/**
* Return the smallest interval that contains this interval and the given
* interval "y".
*/
public function union(R1Interval $y)
{
if ($this->isEmpty()) {
return $y;
}
if ($y->isEmpty()) {
return $this;
}
return new R1Interval(min($this->lo(), $y->lo()), max($this->hi(), $y->hi()));
}
/**
* Return true if the rectangle is empty, i.e. it contains no points at all.
*/
public function isEmpty()
{
return $this->lat->isEmpty();
}
