<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Applies a filter to an image</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.imagefilltoborder.html">imagefilltoborder</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.imageflip.html">imageflip</a></div> <div class="up"><a href="ref.image.html">GD and Image Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="function.imagefilter" class="refentry"> <div class="refnamediv"> <h1 class="refname">imagefilter</h1> <p class="verinfo">(PHP 5)</p><p class="refpurpose"><span class="refname">imagefilter</span> — <span class="dc-title">Applies a filter to an image</span></p> </div> <div class="refsect1 description" id="refsect1-function.imagefilter-description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><strong>imagefilter</strong></span> ( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$image</code></span> , <span class="methodparam"><span class="type">int</span> <code class="parameter">$filtertype</code></span> [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$arg1</code></span> [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$arg2</code></span> [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$arg3</code></span> [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$arg4</code></span> ]]]] )</div> <p class="para rdfs-comment"> <span class="function"><strong>imagefilter()</strong></span> applies the given filter <em><code class="parameter">filtertype</code></em> on the <em><code class="parameter">image</code></em>. </p> </div> <div class="refsect1 parameters" id="refsect1-function.imagefilter-parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><em><code class="parameter"> image</code></em></span><dd> <p class="para">An image resource, returned by one of the image creation functions, such as <span class="function"><a href="function.imagecreatetruecolor.html" class="function">imagecreatetruecolor()</a></span>.</p></dd> </dt> <dt> <span class="term"><em><code class="parameter">filtertype</code></em></span> <dd> <p class="para"> <em><code class="parameter">filtertype</code></em> can be one of the following: <ul class="itemizedlist"> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_NEGATE</code></strong>: Reverses all colors of the image. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_GRAYSCALE</code></strong>: Converts the image into grayscale. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_BRIGHTNESS</code></strong>: Changes the brightness of the image. Use <em><code class="parameter">arg1</code></em> to set the level of brightness. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_CONTRAST</code></strong>: Changes the contrast of the image. Use <em><code class="parameter">arg1</code></em> to set the level of contrast. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_COLORIZE</code></strong>: Like <strong><code>IMG_FILTER_GRAYSCALE</code></strong>, except you can specify the color. Use <em><code class="parameter">arg1</code></em>, <em><code class="parameter">arg2</code></em> and <em><code class="parameter">arg3</code></em> in the form of <em><code class="parameter">red</code></em>, <em><code class="parameter">green</code></em>, <em><code class="parameter">blue</code></em> and <em><code class="parameter">arg4</code></em> for the <em><code class="parameter">alpha</code></em> channel. The range for each color is 0 to 255. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_EDGEDETECT</code></strong>: Uses edge detection to highlight the edges in the image. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_EMBOSS</code></strong>: Embosses the image. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_GAUSSIAN_BLUR</code></strong>: Blurs the image using the Gaussian method. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_SELECTIVE_BLUR</code></strong>: Blurs the image. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_MEAN_REMOVAL</code></strong>: Uses mean removal to achieve a "sketchy" effect. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_SMOOTH</code></strong>: Makes the image smoother. Use <em><code class="parameter">arg1</code></em> to set the level of smoothness. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_PIXELATE</code></strong>: Applies pixelation effect to the image, use <em><code class="parameter">arg1</code></em> to set the block size and <em><code class="parameter">arg2</code></em> to set the pixelation effect mode. </span> </li> </ul> </p> </dd> </dt> <dt> <span class="term"><em><code class="parameter">arg1</code></em></span> <dd> <p class="para"> <ul class="itemizedlist"> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_BRIGHTNESS</code></strong>: Brightness level. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_CONTRAST</code></strong>: Contrast level. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_COLORIZE</code></strong>: Value of red component. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_SMOOTH</code></strong>: Smoothness level. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_PIXELATE</code></strong>: Block size in pixels. </span> </li> </ul> </p> </dd> </dt> <dt> <span class="term"><em><code class="parameter">arg2</code></em></span> <dd> <p class="para"> <ul class="itemizedlist"> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_COLORIZE</code></strong>: Value of green component. </span> </li> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_PIXELATE</code></strong>: Whether to use advanced pixelation effect or not (defaults to <strong><code>FALSE</code></strong>). </span> </li> </ul> </p> </dd> </dt> <dt> <span class="term"><em><code class="parameter">arg3</code></em></span> <dd> <p class="para"> <ul class="itemizedlist"> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_COLORIZE</code></strong>: Value of blue component. </span> </li> </ul> </p> </dd> </dt> <dt> <span class="term"><em><code class="parameter">arg4</code></em></span> <dd> <p class="para"> <ul class="itemizedlist"> <li class="listitem"> <span class="simpara"> <strong><code>IMG_FILTER_COLORIZE</code></strong>: Alpha channel, A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent. </span> </li> </ul> </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues" id="refsect1-function.imagefilter-returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <strong><code>TRUE</code></strong> on success or <strong><code>FALSE</code></strong> on failure. </p> </div> <div class="refsect1 changelog" id="refsect1-function.imagefilter-changelog"> <h3 class="title">Changelog</h3> <p