anchor.diff:                        ;; * (min 0 left), (max width right)
                         ;; * font-ascent / ascent
                         (values left (- font-ascent) right font-descent)))))))))
  -
  
positive.code:                           as char = (aref string i)
                            as code = (char-code char)
                            sum (or (gcache-get width-cache code)
                                    (gcache-set width-cache code (font-glyph-width font char)))
                              #+NIL (clim-clx::font-glyph-width font char))))
             (if (numberp (slot-value font 'fixed-width))
                 (* (slot-value font 'fixed-width) (- end start))
                 (typecase string 
                   (simple-string 
                    (locally (declare (type simple-string string))
                      (compute)))
                   (string 
                    (locally (declare (type string string))
                      (compute)))
                   (t (compute)))))))
  
negative.code: 
  (declaim (inline gcache-get))
  
  (defun gcache-get (cache key-number)
    (declare (optimize (speed 3))
             (type (simple-array t (512))))
    (let ((hash (logand (the fixnum key-number) #xFF)))   ; hello.
  