int scrx = screen_.getx();                     //< Screen width.
        int scry = screen_.gety();                     //< Screen height.
        SDL_Rect area = create_rect(0, 0, scrx, scry); // Screen area.
        surface disp(screen_.getSurface());      // Screen surface.
        // Make everything black.
        sdl_fill_rect(disp,&area,SDL_MapRGB(disp->format,0,0,0));
        update_whole_screen();
        screen_.flip();