//
// function to compute bounding box of two rectangles
//
case class Rectangle(xcoord : Int, ycoord : Int, width : Int, height : Int)

def bbox(r1 : Rectangle, r2 : Rectangle) : Rectangle = {

  val x = r1.xcoord min r2.xcoord
  val y = r1.ycoord min r2.ycoord
  val width = ((r1.xcoord + r1.width) max (r2.xcoord + r2.width)) - x
  val height = ((r1.ycoord + r1.height) max (r2.ycoord + r2.height)) - y

  Rectangle(x, y, width, height)
}