private static function _setRandBackground()
{
$red = self::$isRandBackground ? mt_rand(100, 200) : 255;
$green = self::$isRandBackground ? mt_rand(100, 200) : 255;
$blue = self::$isRandBackground ? mt_rand(100, 200) : 255;
$alpha = 0;
//self::$isRandBackground ? mt_rand(0, 127) : 0;
self::$_background = array('red' => $red, 'green' => $green, 'blue' => $blue, 'alpha' => $alpha);
}