// 缓动函数来自 https://github.com/sole/tween.js/blob/master/src/Tween.js
/**
* @namespace clay.animation.easing
*/
var easing = {
/**
* @alias clay.animation.easing.linear
* @param {number} k
* @return {number}
*/
linear: function(k) {
return k;
},
/**
* @alias clay.animation.easing.quadraticIn
* @param {number} k
* @return {number}
*/
quadraticIn: function(k) {
return k * k;
},
/**
* @alias clay.animation.easing.quadraticOut
* @param {number} k
* @return {number}
*/
quadraticOut: function(k) {
return k * (2 - k);
},
/**
* @alias clay.animation.easing.quadraticInOut
* @param {number} k
* @return {number}
*/
quadraticInOut: function(k) {
if ((k *= 2) < 1) {
return 0.5 * k * k;
}
return - 0.5 * (--k * (k - 2) - 1);
},
/**
* @alias clay.animation.easing.cubicIn
* @param {number} k
* @return {number}
*/
cubicIn: function(k) {
return k * k * k;
},
/**
* @alias clay.animation.easing.cubicOut
* @param {number} k
* @return {number}
*/
cubicOut: function(k) {
return --k * k * k + 1;
},
/**
* @alias clay.animation.easing.cubicInOut
* @param {number} k
* @return {number}
*/
cubicInOut: function(k) {
if ((k *= 2) < 1) {
return 0.5 * k * k * k;
}
return 0.5 * ((k -= 2) * k * k + 2);
},
/**
* @alias clay.animation.easing.quarticIn
* @param {number} k
* @return {number}
*/
quarticIn: function(k) {
return k * k * k * k;
},
/**
* @alias clay.animation.easing.quarticOut
* @param {number} k
* @return {number}
*/
quarticOut: function(k) {
return 1 - (--k * k * k * k);
},
/**
* @alias clay.animation.easing.quarticInOut
* @param {number} k
* @return {number}
*/
quarticInOut: function(k) {
if ((k *= 2) < 1) {
return 0.5 * k * k * k * k;
}
return - 0.5 * ((k -= 2) * k * k * k - 2);
},
/**
* @alias clay.animation.easing.quinticIn
* @param {number} k
* @return {number}
*/
quinticIn: function(k) {
return k * k * k * k * k;
},
/**
* @alias clay.animation.easing.quinticOut
* @param {number} k
* @return {number}
*/
quinticOut: function(k) {
return --k * k * k * k * k + 1;
},
/**
* @alias clay.animation.easing.quinticInOut
* @param {number} k
* @return {number}
*/
quinticInOut: function(k) {
if ((k *= 2) < 1) {
return 0.5 * k * k * k * k * k;
}
return 0.5 * ((k -= 2) * k * k * k * k + 2);
},
/**
* @alias clay.animation.easing.sinusoidalIn
* @param {number} k
* @return {number}
*/
sinusoidalIn: function(k) {
return 1 - Math.cos(k * Math.PI / 2);
},
/**
* @alias clay.animation.easing.sinusoidalOut
* @param {number} k
* @return {number}
*/
sinusoidalOut: function(k) {
return Math.sin(k * Math.PI / 2);
},
/**
* @alias clay.animation.easing.sinusoidalInOut
* @param {number} k
* @return {number}
*/
sinusoidalInOut: function(k) {
return 0.5 * (1 - Math.cos(Math.PI * k));
},
/**
* @alias clay.animation.easing.exponentialIn
* @param {number} k
* @return {number}
*/
exponentialIn: function(k) {
return k === 0 ? 0 : Math.pow(1024, k - 1);
},
/**
* @alias clay.animation.easing.exponentialOut
* @param {number} k
* @return {number}
*/
exponentialOut: function(k) {
return k === 1 ? 1 : 1 - Math.pow(2, - 10 * k);
},
/**
* @alias clay.animation.easing.exponentialInOut
* @param {number} k
* @return {number}
*/
exponentialInOut: function(k) {
if (k === 0) {
return 0;
}
if (k === 1) {
return 1;
}
if ((k *= 2) < 1) {
