@tamagui/react-native-web-lite/src/vendor/react-native/Animated/SpringConfig.js

React Native for Web

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 * @format
 */

const defaultSpringConfig = {
  stiffness: 0,
  damping: 0,
}

function stiffnessFromOrigamiValue(oValue) {
  return (oValue - 30) * 3.62 + 194
}

function dampingFromOrigamiValue(oValue) {
  return (oValue - 8) * 3 + 25
}

function fromOrigamiTensionAndFriction(tension, friction) {
  return {
    stiffness: stiffnessFromOrigamiValue(tension),
    damping: dampingFromOrigamiValue(friction),
  }
}

function fromBouncinessAndSpeed(bounciness, speed) {
  function normalize(value, startValue, endValue) {
    return (value - startValue) / (endValue - startValue)
  }

  function projectNormal(n, start, end) {
    return start + n * (end - start)
  }

  function linearInterpolation(t, start, end) {
    return t * end + (1 - t) * start
  }

  function quadraticOutInterpolation(t, start, end) {
    return linearInterpolation(2 * t - t * t, start, end)
  }

  function b3Friction1(x) {
    return 0.0007 * x ** 3 - 0.031 * x ** 2 + 0.64 * x + 1.28
  }

  function b3Friction2(x) {
    return 0.000044 * x ** 3 - 0.006 * x ** 2 + 0.36 * x + 2
  }

  function b3Friction3(x) {
    return 0.00000045 * x ** 3 - 0.000332 * x ** 2 + 0.1078 * x + 5.84
  }

  function b3Nobounce(tension) {
    if (tension <= 18) {
      return b3Friction1(tension)
    } else if (tension > 18 && tension <= 44) {
      return b3Friction2(tension)
    } else {
      return b3Friction3(tension)
    }
  }

  let b = normalize(bounciness / 1.7, 0, 20)
  b = projectNormal(b, 0, 0.8)
  const s = normalize(speed / 1.7, 0, 20)
  const bouncyTension = projectNormal(s, 0.5, 200)
  const bouncyFriction = quadraticOutInterpolation(b, b3Nobounce(bouncyTension), 0.01)

  return {
    stiffness: stiffnessFromOrigamiValue(bouncyTension),
    damping: dampingFromOrigamiValue(bouncyFriction),
  }
}

const SpringConfig = {
  fromOrigamiTensionAndFriction,
  fromBouncinessAndSpeed,
};

export { SpringConfig }
export default SpringConfig