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README.html
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<div class="document" id="libpnmio-user-manual">
<h1 class="title">libpnmio user manual</h1>
<table border="1" class="docutils">
<colgroup>
<col width="25%" />
<col width="75%" />
</colgroup>
<tbody valign="top">
<tr><td><strong>Title</strong></td>
<td>libpnmio (I/O PNM library)</td>
</tr>
<tr><td><strong>Author</strong></td>
<td>Nikolaos Kavvadias 2012, 2013, 2014, 2015, 2016, 2017,
2018, 2019, 2020</td>
</tr>
<tr><td><strong>Contact</strong></td>
<td><a class="reference external" href="mailto:nikolaos.kavvadias@gmail.com">nikolaos.kavvadias@gmail.com</a></td>
</tr>
<tr><td><strong>Website</strong></td>
<td><a class="reference external" href="http://www.nkavvadias.com">http://www.nkavvadias.com</a></td>
</tr>
<tr><td><strong>Release Date</strong></td>
<td>10 March 2016</td>
</tr>
<tr><td><strong>Version</strong></td>
<td>1.2.6</td>
</tr>
<tr><td><strong>Rev. history</strong></td>
<td> </td>
</tr>
<tr><td><strong>v1.2.6</strong></td>
<td><p class="first">2016-03-10</p>
<p class="last">Add sftbyvec.c, related changes.</p>
</td>
</tr>
<tr><td><strong>v1.2.5</strong></td>
<td><p class="first">2014-10-28</p>
<p class="last">Fixed bugs in PFM format I/O.</p>
</td>
</tr>
<tr><td><strong>v1.2.4</strong></td>
<td><p class="first">2014-10-28</p>
<p class="last">Added names to prototype parameters.</p>
</td>
</tr>
<tr><td><strong>v1.2.3</strong></td>
<td><p class="first">2014-10-28</p>
<p class="last">Documentation update; add <tt class="docutils literal">get_pnm_type</tt> and reference
to the IrfanView image viewer.</p>
</td>
</tr>
<tr><td><strong>v1.2.2</strong></td>
<td><p class="first">2014-10-26</p>
<ul class="last simple">
<li>New test application, <tt class="docutils literal">rnwimg</tt> for reading and
writing PBM, PGM, PPM and PFM images.</li>
<li>Numerous bug fixes to <tt class="docutils literal">read_p*m_header</tt> routines.</li>
<li>Added <tt class="docutils literal">get_pnm_type</tt>.</li>
<li>Removed <tt class="docutils literal">squares.binary.pgm</tt> (all-black image).</li>
<li>Removed <tt class="docutils literal">feep.ascii.ppm</tt> (incomplete image).</li>
<li>PFM reading still needs work.</li>
</ul>
</td>
</tr>
<tr><td><strong>v1.2.1</strong></td>
<td><p class="first">2014-10-25</p>
<p class="last">Added sample PBM, PGM, PPM and PFM images for testing.</p>
</td>
</tr>
<tr><td><strong>v1.2.0</strong></td>
<td><p class="first">2014-10-25</p>
<p class="last">Added support for reading and writing PFM (Portable Float
Map) image data files.</p>
</td>
</tr>
<tr><td><strong>v1.1.1</strong></td>
<td><p class="first">2014-10-01</p>
<p class="last">Date notation change.</p>
</td>
</tr>
<tr><td><strong>v1.1.0</strong></td>
<td><p class="first">2014-09-23</p>
<p class="last">Moved AUTHORS, LICENSE, README, VERSION to top-level.</p>
</td>
</tr>
<tr><td><strong>v1.0.1</strong></td>
<td><p class="first">2014-06-14</p>
<p class="last">Changed README to README.rst.</p>
</td>
</tr>
<tr><td><strong>v1.0.0</strong></td>
<td><p class="first">2014-02-20</p>
<p class="last">First public release.</p>
</td>
</tr>
</tbody>
</table>
<div class="section" id="introduction">
<h1>1. Introduction</h1>
<p>The <tt class="docutils literal">libpnmio</tt> library provides an implementation and API for reading
and writing <a class="reference external" href="http://en.wikipedia.org/wiki/Netpbm_format">PNM</a> (some times termed as Portable AnyMap) images. The <a class="reference external" href="http://en.wikipedia.org/wiki/Netpbm_format">PNM</a>
convention is collectively used to address <a class="reference external" href="http://netpbm.sourceforge.net/doc/pbm.html">PBM</a> (Portable Bitmap), <a class="reference external" href="http://netpbm.sourceforge.net/doc/pgm.html">PGM</a>