class="para"> <table class="doctable informaltable"> <thead> <tr> <th>Version</th> <th>Description</th> </tr> </thead> <tbody class="tbody"> <tr> <td>5.3.0</td> <td> Pixelation support (<strong><code>IMG_FILTER_PIXELATE</code></strong>) was added. </td> </tr> <tr> <td>5.2.5</td> <td> Alpha support for <strong><code>IMG_FILTER_COLORIZE</code></strong> was added. </td> </tr> </tbody> </table> </p> </div> <div class="refsect1 examples" id="refsect1-function.imagefilter-examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example" id="example-3231"> <p><strong>Example #1 <span class="function"><strong>imagefilter()</strong></span> grayscale example</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br />$im </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'dave.png'</span><span style="color: #007700">);<br /><br />if(</span><span style="color: #0000BB">$im </span><span style="color: #007700">&& </span><span style="color: #0000BB">imagefilter</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">IMG_FILTER_GRAYSCALE</span><span style="color: #007700">))<br />{<br /> echo </span><span style="color: #DD0000">'Image converted to grayscale.'</span><span style="color: #007700">;<br /><br /> </span><span style="color: #0000BB">imagepng</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #DD0000">'dave.png'</span><span style="color: #007700">);<br />}<br />else<br />{<br /> echo </span><span style="color: #DD0000">'Conversion to grayscale failed.'</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> </div> </p> <p class="para"> <div class="example" id="example-3232"> <p><strong>Example #2 <span class="function"><strong>imagefilter()</strong></span> brightness example</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br />$im </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'sean.png'</span><span style="color: #007700">);<br /><br />if(</span><span style="color: #0000BB">$im </span><span style="color: #007700">&& </span><span style="color: #0000BB">imagefilter</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">IMG_FILTER_BRIGHTNESS</span><span style="color: #007700">, </span><span style="color: #0000BB">20</span><span style="color: #007700">))<br />{<br /> echo </span><span style="color: #DD0000">'Image brightness changed.'</span><span style="color: #007700">;<br /><br /> </span><span style="color: #0000BB">imagepng</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #DD0000">'sean.png'</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">);<br />}<br />else<br />{<br /> echo </span><span style="color: #DD0000">'Image brightness change failed.'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> </div> </p> <p class="para"> <div class="example" id="example-3233"> <p><strong>Example #3 <span class="function"><strong>imagefilter()</strong></span> colorize example</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br />$im </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'philip.png'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* R, G, B, so 0, 255, 0 is green */<br /></span><span style="color: #007700">if(</span><span style="color: #0000BB">$im </span><span style="color: #007700">&& </span><span style="color: #0000BB">imagefilter</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">IMG_FILTER_COLORIZE</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">255</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">))<br />{<br /> echo </span><span style="color: #DD0000">'Image successfully shaded green.'</span><span style="color: #007700">;<br /><br /> </span><span style="color: #0000BB">imagepng</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #DD0000">'philip.png'</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">);<br />}<br />else<br />{<br /> echo </span><span style="color: #DD0000">'Green shading failed.'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> </div> </p> <p class="para"> <div class="example" id="example-3234"> <p><strong>Example #4 <span class="function"><strong>imagefilter()</strong></span> negate example</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Define our negate function so its portable for <br />// php versions without imagefilter()<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">negate</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">)<br />{<br /> if(</span><span style="color: #0000BB">function_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">'imagefilter'</span><span style="color: #007700">))<br /> {<br /> return </span><span style="color: #0000BB">imagefilter</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">IMG_FILTER_NEGATE</span><span style="color: #007700">);<br /> }<br /><br /> for(</span><span style="color: #0000BB">$x </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">; </span><span style="color: #0000BB">$x </span><span style="color: #007700">< </span><span style="color: #0000BB">imagesx</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">); ++</span><span style="color: #0000BB">$x</span><span style="color: #007700">)<br /> {<br /> for(</span><span style="color: #0000BB">$y </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">; </span><span style="color: #0000BB">$y </span><span style="color: #007700">< </span><span style="color: #0000BB">imagesy</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">); ++</span><span style="color: #0000BB">$y</span><span style="color: #007700">)<br /> {<br /> </span><span style="color: #0000BB">$index </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecolorat</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">$x</span><span style="color: #007700">, </span><span style="color: #0000BB">$y</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$rgb </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecolorsforindex</span><span style="color: #007700">(</span><span style="color: #0000BB">$index</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$color </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecolorallocate</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">255 </span><span style="color: #007700">- </span><span style="color: #0000BB">$rgb</span><span style="color: #007700">[</span><span style="color: #DD0000">'red'</span><span style="color: #007700">], </span><span style="color: #0000BB">255 </span><span style="color: #007700">- </span><span style="color: #0000BB">$rgb</span><span style="color: #007700">[</span><span style="color: #DD0000">'green'</span><span style="color: #007700">], </span><span