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iscroll.js的源码阅读（上） - CSDN博客blog.csdn.net
之前在学习js的时候，就特别期待可以看懂源码 终于可以看懂一些源码了，今天整理了一下
(function (window, document, Math) {
//获取兼容性的requestAnimationFrame
var rAF = window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function (callback) { window.setTimeout(callback, 1000 / 60); };
var utils = (function () {
// 工具函数库
var me = {};
var _elementStyle = document.createElement('div').style;
var _vendor = (function () {
var vendors = ['t', 'webkitT', 'MozT', 'msT', 'OT'],
transform,
i = 0,
l = vendors.length;
for ( ; i < l; i++ ) {
transform = vendors[i] + 'ransform';
if ( transform in _elementStyle ) return vendors[i].substr(0, vendors[i].length-1);
}
return false;
})();
// 补全后缀命名
function _prefixStyle (style) {
if ( _vendor === false ) return false;
if ( _vendor === '' ) return style;
return _vendor + style.charAt(0).toUpperCase() + style.substr(1);
}
// 获取时间戳
me.getTime = Date.now || function getTime () { return new Date().getTime(); };
// 复制对象
me.extend = function (target, obj) {
for ( var i in obj ) {
target[i] = obj[i];
}
};
// 绑定事件
me.addEvent = function (el, type, fn, capture) {
el.addEventListener(type, fn, !!capture);
};
// 移除事件绑定
me.removeEvent = function (el, type, fn, capture) {
el.removeEventListener(type, fn, !!capture);
};
me.prefixPointerEvent = function (pointerEvent) {
// 用于IE
// MSPointerDown 事件 --- > pointerdown 事件
// 修正IE
return window.MSPointerEvent ?
'MSPointer' + pointerEvent.charAt(7).toUpperCase() + pointerEvent.substr(8):
pointerEvent;
};
// 动画计算
me.momentum = function (current, start, time, lowerMargin, wrapperSize, deceleration) {
// 当前位置与初始位置的差值
var distance = current - start,
// 根据差值求出平均速度
speed = Math.abs(distance) / time,
destination,
duration;
// 加速度的初始化
deceleration = deceleration === undefined ? 0.0006 : deceleration;
// 位移公式
// x=Vot+1/2at^2 Vt是末速度,Vo是初速度,a是加速度,t为时间,X是位移距离 x=Vot+1/2at^2 Vt=Vo+at V^2-Vo^2=2ax
destination = current + ( speed * speed ) / ( 2 * deceleration ) * ( distance < 0 ? -1 : 1 );
duration = speed / deceleration;
if ( destination < lowerMargin ) {
// 从左往右动
destination = wrapperSize ? lowerMargin - ( wrapperSize / 2.5 * ( speed / 8 ) ) : lowerMargin;
distance = Math.abs(destination - current);
duration = distance / speed;
} else if ( destination > 0 ) {
// 从右往左动
destination = wrapperSize ? wrapperSize / 2.5 * ( speed / 8 ) : 0;
distance = Math.abs(current) + destination;
duration = distance / speed;
}
return {
destination: Math.round(destination),
duration: duration
};
};
// 补全tranform后缀
var _transform = _prefixStyle('transform');
// 扩展一些属性
// hasTransform 判断有没有transform属性
// hasPerspective 判断有没有perspective属性
// hasTouch 判断有没有ontouchstart事件
// hasPointer 判断有没有指针事件
// hasTransition 判断有没 transition;
me.extend(me, {
hasTransform: _transform !== false,
hasPerspective: _prefixStyle('perspective') in _elementStyle,
hasTouch: 'ontouchstart' in window,
hasPointer: !!(window.PointerEvent || window.MSPointerEvent), // IE10 is prefixed
hasTransition: _prefixStyle('transition') in _elementStyle
});
/*
This should find all Android browsers lower than build 535.19 (both stock browser and webview)
- galaxy S2 is ok
- 2.3.6 : `AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1`
- 4.0.4 : `AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30`
- galaxy S3 is badAndroid (stock brower, webview)
`AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30`
- galaxy S4 is badAndroid (stock brower, webview)
`AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30`
- galaxy S5 is OK
`AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Mobile Safari/537.36 (Chrome/)`
- galaxy S6 is OK
`AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Mobile Safari/537.36 (Chrome/)`
*/
// 判断过期的Adroid内核版本
//
me.isBadAndroid = (function() {
var appVersion = window.navigator.appVersion;
// Android browser is not a chrome browser.