(Portable Greymap) and <a class="reference external" href="http://netpbm.sourceforge.net/doc/ppm.html">PPM</a> (Portable Pixmap) images.</p>
<p>The current version of <tt class="docutils literal">libpnmio</tt> supports the ASCII variation of the
PNM formats, however, it will be extended in order to support the
corresponding binary formats.</p>
<p>The library is accompanied by the following test applications:</p>
<ul class="simple">
<li><tt class="docutils literal">randimg</tt>: produces PBM/PGM/PPM image files filled with random data</li>
<li><tt class="docutils literal">doset</tt>: generates a color illustration of the Mandelbrot set</li>
<li><tt class="docutils literal">rnwimg</tt>: reads and writes PBM/PGM/PPM/PFM images for testing the library</li>
<li><tt class="docutils literal">sftbyvec</tt>: reads an input ASCII PGM image, shifts its contents by a
given vector and then writes it back.</li>
</ul>
<p>Since version 1.2.0, support for the Portable Float Map format (<a class="reference external" href="http://netpbm.sourceforge.net/doc/pfm.html">PFM</a>) has been
added.</p>
<p>Additional information on the PFM format can be found at the
<a class="reference external" href="http://paulbourke.net/dataformats/pbmhdr/">PFM page by Paul Bourke</a>.</p>
<p>Reference documentation for LIBPNMIO can be found in the <tt class="docutils literal">/doc</tt> subdirectory
in plain text, HTML and PDF form.</p>
</div>
<div class="section" id="file-listing">
<h1>2. File listing</h1>
<p>The <tt class="docutils literal">libpnmio</tt> distribution includes the following files:</p>
<table border="1" class="docutils">
<colgroup>
<col width="30%" />
<col width="70%" />
</colgroup>
<tbody valign="top">
<tr><td>/libpnmio</td>
<td>Top-level directory</td>
</tr>
<tr><td>AUTHORS</td>
<td>List of authors.</td>
</tr>
<tr><td>LICENSE</td>
<td>License agreement (modified BSD license).</td>
</tr>
<tr><td>README.rst</td>
<td>This file.</td>
</tr>
<tr><td>README.html</td>
<td>HTML version of README.rst.</td>
</tr>
<tr><td>README.pdf</td>
<td>PDF version of README.rst.</td>
</tr>
<tr><td>VERSION</td>
<td>Current version of the LIBPNMIO distribution.</td>
</tr>
<tr><td>rst2docs.sh</td>
<td>Shell script for generating the documentation using
<tt class="docutils literal">docutils</tt>.</td>
</tr>
<tr><td>/bin</td>
<td>Executables directory (initially empty)</td>
</tr>
<tr><td>/images</td>
<td>Image data (PBM, PGM, PPM, PFM) for testing</td>
</tr>
<tr><td>*.pbm, *.pgm,
*.ppm, *.pfm</td>
<td>Sample images.</td>
</tr>
<tr><td>/lib</td>
<td>Compiled static library directory</td>
</tr>
<tr><td>/src</td>
<td>Source code directory</td>
</tr>
<tr><td>Makefile</td>
<td>Makefile for compiling the library and generating
the executables.</td>
</tr>
<tr><td>doset.c</td>
<td>Generates a color visualization of the Mandelbrot
set.</td>
</tr>
<tr><td>pnmio.c</td>
<td>Implementation of the <tt class="docutils literal">libpnmio</tt> library in C.</td>
</tr>
<tr><td>pnmio.h</td>
<td>Header file (interface) of the <tt class="docutils literal">libpnmio</tt> library.</td>
</tr>
<tr><td>randimg.c</td>
<td>Random PBM/PGM/PPM/PFM image generator.</td>
</tr>
<tr><td>rnwimg.c</td>
<td>Reads and writes PBM/PGM/PPM/PFM images for
exercising the <tt class="docutils literal">libpnmio</tt> API.</td>
</tr>
<tr><td>sftbyvec.c</td>
<td>Read an input ASCII PGM image, shift its contents by
a given vector and then writes it back</td>
</tr>
<tr><td>/test</td>
<td>Test script directory</td>
</tr>
<tr><td>run-doset.sh</td>
<td>Bash script for running the Mandelbrot set example.</td>
</tr>
<tr><td>run-randimg.sh</td>
<td>Bash script for running the random image generator.</td>
