friendly_fractions.php

<?php

/**
 * Generate a human-friendly fraction approximation given a nasty-looking
 * number with lots of digits after the decimal point.
 * 
 * @param double  $number The number for which to calculate the nearest friendly fraction
 * @param boolean $string Return the human-readable string of the fraction (default)
 *                        or return an array of the fractions parts (whole number, numerator,
 *                        and denominator)
 * 
 * @return string|array   Returns a string containing the human-readable representation of the
 *                        friendly fraction (e.g. 4-5/16) or an array of the fractions parts
 *                        that includes the friendly string as well in the "human" key.
 *                        (e.g. ["whole" => 4, "numerator" => 5, "denominator" => 16, "human" => "4-5/16"])
 */
function friendlyFraction($number, $string = true) {
	$allowedDen = array(2, 4, 8, 16);
	$whole = ($number - fmod($number, 1));
	$fraction = fmod($number, 1);
	$num = 0;
	$den = 1;
	$closest = 1;

	foreach ($allowedDen as $attempt) {
		for ($i = 1; $i < $attempt; $i++) {
			$val = ($i / $attempt);

			if ($val == $fraction) {
				$num = $i;
				$den = $attempt;
				$closest = $val;

				break 2;
			}
			else if (abs($val - $fraction) < abs($closest - $fraction)) {
				$closest = $val;
				$num = $i;
				$den = $attempt;
			}
		}
	}

	$human = (($whole > 0) ? "{$whole}-{$num}/{$den}" : "{$num}/{$den}");

	return (($string) ? $human : array("whole" => $whole, "numerator" => $num, "denominator" => $den, "human" => $human));
}

Print "<pre>";
print_r(friendlyFraction(0.286));
Print "</pre>";