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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.3//EN">
<html><head><title>Ppmspread User Manual</title></head>
<body>
<h1>ppmspread</h1>
Updated: 06 March 2021
<br>
<a href="#index">Table Of Contents</a>

<h2>NAME</h2>

ppmspread - displace a PPM image's pixels by a random amount

<h2 id="synopsis">SYNOPSIS</h2>

<b>ppmspread</b> <i>amount</i> [<i>ppmfile</i>]
[<b>-randomseed=</b><i>integer</i>]


<h2 id="description">DESCRIPTION</h2>

<p>This program is part of <a href="index.html">Netpbm</a>.

<p><b>ppmspread</b> reads a PPM image as input and moves every pixel
around a random bit relative to its original position. <i>amount</i>
determines by how many pixels a pixel is to be moved around at most.

<p>Pictures processed with this filter will seem to be somewhat
dissolved or unfocussed (although they appear more coarse than images
processed by something like <i>pnmconvol</i>).

<p>The randomness in the image is limited before Netpbm 10.37 (December
2006) -- if you run the program twice in the same second, you may get
identical output.


<h2 id="options">OPTIONS</h2>

<p>In addition to the options common to all programs based on libnetpbm
(most notably <b>-quiet</b>, see <a href="index.html#commonoptions">
Common Options</a>), <b>ppmspread</b> recognizes the following
command line options:

<dl>
  
<dt><b>-randomseed=</b><i>integer</i>

<dd>This is the seed for the random number generator that generates the
pixels.

<p>Use this to ensure you get the same image on separate invocations.

<p>This option was new in Netpbm 10.94 (March 2021).

</dl>

  
<h2 id="seealso">SEE ALSO</h2>

<a href="ppm.html">ppm</a>, 
<a href="pnmconvol.html">pnmconvol</a>

<h2 id="author">AUTHOR</h2>

Copyright (C) 1993 by Frank Neumann

<hr>
<h2 id="index">Table Of Contents</h2>
<ul>
<li><a href="#synopsis">SYNOPSIS</a>
<li><a href="#description">DESCRIPTION</a>
<li><a href="#options">OPTIONS</a>
<li><a href="#seealso">SEE ALSO</a>
<li><a href="#author">AUTHOR</a>
</ul>
</body>
</html>