anchor.diff:      (when image
         (unless transform
           (destructuring-bind (y-scale x-scale y-shift x-shift y-shear x-shear rotate)
  -            transform-parameters
  +            (coerce transform-parameters 'list)
             (setf transform
                   (make-affine-transformation :y-scale y-scale
                                               :x-scale x-scale
  
positive.code:    (transformed-image :accessor transformed-image :initarg :transformed-image)
     (image-pattern :accessor image-pattern :initarg :image-pattern))
    (:default-initargs :value nil
      :transform-parameters (list 1d0 1d0 0d0 0d0 0d0 0d0 0d0)
      :transform nil
      :transformed-image nil
      :image-pattern nil))
  
negative.code:                                         (list (/ bounding-rectangle-width oldx))))))
                (setf (gadget-value y-scale-slider) scale
                      (gadget-value x-scale-slider) scale)
                (setf (elt transform-parameters 0) scale
                      (elt transform-parameters 1) scale
                      transform nil)))
            (setf image image))))))
  
  