1997.02.13 23:37 "LZW & more than 5 image channels.", by Gabe Foster

1997.02.14 14:35 "Re: LZW & more than 5 image channels.", by Guillaume Muller

I seem to be exercising some rarely used features of the tiff library. Has anyone tried writing more than 4 channels to a file with lzw compression? When I try this with a 720x486 image that is just a grayscale ramp, I get a strangly cropped image. It writes with no error, and reads with no error, but the right hand third (about) of the image is black, the rest is ok.

Any Ideas?

Which version of libTiff are you using? I had the same problem in 3.2, but now it seems to work well in 3.4. I just checked with a 720x486 CMYK+alpha image (5 planes), and then with a RGB+alpha+2 extra-planes image of about 10MB (6 planes). It works in all Strip/Tile or Separate/Contig combinations.

Hope it helps.

Guillaume Muller

Caldera Graphics
Software for Imaging
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Email: gmuller@caldera.fr