// // 判断为安卓浏览器，而不是谷歌浏览器
if (/Android/.test(appVersion) && !(/Chrome\/\d/.test(appVersion))) {
var safariVersion = appVersion.match(/Safari\/(\d+.\d)/);
if(safariVersion && typeof safariVersion === "object" && safariVersion.length >= 2) {
return parseFloat(safariVersion[1]) < 535.19;
} else {
return true;
}
} else {
return false;
}
})();
// 扩展样式
// transform 补全样式
// transitionTimingFunction 补全transition-timeing-function 属性
// transitionDuration 补全transition-duration 属性
// transitionDelay 补全 transition-delay 属性
// transformOrigin 补全 transition-origin 属性
// touchAction 补全touch-action 属性
me.extend(me.style = {}, {
transform: _transform,
transitionTimingFunction: _prefixStyle('transitionTimingFunction'),
transitionDuration: _prefixStyle('transitionDuration'),
transitionDelay: _prefixStyle('transitionDelay'),
transformOrigin: _prefixStyle('transformOrigin'),
touchAction: _prefixStyle('touchAction')
});
// 判断元素是否V有某个class类名
me.hasClass = function (e, c) {
// " op"
// "op"
// " op "
var re = new RegExp("(^|\\s)" + c + "(\\s|$)");
return re.test(e.className);
};
// 给元素添加某个class 类名
me.addClass = function (e, c) {
// 判断是否有某个类名
// 有，就什么都不做
if ( me.hasClass(e, c) ) {
return;
}
// 按空格分割
var newclass = e.className.split(' ');
newclass.push(c);
e.className = newclass.join(' ');
};
// 移除某些样式class类名
me.removeClass = function (e, c) {
if ( !me.hasClass(e, c) ) {
return;
}
var re = new RegExp("(^|\\s)" + c + "(\\s|$)", 'g');
e.className = e.className.replace(re, ' ');
};
// 获取定位值
me.offset = function (el) {
var left = -el.offsetLeft,
top = -el.offsetTop;
// jshint -W084
while (el = el.offsetParent) {
left -= el.offsetLeft;
top -= el.offsetTop;
}
// jshint +W084
return {
left: left,
top: top
};
};
// 扩展除默认事件之外的
me.preventDefaultException = function (el, exceptions) {
for ( var i in exceptions ) {
if ( exceptions[i].test(el[i]) ) {
return true;
}
}
return false;
};
// 扩展事件类型
me.extend(me.eventType = {}, {
// 手机版本
touchstart: 1,
touchmove: 1,
touchend: 1,
// pc版本
mousedown: 2,
mousemove: 2,
mouseup: 2,
pointerdown: 3,
pointermove: 3,
pointerup: 3,
MSPointerDown: 3,
MSPointerMove: 3,
MSPointerUp: 3
});
// 缓动函数
me.extend(me.ease = {}, {
quadratic: {
style: 'cubic-bezier(0.25, 0.46, 0.45, 0.94)',
fn: function (k) {
return k * ( 2 - k );
}
},
circular: {
style: 'cubic-bezier(0.1, 0.57, 0.1, 1)', // Not properly "circular" but this looks better, it should be (0.075, 0.82, 0.165, 1)
fn: function (k) {
return Math.sqrt( 1 - ( --k * k ) );
}
},
back: {
style: 'cubic-bezier(0.175, 0.885, 0.32, 1.275)',
fn: function (k) {
var b = 4;
return ( k = k - 1 ) * k * ( ( b + 1 ) * k + b ) + 1;
}
},
bounce: {
style: '',
fn: function (k) {
if ( ( k /= 1 ) < ( 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;
}
}
},
elastic: {
style: '',
fn: function (k) {
var f = 0.22,
e = 0.4;
if ( k === 0 ) { return 0; }
if ( k == 1 ) { return 1; }
return ( e * Math.pow( 2, - 10 * k ) * Math.sin( ( k - f / 4 ) * ( 2 * Math.PI ) / f ) + 1 );
}
}
});
// 手机端的点击事件
me.tap = function (e, eventName) {
var ev = document.createEvent('Event');
ev.initEvent(eventName, true, true);
ev.pageX = e.pageX;
ev.pageY = e.pageY;
e.target.dispatchEvent(ev);
};
// 扩展pc端click事件
me.click = function (e) {
var target = e.target,
ev;
// 除去select input textarea 不需要点击事件
if ( !(/(SELECT|INPUT|TEXTAREA)/i).test(target.tagName) ) {
// https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/initMouseEvent
// initMouseEvent is deprecated.
