exif-thumbnail.xml

<?xml version="1.0" encoding="utf-8"?>
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<!-- splitted from ./en/functions/image.xml, last change in rev 1.78 -->
<refentry xml:id="function.exif-thumbnail" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>exif_thumbnail</refname>
  <refpurpose>Retrieve the embedded thumbnail of an image</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>string</type><type>false</type></type><methodname>exif_thumbnail</methodname>
   <methodparam><type class="union"><type>resource</type><type>string</type></type><parameter>file</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter role="reference">width</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter role="reference">height</parameter><initializer>&null;</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter role="reference">image_type</parameter><initializer>&null;</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>exif_thumbnail</function> reads the embedded thumbnail of an image. 
  </para>
  <para>
   If you want to deliver thumbnails through this function, you should send
   the mimetype information using the <function>header</function> function.
  </para>
  <para>
   It is possible that <function>exif_thumbnail</function> cannot create an 
   image but can determine its size. In this case, the return value is 
   &false; but <parameter>width</parameter> and <parameter>height</parameter> 
   are set.
  </para>
 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>file</parameter></term>
     <listitem>
      <para>
       The location of the image file. This can either be a path to the file 
       or a stream <type>resource</type>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>width</parameter></term>
     <listitem>
      <para>
       The return width of the returned thumbnail.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>height</parameter></term>
     <listitem>
      <para>
       The returned height of the returned thumbnail.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>image_type</parameter></term>
     <listitem>
      <para>
       The returned image type of the returned thumbnail.  This is either
       <acronym>TIFF</acronym> or <acronym>JPEG</acronym>.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the embedded thumbnail, or &false; if the image contains no 
   thumbnail.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>7.2.0</entry>
       <entry>
        The <parameter>file</parameter> parameter now supports both local files
        and stream resources.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>exif_thumbnail</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$image = exif_thumbnail('/path/to/image.jpg', $width, $height, $type);

if ($image!==false) {
    header('Content-type: ' .image_type_to_mime_type($type));
    echo $image;
    exit;
} else {
    // no thumbnail available, handle the error here
    echo 'No thumbnail available';
}
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    If the <parameter>file</parameter> is used to pass a stream to this function, then the stream 
    must be seekable. Note that the file pointer position is not changed after this function returns.
   </para>
  </note>
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>exif_read_data</function></member>
    <member><function>image_type_to_mime_type</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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