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January 2006
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2006.01.04 19:34 "Re: Reading TIFF(CMYK)", by Bernie Pallek
To expand on what Kai-Uwe suggested, you can take the raw data as the CMYK
data -- deciding how to split it up will depend on the value of the
SamplesPerPixel and BitsPerSample tags. For instance, if you have a
SamplesPerPixel of 4 (C+M+Y+K = 4) then your image data will probably be
divided into groups of 4. Each group's size will be determined by
BitsPerSample (for a CMYK, you might have values of 8, 8, 8, 8). So with
our example values, you have 32 bits for each pixel. Thus, for each 32 bits
of raw data, grab out the channel you want (the 8 bits of whatever component
you're after), and store that in your new buffer/file.
So, suppose each letter below represents 8 bits of raw data, and you want
the 'M' channel, and the data is organized intuitively
("C,M,Y,K,C,M,Y,K,..." -- see FillOrder tag for more).
Then "ABCDEFGHIJKL..." (fetch out 'B', 'F', 'J', etc) becomes "BFJ..."
This is just meant to give you a nudge in the (hopefully) right direction.
Actual details may vary.
I wonder if perhaps you were just asking something like "are the data for
CMYK pointed to by StripOffsets?" and I think the answer is "yes". But I'm
still a novice myself.