code: public boolean intersect(Viewport v) {
          return intersect(v.left, v.top, v.right, v.bottom);
      }
docs: If the specified viewport intersects this viewport, return true and set this viewport to that intersection,
  otherwise return false and do not change this viewport. No check is performed to see if either viewport is empty.
  To just test for intersection, use intersects()
  
  @param v The viewport being intersected with this viewport.
  @return true if the specified viewport and this viewport intersect (and this viewport is then set to that
  intersection) else return false and do not change this viewport.