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From: duncan@csd4.csd.uwm.edu (Shan D Duncan)
Newsgroups: comp.sys.amiga
Subject: Re: Floyd-Steinberg dither
Message-ID: <2713@uwm.edu>
Date: 2 Mar 90 17:12:56 GMT
References: <8100@sdcc6.ucsd.edu>
Sender: news@uwm.edu
Reply-To: duncan@csd4.csd.uwm.edu
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From article <8100@sdcc6.ucsd.edu>, by ln63wkp@sdcc4.ucsd.edu (Viet Ho):
> Does there exist a graphics converter which will convert Amiga IFF
> (HAM, grey or color) into 1 bitplane black & white pic using 
> Floyd Steinberg dithering instead of ordered dither?   I've only
> seen one program so far that will convert AmyColor->1bit which is
> MacView.  Unfortunately it uses the ordered dither method which 
> doesn't look as nice as FS.
>     I know that NewTek's DigiView uses FS for it's dither2
> mode conversion but it only does color or grey scale which looks
> real nice in 16 colors hires but is not applicable to 1 bitplane.
> 
> Any suggestions appreciated.
> 
>                                            -Viet
>                                            vho@ucsd.edu



You might contact Radical Eye Software - Thomas Rokicki

He has a library called pfilt for use in converting raster images
(IFF) for use in a TeX dvi file.

In the AmigaTeX Manual under Dithering he has:

classic - classic spot dithering
ordered - ordered dither of order n
fs - Floyd-Steinberg error diffusion dither in a serpentine raster
threshold - No dithering simple thresholding operation
smooth - smooth=0 no smoothing 1 = maximum
alpha and beta for presharpening level

also

equalize to max. color differences
nonlinear=xypairs  for example nonlinear[0,1][1,0] would produce
a negitive image.



A program call pfiltview can be used to preview using these
options and an outfile can be saved.

Just the combination of pflit.library and pfiltview make a nice
image modification system.   Very fast.


I've also used a program called xcolor to subtract bitplanes

and tried a program called colorlab, both on fish disks.



The macros by Radical Eye are part of AmigaTeX with Printer
support (extra).


If they sound interesting give him a call, drop him a note, send
him some e-mail, log on to his bbs, talk to him on BIX.  He has
been an amazingly helpful person since I've purchased AmigaTeX.

I have reached tom via e-mail at rokicki@Neon.Stanford.edu





On unix PBMplus (portable bitmaps).


Good luck

-Shan