note 85849 modified in function.imagecolorat by felipe
| From: | felipe@php.net | Date: | Tue, 23 Sep 2008 23:26:46 +0000 |
| Subject: | note 85849 modified in function.imagecolorat by felipe | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-144654@lists.php.net to get a copy of this message | ||
With the following functions you can not only convert a 24 bit RGB integer to its corresponding red,
green, and blue values, but also 32 bit RGBA integers to its corresponding red, green, blue, and
ALPHA values.
Not only that, but I even threw in a function for converting those red, green, blue, and alpha
values back into a 32 bit RGBA integer.
Sample usage:
<?php
$int = rgba2int(255, 255, 255, 16);
echo $int . "<br>";
$rgba = int2rgba($int);
print_r($rgba);
?>
What it should output:
285212671
Array
(
[r] => 255
[g] => 255
[b] => 255
[a] => 16
)
<?php
function rgba2int($r, $g, $b, $a=1) {
/*
This function builds a 32 bit integer from 4 values which must be 0-255 (8 bits)
Example 32 bit integer: 00100000010001000000100000010000
The first 8 bits define the alpha
The next 8 bits define the blue
The next 8 bits define the green
The next 8 bits define the red
*/
return ($a << 24) + ($b << 16) + ($g << 8) + $r;
}
function int2rgba($int) {
$a = ($int >> 24) & 0xFF;
$r = ($int >> 16) & 0xFF;
$g = ($int >> 8) & 0xFF;
$b = $int & 0xFF;
return array('r'=>$r, 'g'=>$g, 'b'=>$b,
'a'=>$a);
}
?>
--was--
With the following functions you can not only convert a 24 bit RGB integer to its corresponding red,
green, and blue values, but also 32 bit RGBA integers to its corresponding red, green, blue, and
ALPHA values.
Not only that, but I even threw in a function for converting those red, green, blue, and alpha
values back into a 32 bit RGBA integer.
Sample usage:
$int = rgba2int(255, 255, 255, 16);
echo $int . "<br>";
$rgba = int2rgba($int);
print_r($rgba);
What it should output:
285212671
Array
(
[r] => 255
[g] => 255
[b] => 255
[a] => 16
)
function rgba2int($r, $g, $b, $a=1) {
/*
This function builds a 32 bit integer from 4 values which must be 0-255 (8 bits)
Example 32 bit integer: 00100000010001000000100000010000
The first 8 bits define the alpha
The next 8 bits define the blue
The next 8 bits define the green
The next 8 bits define the red
*/
return ($a << 24) + ($b << 16) + ($g << 8) + $r;
}
function int2rgba($int) {
$a = ($int >> 24) & 0xFF;
$r = ($int >> 16) & 0xFF;
$g = ($int >> 8) & 0xFF;
$b = $int & 0xFF;
return array('r'=>$r, 'g'=>$g, 'b'=>$b,
'a'=>$a);
}
http://php.net/manual/en/function.imagecolorat.php