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)