Re: [Gimp-print-devel] Halftoning algorithms

[Robert L K. <rl...@al...>]

   Date: Mon, 6 Mar 2000 06:12:53 -0800
   From: "Raph Levien" <arc...@db...>

      I've done quite a bit of work over the years on screening
   algorithms. I'm trying to push some of them for commercial
   licensing, see http://www.artofcode.com/eventone/ for details.

Interesting.

      Not to overstate things, but the quality is incredible. It is
   dramatically better than the gs and gimp-print drivers, and, while
   I haven't done serious comparison yet with the bundled windows
   drivers, my guess is that it's comparable or slightly better.

Did you try 1440x720 highest quality?  That gives markedly better
results than any of the other choices.  It's still a randomized error
diffusion, though, so it still creates wormy artifacts.  However, I'm
quite certain that it's not the last word in dithering algorithms :-)

      In the meantime, I want to keep you guys in the loop. I am happy
   to give you guys the code to play around with, with the
   understanding that it is not yet free software, but will be at some
   date in the not too distant future. I talked to Peter Deutsch a few
   days ago, so he's up to speed as well.

For us to be able to use it it will have to be GPL.  I notice that you
have a patent on some of this stuff, so that would have to be worked
out.  However, this would certainly be very interesting to look at.

      I've learned a lot by reading the gimp-print code. I think you
   might enjoy reading through my code. Among other things, I have
   _much_ simpler code for microweaving. At the moment, the code is
   specialized for the stc600 and needs to be parameterized a bit, but
   the entire Epson driver is 236 lines of code.

Well, this code is trying to support all of the different Epson
printers, so there's a good bit more complexity involved, particularly
with the quirky command sets different output modes we support...

-- 
Robert Krawitz <rl...@al...>      http://www.tiac.net/users/rlk/

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lp...@uu...
Project lead for The Gimp Print --  http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton