PHP imagecolorat: Retrieve Pixel Color Index Value

imagecolorat retrieves the color index of a specific pixel in an image when PHP is compiled with GD library 2.0+ and the image is truecolor.

It returns an integer representing the RGB value, which can be split into red, green, and blue components using bitwise shifts and masks.

Return value : The color index of the pixel at the specified coordinates.

Example :

$im = ImageCreateFromPng("rockym.png");
$rgb = ImageColorAt($im, 100, 100);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;