NAME

       ppmdist - simplistic grayscale assignment for machine generated, color images

SYNOPSIS

       ppmdist

       [-intensity|-frequency]

       [ppmfile]

DESCRIPTION

       This program is part of Netpbm(1).

       ppmdist reads a PPM image as input and 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).

       This program is helpful only for images with a very small number of colors.

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common Options ⟨index.html#commonoptions⟩ ), ppmdist  recognizes  the  following  command
       line 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.

SEE ALSO

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

AUTHOR

       Copyright (C) 1993 by Dan Stromberg.

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/ppmdist.html