Function for finding a pixel's RGBa values.
function getPixelColor($image, $x, $y) {
$color_index = imagecolorat($image->resource, $x, $y);
$transparent_index = imagecolortransparent($image->resource);
if ($color_index == $transparent_index) {
return array(
0,
0,
0,
127,
);
}
return array_values(imagecolorsforindex($image->resource, $color_index));
}