anchor.diff:    (with-medium-options (sheet args)
       (medium-draw-glyph medium string x y
   		       align-x align-y
  -		       towards-x towards-y transform-glyphs)))
  +		       toward-x toward-y transform-glyphs)))
   
   (defun draw-arrow (sheet point-1 point-2
   		   &rest args
  
positive.code: 		   text-style text-family text-face text-size))
    (with-medium-options (sheet args)
      (multiple-value-bind (x y) (point-position point)
        (multiple-value-bind (towards-x towards-y)
  	  (if towards-point-p
  	      (point-position towards-point)
  	      (values (1+ x) y))
          (medium-draw-text* medium string x y
                             start end
                             align-x align-y
                             towards-x towards-y transform-glyphs)))))
  
  (defun draw-text* (sheet string x y
  		   &rest args
  		   &key (start 0) (end nil)
  			(align-x :left) (align-y :baseline)
  			(towards-x (1+ x)) (towards-y y) transform-glyphs
  			ink clipping-region transformation
  			text-style text-family text-face text-size)
    (declare (ignore ink clipping-region transformation
  
negative.code:     (medium-draw-text* medium string x y
  		       start end
  		       align-x align-y
  		       toward-x toward-y transform-glyphs)))
  
  ;; This function belong to the extensions package.
  (defun draw-glyph (sheet string x y
  		   &rest args
  		   &key (align-x :left) (align-y :baseline)
  			toward-x toward-y transform-glyphs
  			ink clipping-region transformation
  			text-style text-family text-face text-size)
  " Draws a single character of filled text represented by the given element. 
  