style="color: #0000BB">255 </span><span style="color: #007700">- </span><span style="color: #0000BB">$rgb</span><span style="color: #007700">[</span><span style="color: #DD0000">'blue'</span><span style="color: #007700">]);<br /><br /> </span><span style="color: #0000BB">imagesetpixel</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #0000BB">$x</span><span style="color: #007700">, </span><span style="color: #0000BB">$y</span><span style="color: #007700">, </span><span style="color: #0000BB">$color</span><span style="color: #007700">);<br /> }<br /> }<br /><br /> return(</span><span style="color: #0000BB">true</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">$im </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefromjpeg</span><span style="color: #007700">(</span><span style="color: #DD0000">'kalle.jpg'</span><span style="color: #007700">);<br /><br />if(</span><span style="color: #0000BB">$im </span><span style="color: #007700">&& </span><span style="color: #0000BB">negate</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">))<br />{<br /> echo </span><span style="color: #DD0000">'Image successfully converted to negative colors.'</span><span style="color: #007700">;<br /><br /> </span><span style="color: #0000BB">imagejpeg</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">, </span><span style="color: #DD0000">'kalle.jpg'</span><span style="color: #007700">, </span><span style="color: #0000BB">100</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">);<br />}<br />else<br />{<br /> echo </span><span style="color: #DD0000">'Converting to negative colors failed.'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> </div> </p> <p class="para"> <div class="example" id="example-3235"> <p><strong>Example #5 <span class="function"><strong>imagefilter()</strong></span> pixelate example</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Load the PHP logo, we need to create two instances <br />// to show the differences<br /></span><span style="color: #0000BB">$logo1 </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'./php.png'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$logo2 </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'./php.png'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Create the image instance we want to show the <br />// differences on<br /></span><span style="color: #0000BB">$output </span><span style="color: #007700">= </span><span style="color: #0000BB">imagecreatetruecolor</span><span style="color: #007700">(</span><span style="color: #0000BB">imagesx</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo1</span><span style="color: #007700">) * </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">imagesy</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo1</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">// Apply pixelation to each instance, with a block <br />// size of 3<br /></span><span style="color: #0000BB">imagefilter</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo1</span><span style="color: #007700">, </span><span style="color: #0000BB">IMG_FILTER_PIXELATE</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagefilter</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo2</span><span style="color: #007700">, </span><span style="color: #0000BB">IMG_FILTER_PIXELATE</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Merge the differences onto the output image<br /></span><span style="color: #0000BB">imagecopy</span><span style="color: #007700">(</span><span style="color: #0000BB">$output</span><span style="color: #007700">, </span><span style="color: #0000BB">$logo1</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">imagesx</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo1</span><span style="color: #007700">) - </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">imagesy</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo1</span><span style="color: #007700">) - </span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagecopy</span><span style="color: #007700">(</span><span style="color: #0000BB">$output</span><span style="color: #007700">, </span><span style="color: #0000BB">$logo2</span><span style="color: #007700">, </span><span style="color: #0000BB">imagesx</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo2</span><span style="color: #007700">), </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">imagesx</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo2</span><span style="color: #007700">) - </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">imagesy</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo2</span><span style="color: #007700">) - </span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo1</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$logo2</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Output the differences<br /></span><span style="color: #0000BB">header</span><span style="color: #007700">(</span><span style="color: #DD0000">'Content-Type: image/png'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagepng</span><span style="color: #007700">(</span><span style="color: #0000BB">$output</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$output</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> <div class="example-contents"><p>The above example will output something similar to:</p></div> <div class="mediaobject"> <div class="imageobject"> <img src="images/21009b70229598c6a80eef8b45bf282b-imagefilterpixelate.png" alt="Output of example : imagefilter() pixelate" width="190" height="51" /> </div> </div> </div> </p> </div> <div class="refsect1 notes" id="refsect1-function.imagefilter-notes"> <h3 class="title">Notes</h3> <blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">This function is only available if PHP is compiled with the bundled version of the GD library.</span></p></blockquote> </div> <div class="refsect1 seealso" id="refsect1-function.imagefilter-seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"> <span class="function"><a href="function.imageconvolution.html" class="function" rel="rdfs-seeAlso">imageconvolution()</a> - Apply a 3x3 convolution matrix, using coefficient and offset</span></li> </ul> </p> </div> </div><hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.imagefilltoborder.html">imagefilltoborder</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.imageflip.html">imageflip</a></div> <div class="up"><a href="ref.image.html">GD and Image Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>