private static function _get_luminance( $hex ) {
		$red   = hexdec( substr( $hex, 0, 2 ) );
		$green = hexdec( substr( $hex, 2, 2 ) );
		$blue  = hexdec( substr( $hex, 4, 2 ) );
		$max_rgb = max( $red, $green, $blue );
		$min_rgb = min( $red, $green, $blue );

		return ( $max_rgb + $min_rgb ) / 2 / 255 * 100;
	}
private static function _get_luminance( $hex ) {
		$red   = hexdec( substr( $hex, 0, 2 ) );
		$green = hexdec( substr( $hex, 2, 2 ) );
		$blue  = hexdec( substr( $hex, 4, 2 ) );
		$max_rgb = max( $red, $green, $blue );
		$min_rgb = min( $red, $green, $blue );

		return ( $max_rgb + $min_rgb ) / 2 / 255 * 100;
	}
private static function _get_luminance ( $ hex ) { $ red = hexdec ( substr ( $ hex , 0 , 2 ) ) ; $ green = hexdec ( substr ( $ hex , 2 , 2 ) ) ; $ blue = hexdec ( substr ( $ hex , 4 , 2 ) ) ; $ max_rgb = max ( $ red , $ green , $ blue ) ; $ min_rgb = min ( $ red , $ green , $ blue ) ; return ( $ max_rgb + $ min_rgb ) / 2 / 255 * 100 ; }
Return luminance from hex

@param hex $hex
@return luminance
Return luminance from hex