</tr>
<tr><td>run-rnwimg.sh</td>
<td>Bash script for running the read-and-write API tests.</td>
</tr>
<tr><td>run-sftbyvec.sh</td>
<td>Bash script for running the shift-by-vector tests.</td>
</tr>
</tbody>
</table>
<p>The original sources for the images included in the <tt class="docutils literal">/libpnmio/images</tt>
directory are the following:</p>
<ul class="simple">
<li><em>prague, squares, lena32, fruit, blocks</em><ul>
<li><a class="reference external" href="http://graphics.stanford.edu/~jowens/223b/examples.html">http://graphics.stanford.edu/~jowens/223b/examples.html</a></li>
</ul>
</li>
<li><em>letter_j, feep, ppmex255.ascii, ppmex1</em><ul>
<li><a class="reference external" href="http://en.wikipedia.org/wiki/Netpbm_format">http://en.wikipedia.org/wiki/Netpbm_format</a></li>
</ul>
</li>
<li><em>haus</em><ul>
<li><a class="reference external" href="http://goo.gl/DBbPpF">http://goo.gl/DBbPpF</a></li>
</ul>
</li>
<li><em>ppmex255.binary</em><ul>
<li><a class="reference external" href="http://wiki.multimedia.cx/index.php">http://wiki.multimedia.cx/index.php</a></li>
</ul>
</li>
</ul>
</div>
<div class="section" id="api-description">
<h1>3. API description</h1>
<p>This section summarizes the intended functionality of the functions supported
by the <tt class="docutils literal">libpnmio</tt> application programming interface.</p>
<div class="section" id="get-pnm-type">
<h2>3.1 get_pnm_type</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">int get_pnm_type(FILE *f);</tt></div>
</div>
<p>Read the header contents of a PBM/PGM/PPM/PFM file up to the point of extracting
its type. Valid types for a PNM image are as follows:</p>
<ul class="simple">
<li><tt class="docutils literal">PBM_ASCII</tt> = 1</li>
<li><tt class="docutils literal">PGM_ASCII</tt> = 2</li>
<li><tt class="docutils literal">PPM_ASCII</tt> = 3</li>
<li><tt class="docutils literal">PBM_BINARY</tt> = 4</li>
<li><tt class="docutils literal">PGM_BINARY</tt> = 5</li>
<li><tt class="docutils literal">PPM_BINARY</tt> = 6</li>
<li><tt class="docutils literal">PAM</tt> = 7 (unimplemented)</li>
<li><tt class="docutils literal">PFM_RGB</tt> = 16</li>
<li><tt class="docutils literal">PFM_GREYSCALE</tt> = 17</li>
</ul>
<p>The result (pnm_type) is returned.</p>
</div>
<div class="section" id="read-pbm-header">
<h2>3.2 read_pbm_header</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_pbm_header(FILE *f, int *img_xdim, int *img_ydim, int is_ascii);</tt></div>
</div>
<p>Read the header contents of a PBM (portable bit map) file. A PBM image file
follows the format:</p>
<pre class="literal-block">
P1
<X> <Y>
<I1> <I2> ... <IMAX>
</pre>
<p>A binary PBM image file uses P4 instead of P1 and the data values are
represented in binary.
Comment lines start with <tt class="docutils literal">#</tt>.
<tt class="docutils literal">< ></tt> denote integer values (in decimal). For the PBM format, they can
take only the 0 and 1 values.
<tt class="docutils literal">img_xdim</tt> and <tt class="docutils literal">img_ydim</tt> correspond to <tt class="docutils literal">X</tt> and <tt class="docutils literal">Y</tt>, respectively.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PBM file is assumed; otherwise a binary PBM file
is.</p>
</div>
<div class="section" id="read-pgm-header">
<h2>3.3 read_pgm_header</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">read_pgm_header(FILE *f, int *img_xdim, int *img_ydim, int *img_colors, int is_ascii);</tt></div>
</div>
<p>Read the header contents of a PGM (portable grey map) file. A PGM image file
follows the format:</p>
<pre class="literal-block">
P2
<X> <Y>
<levels>
<I1> <I2> ... <IMAX>
</pre>
<p>A binary PGM image file uses P5 instead of P2 and the data values are
represented in binary.
