anchor.diff:      height))
   
   (defmacro uv-to-screen (screen u v)
  -  `(values ,u (- (the fixnum (stream-height ,screen)) (the fixnum ,v))))
  +  `(values ,u (- (stream-height ,screen) ,v)))
   
   (defmacro screen-to-uv (screen u v)
     `(values ,u (- (the fixnum (stream-height ,screen)) (the fixnum ,v))))
  
positive.code: (defun %clip-line (x1 y1 x2 y2 xl xr yb yt)
    ;; After W.M. Newman, and R.F. Sproull, Principles of Interactive Computer
    ;; Graphics, McGraw-hill, 1973, p. 124
    (declare (type (integer -1000000 1000000) x1 y1 x2 y2 xl xr yb yt))
    ;; Declaring the range of these integers helps inline more of the functions.  JPM.
    (macrolet
      ((code (x y)
  
negative.code:    Alters instance variables dash-ds and last-style."
    ;; KRA: Currently, we do not use with-clipping-internal here though for thick lines,
    ;; we should.  We also don't draw caps on thick dashed lines yet.
    (let ((end-point-p (flip-alu-p alu)))
      (when transform
        (multiple-value-setq (x1 y1) (uv-to-screen stream x1 y1))
  