Last active
September 9, 2022 20:27
Cubic Bezier Curves: http://cubic-bezier.com/JavaScript Library: https://github.com/gre/bezier-easingDemo: https://jsfiddle.net/0x51ew2L/
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/*--------------Library code----------------*/ | |
/** | |
* BezierEasing - use bezier curve for transition easing function | |
* by Gaëtan Renaudeau 2014 – MIT License | |
* | |
* Credits: is based on Firefox's nsSMILKeySpline.cpp | |
* Usage: | |
* var spline = BezierEasing(0.25, 0.1, 0.25, 1.0) | |
* spline(x) => returns the easing value | x must be in [0, 1] range | |
* | |
*/ | |
(function (definition) { | |
if (typeof exports === "object") { | |
module.exports = definition(); | |
} else if (typeof define === 'function' && define.amd) { | |
define([], definition); | |
} else { | |
window.BezierEasing = definition(); | |
} | |
}(function () { | |
var global = this; | |
// These values are established by empiricism with tests (tradeoff: performance VS precision) | |
var NEWTON_ITERATIONS = 4; | |
var NEWTON_MIN_SLOPE = 0.001; | |
var SUBDIVISION_PRECISION = 0.0000001; | |
var SUBDIVISION_MAX_ITERATIONS = 10; | |
var kSplineTableSize = 11; | |
var kSampleStepSize = 1.0 / (kSplineTableSize - 1.0); | |
var float32ArraySupported = 'Float32Array' in global; | |
function A (aA1, aA2) { return 1.0 - 3.0 * aA2 + 3.0 * aA1; } | |
function B (aA1, aA2) { return 3.0 * aA2 - 6.0 * aA1; } | |
function C (aA1) { return 3.0 * aA1; } | |
// Returns x(t) given t, x1, and x2, or y(t) given t, y1, and y2. | |
function calcBezier (aT, aA1, aA2) { | |
return ((A(aA1, aA2)*aT + B(aA1, aA2))*aT + C(aA1))*aT; | |
} | |
// Returns dx/dt given t, x1, and x2, or dy/dt given t, y1, and y2. | |
function getSlope (aT, aA1, aA2) { | |
return 3.0 * A(aA1, aA2)*aT*aT + 2.0 * B(aA1, aA2) * aT + C(aA1); | |
} | |
function binarySubdivide (aX, aA, aB) { | |
var currentX, currentT, i = 0; | |
do { | |
currentT = aA + (aB - aA) / 2.0; | |
currentX = calcBezier(currentT, mX1, mX2) - aX; | |
if (currentX > 0.0) { | |
aB = currentT; | |
} else { | |
aA = currentT; | |
} | |
} while (Math.abs(currentX) > SUBDIVISION_PRECISION && ++i < SUBDIVISION_MAX_ITERATIONS); | |
return currentT; | |
} | |
function BezierEasing (mX1, mY1, mX2, mY2) { | |
// Validate arguments | |
if (arguments.length !== 4) { | |
throw new Error("BezierEasing requires 4 arguments."); | |
} | |
for (var i=0; i<4; ++i) { | |
if (typeof arguments[i] !== "number" || isNaN(arguments[i]) || !isFinite(arguments[i])) { | |
throw new Error("BezierEasing arguments should be integers."); | |
} | |
} | |
if (mX1 < 0 || mX1 > 1 || mX2 < 0 || mX2 > 1) { | |
throw new Error("BezierEasing x values must be in [0, 1] range."); | |
} | |
var mSampleValues = float32ArraySupported ? new Float32Array(kSplineTableSize) : new Array(kSplineTableSize); | |
function newtonRaphsonIterate (aX, aGuessT) { | |
for (var i = 0; i < NEWTON_ITERATIONS; ++i) { | |
var currentSlope = getSlope(aGuessT, mX1, mX2); | |
if (currentSlope === 0.0) return aGuessT; | |
var currentX = calcBezier(aGuessT, mX1, mX2) - aX; | |
aGuessT -= currentX / currentSlope; | |
} | |
return aGuessT; | |
} | |
function calcSampleValues () { | |
for (var i = 0; i < kSplineTableSize; ++i) { | |
mSampleValues[i] = calcBezier(i * kSampleStepSize, mX1, mX2); | |
} | |
} | |
function getTForX (aX) { | |
var intervalStart = 0.0; | |
var currentSample = 1; | |
var lastSample = kSplineTableSize - 1; | |
for (; currentSample != lastSample && mSampleValues[currentSample] <= aX; ++currentSample) { | |
intervalStart += kSampleStepSize; | |
} | |
--currentSample; | |
// Interpolate to provide an initial guess for t | |
var dist = (aX - mSampleValues[currentSample]) / (mSampleValues[currentSample+1] - mSampleValues[currentSample]); | |
var guessForT = intervalStart + dist * kSampleStepSize; | |
var initialSlope = getSlope(guessForT, mX1, mX2); | |
if (initialSlope >= NEWTON_MIN_SLOPE) { | |
return newtonRaphsonIterate(aX, guessForT); | |
} else if (initialSlope === 0.0) { | |
return guessForT; | |
} else { | |
return binarySubdivide(aX, intervalStart, intervalStart + kSampleStepSize); | |
} | |
} | |
var _precomputed = false; | |
function precompute() { | |
_precomputed = true; | |
if (mX1 != mY1 || mX2 != mY2) | |
calcSampleValues(); | |
} | |
var f = function (aX) { | |
if (!_precomputed) precompute(); | |
if (mX1 === mY1 && mX2 === mY2) return aX; // linear | |
// Because JavaScript number are imprecise, we should guarantee the extremes are right. | |
if (aX === 0) return 0; | |
if (aX === 1) return 1; | |
return calcBezier(getTForX(aX), mY1, mY2); | |
}; | |
f.getControlPoints = function() { return [{ x: mX1, y: mY1 }, { x: mX2, y: mY2 }]; }; | |
var args = [mX1, mY1, mX2, mY2]; | |
var str = "BezierEasing("+args+")"; | |
f.toString = function () { return str; }; | |
var css = "cubic-bezier("+args+")"; | |
f.toCSS = function () { return css; }; | |
return f; | |
} | |
// CSS mapping | |
BezierEasing.css = { | |
"ease": BezierEasing(0.25, 0.1, 0.25, 1.0), | |
"linear": BezierEasing(0.00, 0.0, 1.00, 1.0), | |
"ease-in": BezierEasing(0.42, 0.0, 1.00, 1.0), | |
"ease-out": BezierEasing(0.00, 0.0, 0.58, 1.0), | |
"ease-in-out": BezierEasing(0.42, 0.0, 0.58, 1.0) | |
}; | |
return BezierEasing; | |
})); |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
animate(doSomething, 2000, BezierEasing(0.25, 0.1, 0.0, 1.0)); | |
var targetValue = 500; | |
function doSomething (p) { // p move from 0 to 1 | |
var tempValue = p * targetValue; | |
} | |
function animate (render, duration, easing) { | |
var start = Date.now(); | |
(function loop () { | |
var p = (Date.now()-start)/duration; | |
if (p > 1) { | |
render(1); | |
} | |
else { | |
requestAnimationFrame(loop); | |
render(easing(p)); | |
} | |
}()); | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
typo error, need to be
targetValue
instead oftargeValue