+ std::string imagefile_bottom;
+ Vector pos; /**< coordinates of upper-left corner of image */
+ float speed; /**< scroll-speed in horizontal direction */
+ float speed_y; /**< scroll-speed in vertical direction */
+ std::auto_ptr<Surface> image_top; /**< image to draw above pos */
+ std::auto_ptr<Surface> image; /**< image to draw, anchored at pos */
+ std::auto_ptr<Surface> image_bottom; /**< image to draw below pos+screenheight */