1998.12.16 07:38 "Re: TIFF to GIF conversion utility", by Niclas Borlin

I realize that this is not the exactly the correct place to post this message, but here I go.

I am looking for a UNIX utility that can convert TIFF -G4 compression images to GIF images and resize the GIF image to 65% of it's original size. The utility I'm looking for must be able to do such a conversion in 3 seconds or less. I tried ImageMagick, which uses the TIFF library, but it was extremely slow. If you know of any good TIFF to GIF converters for Unix could you please let me know.

Hi Chris,

I did some test runs on my Sun UltraSparc II (Dual 200MHz) with the PBMPLUS package. You have the timings below for an A4-sized test image. The timings are not as good as you would like, but perhaps you could modify the source (for avaliability, see e.g. www.cica.indiana.edu/cica/faq/image_convert/convert.pbmplus.html) to speed things up... I believe a lot of time is spent shuffling data, since the source file is 11k, the resulting .gif file 73k, but the intermediate ppm file is 9M! A program that would read/scale/write strip-by-strip would most centainly be faster...

Good luck!

/Niclas

No scaling:
pixel% date; tifftopnm test.tif | ppmtogif -map map.ppm >! test.gif; date
Wed Dec 16 08:13:48 MET 1998
tifftopnm: writing PBM file
ppmtogif: computing other colormap...
ppmtogif: 256 colors found
Wed Dec 16 08:13:55 MET 1998

With scaling:
pixel% date; tifftopnm test.tif | pnmscale 0.65 | ppmtogif -map map.ppm >! test.gif; date
Wed Dec 16 08:14:25 MET 1998
tifftopnm: writing PBM file
ppmtogif: computing other colormap...
pnmscale: promoting from PBM to PGM
ppmtogif: 256 colors found
Wed Dec 16 08:14:41 MET 1998

--
Niclas Borlin                       email: Niclas.Borlin@cs.umu.se
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