anchor.diff:       (stride
         :allocation :virtual 
         :getter "cairo_image_surface_get_stride"
  -      :reader surface-height
  +      :reader surface-stride
         :type int))
       (:metaclass surface-class))
   
  
positive.code:   (a matrix)
    (b matrix))
  
  (defbinding matrix-transform-distance () nil
    (matrix matrix :in/return)
    (dx double-float)
    (dy double-float))
  
  (defbinding matrix-transform-point () nil
    (matrix matrix :in/return)
    (x double-float)
    (y double-float))
  
  
  
  
negative.code:        (funcall stream 
  	(map-c-vector 'vector #'identity data '(unsigned-byte 8) length)))))
    :success)
  
  
  (defmacro with-surface ((surface cr) &body body)
    `(let ((,cr (make-instance 'context :target ,surface)))
       ,@body))
  
  
  ;; Image Surface
  