PHP Color Shade and Tint

color.php

<?php

$currentR = 66;
$currentG = 85;
$currentB = 123;

$effect = 'tint';
$alpha = 0.1;

list($aR, $aG, $aB) = (function () use ($effect) {
	switch ($effect) {
		case 'shade':
			return [0, 0, 0];
		case 'tint':
			return [255, 255, 255];
		case 'tone':
		default:
			return [128, 128, 128];
	}
})();

var_dump(array(
	$currentR + ($aR - $currentR) * $alpha,
	$currentG + ($aG - $currentG) * $alpha,
	$currentB + ($aB - $currentB) * $alpha,
));