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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML><HEAD><TITLE>Ppmtoarbtxt User Manual</TITLE></HEAD>
<BODY>
<H1>ppmtoarbtxt</H1>
<BR>
Updated: 26 November 2014
<BR>
<A HREF="#index">Table Of Contents</A>
<H2>NAME</H2>
ppmtoarbtxt - generate image in arbitrary text format from PPM image
<H2 id="synopsis">SYNOPSIS</H2>
<B>ppmtoarbtxt</B>
<I>bodyskl</I>
[<B>-hd</B> <I>headskl</I>]
[<B>-tl</B> <I>tailskl</I>]
[<I>ppmfile</I>]
<H2 id="description">DESCRIPTION</H2>
<p>This program is part of <a href="index.html">Netpbm</a>.
<p><b>ppmtoarbtxt</b> generates simple text-based graphics formats based on
format descriptions given as input. A text-based graphics format is one in
which an image is represented by text (like PNM plain format, but unlike
PNM raw format).
<b>ppmtoarbtxt</b> reads a PPM image as input. For each pixel in the
image, <b>ppmtoarbtxt</b> writes the contents of the skeleton file
<I>bodyskl</I>, with certain substitutions based on the value of the
pixel, to stdout. The substitutions are as follows:
<DL COMPACT>
<DT><B>#(ired</B><I> format blackref whiteref</I><B>)</B>
<DD>generates an integer in the range <I>blackref</I> to
<I>whiteref</I> in a format specified by <I>format</I> representing the red
intensity of the pixel. A red intensity of 0 becomes <I>blackref</I>; a red
intensity of maxval becomes <I>whiteref</I>, with the rest linearly
interpolated in between.
<p><i>format</i> is a printf-like format specifier like "%d".
<b>ppmtoarbtxt</b> uses as the entire format string to a <b>fprintf</b> POSIX
library call whose only other argument is the red itensity as an integer data
type. <b>ppmtoarbtxt</b> does not verify that your format string makes sense;
there are values you could specify that could even crash the program.
<p><B>#(ired)</B> is equivalent to <B>#(ired %d 0 255)</B>.
<DT><B>#(igreen</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(ired...</B>, but for green.
<DT><B>#(iblue</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(ired...</B>, but for blue.
<DT><B>#(ilum</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(ired...</B>, but representing the luminance value
(0.299*red + 0.587*green + 0.114*blue) of the pixel.
<DT><B>#(fred</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(ired...</B>, but generates a floating point number instead
of an integer.
<p>In this case, the second argument to the <b>fprintf</b> that uses
<i>format</i> has a double precision floating point data type.
<p><B>#(fred)</B> is equivalent to <B>#(fred %f 0.0 1.0)</B>.
<DT><B>#(fgreen</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(fred...</B>, but for green.
<DT><B>#(fblue</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(fred...</B>, but for blue.
<DT><B>#(flum</B><I> format blackref whiteref</I><B>)</B>
<DD>Same as <B>#(fred...</B>, but representing the luminance value
(0.299*red + 0.587*green + 0.114*blue) of the pixel.
<DT><B>#(width)</B>
<DD>Generates the width in pixels of the image.
<DT><B>#(height)</B>
<DD>Generates the height in pixels of the image.
<DT><B>#(posx)</B>
<DD>Generates the horizontal position of the pixel, in pixels from the left
edge of the image.
<DT><B>#(posy)</B>
<DD>Generates the vertical position of the pixel, in pixels from the top
edge of the image.
</DL>
<P>If the skeleton file ends with a LF-character, <b>ppmtoarbtxt</b>
ignores it -- it does not include it in the output.
<H2 id="options">OPTIONS</H2>
<DL COMPACT>
<DT><B>-hd</B> <I>headskl</I>
<DD>This option causes <b>ppmtoarbtxt</b> to place the contents of
the file named <I>headskl</I> at the beginning of the output, before
the first pixel. It does the same substitutions as for
<I>bodyskl</I>, except substitutions based on a pixel value are
undefined.
<DT><B>-tl</B> <I>tailskl</I>
<DD>This option causes <b>ppmtoarbtxt</b> to place the contents of
the file named <i>tailskl</i> at the end of the output, after the
last pixel. It is analogous to <b>-hd</b>.
</DL>
<H2 id="examples">EXAMPLES</H2>
<h3>gray inversion</H3>
<P>Here we generate a PGM plain-format image with gray inversion
(like <b>ppmtopgm | pnminvert</b>).
<p>Contents of our head skeleton file:
<pre>
P2
#(width) #(height)
255
</pre>
<P>Contents of our body skeleton file:
<pre>
#(ilum %d 255 0)
</pre>
<h3>povray file</h3>
<P>Here we generate a povray file where each pixel is represented by a
sphere at location (x,y,z) = (posx,height-posy,luminance). The color
of the sphere is the color of the pixel.
<p>Contents of our head skeleton:
<pre>
#include "colors.inc"
#include "textures.inc"
camera {
location <#(width) * 0.6, #(height) * 0.7, 80>
look_at <#(width) * 0.5, #(height) * 0.5, 0>
}
light_source { <#(width) * 0.5, #(height) * 0.5, 25> color White
}
</pre>
<p>Contents of our body skeleton:
<pre>
sphere { <#(posx),#(height)-#(posy),#(ilum %d 0 10)>, 0.5
texture {
pigment {
color rgb <#(fred),#(fgreen),#(fblue)>
}
finish {
phong 1
}
}
}
</pre>
<H2 id="seealso">SEE ALSO</H2>
<A href="pnmtoplainpnm.html">pnmtoplainpnm</A>
<A href="ppm.html">ppm</A>
<H2 id="history">HISTORY</H2>
<P><B>ppmtoarbtxt</b> was added to Netpbm in Release 10.14 (March 2003).
It existed under the name <b>ppmtotxt</b> since 1995.
<H2 id="author">AUTHOR</H2>
Copyright (C) 1995 by Peter Kirchgessner
<HR>
<A NAME="index"> </A>
<H2>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="#examples">EXAMPLES</A>
<LI><A HREF="#seealso">SEE ALSO</A>
<LI><A HREF="#history">HISTORY</A>
<LI><A HREF="#author">AUTHOR</A>
</UL>
</BODY>
</HTML>
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