Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!apple!applelink.apple.com!MAC.ROMOS
From: MAC.ROMOS@applelink.apple.com (Ian Hendry)
Newsgroups: comp.sys.mac.programmer
Subject: Re: rowBytes for a pixmap
Message-ID: <2939@internal.Apple.COM>
Date: 20 Jul 89 18:32:41 GMT
References: <21104@andante.UUCP>
Sender: usenet@Apple.COM
Organization: Yeah, I'm organized.
Lines: 18

In article <21104@andante.UUCP> bwb@andante.UUCP (Bruce Ballard) writes:
>       (depth * (Right - Left + 15) div 16) * 2
If you are using Color QuickDraw, then I *believe* you should be using a 
long word aligned width (rather than a word aligned width).  I am 99% sure 
that ColorQD can go *much* faster if rowBytes is long aligned.  The 
formula should read something like this:
      rowBytes := (depth * (Right - Left + 31) div 32) * 4;
or for the C buffs:
      rowBytes =  (depth * (Right - Left + 31) >> 5) << 2;

Ian Hendry
MAC.ROMOS@applelink.apple.com
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