Zepto源码分析-动画(fx fx_method)模块

[mominger]

源码注释

//     Zepto.js
//     (c) 2010-2015 Thomas Fuchs
//     Zepto.js may be freely distributed under the MIT license.

;(function($, undefined){
  var prefix = '', eventPrefix,    // prefix浏览器前缀 -webkit等，eventPrefix事件前缀
    vendors = { Webkit: 'webkit', Moz: '', O: 'o' }, //前缀数据源 不包含IE
    testEl = document.createElement('div'),  //临时DIV容器
    supportedTransforms = /^((translate|rotate|scale)(X|Y|Z|3d)?|matrix(3d)?|perspective|skew(X|Y)?)$/i, //变形检测
    transform,     //变形
    transitionProperty, transitionDuration, transitionTiming, transitionDelay,//过渡
    animationName, animationDuration, animationTiming, animationDelay,     //动画
    cssReset = {}

    //将驼峰字符串转成css属性，如aB-->a-b
  function dasherize(str) { return str.replace(/([a-z])([A-Z])/, '$1-$2').toLowerCase() }
    //修正事件名
  function normalizeEvent(name) { return eventPrefix ? eventPrefix + name : name.toLowerCase() }


    /**
     * 根据浏览器内核，设置CSS前缀，事件前缀
     * 如-webkit， css：-webkit-  event:webkit
     * 这里会在vendors存储webkit，moz，o三种前缀
     */
  $.each(vendors, function(vendor, event){
    if (testEl.style[vendor + 'TransitionProperty'] !== undefined) {
      prefix = '-' + vendor.toLowerCase() + '-'
      eventPrefix = event
      return false
    }
  })

  transform = prefix + 'transform'     //变形
    //过渡
  cssReset[transitionProperty = prefix + 'transition-property'] =
  cssReset[transitionDuration = prefix + 'transition-duration'] =
  cssReset[transitionDelay    = prefix + 'transition-delay'] =
  cssReset[transitionTiming   = prefix + 'transition-timing-function'] =
  cssReset[animationName      = prefix + 'animation-name'] =
  cssReset[animationDuration  = prefix + 'animation-duration'] =
  cssReset[animationDelay     = prefix + 'animation-delay'] =
  cssReset[animationTiming    = prefix + 'animation-timing-function'] = ''

    /**
     * 动画常量数据源
     * @type {{off: boolean, speeds: {_default: number, fast: number, slow: number}, cssPrefix: string, transitionEnd: *, animationEnd: *}}
     */
  $.fx = {
    off: (eventPrefix === undefined && testEl.style.transitionProperty === undefined), //能力检测是否支持动画，具体检测是否支持过渡，支持过渡事件
    speeds: { _default: 400, fast: 200, slow: 600 },
    cssPrefix: prefix,                                //css 前缀  如-webkit-
    transitionEnd: normalizeEvent('TransitionEnd'), //过渡结束事件
    animationEnd: normalizeEvent('AnimationEnd')     //动画播放结束事件
  }

    /**
     * 创建自定义动画
     * @param properties  样式集
     * @param duration 持续事件
     * @param ease    速率
     * @param callback  完成时的回调
     * @param delay     动画延迟
     * @returns {*}
     */
  $.fn.animate = function(properties, duration, ease, callback, delay){
      //参数修正，传参为function(properties,callback)
    if ($.isFunction(duration))
      callback = duration, ease = undefined, duration = undefined
    if ($.isFunction(ease))  //传参为function(properties,duration，callback)
      callback = ease, ease = undefined
    if ($.isPlainObject(duration))  //传参为function(properties,｛｝)
      ease = duration.easing, callback = duration.complete, delay = duration.delay, duration = duration.duration
      // duration 数字：持续时间  字符串：取speeds: { _default: 400, fast: 200, slow: 600 }对应数字
      if (duration) duration = (typeof duration == 'number' ? duration :
                    ($.fx.speeds[duration] || $.fx.speeds._default)) / 1000     //动画持续时间默认值
    if (delay) delay = parseFloat(delay) / 1000    //延迟时间，除以1000转换成s
    return this.anim(properties, duration, ease, callback, delay)
  }

