(PHP 4, PHP 5)
imagecolorat — Get the index of the color of a pixel
Returns the index of the color of the pixel at the specified location in the image specified by image .
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:
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
x-coordinate of the point.
y-coordinate of the point.
Returns the index of the color.
Example #1 Access distinct RGB values
<?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);
?>
The above example will output something similar to:
int(119) int(123) int(180)
Example #2 Human-readable RGB values using imagecolorsforindex()
<?php
$im = imagecreatefrompng("php.png");
$rgb = imagecolorat($im, 10, 15);
list($r, $g, $b, $alpha) = imagecolorsforindex($rgb);
var_dump($r, $g, $b, $alpha);
?>
The above example will output something similar to:
int(119) int(123) int(180) int(127)