javascript动画浅析_javascript技巧

[
[elem,[fn,fn,fn,fn]],
[elem,[fn,fn,fn,fn]],
[elem,[fn,fn,fn,fn]]
]

/**
* create time 2012/08/29
* @author lynx cat.
* @version 0.77beta.
*/

(function(win,doc){
var win = win || window;
var doc = doc || win.document,
pow = Math.pow,
sin = Math.sin,
PI = Math.PI,
BACK_CONST = 1.70158;
var Easing = {
// 匀速运动
linear : function(t){
return t;
},
easeIn : function (t) {
return t * t;
},
easeOut : function (t) {
return ( 2 - t) * t;
},
easeBoth : function (t) {
return (t *= 2) < 1 ?
.5 * t * t :
.5 * (1 - (--t) * (t - 2));
},
easeInStrong : function (t) {
return t * t * t * t;
},
easeOutStrong : function (t) {
return 1 - (--t) * t * t * t;
},
easeBothStrong: function (t) {
return (t *= 2) < 1 ?
.5 * t * t * t * t :
.5 * (2 - (t -= 2) * t * t * t);
},
easeOutQuart : function(t){
return -(pow((t-1), 4) -1)
},
easeInOutExpo : function(t){
if(t===0) return 0;
if(t===1) return 1;
if((t/=0.5) < 1) return 0.5 * pow(2,10 * (t-1));
return 0.5 * (-pow(2, -10 * --t) + 2);
},
easeOutExpo : function(t){
return (t===1) ? 1 : -pow(2, -10 * t) + 1;
},
swingFrom : function(t) {
return t*t*((BACK_CONST+1)*t - BACK_CONST);
},
swingTo: function(t) {
return (t-=1)*t*((BACK_CONST+1)*t + BACK_CONST) + 1;
},
sinusoidal : function(t) {
return (-Math.cos(t*PI)/2) + 0.5;
},
flicker : function(t) {
var t = t + (Math.random()-0.5)/5;
return this.sinusoidal(t < 0 ? 0 : t > 1 ? 1 : t);
},
backIn : function (t) {
if (t === 1) t -= .001;
return t * t * ((BACK_CONST + 1) * t - BACK_CONST);
},
backOut : function (t) {
return (t -= 1) * t * ((BACK_CONST + 1) * t + BACK_CONST) + 1;
},
bounce : function (t) {
var s = 7.5625, r;
if (t < (1 / 2.75)) {
r = s * t * t;
}
else if (t < (2 / 2.75)) {
r = s * (t -= (1.5 / 2.75)) * t + .75;
}
else if (t < (2.5 / 2.75)) {
r = s * (t -= (2.25 / 2.75)) * t + .9375;
}
else {
r = s * (t -= (2.625 / 2.75)) * t + .984375;
}
return r;
}
};
/**
* 基石 用于返回一个包含对话方法的对象
* @param elem
* @return {Object}
*/
function catfx(elem){
elem = typeof elem === 'string' ? doc.getElementById(elem) : elem;
return new fx(elem);
}
/**
* 内部基石 用于返回一个包含对话方法的对象
* @param elem
* @return {Object}
*/
function fx(elem){
this.elem = elem;
return this;
}
/**
* 基础类 包含一些基础方法，和不变量
*/
var fxBase = {
speed : {
slow : 600,
fast : 200,
defaults : 400
},
fxAttrs : [],
fxMap:[],
/**
* 返回对象元素的css值
* @param elem
* @param p
* @return css value
*/
getStyle : function(){
var fn = function (){};
if('getComputedStyle' in win){
fn = function(elem, p){
var p = p.replace(/\-(\w)/g,function(i,str){
return str.toUpperCase();
});
var val = getComputedStyle(elem, null)[p];
if(~(' '+p+' ').indexOf(' left right top bottom ') && val === 'auto'){
val = '0px';
}
return val;
}
}else {
fn = function(elem, p){
var p = p.replace(/\-(\w)/g,function(i,str){
return str.toUpperCase();
});
var val = elem.currentStyle[p];
if(~(' '+p+' ').indexOf(' width height') && val === 'auto'){
var rect = elem.getBoundingClientRect();
val = ( p === 'width' ? rect.right - rect.left : rect.bottom - rect.top ) + 'px';
}
if(p === 'opacity'){
var filter = elem.currentStyle.filter;
if( /opacity/.test(filter) ){
val = filter.match( /\d+/ )[0] / 100;
