40-bit CMYKA images in NSBitmapImageRep

FROM : Jeff Disher
DATE : Sun Nov 24 21:28:02 2002

Hello,

I am working on implementing support for colour spaces other than RGBA
in a program I am working on.  So far I have been successful in adding
the gray-scale ones so now I am working on CMYKA.
For some reason I am getting strange errors when I try to set an image
in a view that has just been created with the NSBitmapImageRep of a
5-channel image (I also had trouble getting a tiff representation of
the data with TIFFRepresentation).  I keep seeing errors like this:
<snip>
TIFF Error: Cannot handle 5-channel data.
TIFF Error: 1: Sample out of range, max 1.
TIFF Error: 2: Sample out of range, max 1.
TIFF Error: 3: Sample out of range, max 1.
TIFF Error: 4: Sample out of range, max 1.
2002-11-25 00:24:53.427 <Program Name>[1805] TIFF error 5
</snip>

Since I haven't worked with CMYKA data before, I was wondering if this
is some odd limitation to the current implementation of Cocoa wherein
you have to be very careful with this data or if it is just some simple
mistake that I have made somewhere.

Thanks for any ideas,
Jeff.