Ppmdither User Manual(1) General Commands Manual Ppmdither User Manual(1)
NAME
ppmdither - ordered dither for color images
SYNOPSIS
ppmdither
[-dim=power]
[-red=n]
[-green=n]
[-blue=n]
[netpbmfile]
All options can be abbreviated to their shortest unique prefix. You
may use two hyphens instead of one to designate an option. You may use
either white space or an equals sign between an option name and its
value.
DESCRIPTION
This program is part of Netpbm(1).
ppmdither reads a Netpbm image as input, and applies dithering to it to
reduce the number of colors used down to the specified number of shades
for each primary. It produces a PPM image as output.
The default number of shades is 5 red, 9 green, and 5 blue, for a total
of 225 colors. To convert the image to a binary rgb format suitable
for primitive color printers, use -red=2 -green=2 -blue=2.
You can do another kind of dither -- Floyd-Steinberg -- with pnmquant
or pnmremap.
OPTIONS
In addition to the options common to all programs based on libnetpbm
(most notably -quiet, see
Common Options ⟨index.html#commonoptions⟩ ), ppmdither recognizes the
following command line options:
-dim power
The size of the dithering matrix. The dithering matrix is a
square whose dimension is a power of 2. power is that power of
2. The default is 4, for a 16 by 16 matrix.
-red=n The number of red shades to be used, including black; minimum of
2.
Default is 5.
-green n
The number of green shades to be used, including black; minimum
of 2.
Default is 9.
-blue n
The number of blue shades to be used, including black; minimum
of 2.
Default is 5.
SEE ALSO
pamditherbw(1), pamdepth(1), pnmquant(1), pnmremap(1), ppm(1)
AUTHOR
Copyright (C) 1991 by Christos Zoulas.
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source. The master documentation is at
http://netpbm.sourceforge.net/doc/ppmdither.html
netpbm documentation 16 December 2009 Ppmdither User Manual(1)
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