function.exif-imagetype.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Determine the type of an image</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="ref.exif.html">Exif Functions</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.exif-read-data.html">exif_read_data</a></div> <div class="up"><a href="ref.exif.html">Exif Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.exif-imagetype" class="refentry"> <div class="refnamediv"> <h1 class="refname">exif_imagetype</h1> <p class="verinfo">(PHP 4 >= 4.3.0, PHP 5)</p><p class="refpurpose"><span class="refname">exif_imagetype</span> — <span class="dc-title">Determine the type of an image</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">int</span> <span class="methodname"><b><b>exif_imagetype</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$filename</tt></span> )</div> <p class="para rdfs-comment"> <b>exif_imagetype()</b> reads the first bytes of an image and checks its signature. </p> <p class="para"> <b>exif_imagetype()</b> can be used to avoid calls to other <a href="ref.exif.html" class="link">exif</a> functions with unsupported file types or in conjunction with <var class="varname"><a href="reserved.variables.server.html" class="classname">$_SERVER['HTTP_ACCEPT']</a></var> to check whether or not the viewer is able to see a specific image in the browser. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">filename</tt></i></span> <dd> <span class="simpara"> The image being checked. </span> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> When a correct signature is found, the appropriate constant value will be returned otherwise the return value is <b><tt>FALSE</tt></b>. The return value is the same value that <a href="function.getimagesize.html" class="function">getimagesize()</a> returns in index 2 but <b>exif_imagetype()</b> is much faster. </p> </div> <div class="refsect1 changelog"> <h3 class="title">ChangeLog</h3> <p class="para"> <table class="informaltable"> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Version</th> <th colspan="1">Description</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.3.2</td> <td colspan="1" rowspan="1" align="left"> Support for <acronym title="Japan Picture">JPC</acronym>, <acronym title="JPEG-2000">JP2</acronym>, <acronym>JPX</acronym>, <acronym title="Joint Bilevel Image Experts Group">JB2</acronym>, <acronym title="X Bitmap">XBM</acronym>, and <acronym title="Wireless Bitmap">WBMP</acronym> </td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.3.0</td> <td colspan="1" rowspan="1" align="left">Support for <acronym>SWC</acronym></td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 constants"> <h3 class="title">Predefined Constants</h3> <p class="para"> The following constants are defined, and represent possible <b>exif_imagetype()</b> return values: <table border="5"> <caption><b>Imagetype Constants</b></caption> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Value</th> <th colspan="1">Constant</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">1</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_GIF</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">2</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_JPEG</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">3</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_PNG</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_SWF</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">5</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_PSD</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">6</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_BMP</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">7</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_TIFF_II</tt></b> (intel byte order)</td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">8</td> <td colspan="1" rowspan="1" align="left"> <b><tt>IMAGETYPE_TIFF_MM</tt></b> (motorola byte order) </td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">9</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_JPC</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">10</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_JP2</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">11</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_JPX</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">12</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_JB2</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">13</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_SWC</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">14</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_IFF</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">15</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_WBMP</tt></b></td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">16</td> <td colspan="1" rowspan="1" align="left"><b><tt>IMAGETYPE_XBM</tt></b></td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>exif_imagetype()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">exif_imagetype</span><span style="color: #007700">(</span><span style="color: #DD0000">'image.gif'</span><span style="color: #007700">) != </span><span style="color: #0000BB">IMAGETYPE_GIF</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">'The picture is not a gif'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.getimagesize.html" class="function" rel="rdfs-seeAlso">getimagesize()</a></li> </ul> </p> </div> </div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="ref.exif.html">Exif Functions</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.exif-read-data.html">exif_read_data</a></div> <div class="up"><a href="ref.exif.html">Exif Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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