php-doc-en/reference/imagick/imagickpixel/issimilar.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xmlns="http://docbook.org/ns/docbook" xml:id="imagickpixel.issimilar">
 <refnamediv>
  <refname>ImagickPixel::isSimilar</refname>
  <refpurpose>Check the distance between this color and another</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>ImagickPixel::isSimilar</methodname>
   <methodparam><type>ImagickPixel</type><parameter>color</parameter></methodparam>
   <methodparam><type>float</type><parameter>fuzz</parameter></methodparam>
  </methodsynopsis>
  &warn.undocumented.func;
  <para>
   Checks the distance between the color described by this ImagickPixel
   object and that of the provided object, by plotting their RGB values
   on the color cube. If the distance between the two points is less than
   the fuzz value given, the colors are similar.
   Deprecated in favour of <link linkend="imagickpixel.ispixelsimilar">ImagickPixel::isPixelSimilar()</link>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>color</parameter></term>
     <listitem>
      <para>
       The ImagickPixel object to compare this object against.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>fuzz</parameter></term>
     <listitem>
      <para>
       The maximum distance within which to consider these colors as similar.
       The theoretical maximum for this value is the square root of three
       (1.732).
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>

 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &imagick.return.success;
  </para>
 </refsect1>



 <refsect1 role="examples">
  &reftitle.examples;
  <para>
    <example>
      <title> <function>ImagickPixel::isSimilar</function></title>
      <programlisting role="php">
      <![CDATA[
<?php
        // The tests below are written with the maximum distance expressed as 255
        // so we need to scale them by the square root of 3 - the diagonal length
        // of a unit cube.
        $root3 = 1.732050807568877;

        $tests = array(
            ['rgb(245, 0, 0)',      'rgb(255, 0, 0)',   9 / $root3,         false,],
            ['rgb(245, 0, 0)',      'rgb(255, 0, 0)',  10 / $root3,         true,],
            ['rgb(0, 0, 0)',        'rgb(7, 7, 0)',     9 / $root3,         false,],
            ['rgb(0, 0, 0)',        'rgb(7, 7, 0)',    10 / $root3,         true,],
            ['rgba(0, 0, 0, 1)',    'rgba(7, 7, 0, 1)', 9 / $root3,         false,],
            ['rgba(0, 0, 0, 1)',    'rgba(7, 7, 0, 1)',    10 / $root3,     true,],
            ['rgb(128, 128, 128)',  'rgb(128, 128, 120)',   7 / $root3,     false,],
            ['rgb(128, 128, 128)',  'rgb(128, 128, 120)',   8 / $root3,     true,],
            ['rgb(0, 0, 0)',        'rgb(255, 255, 255)',   254.9,          false,],
            ['rgb(0, 0, 0)',        'rgb(255, 255, 255)',   255,            true,],
            ['rgb(255, 0, 0)',      'rgb(0, 255, 255)',     254.9,          false,],
            ['rgb(255, 0, 0)',      'rgb(0, 255, 255)',     255,            true,],
            ['black',               'rgba(0, 0, 0)',        0.0,            true],
            ['black',               'rgba(10, 0, 0, 1.0)',  10.0 / $root3,  true],);

        $output = "<table width='100%' class='infoTable'><thead>
                <tr>
                <th>
                Color 1
                </th>
                <th>
                Color 2
                </th>
                <th>
                    Test distance * 255
                </th>
                <th>
                    Is within distance
                </th>
                </tr>
        </thead>";

        $output .= "<tbody>";

        foreach ($tests as $testInfo) {
            $color1 = $testInfo[0];
            $color2 = $testInfo[1];
            $distance = $testInfo[2];
            $expectation = $testInfo[3];
            $testDistance = ($distance / 255.0);

            $color1Pixel = new \ImagickPixel($color1);
            $color2Pixel = new \ImagickPixel($color2);

            $isSimilar = $color1Pixel->isPixelSimilar($color2Pixel, $testDistance);


            if ($isSimilar !== $expectation) {
                echo "Test distance failed. Color [$color1] compared to color [$color2] is not within distance $testDistance FAILED.".NL;
            }

            $layout = "<tr>
                <td>%s</td>
                <td>%s</td>
                <td>%s</td>
                <td style='text-align: center;'>%s</td>
            </tr>";
            
            $output .= sprintf(
                $layout,
                $color1,
                $color2,
                $distance,
                $isSimilar ? 'yes' : 'no'
            );
        }

        $output .= "</tbody></table>";
        
        return $output;

?>
]]>
      </programlisting>
    </example>
  </para>
 </refsect1>

</refentry>

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