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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- splitted from ./en/functions/image.xml, last change in rev 1.81 -->
<refentry xml:id="function.exif-imagetype" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>exif_imagetype</refname>
<refpurpose>Determine the type of an image</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type class="union"><type>int</type><type>false</type></type><methodname>exif_imagetype</methodname>
<methodparam><type>string</type><parameter>filename</parameter></methodparam>
</methodsynopsis>
<para>
<function>exif_imagetype</function> reads the first bytes of an image and
checks its signature.
</para>
<para>
<function>exif_imagetype</function> can be used to avoid calls to other
<link linkend="ref.exif">exif</link> functions with unsupported file types
or in conjunction with <varname>$_SERVER['HTTP_ACCEPT']</varname> to check
whether or not the viewer is able to see a specific image in the browser.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>filename</parameter></term>
<listitem>
<simpara>
The image being checked.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
When a correct signature is found, the appropriate constant value will be
returned otherwise the return value is &false;. The return value is the
same value that <function>getimagesize</function> returns in index 2 but
<function>exif_imagetype</function> is much faster.
</para>
<para>
The following constants are defined, and represent possible
<function>exif_imagetype</function> return values:
<table>
<title>Imagetype Constants</title>
<tgroup cols="2">
<thead>
<row>
<entry>Value</entry>
<entry>Constant</entry>
</row>
</thead>
<tbody>
<row>
<entry>1</entry>
<entry><constant>IMAGETYPE_GIF</constant></entry>
</row>
<row>
<entry>2</entry>
<entry><constant>IMAGETYPE_JPEG</constant></entry>
</row>
<row>
<entry>3</entry>
<entry><constant>IMAGETYPE_PNG</constant></entry>
</row>
<row>
<entry>4</entry>
<entry><constant>IMAGETYPE_SWF</constant></entry>
</row>
<row>
<entry>5</entry>
<entry><constant>IMAGETYPE_PSD</constant></entry>
</row>
<row>
<entry>6</entry>
<entry><constant>IMAGETYPE_BMP</constant></entry>
</row>
<row>
<entry>7</entry>
<entry><constant>IMAGETYPE_TIFF_II</constant> (intel byte order)</entry>
</row>
<row>
<entry>8</entry>
<entry>
<constant>IMAGETYPE_TIFF_MM</constant> (motorola byte order)
</entry>
</row>
<row>
<entry>9</entry>
<entry><constant>IMAGETYPE_JPC</constant></entry>
</row>
<row>
<entry>10</entry>
<entry><constant>IMAGETYPE_JP2</constant></entry>
</row>
<row>
<entry>11</entry>
<entry><constant>IMAGETYPE_JPX</constant></entry>
</row>
<row>
<entry>12</entry>
<entry><constant>IMAGETYPE_JB2</constant></entry>
</row>
<row>
<entry>13</entry>
<entry><constant>IMAGETYPE_SWC</constant></entry>
</row>
<row>
<entry>14</entry>
<entry><constant>IMAGETYPE_IFF</constant></entry>
</row>
<row>
<entry>15</entry>
<entry><constant>IMAGETYPE_WBMP</constant></entry>
</row>
<row>
<entry>16</entry>
<entry><constant>IMAGETYPE_XBM</constant></entry>
</row>
<row>
<entry>17</entry>
<entry><constant>IMAGETYPE_ICO</constant></entry>
</row>
<row>
<entry>18</entry>
<entry><constant>IMAGETYPE_WEBP</constant></entry>
</row>
<row>
<entry>19</entry>
<entry><constant>IMAGETYPE_AVIF</constant></entry>
</row>
</tbody>
</tgroup>
</table>
</para>
<note>
<para>
<function>exif_imagetype</function> will emit an <constant>E_NOTICE</constant>
and return &false; if it is unable to read enough bytes from the file to
determine the image type.
<!-- If the function finds an incomplete PNG header then it may emit an
<constant>E_WARNING</constant> instead. - Is this worth including? -->
</para>
</note>
</refsect1>
<refsect1 role="changelog">
&reftitle.changelog;
<para>
<informaltable>
<tgroup cols="2">
<thead>
<row>
<entry>&Version;</entry>
<entry>&Description;</entry>
</row>
</thead>
<tbody>
<row>
<entry>7.1.0</entry>
<entry>
Added WebP support.
</entry>
</row>
<row>
<entry>8.1.0</entry>
<entry>
Added AVIF support.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>exif_imagetype</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
if (exif_imagetype('image.gif') != IMAGETYPE_GIF) {
echo 'The picture is not a gif';
}
?>
]]>
</programlisting>
</example>
</para>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>image_type_to_mime_type</function></member>
<member><function>getimagesize</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
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