val = (val === 1 || val === 0) ? val.toFixed(0) : val.toFixed(1);
}else if( val === undefined ){
val = 1;
}
}
if(~(' '+p+' ').indexOf(' left right top bottom ') && val === 'auto'){
val = '0px';
}
return val;
}
}
return fn;
}(),
/**
* 返回对象元素的css值
* @param 颜色值(暂不支持red,pink,blue等英文)
* @return rgb(x,x,x)
*/
getColor : function(val){
var r, g, b;
if(/rgb/.test(val)){
var arr = val.match(/\d+/g);
r = arr[0];
g = arr[1];
b = arr[2];
}else if(/#/.test(val)){
var len = val.length;
if( len === 7 ){
r = parseInt( val.slice(1, 3), 16);
g = parseInt( val.slice(3, 5), 16);
b = parseInt( val.slice(5), 16);
}
else if( len === 4 ){
r = parseInt(val.charAt(1) + val.charAt(1), 16);
g = parseInt(val.charAt(2) + val.charAt(2), 16);
b = parseInt(val.charAt(3) + val.charAt(3), 16);
}
}else{
return val;
}
return {
r : parseFloat(r),
g : parseFloat(g),
b : parseFloat(b)
}
},
/**
* 返回解析后的css
* @param prop
* @return {val:val,unit:unit}
*/
parseStyle : function(prop){
var val = parseFloat(prop),
unit = prop.replace(/^[\-\d\.]+/, '');
if(isNaN(val)){
val = this.getColor(unit);
unit = '';
}
return {val : val, unit : unit};
},
/**
* 设置元素的透明度
* @param elem
* @param val
*/
setOpacity : function(elem, val){
if( 'getComputedStyle' in win ){
elem.style.opacity = val === 1 ? '' : val;
}else{
elem.style.zoom = 1;
elem.style.filter = val === 1 ? '' : 'alpha(opacity=' + val * 100 + ')';
}
},
/**
* 设置元素的css值
* @param elem
* @param prop
* @param val
*/
setStyle : function(elem, prop, val){
if(prop != 'opacity'){
prop = prop.replace(/\-(\w)/g,function(i,p){
return p.toUpperCase();
});
elem.style[prop] = val;
}else{
this.setOpacity(elem, val);
}
},
/**
* 返回解析后的prop
* @param prop
* @return {prop}
*/
parseProp : function(prop){
var props = {};
for(var i in prop){
props[i] = this.parseStyle(prop[i].toString());
}
return props;
},
/**
* 修正用户的参数
* @param elem
* @param duration
* @param easing
* @param callback
* @return {options}
*/
setOption : function(elem,duration, easing, callback){
var options = {};
var _this = this;
options.duration = function(duration){
if(typeof duration == 'number'){
return duration;
}else if(typeof duration == 'string' && _this.speed[duration]){
return _this.speed[duration];
}else{
return _this.speed.defaults;
}
}(duration);
options.easing = function(easing){
if(typeof easing == 'function'){
return easing;
}else if(typeof easing == 'string' && Easing[easing]){
return Easing[easing];
}else{
return Easing.linear;
}
}(easing);
options.callback = function(callback){
var _this = this;
return function (){
if(typeof callback == 'function'){
callback.call(elem);
}
}
}(callback)
return options;
},
/**
* 维护setInterval的函数，动画的启动
*/
tick : function(){
var _this = this;
if(!_this.timer){
_this.timer = setInterval(function(){
for(var i = 0, len = _this.fxMap.length; i < len; i++){
var elem = _this.fxMap[i][0];
var core = _this.data(elem)[0];
core(elem);
}
},16);
}
},
/**
* 停止所有动画
*/
stop : function(){
if(this.timer){
clearInterval(this.timer);
this.timer = undefined;
}
},
/**
* 存储或者拿出队列
* @param elem
*/
data : function(elem){
for(var i = 0, len = this.fxMap.length; i < len; i++){
var data = this.fxMap[i];
if(elem === data[0]){
return data[1];
}
}
this.fxMap.push([elem,[]]);