    /**
     * 动画核心方法
     * @param properties  样式集
     * @param duration 持续事件
     * @param ease    速率
     * @param callback  完成时的回调
     * @param delay     动画延迟
     * @returns {*}
     */
  $.fn.anim = function(properties, duration, ease, callback, delay){
    var key, cssValues = {}, cssProperties, transforms = '',      // transforms 变形   cssValues设置给DOM的样式
        that = this, wrappedCallback, endEvent = $.fx.transitionEnd,
        fired = false

      //修正持续时间
    if (duration === undefined) duration = $.fx.speeds._default / 1000
    if (delay === undefined) delay = 0

      //如果浏览器不支持动画，持续时间设为0，直接跳动画结束
    if ($.fx.off) duration = 0

      // properties是动画名
    if (typeof properties == 'string') {
      // keyframe animation
      cssValues[animationName] = properties
      cssValues[animationDuration] = duration + 's'
      cssValues[animationDelay] = delay + 's'
      cssValues[animationTiming] = (ease || 'linear')
      endEvent = $.fx.animationEnd  //动画结束事件
    } else {  //properties 是样式集
      cssProperties = []
      // CSS transitions
      for (key in properties)
          //supportedTransforms.test(key) 正则检测是否为变形
      //key + '(' + properties[key] + ') ' 拼凑成变形方法
        if (supportedTransforms.test(key)) transforms += key + '(' + properties[key] + ') '
        else cssValues[key] = properties[key], cssProperties.push(dasherize(key))

        //变形统一存入  cssValues   cssProperties
      if (transforms) cssValues[transform] = transforms, cssProperties.push(transform)

       // duration > 0可以播放动画，且properties是对象，表明为过渡，上面有字符串，则为animate
      if (duration > 0 && typeof properties === 'object') {
        cssValues[transitionProperty] = cssProperties.join(', ')
        cssValues[transitionDuration] = duration + 's'
        cssValues[transitionDelay] = delay + 's'
        cssValues[transitionTiming] = (ease || 'linear')  //默认线性速率
      }
    }

    //动画完成后的响应函数
    wrappedCallback = function(event){
      if (typeof event !== 'undefined') {
        if (event.target !== event.currentTarget) return // makes sure the event didn't bubble from "below"
        $(event.target).unbind(endEvent, wrappedCallback)
      } else
        $(this).unbind(endEvent, wrappedCallback) // triggered by setTimeout

      fired = true
      $(this).css(cssReset)
      callback && callback.call(this)
    }

     //处理动画结束事件
    if (duration > 0){
        //绑定动画结束事件
      this.bind(endEvent, wrappedCallback)
      // transitionEnd is not always firing on older Android phones
      // so make sure it gets fired

        //延时ms后执行动画，注意这里加了25ms，保持endEvent，动画先执行完。
        //绑定过事件还做延时处理，是transitionEnd在older Android phones不一定触发
      setTimeout(function(){
          //如果触发过，就不处理
        if (fired) return
        wrappedCallback.call(that)
      }, ((duration + delay) * 1000) + 25)
    }

    // trigger page reflow so new elements can animate
      //主动触发页面回流，刷新DOM，让接下来设置的动画可以正确播放
      //更改 offsetTop、offsetLeft、 offsetWidth、offsetHeight；scrollTop、scrollLeft、scrollWidth、scrollHeight；clientTop、clientLeft、clientWidth、clientHeight；getComputedStyle() 、currentStyle（）。这些都会触发回流。回流导致DOM重新渲染，平时要尽可能避免，但这里，为了动画即时生效播放，则主动触发回流，刷新DOM。
    this.size() && this.get(0).clientLeft

      //设置样式，启动动画
    this.css(cssValues)

    // duration为0，即浏览器不支持动画的情况，直接执行动画结束，执行回调。
    if (duration <= 0) setTimeout(function() {
      that.each(function(){ wrappedCallback.call(this) })
    }, 0)

    return this
  }

  testEl = null   //去掉不必要的数据存储，便于垃圾回收
})(Zepto)

//     Zepto.js
//     (c) 2010-2015 Thomas Fuchs
//     Zepto.js may be freely distributed under the MIT license.

