freebsd man page for ppmdither

ppmdither(1)						      General Commands Manual						      ppmdither(1)

NAME
       ppmdither - ordered dither for color images

SYNOPSIS
       ppmdither [-dim power] [-red shades] [-green shades] [-blue shades] [ppmfile]

DESCRIPTION
       Reads  a  portable  pixmap as input, and applies dithering to it to reduce the number of colors used down to the specified number of shades
       for each primary.  The default number of shades is red=5, green=9, blue=5, for a total of 225 colors.  To convert the image to a binary rgb
       format suitable for color printers, use -red 2 -green 2 -blue 2.

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 shades   The number of red shades to be used, including black; minimum of 2.

       -green shades The number of green shades to be used, including black; minimum of 2.

       -blue shades  The number of blue shades to be used, including black; minimum of 2.

SEE ALSO
       pnmdepth(1), ppmquant(1), ppm(5)

AUTHOR
       Copyright (C) 1991 by Christos Zoulas.

								   14 July 1991 						      ppmdither(1)