Ppmdist User Manual(0)					Ppmdist User Manual(0)



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 repeti-
       tions).

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



OPTIONS
       -frequency
	      Sort  input colors by the number of times a color appears in the
	      input, before mapping to evenly distributed graylevels  of  out-
	      put.


       -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.



netpbm documentation		 22 July 1992		Ppmdist User Manual(0)