.TH ppmhist 1 "17 September 2000"
.IX ppmhist
.SH NAME
ppmhist - print a histogram of a portable pixmap

.SH SYNOPSIS
.B ppmhist
.RB [ -hexcolor ]
.RB [ -noheader ]
.RB [ -map ]
.RB [ -nomap ]
.RB [ -sort= { frequency , rgb }]
.RI [ ppmfile ]

.SH DESCRIPTION
Reads a PPM image as input.  Generates a histogram of the colors in
the image, i.e. a list of all the colors and how many pixels of each color
are in the image.

.SH OPTIONS

.TP 
.BR -sort= { frequency , rgb }
The
.B -sort
option determines the order in which the colors are listed in the output.
.B frequency 
means to list them in order of how pixels in the input image have the color,
with the most represented colors first.
.B rgb
means to sort them first by the intensity of the red component of the color,
the of the green, then of the blue, with the least intense first.

The default is 
.BR frequency .

.TP
.B -hexcolor
Print the color components in hexadecimal.  Default is decimal.
.TP
.B -noheader
Do not print the column headings.
.TP
.B -map
Generates a PPM file of the colormap for the image, with the color
histogram as comments.
.TP
.B -nomap
Generates the histogram for human reading.  This is the default.


.SH "SEE ALSO"
.BR ppm (5), 
.BR pgmhist (1),
.BR ppmtomap (1),
.BR pnmhistmap (1),
.BR ppmchange (1)

.SH AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
.\" Permission to use, copy, modify, and distribute this software and its
.\" documentation for any purpose and without fee is hereby granted, provided
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.\" implied warranty.