*/
  public void blend_color (float red, float green, 
    float blue, float alpha) {

    RequestOutputStream o = display.out;
    synchronized (o) {
      begin_render_request (o, 4096, 20);
      o.write_float (red);
      o.write_float (green);    
      o.write_float (blue);
      o.write_float (alpha);
    }
  }