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<!--ARC : LSARC 2005/734 GNOME For Nevada-->
<!--ARC : LSARC 2003/085 libtiff, libjpeg, and libpng-->
<!ENTITY cmd "rdjpgcom">
<!ENTITY % commonents SYSTEM "smancommon.ent">
%commonents;
<!ENTITY % booktitles SYSTEM "booktitles.ent">
%booktitles;
<!ENTITY suncopy "Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved.">
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<refentry id="rdjpgcom-1">
<!-- %Z%%M% %I% %E% SMI; -->
<refmeta><refentrytitle>rdjpgcom</refentrytitle><manvolnum>1</manvolnum>
<refmiscinfo class="date">26 Mar 2004</refmiscinfo>
<refmiscinfo class="sectdesc">&man1;</refmiscinfo>
<refmiscinfo class="software">&release;</refmiscinfo>
<refmiscinfo class="arch">generic</refmiscinfo>
<refmiscinfo class="copyright">&suncopy;</refmiscinfo>
</refmeta>
<indexterm><primary>rdjpgcom</primary></indexterm><indexterm><primary>display
text comments from a JPEG file</primary></indexterm>
<refnamediv id="rdjpgcom-1-name"><refname>rdjpgcom</refname><refpurpose>display
text comments from a JPEG file</refpurpose></refnamediv>
<refsynopsisdiv id="rdjpgcom-1-synp"><title>&synp-tt;</title>
<cmdsynopsis><command>&cmd;</command><arg choice="opt"><option>verbose</option></arg>
<arg choice="opt"><option role="nodash"><replaceable>filename</replaceable></option></arg>
</cmdsynopsis></refsynopsisdiv>
<refsect1 id="rdjpgcom-1-desc"><title>&desc-tt;</title>
<para><command>&cmd;</command> reads the named JPEG or JFIF file, or the standard
input if no file is named, and displays any text comments found in the file
on the standard output.</para>
<para>The JPEG standard allows "comment" (COM) blocks to occur within a JPEG
file. Although the standard does not actually define the intended function
of COM blocks, they are widely used to hold user-supplied text strings. This
enables you to add annotations, titles, index terms, and so on to your JPEG
files, and later retrieve the COM blocks as text. COM blocks do not interfere
with the image stored in the JPEG file. The maximum size of a COM block is
64K, but you can have many COM blocks in one JPEG file.</para>
</refsect1>
<refsect1 id="rdjpgcom-1-opts"><title>&opts-tt;</title>
<para>The following options are supported:</para>
<variablelist termlength="narrow">
<varlistentry><term><option>verbose</option></term><listitem><para>Causes <command>&cmd;</command>
to also display the JPEG image dimensions.</para>
</listitem></varlistentry>
</variablelist></refsect1>
<refsect1 id="rdjpgcom-1-oper"><title>&oper-tt;</title>
<para>The following operands are supported:</para>
<variablelist termlength="narrow">
<varlistentry><term><option role="nodash"><replaceable>filename</replaceable></option></term>
<listitem><para>The name of the JPEG file that contains text comments.</para>
</listitem></varlistentry>
</variablelist></refsect1>
<refsect1 id="rdjpgcom-1-exde"><title>&exde-tt;</title>
<para><command>&cmd;</command> does not depend on the IJG JPEG library. The <command>&cmd;</command>
source code is intended to illustrate the minimum amount of code required
to parse a JPEG file header correctly. </para>
<para>In <option>verbose</option> mode, <command>&cmd;</command> also attempts
to display the contents of any "APP12" markers as text. Some digital cameras
produce APP12 markers that contain useful textual information. You can also
modify the source code to display other APP<replaceable>n</replaceable>
marker types.</para>
</refsect1>
<refsect1 id="rdjpgcom-1-attr"><title>&attr-tt;</title>
<para>See <olink targetdocent="REFMAN5" localinfo="attributes-5"><citerefentry>
<refentrytitle>attributes</refentrytitle><manvolnum>5</manvolnum></citerefentry></olink>
for descriptions of the following attributes:</para>
<informaltable frame="all">
<tgroup cols="2" colsep="1" rowsep="1"><colspec colname="COLSPEC0" colwidth="1*">
<colspec colname="COLSPEC1" colwidth="1*">
<thead>
<row><entry align="center" valign="middle">ATTRIBUTE TYPE</entry><entry align="center"
valign="middle">ATTRIBUTE VALUE</entry></row>
</thead>
<tbody>
<row><entry><para>Availability</para></entry><entry><para>image/library/libjpeg</para></entry>
</row>
<row><entry colname="COLSPEC0"><para>Interface stability</para></entry><entry
colname="COLSPEC1"><para>Volatile</para></entry></row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 id="rdjpgcom-1-also"><title>&also-tt;</title>
<!--Reference to another man page-->
<!--Reference to a Help manual-->
<!--Reference to a book.-->
<para><citerefentry><refentrytitle>cjpeg</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>, <citerefentry><refentrytitle>djpeg</refentrytitle><manvolnum>
1</manvolnum></citerefentry>, <citerefentry><refentrytitle>jpegtran</refentrytitle>
<manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>wrjpgcom
</refentrytitle><manvolnum>1</manvolnum></citerefentry></para>
</refsect1>
<refsect1 id="rdjpgcom-1-note"><title>&note-tt;</title>
<para>This man page was originally written by the Independent JPEG Group.
Updated by Breda McColgan, Sun Microsystems Inc., 2004. </para>
</refsect1>
</refentry>