Comment lines start with <tt class="docutils literal">#</tt>.
<tt class="docutils literal">< ></tt> denote integer values (in decimal).
<tt class="docutils literal">img_xdim</tt>, <tt class="docutils literal">img_ydim</tt>, and <tt class="docutils literal">img_colors</tt> correspond to <tt class="docutils literal">X</tt>, <tt class="docutils literal">Y</tt>
and <tt class="docutils literal">levels</tt>, respectively.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PGM file is assumed; otherwise a binary PGM file
is.</p>
</div>
<div class="section" id="read-ppm-header">
<h2>3.4 read_ppm_header</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_ppm_header(FILE *f, int *img_xdim, int *img_ydim, int *img_colors, int is_ascii);</tt></div>
</div>
<p>Read the header contents of a PPM (portable pix map) file. A PPM image file
follows the format:</p>
<pre class="literal-block">
P3
<X> <Y>
<levels>
<R1> <G1> <B1> ... <RMAX> <GMAX> <BMAX>
</pre>
<p>A binary PPM image file uses P6 instead of P3 and the data values are
represented in binary.
Comment lines start with <tt class="docutils literal">#</tt>.
<tt class="docutils literal">< ></tt> denote integer values (in decimal).
<tt class="docutils literal">img_xdim</tt>, <tt class="docutils literal">img_ydim</tt>, and <tt class="docutils literal">img_colors</tt> correspond to <tt class="docutils literal">X</tt>, <tt class="docutils literal">Y</tt>
and <tt class="docutils literal">levels</tt>, respectively. Each color component, R, G, and B can take any
value from 0 to levels.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PPM file is assumed; otherwise a binary PPM file
is.</p>
</div>
<div class="section" id="read-pfm-header">
<h2>3.5 read_pfm_header</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_pfm_header(FILE *f, int *img_xdim, int *img_ydim, int *img_type, int *endianess);</tt></div>
</div>
<p>Read the header contents of a PFM (portable float map) file. A PFM image file
follows the format:</p>
<pre class="literal-block">
[PF|Pf]
<X> <Y>
(endianess)
{R1}{G1}{B1} ... {RMAX}{GMAX}{BMAX}
</pre>
<p>A PFM image file has its data values represented in binary.
Comment lines start with <tt class="docutils literal">#</tt>.
<tt class="docutils literal">< ></tt> denote integer values (in decimal).
<tt class="docutils literal">( )</tt> denote floating-point values (in decimal).
<tt class="docutils literal">{ }</tt> denote floating-point values (coded in binary).
<tt class="docutils literal">img_xdim</tt> and <tt class="docutils literal">img_ydim</tt> correspond to <tt class="docutils literal">X</tt> and <tt class="docutils literal">Y</tt>, respectively. If
<tt class="docutils literal">img_type</tt> is equal to 1, the PFM image encodes RGB (color) information,
otherwise if it is equal to 0, it stores greyscale information.
If <tt class="docutils literal">endianess</tt> is negative (-1), the binary data are encoded in little-endian
ordering, otherwise if <tt class="docutils literal">endianess</tt> is positive (+1), the data follow
big-endian ordering.</p>
</div>
<div class="section" id="read-pbm-data">
<h2>3.6 read_pbm_data</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_pgm_data(FILE *f, int *img_in, int is_ascii);</tt></div>
</div>
<p>Read the data contents of a PBM (portable bit map) file.
<tt class="docutils literal">img_in</tt> denotes an array of integer values representing image data.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PBM file is assumed; otherwise a binary PBM file
is.</p>
</div>
<div class="section" id="read-pgm-data">
<h2>3.7 read_pgm_data</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_pgm_data(FILE *f, int *img_in, int is_ascii);</tt></div>
</div>
<p>Read the data contents of a PGM (portable grey map) file.
