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<refentry xml:id="function.imagecopyresampled" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>imagecopyresampled</refname>
  <refpurpose>Copy and resize part of an image with resampling</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>imagecopyresampled</methodname>
   <methodparam><type>resource</type><parameter>dst_image</parameter></methodparam>
   <methodparam><type>resource</type><parameter>src_image</parameter></methodparam>
   <methodparam><type>int</type><parameter>dst_x</parameter></methodparam>
   <methodparam><type>int</type><parameter>dst_y</parameter></methodparam>
   <methodparam><type>int</type><parameter>src_x</parameter></methodparam>
   <methodparam><type>int</type><parameter>src_y</parameter></methodparam>
   <methodparam><type>int</type><parameter>dst_w</parameter></methodparam>
   <methodparam><type>int</type><parameter>dst_h</parameter></methodparam>
   <methodparam><type>int</type><parameter>src_w</parameter></methodparam>
   <methodparam><type>int</type><parameter>src_h</parameter></methodparam>
  </methodsynopsis>
  <para>
   <function>imagecopyresampled</function> copies a rectangular
   portion of one image to another image, smoothly interpolating pixel
   values so that, in particular, reducing the size of an image still
   retains a great deal of clarity.
  </para>
  <para>
   In other words, <function>imagecopyresampled</function> will take an 
   rectangular area from <parameter>src_image</parameter> of width 
   <parameter>src_w</parameter> and height <parameter>src_h</parameter> at 
   position (<parameter>src_x</parameter>,<parameter>src_y</parameter>) 
   and place it in a rectangular area of <parameter>dst_image</parameter> 
   of width <parameter>dst_w</parameter> and height <parameter>dst_h</parameter>
   at position (<parameter>dst_x</parameter>,<parameter>dst_y</parameter>).
  </para>
  <para>
   If the source and destination coordinates and width and heights
   differ, appropriate stretching or shrinking of the image fragment
   will be performed. The coordinates refer to the upper left
   corner.  This function can be used to copy regions within the
   same image (if <parameter>dst_image</parameter> is the same as
   <parameter>src_image</parameter>) but if the regions overlap the
   results will be unpredictable.
  </para>
 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>dst_im</parameter></term>
     <listitem>
      <para>
       Destination image link resource.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>src_im</parameter></term>
     <listitem>
      <para>
       Source image link resource.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>dst_x</parameter></term>
     <listitem>
      <para>
       x-coordinate of destination point.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>dst_y</parameter></term>
     <listitem>
      <para>
       y-coordinate of destination point.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>src_x</parameter></term>
     <listitem>
      <para>
       x-coordinate of source point.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>src_y</parameter></term>
     <listitem>
      <para>
       y-coordinate of source point.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>dst_w</parameter></term>
     <listitem>
      <para>
       Destination width.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>dst_h</parameter></term>
     <listitem>
      <para>
       Destination height.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>src_w</parameter></term>
     <listitem>
      <para>
       Source width.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>src_h</parameter></term>
     <listitem>
      <para>
       Source height.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &return.success;
  </para>
 </refsect1>
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>Simple example</title>
    <para>
     This example will resample an image to half its original size.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
// The file
$filename = 'test.jpg';
$percent = 0.5;

// Content type
header('Content-type: image/jpeg');

// Get new dimensions
list($width, $height) = getimagesize($filename);
$new_width = $width * $percent;
$new_height = $height * $percent;

// Resample
$image_p = imagecreatetruecolor($new_width, $new_height);
$image = imagecreatefromjpeg($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

// Output
imagejpeg($image_p, null, 100);
?>
]]>
    </programlisting>
    &example.outputs.similar;
    <mediaobject>
     <imageobject>
      <imagedata fileref="figures/image.imagecopyresampled.jpg"/>
     </imageobject>
    </mediaobject>
   </example>
  </para>
  <para>
   <example>
    <title>Resampling an image proportionally</title>
    <para>
     This example will display an image with the maximum width,
     or height, of 200 pixels.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
// The file
$filename = 'test.jpg';

// Set a maximum height and width
$width = 200;
$height = 200;

// Content type
header('Content-type: image/jpeg');

// Get new dimensions
list($width_orig, $height_orig) = getimagesize($filename);

$ratio_orig = $width_orig/$height_orig;

if ($width/$height > $ratio_orig) {
   $width = $height*$ratio_orig;
} else {
   $height = $width/$ratio_orig;
}

// Resample
$image_p = imagecreatetruecolor($width, $height);
$image = imagecreatefromjpeg($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);

// Output
imagejpeg($image_p, null, 100);
?>
]]>
    </programlisting>
    &example.outputs.similar;
    <mediaobject>
     <imageobject>
      <imagedata fileref="figures/image.imagecopyresampled_2.jpg"/>
     </imageobject>
    </mediaobject>
   </example>
  </para>
 </refsect1>
 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    There is a problem due to palette image limitations (255+1 colors).
    Resampling or filtering an image commonly needs more colors than 255, a
    kind of approximation is used to calculate the new resampled pixel and its
    color.  With a palette image we try to allocate a new color, if that
    failed, we choose the closest (in theory) computed color.  This is
    not always the closest visual color. That may produce a weird result, like
    blank (or visually blank) images.  To skip this problem, please use a
    truecolor image as a destination image, such as one created by
    <function>imagecreatetruecolor</function>.
   </para>
  </note>
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <function>imagecopyresized</function>
  </para>
 </refsect1>
</refentry>

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