1997.05.05 18:19 "I have a little problem with CCITT compression", by Gabriela Vaida

Hi Silicon Graphics,

My name is Gabriela Vaida and I'm using Libtiff version 3.4beta024 with WINNT40. It's a really great job there, thanks for sharing it.

But I'd like to know if it's my mistake or you know something about using CCITT compression.

I have this line in my code:

TIFFSetField(tif, TIFFTAG_COMPRESSION, COMPRESSION_CCITTFAX4)

which really compress the tiff image I'm creating, but my image has always the colors inverted after compression. It doesn't matter if I choose the photometric interpretation PHOTOMETRIC_MINISBLACK or PHOTOMETRIC_MINISWHITE (the second one it's normal for CCITT compression, I know!). If I don't want commpression (COMPRESSION_NONE)my tiff image has the colors I want - the problem is there only when using CCITT compression.

Thank you very much,

Gabriela Vaida
Silanis Technology Inc
Montreal