anchor.diff:  	 (with-sheet-medium (medium stream)
   	   (when (stream-recording-p stream)
   	     (let ((record (make-instance ',class-name
  -			     :stream stream
  -			     ,@arg-list)))
  +                                          :stream stream
  +                                          ,@arg-list)))
   	       (stream-add-output-record stream record)))
   	   (when (stream-drawing-p stream)
  -	     (call-next-method))))
  +             (with-identity-transformation (medium)
  +               (,method-name medium ,@args)))))
          (defmethod replay-output-record ((record ,class-name) stream
   					&optional (region +everywhere+)
                                           (x-offset 0) (y-offset 0))
  
positive.code: 				    stream state)
    ;; XXX DC
    ;; XXX Disable recording?
    (letf (((medium-transformation stream) +identity-transformation+))
      (multiple-value-bind (x1 y1 x2 y2)
          (output-record-hit-detection-rectangle* record)
        (ecase state
  
negative.code:       (minf min-y y)
        (maxf max-x x)
        (maxf max-y y))
      (values (floor (- min-x border))
              (floor (- min-y border))
              (ceiling (+ max-x border))
              (ceiling (+ max-y border)))))
  
  ;;; x1, y1 slots must exist in class...
  
  