return 0.5 * Math.pow(1024, k - 1);
}
return 0.5 * (- Math.pow(2, - 10 * (k - 1)) + 2);
},
/**
* @alias clay.animation.easing.circularIn
* @param {number} k
* @return {number}
*/
circularIn: function(k) {
return 1 - Math.sqrt(1 - k * k);
},
/**
* @alias clay.animation.easing.circularOut
* @param {number} k
* @return {number}
*/
circularOut: function(k) {
return Math.sqrt(1 - (--k * k));
},
/**
* @alias clay.animation.easing.circularInOut
* @param {number} k
* @return {number}
*/
circularInOut: function(k) {
if ((k *= 2) < 1) {
return - 0.5 * (Math.sqrt(1 - k * k) - 1);
}
return 0.5 * (Math.sqrt(1 - (k -= 2) * k) + 1);
},
/**
* @alias clay.animation.easing.elasticIn
* @param {number} k
* @return {number}
*/
elasticIn: function(k) {
var s, a = 0.1, p = 0.4;
if (k === 0) {
return 0;
}
if (k === 1) {
return 1;
}
if (!a || a < 1) {
a = 1; s = p / 4;
}else{
s = p * Math.asin(1 / a) / (2 * Math.PI);
}
return - (a * Math.pow(2, 10 * (k -= 1)) *
Math.sin((k - s) * (2 * Math.PI) / p));
},
/**
* @alias clay.animation.easing.elasticOut
* @param {number} k
* @return {number}
*/
elasticOut: function(k) {
var s, a = 0.1, p = 0.4;
if (k === 0) {
return 0;
}
if (k === 1) {
return 1;
}
if (!a || a < 1) {
a = 1; s = p / 4;
}
else{
s = p * Math.asin(1 / a) / (2 * Math.PI);
}
return (a * Math.pow(2, - 10 * k) *
Math.sin((k - s) * (2 * Math.PI) / p) + 1);
},
/**
* @alias clay.animation.easing.elasticInOut
* @param {number} k
* @return {number}
*/
elasticInOut: function(k) {
var s, a = 0.1, p = 0.4;
if (k === 0) {
return 0;
}
if (k === 1) {
return 1;
}
if (!a || a < 1) {
a = 1; s = p / 4;
}
else{
s = p * Math.asin(1 / a) / (2 * Math.PI);
}
if ((k *= 2) < 1) {
return - 0.5 * (a * Math.pow(2, 10 * (k -= 1))
* Math.sin((k - s) * (2 * Math.PI) / p));
}
return a * Math.pow(2, -10 * (k -= 1))
* Math.sin((k - s) * (2 * Math.PI) / p) * 0.5 + 1;
},
/**
* @alias clay.animation.easing.backIn
* @param {number} k
* @return {number}
*/
backIn: function(k) {
var s = 1.70158;
return k * k * ((s + 1) * k - s);
},
/**
* @alias clay.animation.easing.backOut
* @param {number} k
* @return {number}
*/
backOut: function(k) {
var s = 1.70158;
return --k * k * ((s + 1) * k + s) + 1;
},
/**
* @alias clay.animation.easing.backInOut
* @param {number} k
* @return {number}
*/
backInOut: function(k) {
var s = 1.70158 * 1.525;
if ((k *= 2) < 1) {
return 0.5 * (k * k * ((s + 1) * k - s));
}
return 0.5 * ((k -= 2) * k * ((s + 1) * k + s) + 2);
},
/**
* @alias clay.animation.easing.bounceIn
* @param {number} k
* @return {number}
*/
bounceIn: function(k) {
return 1 - easing.bounceOut(1 - k);
},
/**
* @alias clay.animation.easing.bounceOut
* @param {number} k
* @return {number}
*/
bounceOut: function(k) {
if (k < (1 / 2.75)) {
return 7.5625 * k * k;
}
else if (k < (2 / 2.75)) {
return 7.5625 * (k -= (1.5 / 2.75)) * k + 0.75;
} else if (k < (2.5 / 2.75)) {
return 7.5625 * (k -= (2.25 / 2.75)) * k + 0.9375;
} else {
return 7.5625 * (k -= (2.625 / 2.75)) * k + 0.984375;
}
},
/**
* @alias clay.animation.easing.bounceInOut
* @param {number} k
* @return {number}
*/
bounceInOut: function(k) {
if (k < 0.5) {
return easing.bounceIn(k * 2) * 0.5;
}
return easing.bounceOut(k * 2 - 1) * 0.5 + 0.5;
}
};
export default easing;