;(function($, undefined){
  var prefix = '', eventPrefix,    // prefix浏览器前缀 -webkit等，eventPrefix事件前缀
    vendors = { Webkit: 'webkit', Moz: '', O: 'o' }, //前缀数据源 不包含IE
    testEl = document.createElement('div'),  //临时DIV容器
    supportedTransforms = /^((translate|rotate|scale)(X|Y|Z|3d)?|matrix(3d)?|perspective|skew(X|Y)?)$/i, //变形检测
    transform,     //变形
    transitionProperty, transitionDuration, transitionTiming, transitionDelay,//过渡
    animationName, animationDuration, animationTiming, animationDelay,     //动画
    cssReset = {}

    //将驼峰字符串转成css属性，如aB-->a-b
  function dasherize(str) { return str.replace(/([a-z])([A-Z])/, '$1-$2').toLowerCase() }
    //修正事件名
  function normalizeEvent(name) { return eventPrefix ? eventPrefix + name : name.toLowerCase() }


    /**
     * 根据浏览器内核，设置CSS前缀，事件前缀
     * 如-webkit， css：-webkit-  event:webkit
     * 这里会在vendors存储webkit，moz，o三种前缀
     */
  $.each(vendors, function(vendor, event){
    if (testEl.style[vendor + 'TransitionProperty'] !== undefined) {
      prefix = '-' + vendor.toLowerCase() + '-'
      eventPrefix = event
      return false
    }
  })

  transform = prefix + 'transform'     //变形
    //过渡
  cssReset[transitionProperty = prefix + 'transition-property'] =
  cssReset[transitionDuration = prefix + 'transition-duration'] =
  cssReset[transitionDelay    = prefix + 'transition-delay'] =
  cssReset[transitionTiming   = prefix + 'transition-timing-function'] =
  cssReset[animationName      = prefix + 'animation-name'] =
  cssReset[animationDuration  = prefix + 'animation-duration'] =
  cssReset[animationDelay     = prefix + 'animation-delay'] =
  cssReset[animationTiming    = prefix + 'animation-timing-function'] = ''

    /**
     * 动画常量数据源
     * @type {{off: boolean, speeds: {_default: number, fast: number, slow: number}, cssPrefix: string, transitionEnd: *, animationEnd: *}}
     */
  $.fx = {
    off: (eventPrefix === undefined && testEl.style.transitionProperty === undefined), //能力检测是否支持动画，具体检测是否支持过渡，支持过渡事件
    speeds: { _default: 400, fast: 200, slow: 600 },
    cssPrefix: prefix,                                //css 前缀  如-webkit-
    transitionEnd: normalizeEvent('TransitionEnd'), //过渡结束事件
    animationEnd: normalizeEvent('AnimationEnd')     //动画播放结束事件
  }

    /**
     * 创建自定义动画
     * @param properties  样式集
     * @param duration 持续事件
     * @param ease    速率
     * @param callback  完成时的回调
     * @param delay     动画延迟
     * @returns {*}
     */
  $.fn.animate = function(properties, duration, ease, callback, delay){
      //参数修正，传参为function(properties,callback)
    if ($.isFunction(duration))
      callback = duration, ease = undefined, duration = undefined
    if ($.isFunction(ease))  //传参为function(properties,duration，callback)
      callback = ease, ease = undefined
    if ($.isPlainObject(duration))  //传参为function(properties,｛｝)
      ease = duration.easing, callback = duration.complete, delay = duration.delay, duration = duration.duration
      // duration 数字：持续时间  字符串：取speeds: { _default: 400, fast: 200, slow: 600 }对应数字
      if (duration) duration = (typeof duration == 'number' ? duration :
                    ($.fx.speeds[duration] || $.fx.speeds._default)) / 1000     //动画持续时间默认值
    if (delay) delay = parseFloat(delay) / 1000    //延迟时间，除以1000转换成s
    return this.anim(properties, duration, ease, callback, delay)
  }

