code: public void update(double screenX, double screenY)
      {
          for (final Image current : surfaces.values())
          {
              current.setLocation(screenX + offsetX, screenY + offsetY);
          }
          if (nextSurface != null)
          {
              surface = nextSurface;
              nextSurface = null;
          }
      }
docs: Update renderer location and surface ID.
  
  @param screenX The horizontal location on screen.
  @param screenY The vertical location on screen.