code: public boolean contains(float x, float y) {
          return left < right && bottom < top // check for empty first
                  && x >= left && x < right && y >= bottom && y < top;
      }
docs: Returns true if (x,y) is inside the viewport. The left and top are considered to be inside, while the right and
  bottom are not. This means that for a x,y to be contained: {@code left <= x < right and bottom <= y < top}. An
  empty viewport never contains any point.
  
  @param x The X coordinate of the point being tested for containment
  @param y The Y coordinate of the point being tested for containment
  @return true iff (x,y) are contained by the viewport, where containment means {@code left <= x < right and top <=
  y < bottom}