anchor.diff:  
   (defun reset ()
     (dolist (slider (list *brightness* *contrast* *gamma*))
  -    (qset slider "value" 127)))
  +    (qset slider "value" 0)))
   
   (let ((pnt (qnew "QPainter")))
     (defun paint (ev)
  
positive.code:   (qfun *display* "setFixedSize" (qfun *image* "size"))
    (dolist (slider (list *brightness* *contrast* *gamma*))
      (x:do-with (qset slider)
        ("minimum" 0)
        ("maximum" 255)
        ("value" 127))
      (qconnect slider "valueChanged(int)" 'change))
    (qconnect *reset* "clicked()" 'reset)
    (qoverride *display* "paintEvent(QPaintEvent*)" 'paint)
  
negative.code: 
  (defpackage :image-manipulation
    (:use :common-lisp :eql)
    (:export
     #:start))
  
  (in-package :image-manipulation)
  
  