<tt class="docutils literal">img_in</tt> denotes an array of integer values representing image data.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PGM file is assumed; otherwise a binary PGM file
is.</p>
</div>
<div class="section" id="read-ppm-data">
<h2>3.8 read_ppm_data</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_ppm_data(FILE *f, int *img_in, int is_ascii);</tt></div>
</div>
<p>Read the data contents of a PPM (portable pix map) file.
<tt class="docutils literal">img_in</tt> denotes an array of integer values representing image data.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PPM file is assumed; otherwise a binary PPM file
is.</p>
</div>
<div class="section" id="read-pfm-data">
<h2>3.9 read_pfm_data</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void read_ppm_data(FILE *f, float *img_in, int img_type, int endianess);</tt></div>
</div>
<p>Read the data contents of a PFM (portable float map) file.
<tt class="docutils literal">img_in</tt> denotes an array of floating-point (<tt class="docutils literal">float</tt>) values representing
image data. If <tt class="docutils literal">img_type</tt> is 1, color/RGB image data are assumed; otherwise
(0) the image data are in greyscale. A negative <tt class="docutils literal">endianess</tt> indicates
little-endian ordering and positive one, big-endian.</p>
</div>
<div class="section" id="write-pbm-file">
<h2>3.10 write_pbm_file</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void write_pbm_file(FILE *f, int *img_out,</tt></div>
<div class="line"><tt class="docutils literal">int x_size, int y_size, int x_scale_val, int y_scale_val, int linevals, int is_ascii);</tt></div>
</div>
<p>Write the contents of a PBM (portable bit map) file.
Data stored in array <tt class="docutils literal">img_out</tt> are written to file <tt class="docutils literal">f</tt>. The
image data represent an image of size <tt class="docutils literal">x_size</tt> by <tt class="docutils literal">y_size</tt>. x-axis and
y-axis scaling factors can be defined by <tt class="docutils literal">x_scale_val</tt> and <tt class="docutils literal">y_scale_val</tt>.
<tt class="docutils literal">linevals</tt> determines the emission of newline characters for easier
reading of the PBM file data.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PBM file is assumed; otherwise a binary PBM file
is.</p>
</div>
<div class="section" id="write-pgm-file">
<h2>3.11 write_pgm_file</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void write_pgm_file(FILE *f, int *img_out,</tt></div>
<div class="line"><tt class="docutils literal">int x_size, int y_size, int x_scale_val, int y_scale_val, int img_colors,</tt></div>
<div class="line"><tt class="docutils literal">int linevals, int is_ascii);</tt></div>
</div>
<p>Write the contents of a PGM (portable grey map) file.
Data stored in array <tt class="docutils literal">img_out</tt> are written to file <tt class="docutils literal">f</tt>. The
image data represent an image of size <tt class="docutils literal">x_size</tt> by <tt class="docutils literal">y_size</tt>. x-axis and
y-axis scaling factors can be defined by <tt class="docutils literal">x_scale_val</tt> and <tt class="docutils literal">y_scale_val</tt>.
<tt class="docutils literal">img_colors</tt> determines the levels (0 to levels) for the common color
component.
<tt class="docutils literal">linevals</tt> determines the emission of newline characters for easier
reading of the PGM file data.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PGM file is assumed; otherwise a binary PGM file
is.</p>
</div>
<div class="section" id="write-ppm-file">
<h2>3.12 write_ppm_file</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void write_ppm_file(FILE *f, int *img_out,</tt></div>
<div class="line"><tt class="docutils literal">int x_size, int y_size, int x_scale_val, int y_scale_val, int img_colors, int is_ascii);</tt></div>
</div>
<p>Write the contents of a PPM (portable pix map) file.
Data stored in array <tt class="docutils literal">img_out</tt> are written to file <tt class="docutils literal">f</tt>. The
image data represent an image of size <tt class="docutils literal">x_size</tt> by <tt class="docutils literal">y_size</tt>. x-axis and
y-axis scaling factors can be defined by <tt class="docutils literal">x_scale_val</tt> and <tt class="docutils literal">y_scale_val</tt>.
<tt class="docutils literal">img_colors</tt> determines the levels (0 to levels) for the common color
component. Each R-G-B triplet is printed to a separate line.
