常见的缓动曲线及其公式

前言 本篇在讲什么 本章节记录常见的缓动曲线，及其计算公式，以作学习和记录 本篇适合什么 适合想要了解缓动曲线原理的小白 适合入门的前端程序 本篇需要什么 简单的数学基础 本篇的特色 具有全流程的图文教学 重实践，轻理论，快速上手 提供全流程的源码内容

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★提高阅读体验★ ♠ 一级标题 ♥ 二级标题 ♣ 三级标题 ♦ 四级标题

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♠ 曲线

下图是我们常见的曲线列表，章节内所有公式和图表摘自网站easings.net有需要可以自行查看

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♥ easeInSine

function easeInSine(x: number): number {
    return 1 - Math.cos((x * Math.PI) / 2);
}

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♥ easeOutSine

function easeOutSine(x: number): number {
    return Math.sin((x * Math.PI) / 2);
}

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♥ easeInOutSine

function easeInOutSine(x: number): number {
    return -(Math.cos(Math.PI * x) - 1) / 2;
}

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♥ easeInQuad

function easeInQuad(x: number): number {
    return x * x;
}

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♥ easeOutQuad

function easeOutQuad(x: number): number {
    return 1 - (1 - x) * (1 - x);
}

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♥ easeInOutQuad

function easeInOutQuad(x: number): number {
    return x < 0.5 ? 2 * x * x : 1 - Math.pow(-2 * x + 2, 2) / 2;
}

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♥ easeInCubic

function easeInCubic(x: number): number {
    return x * x * x;
}

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♥ easeOutCubic

function easeOutCubic(x: number): number {
    return 1 - Math.pow(1 - x, 3);
}

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♥ easeInOutCubic

function easeInOutCubic(x: number): number {
    return x < 0.5 ? 4 * x * x * x : 1 - Math.pow(-2 * x + 2, 3) / 2;
}

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♥ easeInQuart

function easeInQuart(x: number): number {
    return x * x * x * x;
}

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♥ easeOutQuart

function easeOutQuart(x: number): number {
    return 1 - Math.pow(1 - x, 4);
}

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♥ easeInOutQuart

function easeInOutQuart(x: number): number {
    return x < 0.5 ? 8 * x * x * x * x : 1 - Math.pow(-2 * x + 2, 4) / 2;
}

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♥ easeInQuint

function easeInQuint(x: number): number {
    return x * x * x * x * x;
}

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♥ easeOutQuint

function easeOutQuint(x: number): number {
    return 1 - Math.pow(1 - x, 5);
}

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♥ easeInOutQuint

function easeInOutQuint(x: number): number {
return x < 0.5 ? 16 * x * x * x * x * x : 1 - Math.pow(-2 * x + 2, 5) / 2;
}

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♥ easeInExpo

function easeInExpo(x: number): number {
    return x === 0 ? 0 : Math.pow(2, 10 * x - 10);
}

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♥ easeOutExpo

function easeOutExpo(x: number): number {
    return x === 1 ? 1 : 1 - Math.pow(2, -10 * x);
}

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♥ easeInOutExpo

function easeInOutExpo(x: number): number {
    return x === 0
        ? 0
        : x === 1
        ? 1
        : x < 0.5 ? Math.pow(2, 20 * x - 10) / 2
        : (2 - Math.pow(2, -20 * x + 10)) / 2;
}

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♥ easeInCirc

function easeInCirc(x: number): number {
    return 1 - Math.sqrt(1 - Math.pow(x, 2));
}

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♥ easeOutCirc

function easeOutCirc(x: number): number {
    return sqrt(1 - Math.pow(x - 1, 2));
}

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♥ easeInOutCirc

function easeInOutCirc(x: number): number {
    return x < 0.5
        ? (1 - Math.sqrt(1 - Math.pow(2 * x, 2))) / 2
        : (Math.sqrt(1 - Math.pow(-2 * x + 2, 2)) + 1) / 2;
}

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♥ easeInBack

function easeInBack(x: number): number {
    const c1 = 1.70158;
    const c3 = c1 + 1;

    return c3 * x * x * x - c1 * x * x;
}

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♥ easeOutBack

function easeOutBack(x: number): number {
    const c1 = 1.70158;
    const c3 = c1 + 1;

    return 1 + c3 * Math.pow(x - 1, 3) + c1 * Math.pow(x - 1, 2);
}

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♥ easeInOutBack

function easeInOutBack(x: number): number {
    const c1 = 1.70158;
    const c2 = c1 * 1.525;

    return x < 0.5
  ? (Math.pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2
  : (Math.pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
}

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♥ easeInElastic

function easeInElastic(x: number): number {
    const c4 = (2 * Math.PI) / 3;

    return x === 0
        ? 0
        : x === 1
        ? 1
        : -Math.pow(2, 10 * x - 10) * Math.sin((x * 10 - 10.75) * c4);
}

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♥ easeOutElastic

function easeOutElastic(x: number): number {
    const c4 = (2 * Math.PI) / 3;

    return x === 0
        ? 0
        : x === 1
        ? 1
        : Math.pow(2, -10 * x) * Math.sin((x * 10 - 0.75) * c4) + 1;
}

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♥ easeInOutElastic

function easeInOutElastic(x: number): number {
    const c5 = (2 * Math.PI) / 4.5;

    return x === 0
        ? 0
        : x === 1
        ? 1
        : x < 0.5
        ? -(Math.pow(2, 20 * x - 10) * Math.sin((20 * x - 11.125) * c5)) / 2
        : (Math.pow(2, -20 * x + 10) * Math.sin((20 * x - 11.125) * c5)) / 2 + 1;
}

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♥ easeInBounce

function easeInBounce(x: number): number {
    return 1 - easeOutBounce(1 - x);
}

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♥ easeOutBounce

function easeOutBounce(x: number): number {
    const n1 = 7.5625;
    const d1 = 2.75;

    if (x < 1 / d1) {
        return n1 * x * x;
    } else if (x < 2 / d1) {
        return n1 * (x -= 1.5 / d1) * x + 0.75;
    } else if (x < 2.5 / d1) {
        return n1 * (x -= 2.25 / d1) * x + 0.9375;
    } else {
        return n1 * (x -= 2.625 / d1) * x + 0.984375;
    }
}

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♥ easeInOutBounce

function easeInOutBounce(x: number): number {
    return x < 0.5
        ? (1 - easeOutBounce(1 - 2 * x)) / 2
        : (1 + easeOutBounce(2 * x - 1)) / 2;
}

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♠ 推送

• Github

https://github.com/KingSun5

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♠ 结语

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