public void addRenderer(Renderer renderer) {
   mClients.add(renderer);
   renderer.setOverlay(this);
   if (renderer.handlesTouch()) {
     mTouchClients.add(0, renderer);
   }
 }
 public void remove(Renderer renderer) {
   mClients.remove(renderer);
   renderer.setOverlay(null);
 }
 public void addRenderer(int pos, Renderer renderer) {
   mClients.add(pos, renderer);
   renderer.setOverlay(this);
 }