316 lines
6.5 KiB
JavaScript
316 lines
6.5 KiB
JavaScript
'use strict';
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import { Bezier } from './Bezier';
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/**
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* The `Easing` module implements common easing functions. This module is used
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* by [Animate.timing()](docs/animate.html#timing) to convey physically
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* believable motion in animations.
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*
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* You can find a visualization of some common easing functions at
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* http://easings.net/
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*
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* ### Predefined animations
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*
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* The `Easing` module provides several predefined animations through the
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* following methods:
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*
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* - [`back`](docs/easing.html#back) provides a simple animation where the object
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* goes slightly back before moving forward
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* - [`bounce`](docs/easing.html#bounce) provides a bouncing animation
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* - [`ease`](docs/easing.html#ease) provides a simple inertial animation
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* - [`elastic`](docs/easing.html#elastic) provides a simple spring interaction
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*
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* ### Standard functions
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*
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* Three standard easing functions are provided:
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*
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* - [`linear`](docs/easing.html#linear)
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* - [`quad`](docs/easing.html#quad)
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* - [`cubic`](docs/easing.html#cubic)
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*
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* The [`poly`](docs/easing.html#poly) function can be used to implement
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* quartic, quintic, and other higher power functions.
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*
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* ### Additional functions
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*
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* Additional mathematical functions are provided by the following methods:
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*
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* - [`bezier`](docs/easing.html#bezier) provides a cubic bezier curve
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* - [`circle`](docs/easing.html#circle) provides a circular function
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* - [`sin`](docs/easing.html#sin) provides a sinusoidal function
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* - [`exp`](docs/easing.html#exp) provides an exponential function
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*
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* The following helpers are used to modify other easing functions.
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*
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* - [`in`](docs/easing.html#in) runs an easing function forwards
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* - [`inOut`](docs/easing.html#inout) makes any easing function symmetrical
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* - [`out`](docs/easing.html#out) runs an easing function backwards
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*/
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/**
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* A linear function, `f(t) = t`. Position correlates to elapsed time one to
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* one.
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*
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* http://cubic-bezier.com/#0,0,1,1
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*/
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function linear(t) {
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'worklet';
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return t;
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}
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/**
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* A simple inertial interaction, similar to an object slowly accelerating to
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* speed.
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*
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* http://cubic-bezier.com/#.42,0,1,1
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*/
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function ease(t) {
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'worklet';
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return Bezier(0.42, 0, 1, 1)(t);
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}
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/**
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* A quadratic function, `f(t) = t * t`. Position equals the square of elapsed
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* time.
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*
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* http://easings.net/#easeInQuad
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*/
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function quad(t) {
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'worklet';
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return t * t;
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}
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/**
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* A cubic function, `f(t) = t * t * t`. Position equals the cube of elapsed
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* time.
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*
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* http://easings.net/#easeInCubic
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*/
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function cubic(t) {
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'worklet';
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return t * t * t;
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}
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/**
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* A power function. Position is equal to the Nth power of elapsed time.
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*
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* N = 4: http://easings.net/#easeInQuart n = 5: http://easings.net/#easeInQuint
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*/
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function poly(n) {
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'worklet';
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return t => {
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'worklet';
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return Math.pow(t, n);
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};
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}
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/**
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* A sinusoidal function.
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*
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* http://easings.net/#easeInSine
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*/
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function sin(t) {
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'worklet';
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return 1 - Math.cos(t * Math.PI / 2);
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}
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/**
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* A circular function.
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*
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* http://easings.net/#easeInCirc
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*/
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function circle(t) {
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'worklet';
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return 1 - Math.sqrt(1 - t * t);
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}
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/**
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* An exponential function.
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*
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* http://easings.net/#easeInExpo
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*/
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function exp(t) {
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'worklet';
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return Math.pow(2, 10 * (t - 1));
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}
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/**
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* A simple elastic interaction, similar to a spring oscillating back and forth.
