2001.10.22 23:47 "Compression = 3?", by Dave Sopchak

2001.10.22 23:47 "Compression = 3?", by Dave Sopchak


After neglecting a little TIFF app I wrote for the Mac about 9 years ago, I decided to use it as an exercise in porting to OS X. Right now Apple's Preview app that comes with OS X doesn't show other than the first page of multi page TIFFs, so I'm hoping to get my app up to the task and it could fill a useful niche, if only for viewing faxes. Right now my app only supports single page PackBits compression of 1 bit TIFFs.

After getting my app over to OS X, I started trying to open some multi page TIFF files I have. I couldn't open them, even the first page, because they don't use PackBits compression (compression = 32773). These TIFFs have a compression type of 3 listed in their files (tag 259). Looking at the TIFF 6.0 spec from 1992, there are only 3 types of compression listed, types 1, 2 and 32773. Am I missing something here? I can't find any newer "offical TIFF" docs that talk about any other compression schemes. Apple's Preview app and other apps I have can open the first or last page of these TIFFs, so I must be missing something...

Also, I was not able to log into the ftp.onshore.com/pub/libtiff as anonymous. It said anonymous was OK, but when I put in my email as a password, it said access denied.

Any and all help would be greatly appreciated.


"Progress" is our middle name.
Unfortunately, "No" is our first name

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