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2008.04.17 13:48 "Re: efficient thumbnailing", by Joris Van Damme
Mike, Dr. Michael J. Chudobiak wrote: > > Stating the obvious but much neglected, make sure you use all and > > any thumbnails present in the file for starters. > > Thanks for the comments - but I have never trusted embedded > thumbnails. In my experience, too many programs are unaware of them > or handle them improperly for them to be trustworthy. (As a gThumb > developer, I know that gThumb used to leave jpeg-exif thumbnails > unchanged after rotating or cropping, for example.) I can't argue with this. But I do think, though, that this is a case where the cure is worse then the disease. Missing out on thumbnails, this way, is missing a very vital functionality and you can't make up for it any other way. In my personal opinion, it's actually better to show your user inconsistent results as a consequence of (gThumb) bad practice, and document the cause to ease the pain (and help motivate people to cure their bugs). You can't go overboard in throwing away your own functionality so as to compensate for someone else's bugs, not to the extend that your app becomes partically unusable. My personal experience with TIFF has shown me that bugs are often instances of the chicken and egg problem, where the bug is just the chicken, and our compensating for the bug is the egg. That's another point of view on the same problem: if everyone compensates for everyone's bugs, nobody is busy debugging anymore. There's all too many examples in the TIFF realm of this situation growing out of control and resulting in major loss of functionality. So too much compensating, might not be the actual 'social' thing to do in all cases. Or at least, that's my personal opion. It's just a matter of opinion. We should all agree on one thing though: not being aware of thumbnails in whatever flavour of encoding is no excuse to handle them badly: anything not understood should not ever be left in upon updating nor blindly copied upon converting, but should be ignored instead. That's the only way TIFF and its extendability can ever work. Best regards, Joris Van Damme info@awaresystems.be http://www.awaresystems.be/ Download your free TIFF tag viewer for windows here: http://www.awaresystems.be/imaging/tiff/astifftagviewer.html