Tween 缓动动画
Linear
quad easeIn
quad easeOut
quad easeInOut
js
/**
* t: current time（当前时间）
* b: beginning value（初始值）
* c: change in value（变化量）
* d: duration（持续时间）。
*/
const tween = {
linear: function (t, b, c, d) {
return (c * t) / d + b;
},
quad: {
easeIn: (t, b, c, d) => {
return c * (t /= d) * t + b;
},
easeOut: function (t, b, c, d) {
return -c * (t /= d) * (t - 2) + b;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) {
return (c / 2) * t * t + b;
} else {
return (-c / 2) * (t * (t - 2) - 1) + b;
}
},
},
cubic: {
easeIn: function (t, b, c, d) {
return c * (t /= d) * t * t + b;
},
easeOut: function (t, b, c, d) {
return c * ((t = t / d - 1) * t * t + 1) + b;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) return (c / 2) * t * t * t + b;
return (c / 2) * ((t -= 2) * t * t + 2) + b;
},
},
quart: {
easeIn: function (t, b, c, d) {
return c * (t /= d) * t * t * t + b;
},
easeOut: function (t, b, c, d) {
return -c * ((t = t / d - 1) * t * t * t - 1) + b;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) return (c / 2) * t * t * t * t + b;
return (-c / 2) * ((t -= 2) * t * t * t - 2) + b;
},
},
quint: {
easeIn: function (t, b, c, d) {
return c * (t /= d) * t * t * t * t + b;
},
easeOut: function (t, b, c, d) {
return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) return (c / 2) * t * t * t * t * t + b;
return (c / 2) * ((t -= 2) * t * t * t * t + 2) + b;
},
},
sine: {
easeIn: function (t, b, c, d) {
return -c * Math.cos((t / d) * (Math.PI / 2)) + c + b;
},
easeOut: function (t, b, c, d) {
return c * Math.sin((t / d) * (Math.PI / 2)) + b;
},
easeInOut: function (t, b, c, d) {
return (-c / 2) * (Math.cos((Math.PI * t) / d) - 1) + b;
},
},
expo: {
easeIn: function (t, b, c, d) {
return t == 0 ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
},
easeOut: function (t, b, c, d) {
return t == d ? b + c : c * (-Math.pow(2, (-10 * t) / d) + 1) + b;
},
easeInOut: function (t, b, c, d) {
if (t == 0) return b;
if (t == d) return b + c;
if ((t /= d / 2) < 1) return (c / 2) * Math.pow(2, 10 * (t - 1)) + b;
return (c / 2) * (-Math.pow(2, -10 * -t) + 2) + b;
},
},
circ: {
easeIn: function (t, b, c, d) {
return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
},
easeOut: function (t, b, c, d) {
return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
},
easeInOut: function (t, b, c, d) {
if ((t /= d / 2) < 1) return (-c / 2) * (Math.sqrt(1 - t * t) - 1) + b;
return (c / 2) * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
},
},
elastic: {
easeIn: function (t, b, c, d, a, p) {
if (t == 0) return b;
if ((t /= d) == 1) return b + c;
if (!p) p = d * 0.3;
if (!a || a < Math.abs(c)) {
a = c;
const s = p / 4;
return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin(((t * d - s) * (2 * Math.PI)) / p)) + b;
} else {
const s = (p / (2 * Math.PI)) * Math.asin(c / a);
return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin(((t * d - s) * (2 * Math.PI)) / p)) + b;
}
},
easeOut: function (t, b, c, d, a, p) {
if (t == 0) return b;
if ((t /= d) == 1) return b + c;
if (!p) p = d * 0.3;
if (!a || a < Math.abs(c)) {
a = c;
const s = p / 4;
return a * Math.pow(2, -10 * t) * Math.sin(((t * d - s) * (2 * Math.PI)) / p) + c + b;
} else {
const s = (p / (2 * Math.PI)) * Math.asin(c / a);
return a * Math.pow(2, -10 * t) * Math.sin(((t * d - s) * (2 * Math.PI)) / p) + c + b;
}
},
easeInOut: function (t, b, c, d, a, p) {
if (t == 0) return b;
if ((t /= d / 2) == 2) return b + c;
if (!p) p = d * (0.31 * 0.5);
let s = 0;
if (!a || a < Math.abs(c)) {
a = c;
s = p / 4;
} else s = (p / (2 * Math.PI)) * Math.asin(c / a);
if (t < 1) return -0.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin(((t * d - s) * (2 * Math.PI)) / p)) + b;
return a * Math.pow(2, -10 * (t -= 1)) * Math.sin(((t * d - s) * (2 * Math.PI)) / p) * 0.5 + c + b;
},
},
back: {
easeIn: function (t, b, c, d, s) {
if (s == undefined) s = 1.70158;
return c * (t /= d) * t * ((s + 1) * t - s) + b;
},
easeOut: function (t, b, c, d, s) {
if (s == undefined) s = 1.70158;
return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
},
easeInOut: function (t, b, c, d, s) {
if (s == undefined) s = 1.70158;
if ((t /= d / 2) < 1) return (c / 2) * (t * t * (((s = 1.525) + 1) * t - s)) + b;
return (c / 2) * ((t -= 2) * t * (((s = 1.525) + 1) * t + s) + 2) + b;
},
},
bounce: {
easeIn: function (t, b, c, d) {
return c - tween.bounce.easeOut(d - t, 0, c, d) + b;
},
easeOut: function (t, b, c, d) {
if ((t /= d) < 1 / 2.75) {
return c * (7.5625 * t * t) + b;
} else if (t < 2 / 2.75) {
return c * (7.5625 * (t -= 1.5 / 2.75) * t + 0.75) + b;
} else if (t < 2.5 / 2.75) {
return c * (7.5625 * (t -= 2.25 / 2.75) * t + 0.9375) + b;
} else {
return c * (7.5625 * (t -= 2.625 / 2.75) * t + 0.984375) + b;
}
},
easeInOut: function (t, b, c, d) {
if (t < d / 2) return tween.bounce.easeIn(t * 2, 0, c, d) * 0.5 + b;
else return tween.bounce.easeOut(t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b;
},
},
};