g3togif (was: web fax viewer...)

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> > g3topbm | pnmscale -xscale 0.5 -yscale 0.5 | ppmtogif
> 
> I think pnmscale does not do antialiasing, but I'll try it.

well I take it back... it works pretty well. It is even reasonably
fast, I converted about 20 pages with the above pipe in 6 minutes, on a
P5-133 w/32MB while the system was also running netscape3 and viewfax.
An integrated converter should be way faster. Scaling to 1/2 size
produces files with 3 grey levels, and have at most the same size
as the originals for all documents I have (normal res, max 65KB),
although short faxes tend to become shorter.

I have also tried scaling to 0.25, but pnmscale produces 10 grey
levels which I think has a negative effect on compression. A scale 0.25
file has approx 2/3 the size of a scale 0.5 file, and is much less
readable (except for header pages). I think a specialized scaler to
0.25 should limit to 8 grey level to improve compression.

All in all the experiment was quite satisfactory -- the script handling
incoming faxes could easily produce the gif files and an HTML page with
pointers to all received pages, possibly in both resolutions, etc. etc.

Does anyone know if modern browsers are able to parse png files, and
how good is conversion to png ?

	Cheers
	Luigi
-----------------------------+--------------------------------------
Luigi Rizzo   | Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it | Universita' di Pisa
tel: +39-50-568533   | via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522   | http://www.iet.unipi.it/~luigi/
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