and the
Macintosh II ..." This part I'm not sure on, and a look at the tech
notes may be in order.

Paul Eric Menchen
meuchen@grad1.cis.upenn.edu