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============================================================================================ Easing Equations v2.0 September 1, 2003 (c) 2003 Robert Penner, all rights reserved. This work is subject to the terms in http://www.robertpenner.com/easing_terms_of_use.html. ============================================================================================

  
  
  
[lang:ja] イージング関数ライブラリ {gray enchant.Easing} 以下にある関数は全て t(現在の時刻), b(初期値), c(変化後の値), d(値の変化にかける時間) の引数を取り、指定した時刻に取る値を返す。 ActionScript で広く使われている Robert Penner による Easing Equations を JavaScript に移植した。
see: www.robertpenner.com/easing/
see: www.robertpenner.com/easing/penner_chapter7_tweening.pdf [/lang] [lang:en] [/lang] Easing function library, from "Easing Equations" by Robert Penner. @type {Object} @namespace {gray enchant.Tween} クラスで用いるイージング関数のライブラリ名前空間.

  
  enchant.Easing = {
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      LINEAR: function(t, b, c, d) {
          return c * t / d + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      SWING: function(t, b, c, d) {
          return c * (0.5 - Math.cos(((t / d) * Math.PI)) / 2) + b;
      },
      // quad
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUAD_EASEIN: function(t, b, c, d) {
          return c * (t /= d) * t + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUAD_EASEOUT: function(t, b, c, d) {
          return -c * (t /= d) * (t - 2) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUAD_EASEINOUT: function(t, b, c, d) {
          if ((t /= d / 2) < 1) {
              return c / 2 * t * t + b;
          }
          return -c / 2 * ((--t) * (t - 2) - 1) + b;
      },
      // cubic
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      CUBIC_EASEIN: function(t, b, c, d) {
          return c * (t /= d) * t * t + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      CUBIC_EASEOUT: function(t, b, c, d) {
          return c * ((t = t / d - 1) * t * t + 1) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      CUBIC_EASEINOUT: function(t, b, c, d) {
          if ((t /= d / 2) < 1) {
              return c / 2 * t * t * t + b;
          }
          return c / 2 * ((t -= 2) * t * t + 2) + b;
      },
      // quart
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUART_EASEIN: function(t, b, c, d) {
          return c * (t /= d) * t * t * t + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUART_EASEOUT: function(t, b, c, d) {
          return -c * ((t = t / d - 1) * t * t * t - 1) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUART_EASEINOUT: function(t, b, c, d) {
          if ((t /= d / 2) < 1) {
              return c / 2 * t * t * t * t + b;
          }
          return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
      },
      // quint
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUINT_EASEIN: function(t, b, c, d) {
          return c * (t /= d) * t * t * t * t + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUINT_EASEOUT: function(t, b, c, d) {
          return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      QUINT_EASEINOUT: function(t, b, c, d) {
          if ((t /= d / 2) < 1) {
              return c / 2 * t * t * t * t * t + b;
          }
          return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
      },
      //sin
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      SIN_EASEIN: function(t, b, c, d) {
          return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      SIN_EASEOUT: function(t, b, c, d) {
          return c * Math.sin(t / d * (Math.PI / 2)) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      SIN_EASEINOUT: function(t, b, c, d) {
          return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
      },
      // circ
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      CIRC_EASEIN: function(t, b, c, d) {
          return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      CIRC_EASEOUT: function(t, b, c, d) {
          return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      CIRC_EASEINOUT: function(t, b, c, d) {
          if ((t /= d / 2) < 1) {
              return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
          }
          return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
      },
      // elastic
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      ELASTIC_EASEIN: function(t, b, c, d, a, p) {
          if (t === 0) {
              return b;
          }
          if ((t /= d) === 1) {
              return b + c;
          }
  
          if (!p) {
              p = d * 0.3;
          }
  
          var s;
          if (!a || a < Math.abs(c)) {
              a = c;
              s = p / 4;
          } else {
              s = p / (2 * Math.PI) * Math.asin(c / a);
          }
          return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      ELASTIC_EASEOUT: function(t, b, c, d, a, p) {
          if (t === 0) {
              return b;
          }
          if ((t /= d) === 1) {
              return b + c;
          }
          if (!p) {
              p = d * 0.3;
          }
          var s;
          if (!a || a < Math.abs(c)) {
              a = c;
              s = p / 4;
          } else {
              s = p / (2 * Math.PI) * Math.asin(c / a);
          }
          return (a * Math.pow(2, -10 * t) * Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b);
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      ELASTIC_EASEINOUT: function(t, b, c, d, a, p) {
          if (t === 0) {
              return b;
          }
          if ((t /= d / 2) === 2) {
              return b + c;
          }
          if (!p) {
              p = d * (0.3 * 1.5);
          }
          var s;
          if (!a || a < Math.abs(c)) {
              a = c;
              s = p / 4;
          } else {
              s = p / (2 * Math.PI) * Math.asin(c / a);
          }
          if (t < 1) {
              return -0.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
          }
          return a * Math.pow(2, -10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p) * 0.5 + c + b;
      },
      // bounce
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      BOUNCE_EASEOUT: function(t, b, c, d) {
          if ((t /= d) < (1 / 2.75)) {
              return c * (7.5625 * t * t) + b;
          } else if (t < (2 / 2.75)) {
              return c * (7.5625 * (t -= (1.5 / 2.75)) * t + 0.75) + b;
          } else if (t < (2.5 / 2.75)) {
              return c * (7.5625 * (t -= (2.25 / 2.75)) * t + 0.9375) + b;
          } else {
              return c * (7.5625 * (t -= (2.625 / 2.75)) * t + 0.984375) + b;
          }
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      BOUNCE_EASEIN: function(t, b, c, d) {
          return c - enchant.Easing.BOUNCE_EASEOUT(d - t, 0, c, d) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      BOUNCE_EASEINOUT: function(t, b, c, d) {
          if (t < d / 2) {
              return enchant.Easing.BOUNCE_EASEIN(t * 2, 0, c, d) * 0.5 + b;
          } else {
              return enchant.Easing.BOUNCE_EASEOUT(t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b;
          }
  
      },
      // back
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      BACK_EASEIN: function(t, b, c, d, s) {
          if (s === undefined) {
              s = 1.70158;
          }
          return c * (t /= d) * t * ((s + 1) * t - s) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      BACK_EASEOUT: function(t, b, c, d, s) {
          if (s === undefined) {
              s = 1.70158;
          }
          return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      BACK_EASEINOUT: function(t, b, c, d, s) {
          if (s === undefined) {
              s = 1.70158;
          }
          if ((t /= d / 2) < 1) {
              return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
          }
          return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
      },
      // expo
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      EXPO_EASEIN: function(t, b, c, d) {
          return (t === 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      EXPO_EASEOUT: function(t, b, c, d) {
          return (t === d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
      },
      

parameter: t
parameter: b
parameter: c
parameter: d
returns: {Number}

  
      EXPO_EASEINOUT: function(t, b, c, d) {
          if (t === 0) {
              return b;
          }
          if (t === d) {
              return b + c;
          }
          if ((t /= d / 2) < 1) {
              return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
          }
          return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
      }
  };
  
  
Easing Equations v2.0

  
  


(C) Æliens 04/09/2009

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