php-doc-en/reference/image/functions/imageconvolution.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.imageconvolution" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>imageconvolution</refname>
  <refpurpose>Apply a 3x3 convolution matrix, using coefficient and offset</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>imageconvolution</methodname>
   <methodparam><type>resource</type><parameter>image</parameter></methodparam>
   <methodparam><type>array</type><parameter>matrix</parameter></methodparam>
   <methodparam><type>float</type><parameter>div</parameter></methodparam>
   <methodparam><type>float</type><parameter>offset</parameter></methodparam>
  </methodsynopsis>
  <para>
   Applies a convolution matrix on the image, using the given coefficient and
   offset.
  </para>
 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    &gd.image.description;
    <varlistentry>
     <term><parameter>matrix</parameter></term>
     <listitem>
      <para>
       A 3x3 matrix: an array of three arrays of three floats.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>div</parameter></term>
     <listitem>
      <para>
       The divisor of the result of the convolution, used for normalization.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>offset</parameter></term>
     <listitem>
      <para>
       Color offset.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &return.success;
  </para>
 </refsect1>
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>Embossing the PHP.net logo</title>
    <programlisting role="php">
<![CDATA[
<?php
$image = imagecreatefromgif('http://www.php.net/images/php.gif');

$emboss = array(array(2, 0, 0), array(0, -1, 0), array(0, 0, -1));
imageconvolution($image, $emboss, 1, 127);

header('Content-Type: image/png');
imagepng($image, null, 9);
?>
]]>
    </programlisting>
    &example.outputs;
    <mediaobject>
     <alt>Output of example : Embossing the PHP.net logo</alt>
     <imageobject>
      <imagedata fileref="en/reference/image/figures/imageconvolution_emboss.png"/>
     </imageobject>
    </mediaobject>
   </example>
   <example>
    <title>Gaussian blur</title>
    <programlisting role="php">
<![CDATA[
<?php
$image = imagecreatetruecolor(180,40);

// Writes the text and apply a gaussian blur on the image
imagestring($image, 5, 10, 8, 'Gaussian Blur Text', 0x00ff00);
$gaussian = array(array(1.0, 2.0, 1.0), array(2.0, 4.0, 2.0), array(1.0, 2.0, 1.0));
imageconvolution($image, $gaussian, 16, 0);

// Rewrites the text for comparison
imagestring($image, 5, 10, 18, 'Gaussian Blur Text', 0x00ff00);

header('Content-Type: image/png');
imagepng($image, null, 9);
?>
]]>
    </programlisting>
    &example.outputs;
    <mediaobject>
     <alt>Output of example : Gaussian blur</alt>
     <imageobject>
      <imagedata fileref="en/reference/image/figures/imageconvolution_gaussian.png"/>
     </imageobject>
    </mediaobject>
   </example>
  </para>
 </refsect1>
 <refsect1 role="notes">
  &reftitle.notes;
  &note.bundled.gd;
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>imagefilter</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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