NSUnionRect(_:_:)
Calculates the union of two rectangles.
Declaration
func NSUnionRect(_ aRect: NSRect, _ bRect: NSRect) -> NSRectDiscussion
Returns the smallest rectangle that completely encloses both aRect and bRect. If one of the rectangles has 0 (or negative) width or height, a copy of the other rectangle is returned; but if both have 0 (or negative) width or height, the returned rectangle has its origin at (0.0, 0.0) and has 0 width and height.