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