[comp.sys.mac.programmer] ColorQD vs QD32

hsieh@rscene.hac.com (Julia Hsieh) (10/23/90)

How do I use 32 bit QuickDraw?  How is it different from Color QuickDraw
which is documented in IM vol V?  I have an image file that contains
10 bits of color that maps into 24 bits of rgb.  I can generate an internal
lookup table, but can't figure out how to display it in 24 bits.

Is 32 bit QD documented somewhere?

There is probably a real easy answer, but I can't find it.  Any help
would be greatly appreciated.

Thanks in advance.
Julia


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julia hsieh              My opinions are not intended to reflect
hsieh@rscene.hac.com     those of Hughes Aircraft Company.
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rfischer@Neon.Stanford.EDU (Raymond C. Fischer) (10/25/90)

In article <11285@hacgate.UUCP> hsieh@rscene.hac.com (Julia Hsieh) writes:
>How do I use 32 bit QuickDraw?  How is it different from Color QuickDraw
>which is documented in IM vol V?  I have an image file that contains
>10 bits of color that maps into 24 bits of rgb.  I can generate an internal
>lookup table, but can't figure out how to display it in 24 bits.
>
>Is 32 bit QD documented somewhere?
>
>There is probably a real easy answer, but I can't find it.  Any help
>would be greatly appreciated.

Wrong.  No easy answer.  Fortunately, not too difficult either.

32bit CQD is a superset of 8bit CQD.  The calls in IM-V still apply, but
now there are a few new ones and the old ones do more.  In general, the 
routines described in IM-V all take RGB colors already.  With 32bit CQD,
if the color can be displayed in 24-bit color (i.e., you have a 24-bit
color card) it will be.  Thus, all you have to do is set your monitor
to 24-bit color and display the image as usual.

This assumes you have 32bit CQD (Color QuickDraw) installed.  If you
have an SE/30, Mac II, IIx, or IIcx you'll need to put the 32-bit color
quickdraw file in your system folder and reboot.  The file has been available
on system software disks since 6.0.5.

Of course, I've glossed over a LOT of details.  32bit CQD is described 
in the first issue of Develop.  The official documentation is available
from APDA.

Ray Fischer
rfischer@cs.stanford.edu

wiechman@athos.rutgers.edu (NightMeower) (10/28/90)

One interesting point is that there have been several version of
32-bit QD.  Apple has made a number of improvements and as a new
version of the OS is released bugs and enhancements are added.  For
safety reasons the OS will only use the version of 32-bit QD that it
was intended to use.  For example, 6.0.5 will not allow a 6.0.2
version 32-bit QD to be loaded.  So either know what you are doing or
use the installer to guarantee that you do indeed get 32-bit running.

Kevin
-- 
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Kevin S. Wiechmann			arpa:  wiechman@rutgers.rutgers.edu

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