Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: Saving SHR screen from p8
Message-ID: <35233@apple.Apple.COM>
Date: 3 Oct 89 18:55:14 GMT
References: <12831@orstcs.CS.ORST.EDU> <4473@wpi.wpi.edu>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 26

In article <4473@wpi.wpi.edu> dseah@wpi.wpi.edu (David I Seah) writes:
>In article <12831@orstcs.CS.ORST.EDU> throoph@jacobs.CS.ORST.EDU.UUCP (Henry Throop) writes:
>>
>>Is there some way to save the SHR screen from ProDOS 8, so it can be loaded
>>into a paint program and modified?
>>[...] for some reason when I load the resulting file, it has about 6 small
>>copies of the screen on the image, and the palette is messed up.
>
>Perhaps you forgot to linearize the screen buffer before moving the picture
>from bank $e1.  You can do this by storing a $41 in $e0c029 before moving the
>picture.  Things ought to work just fine then.

Yup, the linearization bit is what's causing you trouble here.  Please note
that if you're writing a program that fiddles with $C029, you should *not*
store hard-coded values directly in there--there are *reserved* bits there
that you must not alter.  In a program, you need to use LDA/ORA/STA, or
LDA/AND/STA, or LDA/TSB, or LDA/TRB, or whatever.
-- 

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