/*
Based on Easing Equations v2.0
(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 Scriptaculous by Ken Snyder (kendsnyder ~at~ gmail ~dot~ com) June 2006
*/

Object.extend(Effect.Transitions, {
  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);
  }
});