remotion/dist/bezier.js

"use strict";
// Taken from https://github.com/facebook/react-native/blob/0b9ea60b4fee8cacc36e7160e31b91fc114dbc0d/Libraries/Animated/src/bezier.js
Object.defineProperty(exports, "__esModule", { value: true });
exports.bezier = void 0;
const NEWTON_ITERATIONS = 4;
const NEWTON_MIN_SLOPE = 0.001;
const SUBDIVISION_PRECISION = 0.0000001;
const SUBDIVISION_MAX_ITERATIONS = 10;
const kSplineTableSize = 11;
const kSampleStepSize = 1.0 / (kSplineTableSize - 1.0);
const float32ArraySupported = typeof Float32Array === 'function';
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, mX1, mX2, }) {
    let currentX;
    let currentT;
    let i = 0;
    let aA = _aA;
    let aB = _aB;
    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 newtonRaphsonIterate(aX, _aGuessT, mX1, mX2) {
    let aGuessT = _aGuessT;
    for (let i = 0; i < NEWTON_ITERATIONS; ++i) {
        const currentSlope = getSlope(aGuessT, mX1, mX2);
        if (currentSlope === 0.0) {
            return aGuessT;
        }
        const currentX = calcBezier(aGuessT, mX1, mX2) - aX;
        aGuessT -= currentX / currentSlope;
    }
    return aGuessT;
}
function bezier(mX1, mY1, mX2, mY2) {
    if (!(mX1 >= 0 && mX1 <= 1 && mX2 >= 0 && mX2 <= 1)) {
        throw new Error('bezier x values must be in [0, 1] range');
    }
    // Precompute samples table
    const sampleValues = float32ArraySupported
        ? new Float32Array(kSplineTableSize)
        : new Array(kSplineTableSize);
    if (mX1 !== mY1 || mX2 !== mY2) {
        for (let i = 0; i < kSplineTableSize; ++i) {
            sampleValues[i] = calcBezier(i * kSampleStepSize, mX1, mX2);
        }
    }
    function getTForX(aX) {
        let intervalStart = 0.0;
        let currentSample = 1;
        const lastSample = kSplineTableSize - 1;
        for (; currentSample !== lastSample && sampleValues[currentSample] <= aX; ++currentSample) {
            intervalStart += kSampleStepSize;
        }
        --currentSample;
        // Interpolate to provide an initial guess for t
        const dist = (aX - sampleValues[currentSample]) /
            (sampleValues[currentSample + 1] - sampleValues[currentSample]);
        const guessForT = intervalStart + dist * kSampleStepSize;
        const initialSlope = getSlope(guessForT, mX1, mX2);
        if (initialSlope >= NEWTON_MIN_SLOPE) {
            return newtonRaphsonIterate(aX, guessForT, mX1, mX2);
        }
        if (initialSlope === 0.0) {
            return guessForT;
        }
        return binarySubdivide({
            aX,
            _aA: intervalStart,
            _aB: intervalStart + kSampleStepSize,
            mX1,
            mX2,
        });
    }
    return function (x) {
        if (mX1 === mY1 && mX2 === mY2) {
            return x; // linear
        }
        // Because JavaScript number are imprecise, we should guarantee the extremes are right.
        if (x === 0) {
            return 0;
        }
        if (x === 1) {
            return 1;
        }
        return calcBezier(getTForX(x), mY1, mY2);
    };
}
exports.bezier = bezier;