* Animise

  /General purpose tweens and easing/ 

  Animise is a small library that you may use to orchestrate any time-varying
  numerical values. While animise is intended to be used as a general purpose
  [[https://en.wikipedia.org/wiki/Inbetweening][tweening]] solution for your Common Lisp projects, you could use it for other
  purposes as well (e.g. modulating audio signals).

  Here is a short example using animise to define an animated a box using SDL2

  #+begin_src lisp
;; ... snip

(let* ((rect (sdl2:make-rect 0 0 100 100))
         (color (list 255 0 0 255))

         (anim (sequencing (:loop-mode :looping :targeting rect)
                 (pausing :for 200 :start (sdl2:get-ticks))
                 (grouping (:with-duration 1200)
                   (animating :linearly :the 'cadddr :of color :to 0)
                   (animating :quading-out :the 'sdl2:rect-x :to 400)
                   (animating :bouncing-out :the 'sdl2:rect-y :to 300))
                 (grouping (:with-duration 1000)
                   (animating :linearly :the 'cadddr :of color :to 255)
                   (animating :elastically-out :the 'sdl2:rect-x :to 0))
                 (animating :cubically-in-out :the 'sdl2:rect-y :to 0 :for 800))))

 ;; ... snip
  
  #+end_src

And here is what the above looks like

<img src=".images/animise-eg-3.gif" width="272" height="223"/>