anchor.diff:                     (dotimes (y height)
                        (dotimes (x width)
                          (setf (mezzano.gui:surface-pixel framebuffer (+ left x) (+ top y))
  -                             (render-mandelbrot (float x) (float y) (float width) (float height) (float hue-offset))))
  +                             (render-mandelbrot (float x) (float y)
  +                                                (float width) (float height)
  +                                                (float hue-offset)
  +                                                (juliap app))))
                        (mezzano.gui.compositor:damage-window window left (+ top y) width 1)
                        (loop
                           (let ((evt (mezzano.supervisor:fifo-pop fifo nil)))
  
positive.code:       ((< h* 5.0f0) (values x     0.0f0 1.0f0))
        ((< h* 6.0f0) (values 1.0f0 0.0f0 x)))))
  
  (defun m (cr ci iterations)
    (declare (optimize (speed 3) (safety 0))
             (type single-float cr ci)
             (type fixnum iterations))
    (let ((zr 0.0f0) (zi 0.0f0))
      (declare (type single-float zr zi))
      (dotimes (i iterations nil)
        (declare (type fixnum i))
        (let ((zr2 (* zr zr))
              (zi2 (* zi zi)))
          (declare (type single-float zr2 zi2))
          (psetf zr (+ cr (- zr2 zi2))
                 zi (+ ci (* zi zr) (* zr zi)))
          (when (> (+ zr2 zi2) 4.0f0)
            (return (* (/ (float i 0.0f0) (float iterations 0.0f0)) 360.0f0)))))))
  
  (defun render-mandelbrot (x y width height hue-offset)
    "Render one pixel."
    (declare (optimize (speed 3) (safety 0))
             (type single-float x y width height hue-offset))
  
negative.code: (defmethod dispatch-event (app (event mezzano.gui.compositor:resize-event))
    (signal 'must-redraw))
  
  (defmethod dispatch-event (app (event mezzano.gui.compositor:key-event))
    (when (mezzano.gui.compositor:key-releasep event)
      (case (mezzano.gui.compositor:key-key event)
        ((#\j #\J)
         (setf (juliap app) t))
        ((#\m #\M)
         (setf (juliap app) nil)))
      (signal 'must-redraw)))
  
  (defun benchmark (&optional (width 500) (height width) julia)
    (let ((framebuffer (mezzano.gui:make-surface width height))
          (hue-offset (rem (get-universal-time) 360)))
      (dotimes (y height)
        (dotimes (x width)
          (setf (mezzano.gui:surface-pixel framebuffer x y)
                (render-mandelbrot (float x 0.0f0) (float y 0.0f0)
                                   (float width 0.0f0) (float height 0.0f0)
                                   (float hue-offset 0.0f0)
                                   julia))))
      framebuffer))
  
  (defun mandelbrot-main (width height)
  