这里的tweenjs不是依托于createjs的tewwnjs，而是一系列缓动算法集合。因为本身是算法，可以用在各个业务场景中，这也正是总结学习它的价值所在。tweenjs代码详情：
/* * Tween.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）。 * you can visit 'http://easings.net/zh-cn' to get effect */ var Tween = { Linear: function(t, b, c, d) { return c * t / d + b; }, Quad: { easeIn: function(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; 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) { var s; if (t==0) return b; if ((t /= d) == 1) return b + c; if (typeof p == "undefined") p = d * .3; if (!a || a < Math.abs(c)) { s = p / 4; a = c; } else { 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) { var s; if (t==0) return b; if ((t /= d) == 1) return b + c; if (typeof p == "undefined") p = d * .3; if (!a || a < Math.abs(c)) { a = c; s = p / 4; } else { 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) { var s; if (t==0) return b; if ((t /= d / 2) == 2) return b+c; if (typeof p == "undefined") p = d * (.3 * 1.5); 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 -.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 ) * .5 + c + b; } }, Back: { easeIn: function(t, b, c, d, s) { if (typeof s == "undefined") s = 1.70158; return c * (t /= d) * t * ((s + 1) * t - s) + b; }, easeOut: function(t, b, c, d, s) { if (typeof 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 (typeof 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 + .75) + b; } else if (t < (2.5 / 2.75)) { return c * (7.5625 * (t -= (2.25 / 2.75)) * t + .9375) + b; } else { return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b; } }, easeInOut: function(t, b, c, d) { if (t < d / 2) { return Tween.Bounce.easeIn(t * 2, 0, c, d) * .5 + b; } else { return Tween.Bounce.easeOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b; } } } } Math.tween = Tween;
具体每种算法的操作实例，可以看大神张鑫旭的博客实例：
当然，以上这些算法仅仅是一个状态，需要配合时间上的变化，才能实现缓动，这里使用的是requestAnimationFrame，具体代码好吧，也是拿来主义