anchor.diff:    (%font-options-create))
   
   (defbinding font-options-merge () nil
  -  (options1 font-options :return)
  +  (options1 font-options :in/return)
     (options2 font-options))
   
   (defbinding font-options-hash () unsigned-int
  
positive.code: 
  (defbinding %destroy () nil
    (location pointer))
  
  (defmethod reference-foreign ((class (eql (find-class 'context))) location)
    (%reference location))
  
  (defmethod unreference-foreign ((class (eql (find-class 'context))) location)
    (%destroy location))
  
  (defbinding (save-context "cairo_save") () nil
    (cr context))
  
negative.code:       :writer (setf matrix)
        :type matrix)
       )
      (:metaclass proxy-class)
      (:ref %reference)
      (:unref %destroy))
  
    (defclass image-surface (surface)
      ((width
  