TIFF and LibTiff Mail List Archive


2000.12.15 09:50 "Stripes in thumbnail", by Christian Bednarek
2000.12.18 13:06 "Re: Stripes in thumbnail", by Joris Van Damme
2000.12.18 16:29 "Re: Stripes in thumbnail", by Sam Leffler
2000.12.19 05:36 "Re: Stripes in thumbnail", by Steve Underwood

2000.12.18 16:29 "Re: Stripes in thumbnail", by Sam Leffler

LibTiff fax decompression has been reported to behave differently from other decompressors like eg the one in Photoshop. My guess is that some scanlines in the original g4 tiff(s) cannot be correctly interpretted by LibTiff, and are simply (partially) skipped, leaving a (partially) blank line. Warning and error behaviour of the g3/g4 decompressors has been reported to be imperfect, so it's even possible you don't even get a warning about this, I guess...

The G3 and G4 codecs in the library should follow the published specs; if they don't please provide an example image where they don't. Suggesting that they behave differently than other codecs (e.g. Photoshop) is nonsense.

No, I'm not going to take up the responsability to prove that point. For starters, I did not say for a fact that it behaves differently. I said it has been reported to behave differently. Which is something quite different. Which refers to a number of postings on this mailing list reporting so, from different independent sources, and you must have read them and know what I'm talking about.

Over the years I've seen rumours started (or perpetuated) by postings like yours. While I'm not about to rule out bugs in the software the library has been around for a long time and incorporated in many many products. Given that exposure I would have expected to hear of any problem of the sort you alluded to.

I've seen postings from folks suggesting bugs for >10 years. Some have been correct. Most have not. I used to follow up on all of them. I don't anymore 'cuz the software isn't mine to maintain. Nonetheless the issue is still the same: if you've found a problem provide a way to reproduce it.

Sorry if my note came off as confrontational. I'll shut up and leave it to the current maintainers to deal with your issues.