return this.fxMap[this.fxMap.length - 1][1];
},
/**
* 删除队列
* @param elem
*/
removeData : function(elem){
for(var i = 0, len = this.fxMap.length; i < len; i++){
var data = this.fxMap[i];
if(elem === data[0]){
this.fxMap.splice(i, 1);
if(this.isDataEmpty()){
this.stop();
}
}
}
},
isDataEmpty : function(){
return this.fxMap.length == 0;
}
}, $ = fxBase;
/**
* 核心对象，用于生成动画对象。
* @param elem
* @param props
* @param options
* @return {Object}
*/
function fxCore(elem, props, options){
this.elem = elem;
this.props = props;
this.options = options;
this.start();
}
fxCore.prototype = {
constructor : fxCore,
/**
* 将动画函数加入到队列中，并启动动画。
*/
start : function(){
var cores = $.data(this.elem);
cores.push(this.step());
$.tick();
},
/**
* 核心方法，控制每一帧元素的状态。
* @return function
*/
step : function(){
var _this = this;
var fn = function(elem){
var t = Date.now() - this.startTime;
if(Date.now() < this.startTime + this.options.duration){
if(t <= 1){ t = 1;}
for(var i in this.target){
if(typeof this.source[i]['val'] === 'number'){
var val = parseFloat((this.source[i]['val'] + (this.target[i]['val'] - this.source[i]['val']) * this.options.easing(t / this.options.duration)).toFixed(7));
}else{
var r = parseInt(this.source[i]['val']['r'] + (this.target[i]['val']['r'] - this.source[i]['val']['r']) * this.options.easing(t / this.options.duration));
var g = parseInt(this.source[i]['val']['g'] + (this.target[i]['val']['g'] - this.source[i]['val']['g']) * this.options.easing(t / this.options.duration));
var b = parseInt(this.source[i]['val']['b'] + (this.target[i]['val']['b'] - this.source[i]['val']['b']) * this.options.easing(t / this.options.duration));
var val = 'rgb(' + r + ',' + g + ',' + b + ')';
}
$.setStyle(this.elem,i,val + this.source[i]['unit']);
}
}else{
for(var i in this.target){
if(typeof this.target[i]['val'] === 'number'){
var val = this.target[i]['val'];
}else{
var val = 'rgb(' + this.target[i]['val']['r'] + ',' + this.target[i]['val']['g'] + ',' + this.target[i]['val']['b'] + ')';
}
$.setStyle(elem,i,val + this.source[i]['unit']);
}
var cores = $.data(elem);
cores.shift();
this.options.callback();
if(cores.length == 0){
$.setStyle(elem,'overflow',this.overflow);
$.removeData(elem);
}
}
}
return function(elem){
if(!_this.startTime){
var source = {};
_this.target = _this.props;
for(var i in _this.props){
var val = $.getStyle(_this.elem, i);
source[i] = $.parseStyle(val);
}
_this.source = source;
_this.startTime = Date.now();
_this.overflow = $.getStyle(elem,'overflow');
$.setStyle(elem,'overflow','hidden');
}
fn.call(_this,elem);
}
}
}
/**
* 外部接口类。
*/
fx.prototype = {
constructor :　fx,
/**
* 动画方法
* @param prop
* @param duration
* @param easing
* @param callback
* @return {Object}
*/
animate : function(prop, duration, easing, callback){
if(arguments.length == 3 && typeof easing === 'function'){ //多数时候用户第三个参数是回调
callback = easing;
easing = undefined;
}
var props = $.parseProp(prop);
var options = $.setOption(this.elem,duration,easing,callback);
var core = new fxCore(this.elem,props,options);
return this;
},
/**
* 停止动画方法
* 使用方法 catjs('your element id').stop();
*/
stop : function(){
$.removeData(this.elem);
}
}
win.catfx = catfx;
})(this,document);