remotion
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Render videos in React
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JavaScript
;
// 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;
//# sourceMappingURL=bezier.js.map