NAME

       ppmdist - simplistic grayscale assignment for machine generated, color images

SYNOPSIS

       ppmdist [-intensity|-frequency] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as  input,  performs  a simplistic grayscale assignment intended for use with
       grayscale or bitmap printers.

       Often conversion from ppm to pgm will yield an image with contrast too low for good printer output.   The
       program maximizes contrast between the gray levels output.

       A  ppm  input  of  n  colors is read, and a pgm of n gray levels is written.  The gray levels take on the
       values 0..n-1, while maxval takes on n-1.

       The mapping from color to stepped grayscale can be performed in order of input pixel intensity, or  input
       pixel frequency (number of repetitions).

OPTIONS

       -frequency    Sort  input  colors  by the number of times a color appears in the input, before mapping to
                     evenly distributed graylevels of output.  -intensity Sort input colors by  their  grayscale
                     intensity, before mapping to evenly distributed graylevels of output.  This is the default.

BUGS

       Helpful  only  for  images  with  a  very  small number of colors.  Perhaps should have been an option to
       ppmtopgm(1).

SEE ALSO

       ppmtopgm(1), ppmhist(1), ppm(5)

AUTHOR

       Copyright (C) 1993 by Dan Stromberg.

                                                  22 July 1992                                        ppmdist(1)