mirror of
https://github.com/sigmasternchen/php-doc-en
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121 lines
3.3 KiB
XML
121 lines
3.3 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="function.imagetruecolortopalette" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>imagetruecolortopalette</refname>
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<refpurpose>Convert a true color image to a palette image</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>bool</type><methodname>imagetruecolortopalette</methodname>
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<methodparam><type>GdImage</type><parameter>image</parameter></methodparam>
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<methodparam><type>bool</type><parameter>dither</parameter></methodparam>
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<methodparam><type>int</type><parameter>num_colors</parameter></methodparam>
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</methodsynopsis>
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<para>
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<function>imagetruecolortopalette</function> converts a truecolor image
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to a palette image. The code for this function was originally drawn from
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the Independent JPEG Group library code, which is excellent. The code
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has been modified to preserve as much alpha channel information as
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possible in the resulting palette, in addition to preserving colors as
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well as possible. This does not work as well as might be hoped. It is
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usually best to simply produce a truecolor output image instead, which
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guarantees the highest output quality.
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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&gd.image.description;
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<varlistentry>
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<term><parameter>dither</parameter></term>
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<listitem>
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<para>
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Indicates if the image should be dithered - if it is &true; then
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dithering will be used which will result in a more speckled image but
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with better color approximation.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>num_colors</parameter></term>
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<listitem>
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<para>
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Sets the maximum number of colors that should be retained in the palette.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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&return.success;
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</para>
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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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&gd.changelog.image-param;
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</tbody>
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</tgroup>
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</informaltable>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title>Converting a true color image to a palette-based image</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Create a new true color image
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$im = imagecreatetruecolor(100, 100);
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// Convert to palette-based with no dithering and 255 colors
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imagetruecolortopalette($im, false, 255);
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// Save the image
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imagepng($im, './paletteimage.png');
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imagedestroy($im);
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?>
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]]>
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</programlisting>
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</example>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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