1998.03.02 14:32 "Urgently needed: Fast CCITT G4 (TIFF T6) to GIF with scaling. Small footprint", by Michel Plungjan

1998.03.02 16:37 "Re: Urgently needed: Fast CCITT G4 (TIFF T6) to GIF with scaling. Small footprint", by Alberto Accomazzi

I need to convert A4/Letter sized images from CCITT G4 (can be presented as TIFF T6 if needed) to GIF and scale from 2592x3508 to 1200x817 in the process

ImageMagick/libTiff can do this with a Mitchell filter but this is REALLY a pig, hogging both memory/swap file and cpu.

Normally this would not be a problem, but since this will be done on the fly and perhaps several times concurrently I am really unhappy. Does anyone have any alternatives?

Ok, I know that I may end up regretting this some day, but here it goes...


I wrote a C program that uses libtiff to do precisely what you describe (it was written so that it would do fast integer resampling, conversion to grayscale GIF and possibly caching on the fly; it can be compiled so that it runs as a CGI script). The reason why I have been hesitant to give the code out is that it's real ugly and some parts of it are very specific to the way we use it on our web site. Despite my intention to clean it up some day so that it would be more useful to others, I've never gotten around to it, and I can't spend any time supporting the code or enhancing it further to meet other people's needs.


If you're still reading and don't mind hacking the code, feel free to fetch it from: http://cfa-www.harvard.edu/~alberto/tiff/tiff2gif.c


-- Alberto

Alberto Accomazzi                 NASA Astrophysics Data System / SIMBAD USA
aaccomazzi@cfa.harvard.edu             Smithsonian Astrophysical Observatory
v/f: 617-495-7076/617-496-7577                60 Garden Street, Mail Stop 83
http://cfa-www.harvard.edu/~alberto                 Cambridge, MA 02138  USA