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TIFF and LibTiff Mail List Archive

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2006.01.04 18:15 "[Tiff] Reading TIFF(CMYK)", by
2006.01.04 18:39 "Re: [Tiff] Reading TIFF(CMYK)", by Bob Friesenhahn
2006.01.04 18:50 "Re: [Tiff] Reading TIFF(CMYK)", by
2006.01.04 19:34 "RE: [Tiff] Reading TIFF(CMYK)", by
2006.01.04 19:41 "Re: [Tiff] Reading TIFF(CMYK)", by Bob Friesenhahn
2006.01.04 19:45 "Re: [Tiff] Reading TIFF(CMYK)", by Kai-Uwe Behrmann
2006.01.06 14:48 "[Tiff] LZW", by Rocky Pulley
2006.01.06 14:55 "Re: [Tiff] LZW", by Chris Losinger
2006.01.06 15:14 "RE: [Tiff] LZW", by Steve Eddins
2006.01.06 19:22 "[Tiff] configuring LZW in libtiff 3.7.2", by monee singh
2006.01.07 01:11 "Re: [Tiff] LZW in libtiff 3.7.2", by Bob Friesenhahn
2006.01.04 18:51 "Re: [Tiff] Reading TIFF(CMYK)", by Kai-Uwe Behrmann

2006.01.04 19:34 "RE: [Tiff] Reading TIFF(CMYK)", by

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.

> -----Original Message-----
> From: tiff-bounces@lists.maptools.org
> [mailto:tiff-bounces@lists.maptools.org]On Behalf Of

a.malka@comptel.pl

So maybe i ask another way...

i read tiff specification and can't find in which tag are saved CMYK channel...

Any suggestion?