public function xy($x, $y)
{
// Don't continue if x or y values are invalid
foreach (array($x, $y) as $value) {
if (!(self::XY_MIN <= $value && $value <= self::XY_MAX)) {
throw new \InvalidArgumentException("x/y value must be between " . self::XY_MIN . " and " . self::XY_MAX);
}
}
$this->params['xy'] = array((double) $x, (double) $y);
return $this;
}