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Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!brutus.cs.uiuc.edu!apple!umt!cs__sjh
From: cs__sjh@umt.UUCP (Jeffrey Heng)
Newsgroups: comp.sys.mac.programmer,comp.sys.mac
Subject: Color QuickDraw and 32Bit Quickdraw
Keywords: Color QuickDraw
Message-ID: <833@umt.UUCP>
Date: 1 Mar 90 08:52:45 GMT
Followup-To: poster
Organization: University of Montana CIS - Missoula, MT
Lines: 20


Hi,	
	I'm currently trying to do some mac programming using Color
QuickDraw.  Can anyone recommend a good book on Color QuickDraw (other
than Inside Macintosh Vol. V) ? I'm trying to change the color lookup
tables to explore the various effects on my scanned in pictures.  Right
now I'm able to display the scanned in pictures using SetPixel. I've 
encountered the following problem when exploring with different lookup
tables:
In the first case, I set up a color lookup table with 256 shades of gray and
then used this CLUT to display a picture using SetPixel. In the second case,
I used the default lookup table to draw the same picture.  After this picture
was displayed, I changed the CLUT to 256 shades of gray without redrawing
and I get a picture of poorer quality than in the first case. Why is this so?
What is the colorSpec.value field for ? It appears to be different for gDevice
and pixmap.  I also realise that the 32-Bit quickdraw does change the grayscale
pictures that I draw.  Can anyone out there answer some of these questions ?
I'd appreciate any help. Thank you.

Jeff