Robert Penners easing functions js (compatible with scroll-utility)

May 6, 2019 · View on GitHub

/* ============================================================

const Easing = { // t: current time, b: begInnIng value, c: change In value, d: duration easeInQuad: function(t, b, c, d) { return c * (t /= d) * t + b }, easeOutQuad: function(t, b, c, d) { return -c * (t /= d) * (t - 2) + b }, easeInOutQuad: function(t, b, c, d) { if ((t /= d / 2) < 1) return (c / 2) * t * t + b return (-c / 2) * (--t * (t - 2) - 1) + b }, easeInCubic: function(t, b, c, d) { return c * (t /= d) * t * t + b }, easeOutCubic: function(t, b, c, d) { return c * ((t = t / d - 1) * t * t + 1) + b }, easeInOutCubic: 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 }, easeInQuart: function(t, b, c, d) { return c * (t /= d) * t * t * t + b }, easeOutQuart: function(t, b, c, d) { return -c * ((t = t / d - 1) * t * t * t - 1) + b }, easeInOutQuart: 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 }, easeInQuint: function(t, b, c, d) { return c * (t /= d) * t * t * t * t + b }, easeOutQuint: function(t, b, c, d) { return c * ((t = t / d - 1) * t * t * t * t + 1) + b }, easeInOutQuint: 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 }, easeInSine: function(t, b, c, d) { return -c * Math.cos((t / d) * (Math.PI / 2)) + c + b }, easeOutSine: function(t, b, c, d) { return c * Math.sin((t / d) * (Math.PI / 2)) + b }, easeInOutSine: function(t, b, c, d) { return (-c / 2) * (Math.cos((Math.PI * t) / d) - 1) + b }, easeInExpo: function(t, b, c, d) { return t == 0 ? b : c * Math.pow(2, 10 * (t / d - 1)) + b }, easeOutExpo: function(t, b, c, d) { return t == d ? b + c : c * (-Math.pow(2, (-10 * t) / d) + 1) + b }, easeInOutExpo: 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 }, easeInCirc: function(t, b, c, d) { return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b }, easeOutCirc: function(t, b, c, d) { return c * Math.sqrt(1 - (t = t / d - 1) * t) + b }, easeInOutCirc: 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 }, easeInElastic: function(t, b, c, d) { var s = 1.70158 var p = 0 var a = c if (t == 0) return b if ((t /= d) == 1) return b + c if (!p) p = d * 0.3 if (a < Math.abs(c)) { a = c var s = p / 4 } else var 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 }, easeOutElastic: function(t, b, c, d) { var s = 1.70158 var p = 0 var a = c if (t == 0) return b if ((t /= d) == 1) return b + c if (!p) p = d * 0.3 if (a < Math.abs(c)) { a = c var s = p / 4 } else var 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 }, easeInOutElastic: function(t, b, c, d) { var s = 1.70158 var p = 0 var a = c if (t == 0) return b if ((t /= d / 2) == 2) return b + c if (!p) p = d * (0.3 * 1.5) if (a < Math.abs(c)) { a = c var s = p / 4 } else var 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 ) }, easeInBack: function(t, b, c, d, s) { if (s == undefined) s = 1.70158 return c * (t /= d) * t * ((s + 1) * t - s) + b }, easeOutBack: 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 }, easeInOutBack: 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 }, easeInBounce: function(t, b, c, d) { return c - Easing.easeOutBounce(d - t, 0, c, d) + b }, easeOutBounce: 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 } }, easeInOutBounce: function(t, b, c, d) { if (t < d / 2) return Easing.easeInBounce(t * 2, 0, c, d) * 0.5 + b return Easing.easeOutBounce(t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b }, }

window.Easing = Easing

/* *

  • TERMS OF USE - EASING EQUATIONS
  • Open source under the BSD License.
  • Copyright © 2001 Robert Penner
  • All rights reserved.
  • Redistribution and use in source and binary forms, with or without modification,
  • are permitted provided that the following conditions are met:
  • Redistributions of source code must retain the above copyright notice, this list of
  • conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list
  • of conditions and the following disclaimer in the documentation and/or other materials
  • provided with the distribution.
  • Neither the name of the author nor the names of contributors may be used to endorse
  • or promote products derived from this software without specific prior written permission.
  • THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  • EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  • MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  • COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  • EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  • GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  • AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  • NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  • OF THE POSSIBILITY OF SUCH DAMAGE.

*/