anchor.diff:    (format (postscript-medium-file-stream medium) "grestore~%"))
   
   (defun invoke-with-graphics-state (medium continuation)
  -  (let ((stream (postscript-medium-file-stream medium)))
  -    (postscript-save-graphics-state medium)
  -    (funcall continuation)
  -    (postscript-restore-graphics-state medium)))
  +  (postscript-save-graphics-state medium)
  +  (funcall continuation)
  +  (postscript-restore-graphics-state medium))
   
   (defmacro with-graphics-state ((medium) &body body)
     `(invoke-with-graphics-state ,medium
  
positive.code:   (format stream "clip~%"))
  
  (defmethod postscript-set-clipping-region (stream (region (eql +everywhere+)))
    (declare (ignore stream region)))
  
  (defmethod postscript-set-clipping-region (stream (region (eql +nowhere+)))
    (declare (ignore region))
    (format stream "newpath 0 0 moveto closepath clip~%"))
  
  (defmethod postscript-set-graphics-state (stream medium
  
negative.code:    to the current path of STREAM."))
  
  (defmethod postscript-add-path (stream (region (eql +nowhere+)))
    (declare (ignore stream)))
  
  (defmethod postscript-add-path (stream (region standard-region-union))
    (map-over-region-set-regions (lambda (region)
  