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*
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* Default bounciness is 1, which overshoots a little bit once. 0 bounciness
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* doesn't overshoot at all, and bounciness of N `>` 1 will overshoot about N
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* times.
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*
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* http://easings.net/#easeInElastic
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*/
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function elastic(bounciness = 1) {
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'worklet';
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const p = bounciness * Math.PI;
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return t => {
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'worklet';
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return 1 - Math.pow(Math.cos(t * Math.PI / 2), 3) * Math.cos(t * p);
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};
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}
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/**
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* Use with `Animated.parallel()` to create a simple effect where the object
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* animates back slightly as the animation starts.
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*
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* Wolfram Plot:
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*
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* - http://tiny.cc/back_default (s = 1.70158, default)
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*/
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function back(s = 1.70158) {
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'worklet';
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return t => {
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'worklet';
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return t * t * ((s + 1) * t - s);
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};
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}
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/**
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* Provides a simple bouncing effect.
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*
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* http://easings.net/#easeInBounce
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*/
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function bounce(t) {
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'worklet';
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if (t < 1 / 2.75) {
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return 7.5625 * t * t;
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}
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if (t < 2 / 2.75) {
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const t2 = t - 1.5 / 2.75;
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return 7.5625 * t2 * t2 + 0.75;
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}
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if (t < 2.5 / 2.75) {
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const t2 = t - 2.25 / 2.75;
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return 7.5625 * t2 * t2 + 0.9375;
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}
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const t2 = t - 2.625 / 2.75;
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return 7.5625 * t2 * t2 + 0.984375;
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}
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/**
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* Provides a cubic bezier curve, equivalent to CSS Transitions'
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* `transition-timing-function`.
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*
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* A useful tool to visualize cubic bezier curves can be found at
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* http://cubic-bezier.com/
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*/
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function bezier(x1, y1, x2, y2) {
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'worklet';
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return {
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factory: () => {
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'worklet';
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return Bezier(x1, y1, x2, y2);
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}
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};
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}
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function bezierFn(x1, y1, x2, y2) {
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'worklet';
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return Bezier(x1, y1, x2, y2);
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}
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/** Runs an easing function forwards. */
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function in_(easing) {
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'worklet';
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return easing;
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}
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/** Runs an easing function backwards. */
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function out(easing) {
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'worklet';
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return t => {
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'worklet';
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return 1 - easing(1 - t);
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};
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}
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/**
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* Makes any easing function symmetrical. The easing function will run forwards
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* for half of the duration, then backwards for the rest of the duration.
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*/
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function inOut(easing) {
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'worklet';
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return t => {
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'worklet';
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if (t < 0.5) {
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return easing(t * 2) / 2;
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}
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return 1 - easing((1 - t) * 2) / 2;
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};
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}
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/**
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* The `steps` easing function jumps between discrete values at regular
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* intervals, creating a stepped animation effect. The `n` parameter determines
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* the number of steps in the animation, and the `roundToNextStep` parameter
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* determines whether the animation should start at the beginning or end of each
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* step.
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*/
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function steps(n = 10, roundToNextStep = true) {
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'worklet';
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return t => {
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'worklet';
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const value = Math.min(Math.max(t, 0), 1) * n;
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if (roundToNextStep) {
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return Math.ceil(value) / n;
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}
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return Math.floor(value) / n;
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};
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}
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const EasingObject = {
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linear,
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ease,
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quad,
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cubic,
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poly,
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sin,
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circle,
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exp,
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elastic,
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back,
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bounce,
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bezier,
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bezierFn,
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steps,
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in: in_,
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out,
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inOut
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};
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export const EasingNameSymbol = Symbol('easingName');
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for (const [easingName, easing] of Object.entries(EasingObject)) {
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Object.defineProperty(easing, EasingNameSymbol, {
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value: easingName,
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configurable: false,
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enumerable: false,
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writable: false
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});
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}
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export const Easing = EasingObject;
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//# sourceMappingURL=Easing.js.map
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