anchor.diff:                       (eq (line-style-unit line-style)
                            (line-style-unit old-line-style)))
             (setf (xlib:gcontext-line-width gc)
  -                (line-style-effective-thickness line-style medium)))
  +                (round (line-style-effective-thickness line-style medium))))
           (unless (eq (line-style-cap-shape line-style)
                       (line-style-cap-shape old-line-style))
             (setf (xlib:gcontext-cap-style gc)
  
positive.code:                 (text-style-mapping (port medium) (medium-text-style medium))))))))
  
  ;;; Translate from CLIM styles to CLX styles.
  (defconstant +cap-shape-map+ '((:butt . :butt)
                                 (:square . :projecting)
                                 (:round . :round)
                                 (:no-end-point . :not-last)))
  
  (defun translate-cap-shape (clim-shape)
    (let ((clx-shape (cdr (assoc clim-shape +cap-shape-map+))))
      (if clx-shape
          clx-shape
          (progn
            (warn "Unknown cap style ~S, using :round" clim-shape)
            :round))))
  
  ;;; XXX: this should be refactored into a reusable protocol in clim-backend
  ;;; with specialization on medium. -- jd 2018-10-31
  
negative.code:                                (medium-sheet medium))
                                x y)
      (with-clx-graphics () medium
        (let ((diameter (line-style-effective-thickness line-style medium)))
          (if (< diameter 2)
              (let ((x (round-coordinate x))
                    (y (round-coordinate y)))
                (when (and (typep x '(signed-byte 16))
                           (typep y '(signed-byte 16)))
                  (xlib:draw-point mirror gc x y)))
              (let* ((radius   (round diameter 2))
                     (diameter (round diameter))
                     (min-x    (round-coordinate (- x radius)))
                     (min-y    (round-coordinate (- y radius))))
                (when (and (typep min-x '(signed-byte 16))
                           (typep min-y '(signed-byte 16)))
                  (xlib:draw-arc mirror gc min-x min-y
                                 diameter diameter
                                 0 (* 2 pi) t))))))))
  
  
  (defmethod medium-draw-points* ((medium clx-medium) coord-seq)
  