*** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.ccp4.ac.uk ***
On Thursday 30 March 2006 12:54 am, you wrote: > > >> Ick - TIFF is an evil, encumbered format. Use PNGs (which also use > >> more efficient and free lossless compression algorithms): > > > > I'm not sure what you're thinking of here. > > Perhaps, Tim was referring to the Unisys LZW compression patent on TIFF > format that made the good, old, loseless, LZW-compressed TIFF unavailable to > free and/or open source programs such as not-so-old linux libraries that are > used by a few programs including Raster3D... The LZW fiasco indeed caused a lot of turmoil in open source graphics libraries. But even back then the TIFF spec offered encoding/compression schemes other than LZW. They just weren't used much, because mostly the applications built on top of the library were hard-coded to request LZW. TIFF was an innocent bystander, but many apps (including Raster3D) switched to PNG output rather than re-coding their use of the TIFF library. It is a bit unfortunate that whoever drew up the PNG spec didn't put a little more thought into providing slots for additional envelope information. This is particularly true because the higher level graphics libraries built on top of PNG (e.g. libgd) tend not to support the hide-the-info-in-comments hackery that could otherwise ameliorate this omission from the spec. -- Ethan A Merritt Biomolecular Structure Center University of Washington, Seattle WA
