Number rounding for chart scales

nice_number.php

<?php

function nice_number($num, $round=false) {
	$m = pow(10, floor(log10($num)));
	if ($m == 0) {
		return 0;
	}

	$f = $num / $m;
	if ($round) {
		if ($f < 1.5) $nf = 1;
		elseif ($f < 3) $nf = 2;
		elseif ($f < 7) $nf = 5;
		else $nf = 10;
	} else {
		if ($f <= 1) $nf = 1;
		elseif ($f <= 2) $nf = 2;
		elseif ($f <= 5) $nf = 5;
		else $nf = 10;
	}
	return $nf * $m;
}