If <tt class="docutils literal">is_ascii</tt> is 1, an ASCII PPM file is assumed; otherwise a binary PPM file
is.</p>
</div>
<div class="section" id="write-pfm-file">
<h2>3.13 write_pfm_file</h2>
<div class="line-block">
<div class="line"><tt class="docutils literal">void write_pfm_file(FILE *f, float *img_out,</tt></div>
<div class="line"><tt class="docutils literal">int x_size, int y_size, int img_type, int endianess);</tt></div>
</div>
<p>Write the contents of a PFM (portable float map) file.
Data stored in array <tt class="docutils literal">img_out</tt> are written to file <tt class="docutils literal">f</tt>. The
image data represent an image of size <tt class="docutils literal">x_size</tt> by <tt class="docutils literal">y_size</tt>. x-axis and
y-axis scaling factors can be defined by <tt class="docutils literal">x_scale_val</tt> and <tt class="docutils literal">y_scale_val</tt>.
If <tt class="docutils literal">img_type</tt> is equal to 1, the PFM image encodes RGB (color) information,
otherwise if it is equal to 0, it stores greyscale information.
If <tt class="docutils literal">endianess</tt> is negative (-1), the binary data are encoded in little-endian
ordering, otherwise if <tt class="docutils literal">endianess</tt> is positive (+1), the data follow
big-endian ordering.</p>
</div>
</div>
<div class="section" id="build-and-setup">
<h1>4. Build and setup</h1>
<p>In order to produce the static library, change directory to <tt class="docutils literal">/src</tt> and
run the Makefile as follows:</p>
<div class="line-block">
<div class="line"><tt class="docutils literal">$ make clean ; make</tt></div>
</div>
<p>This will produce the static library <tt class="docutils literal">libpnmio.a</tt> and copy it to the
<tt class="docutils literal">/lib</tt> subdirectory of the distribution. The executable files for the
reference applications will also be generated and copied to the <tt class="docutils literal">/bin</tt>
subdirectory.</p>
</div>
<div class="section" id="run-tests">
<h1>5. Run tests</h1>
<p>Two sample scripts are provided in the <tt class="docutils literal">/test</tt> subdirectory. Change
directory to <tt class="docutils literal">/test</tt> and run the scripts as follows:</p>
<div class="line-block">
<div class="line"><tt class="docutils literal">$ cd test</tt></div>
<div class="line"><tt class="docutils literal">$ <span class="pre">./run-doset.sh</span></tt></div>
<div class="line"><tt class="docutils literal">$ <span class="pre">./run-randimg.sh</span></tt></div>
<div class="line"><tt class="docutils literal">$ <span class="pre">./run-rnwimg.sh</span></tt></div>
<div class="line"><tt class="docutils literal">$ <span class="pre">./run-sftbyvec.sh</span></tt></div>
</div>
<p>PBM, PGM and PPM files can be directly visualized by using freeware image
viewers such as <a class="reference external" href="http://www.xnview.com">XnView</a>, <a class="reference external" href="http://www.irfanview.com">IrfanView</a> (non-commercial use only) and <a class="reference external" href="http://www.nyam.pe.kr/">Imagine</a>. The
informal/non-standardized PFM format was introduced by <a class="reference external" href="http://www.pauldebevec.com/Research/HDR/">Paul Debevec</a>. A PFM
viewer (<tt class="docutils literal">HDRView</tt>) can be found here:
<a class="reference external" href="http://web.archive.org/web/20060614160328/http://www.debevec.org/FiatLux/hdrview/">http://web.archive.org/web/20060614160328/http://www.debevec.org/FiatLux/hdrview/</a> .</p>
</div>
<div class="section" id="prerequisites">
<h1>6. Prerequisites</h1>
<ul>
<li><p class="first">Standard UNIX-based tools (tested with gcc-4.6.2 and gcc-4.8.1 on MinGW/x64).</p>
<ul class="simple">
<li>make</li>
<li>bash (shell)</li>
</ul>
<p>For this reason, MinGW (<a class="reference external" href="http://www.mingw.org">http://www.mingw.org</a>) or Cygwin
(<a class="reference external" href="http://sources.redhat.com/cygwin">http://sources.redhat.com/cygwin</a>) are suggested, since POSIX emulation
environments of sufficient completeness.</p>
</li>
</ul>
</div>
</div>
</body>
</html>