    /**
     * 动画核心方法
     * @param properties  样式集
     * @param duration 持续事件
     * @param ease    速率
     * @param callback  完成时的回调
     * @param delay     动画延迟
     * @returns {*}
     */
  $.fn.anim = function(properties, duration, ease, callback, delay){
    var key, cssValues = {}, cssProperties, transforms = '',      // transforms 变形   cssValues设置给DOM的样式
        that = this, wrappedCallback, endEvent = $.fx.transitionEnd,
        fired = false

      //修正持续时间
    if (duration === undefined) duration = $.fx.speeds._default / 1000
    if (delay === undefined) delay = 0

      //如果浏览器不支持动画，持续时间设为0，直接跳动画结束
    if ($.fx.off) duration = 0

      // properties是动画名
    if (typeof properties == 'string') {
      // keyframe animation
      cssValues[animationName] = properties
      cssValues[animationDuration] = duration + 's'
      cssValues[animationDelay] = delay + 's'
      cssValues[animationTiming] = (ease || 'linear')
      endEvent = $.fx.animationEnd  //动画结束事件
    } else {  //properties 是样式集
      cssProperties = []
      // CSS transitions
      for (key in properties)
          //supportedTransforms.test(key) 正则检测是否为变形
      //key + '(' + properties[key] + ') ' 拼凑成变形方法
        if (supportedTransforms.test(key)) transforms += key + '(' + properties[key] + ') '
        else cssValues[key] = properties[key], cssProperties.push(dasherize(key))

        //变形统一存入  cssValues   cssProperties
      if (transforms) cssValues[transform] = transforms, cssProperties.push(transform)

       // duration > 0可以播放动画，且properties是对象，表明为过渡，上面有字符串，则为animate
      if (duration > 0 && typeof properties === 'object') {
        cssValues[transitionProperty] = cssProperties.join(', ')
        cssValues[transitionDuration] = duration + 's'
        cssValues[transitionDelay] = delay + 's'
        cssValues[transitionTiming] = (ease || 'linear')  //默认线性速率
      }
    }

    //动画完成后的响应函数
    wrappedCallback = function(event){
      if (typeof event !== 'undefined') {
        if (event.target !== event.currentTarget) return // makes sure the event didn't bubble from "below"
        $(event.target).unbind(endEvent, wrappedCallback)
      } else
        $(this).unbind(endEvent, wrappedCallback) // triggered by setTimeout

      fired = true
      $(this).css(cssReset)
      callback && callback.call(this)
    }

     //处理动画结束事件
    if (duration > 0){
        //绑定动画结束事件
      this.bind(endEvent, wrappedCallback)
      // transitionEnd is not always firing on older Android phones
      // so make sure it gets fired

        //延时ms后执行动画，注意这里加了25ms，保持endEvent，动画先执行完。
        //绑定过事件还做延时处理，是transitionEnd在older Android phones不一定触发
      setTimeout(function(){
          //如果触发过，就不处理
        if (fired) return
        wrappedCallback.call(that)
      }, ((duration + delay) * 1000) + 25)
    }

    // trigger page reflow so new elements can animate
      //主动触发页面回流，刷新DOM，让接下来设置的动画可以正确播放
      //更改 offsetTop、offsetLeft、 offsetWidth、offsetHeight；scrollTop、scrollLeft、scrollWidth、scrollHeight；clientTop、clientLeft、clientWidth、clientHeight；getComputedStyle() 、currentStyle（）。这些都会触发回流。回流导致DOM重新渲染，平时要尽可能避免，但这里，为了动画即时生效播放，则主动触发回流，刷新DOM。
    this.size() && this.get(0).clientLeft

      //设置样式，启动动画
    this.css(cssValues)

    // duration为0，即浏览器不支持动画的情况，直接执行动画结束，执行回调。
    if (duration <= 0) setTimeout(function() {
      that.each(function(){ wrappedCallback.call(this) })
    }, 0)

    return this
  }

  testEl = null   //去掉不必要的数据存储，便于垃圾回收
})(Zepto)

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