1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.11 $ -->
<refentry xml:id="function.imagecolorat" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>imagecolorat</refname>
<refpurpose>Get the index of the color of a pixel</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>int</type><methodname>imagecolorat</methodname>
<methodparam><type>resource</type><parameter>image</parameter></methodparam>
<methodparam><type>int</type><parameter>x</parameter></methodparam>
<methodparam><type>int</type><parameter>y</parameter></methodparam>
</methodsynopsis>
<para>
Returns the index of the color of the pixel at the
specified location in the image specified by <parameter>image</parameter>.
</para>
<para>
If PHP is compiled against GD library 2.0 or higher and the image is a
truecolor image, this function returns the RGB value of that pixel as
integer. Use bitshifting and masking to access the distinct red, green and blue
component values:
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
&gd.image.description;
<varlistentry>
<term><parameter>x</parameter></term>
<listitem>
<para>
x-coordinate of the point.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>y</parameter></term>
<listitem>
<para>
y-coordinate of the point.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
Returns the index of the color.
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title>Access distinct RGB values</title>
<programlisting role="php">
<![CDATA[
<?php
$im = imagecreatefrompng("php.png");
$rgb = imagecolorat($im, 10, 15);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
var_dump($r, $g, $b);
?>
]]>
</programlisting>
&example.outputs.similar;
<screen>
<![CDATA[
int(119)
int(123)
int(180)
]]>
</screen>
</example>
<example>
<title>Human-readable RGB values using <function>imagecolorsforindex</function></title>
<programlisting role="php">
<![CDATA[
<?php
$im = imagecreatefrompng("php.png");
$rgb = imagecolorat($im, 10, 15);
list($r, $g, $b, $alpha) = imagecolorsforindex($rgb);
var_dump($r, $g, $b, $alpha);
?>
]]>
</programlisting>
&example.outputs.similar;
<screen>
<![CDATA[
int(119)
int(123)
int(180)
int(127)
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>imagecolorset</function></member>
<member><function>imagecolorsforindex</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"../../../../manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->
|
