缓动函数 是用来表述 位置与时间发生变化的函数
先实现一个简单的函数，用来计算当前值
--[[
t:Number — 指定当前时间，介于 0 和持续时间之间（包括二者）。
b:Number — 指定动画属性的初始值。
c:Number — 指定动画属性的更改总计。
d:Number — 指定运动的持续时
]]
local function calc(t, b, c, d) --cube
if t == d then
return c
end
local x = t / d
x = ease[1](x) --这个就是缓动函数
return (c - b) * x + b
end
缓动函数列表
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function easeInSine(x: number): number {
return 1 - cos((x * PI) / 2);
}
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function easeOutSine(x: number): number {
return sin((x * PI) / 2);
}
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function easeInOutSine(x: number): number {
return -(cos(PI * x) - 1) / 2;
}
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function easeInQuad(x: number): number {
return x * x;
}
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function easeInOutQuad(x: number): number {
return x < 0.5 ? 2 * x * x : 1 - pow(-2 * x + 2, 2) / 2;
}
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function easeInCubic(x: number): number {
return x * x * x;
}
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function easeOutCubic(x: number): number {
return 1 - pow(1 - x, 3);
}
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function easeInOutCubic(x: number): number {
return x < 0.5 ? 4 * x * x * x : 1 - pow(-2 * x + 2, 3) / 2;
}
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function easeInQuart(x: number): number {
return x * x * x * x;
}
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function easeOutQuart(x: number): number {
return 1 - pow(1 - x, 4);
}
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function easeInOutQuart(x: number): number {
return x < 0.5 ? 8 * x * x * x * x : 1 - pow(-2 * x + 2, 4) / 2;
}
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function easeInQuint(x: number): number {
return x * x * x * x * x;
}
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function easeOutQuint(x: number): number {
return 1 - pow(1 - x, 5);
}
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function easeInOutQuint(x: number): number {
return x < 0.5 ? 16 * x * x * x * x * x : 1 - pow(-2 * x + 2, 5) / 2;
}
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function easeInExpo(x: number): number {
return x === 0 ? 0 : pow(2, 10 * x - 10);
}
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function easeOutExpo(x: number): number {
return x === 1 ? 1 : 1 - pow(2, -10 * x);
}
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function easeInOutExpo(x: number): number {
return x === 0
? 0
: x === 1
? 1
: x < 0.5 ? pow(2, 20 * x - 10) / 2
: (2 - pow(2, -20 * x + 10)) / 2;
}
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function easeInCirc(x: number): number {
return 1 - sqrt(1 - pow(x, 2));
}
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function easeOutCirc(x: number): number {
return sqrt(1 - pow(x - 1, 2));
}
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function easeInOutCirc(x: number): number {
return x < 0.5
? (1 - sqrt(1 - pow(2 * x, 2))) / 2
: (sqrt(1 - pow(-2 * x + 2, 2)) + 1) / 2;
}
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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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function easeOutBack(x: number): number {
const c1 = 1.70158;
const c3 = c1 + 1;
return 1 + c3 * pow(x - 1, 3) + c1 * pow(x - 1, 2);
}
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function easeInOutBack(x: number): number {
const c1 = 1.70158;
const c2 = c1 * 1.525;
return x < 0.5
? (pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2
: (pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
}
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function easeInElastic(x: number): number {
const c4 = (2 * Math.PI) / 3;
return x === 0
? 0
: x === 1
? 1
: -pow(2, 10 * x - 10) * sin((x * 10 - 10.75) * c4);
}
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function easeOutElastic(x: number): number {
const c4 = (2 * Math.PI) / 3;
return x === 0
? 0
: x === 1
? 1
: pow(2, -10 * x) * sin((x * 10 - 0.75) * c4) + 1;
}
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function easeInOutElastic(x: number): number {
const c5 = (2 * Math.PI) / 4.5;
return x === 0
? 0
: x === 1
? 1
: x < 0.5
? -(pow(2, 20 * x - 10) * sin((20 * x - 11.125) * c5)) / 2
: (pow(2, -20 * x + 10) * sin((20 * x - 11.125) * c5)) / 2 + 1;
}
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function easeInBounce(x: number): number {
return 1 - easeOutBounce(1 - x);
}
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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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function easeInOutBounce(x: number): number {
return x < 0.5
? (1 - easeOutBounce(1 - 2 * x)) / 2
: (1 + easeOutBounce(2 * x - 1)) / 2;
}
最后，来一张合集
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注：本文摘自
https://easings.net/