anchor.diff:  (defbinding new-path () nil
     (cr context))
   
  +#?(pkg-exists-p "cairo" :atleast-version "1.2")
  +(defbinding new-sub-path () nil
  +  (cr context))
  +
   (defbinding close-path () nil
     (cr context))
   
  
positive.code:   (x double-float :in/out)
    (y double-float :in/out))
  
  (defbinding user-to-device-distance () nil
    (cr context)
    (dx double-float :in/out)
    (dy double-float :in/out))
  
negative.code: (defbinding status () status
    (cr context))
  
  (defun ensure-color-component (component)
    (etypecase component
      (float component)
      (integer (/ component 256.0))))
  
  (defbinding (set-source-color "cairo_set_source_rgba") (cr red green blue &optional (alpha 1.0)) nil
    (cr context)
    ((ensure-color-component red) double-float)
    ((ensure-color-component green) double-float)
    ((ensure-color-component blue) double-float)
    ((ensure-color-component alpha) double-float))
  
  (defbinding set-source-surface () nil
    (cr context)
  