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From: lsr@apple.UUCP (Larry Rosenstein)
Newsgroups: comp.sys.mac
Subject: Re: Video memory and the Mac II
Message-ID: <6537@apple.UUCP>
Date: Thu, 22-Oct-87 20:19:12 EST
Article-I.D.: apple.6537
Posted: Thu Oct 22 20:19:12 1987
Date-Received: Sun, 25-Oct-87 14:09:07 EST
References: <11827@decwrl.DEC.COM>
Reply-To: lsr@apple.UUCP (Larry Rosenstein)
Organization: Advanced Technology Group, Apple Computer
Lines: 32

In article <11827@decwrl.DEC.COM> hunt@firqb.dec.com (Phil Hunt) writes:
> 
>   I was wondering how the Mac II video memory lays out.  In other words, how
>do they make old pgms compatible with the new memory map??   I know the video

Most application do not deal directly with screen memory, and are
insensitive to where it is located.

Some application do write directly to screen memory, but examine the
Quickdraw data structures to see where it is located.  Such application
won't work on a Mac II unless the screen is set for 2 colors.  (The symptom
of this is seeing a bunch of tiny images at the top of the screen.)

>   Also, I have found some old pgms (1984-1986) that run IN COLOR. The old
>Cricket Graph 1.0 (Yes, 1.0!!) runs on MY MAC II in COLOR,  so does some
>card games.  The diamonds and hearts are in color!!!   Is this a maaping 
>between othe old Quickdraw 8 color (IE IM II mapping) and the new CQD???

Color Quickdraw supports the old Quickdraw color model of 8 fixed colors and
maps those colors into the closest available color..

Larry Rosenstein

-- 
Larry Rosenstein

Object Specialist
Apple Computer

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