After Effects Easing Functions

ease.js

function easeExpo(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeExpo(beginValue[0], endValue[0], duration, offset);
      y = easeExpo(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeExpo(beginValue[0], endValue[0], duration, offset);
      y = easeExpo(beginValue[1], endValue[1], duration, offset);
      z = easeExpo(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration / 2;
  if (t < 1) return (c / 2) * Math.pow(2, 10 * (t - 1)) + beginValue;
  t--;
  return (c / 2) * (-Math.pow(2, -10 * t) + 2) + beginValue;
}


function easeCirc(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeCirc(beginValue[0], endValue[0], duration, offset);
      y = easeCirc(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeCirc(beginValue[0], endValue[0], duration, offset);
      y = easeCirc(beginValue[1], endValue[1], duration, offset);
      z = easeCirc(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration / 2;
  if (t < 1) return (-c / 2) * (Math.sqrt(1 - t * t) - 1) + beginValue;
  t -= 2;
  return (c / 2) * (Math.sqrt(1 - t * t) + 1) + beginValue;
}

function easeQuart(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeQuart(beginValue[0], endValue[0], duration, offset);
      y = easeQuart(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeQuart(beginValue[0], endValue[0], duration, offset);
      y = easeQuart(beginValue[1], endValue[1], duration, offset);
      z = easeQuart(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration / 2;
  if (t < 1) return (c / 2) * t * t * t * t + beginValue;
  t -= 2;
  return (-c / 2) * (t * t * t * t - 2) + beginValue;
}

function easeExpoIn(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeExpoIn(beginValue[0], endValue[0], duration, offset);
      y = easeExpoIn(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeExpoIn(beginValue[0], endValue[0], duration, offset);
      y = easeExpoIn(beginValue[1], endValue[1], duration, offset);
      z = easeExpoIn(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration;
  return c * Math.pow(2, 10 * (t - 1)) + beginValue;
}

function easeCircIn(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeCircIn(beginValue[0], endValue[0], duration, offset);
      y = easeCircIn(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeCircIn(beginValue[0], endValue[0], duration, offset);
      y = easeCircIn(beginValue[1], endValue[1], duration, offset);
      z = easeCircIn(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration;
  return -c * (Math.sqrt(1 - t * t) - 1) + beginValue;
}

function easeQuartIn(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeQuartIn(beginValue[0], endValue[0], duration, offset);
      y = easeQuartIn(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeQuartIn(beginValue[0], endValue[0], duration, offset);
      y = easeQuartIn(beginValue[1], endValue[1], duration, offset);
      z = easeQuartIn(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration;
  return c * t * t * t * t + beginValue;
}

function easeExpoOut(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeExpoOut(beginValue[0], endValue[0], duration, offset);
      y = easeExpoOut(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeExpoOut(beginValue[0], endValue[0], duration, offset);
      y = easeExpoOut(beginValue[1], endValue[1], duration, offset);
      z = easeExpoOut(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration;
  return c * (-Math.pow(2, -10 * t) + 1) + beginValue;
}

function easeCircOut(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeCircOut(beginValue[0], endValue[0], duration, offset);
      y = easeCircOut(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeCircOut(beginValue[0], endValue[0], duration, offset);
      y = easeCircOut(beginValue[1], endValue[1], duration, offset);
      z = easeCircOut(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration;
  t--;
  return c * Math.sqrt(1 - t * t) + beginValue;
}

function easeQuartOut(beginValue, endValue, duration, offset) {
  t = time - offset;
  if (t < 0) return beginValue;
  if (t > duration) return endValue;
  if (beginValue.constructor == Array) {
    x = 0;
    y = 0;
    z = 0;
    if (beginValue.length == 2) {
      x = easeQuartOut(beginValue[0], endValue[0], duration, offset);
      y = easeQuartOut(beginValue[1], endValue[1], duration, offset);
      return [x, y];
    } else {
      x = easeQuartOut(beginValue[0], endValue[0], duration, offset);
      y = easeQuartOut(beginValue[1], endValue[1], duration, offset);
      z = easeQuartOut(beginValue[2], endValue[2], duration, offset);
      return [x, y, z];
    }
  }
  c = endValue - beginValue;
  t /= duration;
  t--;
  return -c * (t * t * t * t - 1) + beginValue;
}

function scaleToFit(a, b) {
  myW = thisLayer.sourceRectAtTime(thisComp.duration / 2).width;
  myH = thisLayer.sourceRectAtTime(thisComp.duration / 2).height;
  calcW = (a / myW) * 100;
  calcH = (b / myH) * 100;
  lowest = calcW;
  calcH < calcW && (lowest = calcH);
  return [lowest, lowest];
}