PHP get dominant color

get_dominant_color.php

<?php

function get_featured_color() {
	/* Here is an example for wordpress, replace $filepath in your situation. */
	$post_thumbnail_id = get_post_thumbnail_id();
	$filepath = get_attached_file($post_thumbnail_id);
	$im = imagecreatefromstring(file_get_contents($filepath));

	$nx = imagesx($im);
	$ny = imagesy($im);

	/* Calculate only for the center part of the image. */
	$sx = (int) ($nx * 0.4);
	$ex = (int) ($nx * 0.6);
	$sy = (int) ($ny * 0.4);
	$ey = (int) ($ny * 0.6);

	/* Down sample to around 100 X 100 */
	$step = (int) (($ex - $sx) / 100);
	$step = $step > 1 ? $step : 1;

	$R = 0;
	$G = 0;
	$B = 0;

	$c = 0;

	for ($x = $sx; $x < $ex; $x += $step) {
		for ($y = $sy; $y < $ey; $y += $step) {

			$rgb = imagecolorat($im, $x, $y);

			$r = ($rgb >> 16) & 0xFF;
			$g = ($rgb >> 8) & 0xFF;
			$b = $rgb & 0xFF;

			$R += $r;
			$G += $g;
			$B += $b;
			$c += 1;

		}
	}

	if ($c !== 0) {
		return sprintf('#%02x%02x%02x', (int) ($R / $c), (int) ($G / $c), (int) ($B / $c));
	} else {
		/* Fallback color */
		return '#e2eb88';
	}

}