// Based on Easing Equations (c) 2003 Robert Penner, all rights reserved.
// This work is subject to the terms in http://www.robertpenner.com/easing_terms_of_use.html
// Adapted for script.aculo.us by
// Brian Crescimanno <brian.crescimanno@gmail.com>
// Ken Snyder <kendsnyder@gmail.com)

Object.extend(Effect.Transitions, {
  easeInQuad: function(pos){
     return Math.pow(pos, 2);
   },

   easeOutQuad: function(pos){
     return -(Math.pow((pos-1), 2) -1);
   },

   easeInOutQuad: function(pos){
     if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,2);
     return -0.5 * ((pos-=2)*pos - 2);
   },

   easeInCubic: function(pos){
     return Math.pow(pos, 3);
   },

   easeOutCubic: function(pos){
     return (Math.pow((pos-1), 3) +1);
   },

   easeInOutCubic: function(pos){
     if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,3);
     return 0.5 * (Math.pow((pos-2),3) + 2);
   },

   easeInQuart: function(pos){
     return Math.pow(pos, 4);
   },

   easeOutQuart: function(pos){
     return -(Math.pow((pos-1), 4) -1)
   },

   easeInOutQuart: function(pos){
     if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,4);
     return -0.5 * ((pos-=2)*Math.pow(pos,3) - 2);
   },

   easeInQuint: function(pos){
     return Math.pow(pos, 5);
   },

   easeOutQuint: function(pos){
     return (Math.pow((pos-1), 5) +1);
   },

   easeInOutQuint: function(pos){
     if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,5);
     return 0.5 * (Math.pow((pos-2),5) + 2);
   },

   easeInSine: function(pos){
     return -Math.cos(pos * (Math.PI/2)) + 1;
   },

   easeOutSine: function(pos){
     return Math.sin(pos * (Math.PI/2));
   },

   easeInOutSine: function(pos){
     return (-.5 * (Math.cos(Math.PI*pos) -1));
   },

   easeInExpo: function(pos){
     return (pos==0) ? 0 : Math.pow(2, 10 * (pos - 1));
   },

   easeOutExpo: function(pos){
     return (pos==1) ? 1 : -Math.pow(2, -10 * pos) + 1;
   },

   easeInOutExpo: function(pos){
     if(pos==0) return 0;
     if(pos==1) return 1;
     if((pos/=0.5) < 1) return 0.5 * Math.pow(2,10 * (pos-1));
     return 0.5 * (-Math.pow(2, -10 * --pos) + 2);
   },

   easeInCirc: function(pos){
     return -(Math.sqrt(1 - (pos*pos)) - 1);
   },

   easeOutCirc: function(pos){
     return Math.sqrt(1 - Math.pow((pos-1), 2))
   },

   easeInOutCirc: function(pos){
     if((pos/=0.5) < 1) return -0.5 * (Math.sqrt(1 - pos*pos) - 1);
     return 0.5 * (Math.sqrt(1 - (pos-=2)*pos) + 1);
   },

   easeOutBounce: function(pos){
     if ((pos) < (1/2.75)) {
       return (7.5625*pos*pos);
     } else if (pos < (2/2.75)) {
       return (7.5625*(pos-=(1.5/2.75))*pos + .75);
     } else if (pos < (2.5/2.75)) {
       return (7.5625*(pos-=(2.25/2.75))*pos + .9375);
     } else {
       return (7.5625*(pos-=(2.625/2.75))*pos + .984375);
     }
   },

   easeInBack: function(pos){
     var s = 1.70158;
     return (pos)*pos*((s+1)*pos - s);
   },

   easeOutBack: function(pos){
     var s = 1.70158;
     return (pos=pos-1)*pos*((s+1)*pos + s) + 1;
   },

   easeInOutBack: function(pos){
     var s = 1.70158;
     if((pos/=0.5) < 1) return 0.5*(pos*pos*(((s*=(1.525))+1)*pos -s));
     return 0.5*((pos-=2)*pos*(((s*=(1.525))+1)*pos +s) +2);
   },

   elastic: function(pos) {
     return -1 * Math.pow(4,-8*pos) * Math.sin((pos*6-1)*(2*Math.PI)/2) + 1;
   },

   swingFromTo: function(pos) {
     var s = 1.70158;
     return ((pos/=0.5) < 1) ? 0.5*(pos*pos*(((s*=(1.525))+1)*pos - s)) :
       0.5*((pos-=2)*pos*(((s*=(1.525))+1)*pos + s) + 2);
   },

   swingFrom: function(pos) {
     var s = 1.70158;
     return pos*pos*((s+1)*pos - s);
   },

   swingTo: function(pos) {
     var s = 1.70158;
     return (pos-=1)*pos*((s+1)*pos + s) + 1;
   },

   bounce: function(pos) {
     if (pos < (1/2.75)) {
         return (7.5625*pos*pos);
     } else if (pos < (2/2.75)) {
         return (7.5625*(pos-=(1.5/2.75))*pos + .75);
     } else if (pos < (2.5/2.75)) {
         return (7.5625*(pos-=(2.25/2.75))*pos + .9375);
     } else {
         return (7.5625*(pos-=(2.625/2.75))*pos + .984375);
     }
   },

   bouncePast: function(pos) {
     if (pos < (1/2.75)) {
         return (7.5625*pos*pos);
     } else if (pos < (2/2.75)) {
         return 2 - (7.5625*(pos-=(1.5/2.75))*pos + .75);
     } else if (pos < (2.5/2.75)) {
         return 2 - (7.5625*(pos-=(2.25/2.75))*pos + .9375);
     } else {
         return 2 - (7.5625*(pos-=(2.625/2.75))*pos + .984375);
     }
   },

   easeFromTo: function(pos) {
     if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,4);
     return -0.5 * ((pos-=2)*Math.pow(pos,3) - 2);
   },

   easeFrom: function(pos) {
     return Math.pow(pos,4);
   },

   easeTo: function(pos) {
     return Math.pow(pos,0.25);
   }
});