@smoovy/tween/easing.js

simple and easy-to-use tween lib

"use strict";
export const linear = (x) => {
  return x;
};
export const easeInSine = (x) => {
  return 1 + Math.sin(Math.PI / 2 * x - Math.PI / 2);
};
export const easeOutSine = (x) => {
  return Math.sin(Math.PI / 2 * x);
};
export const easeInOutSine = (x) => {
  return (1 + Math.sin(Math.PI * x - Math.PI / 2)) / 2;
};
export const easeInQuad = (x) => {
  return x * x;
};
export const easeOutQuad = (x) => {
  return x * (2 - x);
};
export const easeInOutQuad = (x) => {
  return x < 0.5 ? 2 * x * x : -1 + (4 - 2 * x) * x;
};
export const easeInCubic = (x) => {
  return x * x * x;
};
export const easeOutCubic = (x) => {
  return --x * x * x + 1;
};
export const easeInOutCubic = (x) => {
  return x < 0.5 ? 4 * x * x * x : (x - 1) * (2 * x - 2) * (2 * x - 2) + 1;
};
export const easeInQuart = (x) => {
  return x * x * x * x;
};
export const easeOutQuart = (x) => {
  return 1 - --x * x * x * x;
};
export const easeInOutQuart = (x) => {
  return x < 0.5 ? 8 * x * x * x * x : 1 - 8 * --x * x * x * x;
};
export const easeInQuint = (x) => {
  return x * x * x * x * x;
};
export const easeOutQuint = (x) => {
  return 1 + --x * x * x * x * x;
};
export const easeInOutQuint = (x) => {
  return x < 0.5 ? 16 * x * x * x * x * x : 1 + 16 * --x * x * x * x * x;
};
export const easeInExpo = (x) => {
  return x === 0 ? 0 : Math.pow(2, 10 * x - 10);
};
export const easeOutExpo = (x) => {
  return x === 1 ? 1 : 1 - Math.pow(2, -10 * x);
};
export const easeInOutExpo = (x) => {
  return x === 0 ? 0 : x === 1 ? 1 : x < 0.5 ? Math.pow(2, 20 * x - 10) / 2 : (2 - Math.pow(2, -20 * x + 10)) / 2;
};
export const easeInCirc = (x) => {
  return 1 - Math.sqrt(1 - Math.pow(x, 2));
};
export const easeOutCirc = (x) => {
  return Math.sqrt(1 - Math.pow(x - 1, 2));
};
export const easeInOutCirc = (x) => {
  return x < 0.5 ? (1 - Math.sqrt(1 - Math.pow(2 * x, 2))) / 2 : (Math.sqrt(1 - Math.pow(-2 * x + 2, 2)) + 1) / 2;
};
export const easeInBack = (x) => {
  const c1 = 1.70158;
  const c3 = c1 + 1;
  return c3 * x * x * x - c1 * x * x;
};
export const easeOutBack = (x) => {
  const c1 = 1.70158;
  const c3 = c1 + 1;
  return 1 + c3 * Math.pow(x - 1, 3) + c1 * Math.pow(x - 1, 2);
};
export const easeInOutBack = (x) => {
  const c1 = 1.70158;
  const c2 = c1 * 1.525;
  return x < 0.5 ? Math.pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2) / 2 : (Math.pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
};
export const easeInElastic = (x) => {
  return (0.04 - 0.04 / x) * Math.sin(25 * x) + 1;
};
export const easeOutElastic = (x) => {
  return 0.04 * x / --x * Math.sin(25 * x);
};
export const easeInOutElastic = (x) => {
  return (x -= 0.5) < 0 ? (0.02 + 0.01 / x) * Math.sin(50 * x) : (0.02 - 0.01 / x) * Math.sin(50 * x) + 1;
};
export const easeInBounce = (x) => {
  return 1 - easeOutBounce(1 - x);
};
export const easeOutBounce = (x) => {
  const n1 = 7.5625;
  const d1 = 2.75;
  if (x < 1 / d1) {
    return n1 * x * x;
  } else if (x < 2 / d1) {
    return n1 * (x -= 1.5 / d1) * x + 0.75;
  } else if (x < 2.5 / d1) {
    return n1 * (x -= 2.25 / d1) * x + 0.9375;
  } else {
    return n1 * (x -= 2.625 / d1) * x + 0.984375;
  }
};
export const easeInOutBounce = (x) => {
  return x < 0.5 ? (1 - easeOutBounce(1 - 2 * x)) / 2 : (1 + easeOutBounce(2 * x - 1)) / 2;
};