easeOutElastic easing function

easeOutElastic.php

// t: current time, b: begInnIng value, c: change In value, d: duration

function ani ($t, $b, $c, $d)
{
  $s = 1.70158;
  $p = 0;
  $a = $c;

	if ($t == 0) return $b;
	if (($t /= $d) == 1) return $b + $c;
	if (!$p) $p = $d * .3;
	if ($a < abs($c))
	{
		$a = $c;
		$s = $p / 4;
	}
	else $s = $p / (2 * pi()) * asin ($c / $a);
	return $a * pow(2, -10 * $t) * sin(($t * $d - $s) * (2 * pi()) / $p ) + $c + $b;
}