anchor.diff:  ;;; - clipping
   ;;; - - more regions to draw
   ;;; - (?) blending
  -;;; - check MEDIUM-DRAW-TEXT*
  +;;; - MEDIUM-DRAW-TEXT*
  +;;; - - :towards-(x,y)
  +;;; - - landscape orientation
  +;;; - - (?) :transform-glyphs
   ;;; - POSTSCRIPT-ACTUALIZE-GRAPHICS-STATE: fix CLIPPING-REGION reusing logic
   ;;; - MEDIUM-DRAW-... should not duplicate code from POSTSCRIPT-ADD-PATH
   ;;; - structure this file
  
positive.code:   (multiple-value-bind (font size)
        (text-style->postscript-font
         (merge-text-styles text-style
                            (medium-text-style medium)))
      (text-size-in-font font size
                         string start (or end (length string)))))
  
negative.code: 
  (defconstant +normal-line-width+ (/ 2.0 3.0))
  
  (defun line-style-scale (line-style)
    (let ((unit (line-style-unit line-style)))
      (ecase unit
        (:normal +normal-line-width+)
        (:point 1)
        (:coordinate (error ":COORDINATE line unit not implemented.")))))
  
  (defmethod line-style-effective-thickness
      (line-style (medium postscript-medium))
    (* (line-style-thickness line-style)
       (line-style-scale line-style)))
  
  (defun medium-line-thickness (medium)
    (line-style-effective-thickness (medium-line-style medium) medium))
  
  (defmethod postscript-set-graphics-state (stream medium
                                            (kind (eql :line-style)))
    (let* ((line-style (medium-line-style medium))
           (scale (line-style-scale line-style)))
      (format stream "~D setlinewidth ~A setlinejoin ~A setlinecap~%"
              (format-postscript-number
               (* scale (line-style-thickness line-style)))
  