anchor.diff:  buffer offset `start-offset', and will be drawn starting
   at (`cursor-x', `cursor-y')."
     (let* ((line (line-information view (displayed-lines-count view)))
  -         (old-line-height (dimensions-height (line-dimensions line)))
  -         (old-line-width (dimensions-width (line-dimensions line)))
            (orig-x-offset cursor-x)
            (offset-change (- start-offset (line-start-offset line)))
            (line-spacing (stream-vertical-spacing pane)))
  
positive.code: of the stroke."
    (loop with parts = (analyse-stroke-string stroke-string)
       with width = 0
       with widths = (make-array (length parts) :adjustable t :fill-pointer t)
       with tab-width
       for (start end object) in parts
       do (cond ((and object (eql object #\Tab))
  
negative.code:          for stroke-dimensions = (stroke-dimensions stroke)
           do (draw-stroke pane view stroke (x1 stroke-dimensions) baseline)
           finally (progn (end-line-cleaning-up pane line orig-x-offset cursor-y
                                                line-width line-height)
                          (incf (displayed-lines-count view))
                          (return (values pump-state line-height)))))))
  
  