ev = document.createEvent(window.MouseEvent ? 'MouseEvents' : 'Event');
ev.initEvent('click', true, true);
ev.view = e.view || window;
ev.detail = 1;
ev.screenX = target.screenX || 0;
ev.screenY = target.screenY || 0;
ev.clientX = target.clientX || 0;
ev.clientY = target.clientY || 0;
ev.ctrlKey = !!e.ctrlKey;
ev.altKey = !!e.altKey;
ev.shiftKey = !!e.shiftKey;
ev.metaKey = !!e.metaKey;
ev.button = 0;
ev.relatedTarget = null;
ev._constructed = true;
target.dispatchEvent(ev);
}
};
// 扩展手机端触摸动作
// 获取触摸动作
me.getTouchAction = function(eventPassthrough, addPinch) {
var touchAction = 'none';
// 判断手指滑动方向
if ( eventPassthrough === 'vertical' ) {
touchAction = 'pan-y';
} else if (eventPassthrough === 'horizontal' ) {
touchAction = 'pan-x';
}
if (addPinch && touchAction != 'none') {
// add pinch-zoom support if the browser supports it, but if not (eg. Chrome <55) do nothing
touchAction += ' pinch-zoom';
}
return touchAction;
};
// 获取元素的定位
// 获取元素的宽高
// 分两种
// 一种是 SVG
// 一种是 一般元素
me.getRect = function(el) {
if (el instanceof SVGElement) {
var rect = el.getBoundingClientRect();
return {
top : rect.top,
left : rect.left,
width : rect.width,
height : rect.height
};
} else {
return {
top : el.offsetTop,
left : el.offsetLeft,
width : el.offsetWidth,
height : el.offsetHeight
};
}
};
return me;
})();
// 构造函数IScroll
function IScroll (el, options) {
// 获取元素
this.wrapper = typeof el == 'string' ? document.querySelector(el) : el;
// 保存滚动元素
this.scroller = this.wrapper.children[0];
// 保存滚动元素样式
this.scrollerStyle = this.scroller.style; // cache style for better performance
this.options = {
// resize 滚动条
resizeScrollbars: true,
// 鼠标滚动速度
mouseWheelSpeed: 20,
// 触摸时间
snapThreshold: 0.334,
// INSERT POINT: OPTIONS
// 禁止鼠标事件
// 触摸事件
// 指针事件
disablePointer : !utils.hasPointer,
// 在手机上
disableTouch : utils.hasPointer || !utils.hasTouch,
// 在PC端
disableMouse : utils.hasPointer || utils.hasTouch,
// 初始化为最上边，最左边
startX: 0,
startY: 0,
// 默认y可以滚动
scrollY: true,
// 方向锁定时间
directionLockThreshold: 5,
// 计算距离
momentum: true,
// 回弹
bounce: true,
// 回弹时间
bounceTime: 600,
// 缓动函数
bounceEasing: '',
// 默认开启阻止默认事件
preventDefault: true,
// 不阻止默认事件
preventDefaultException: { tagName: /^(INPUT|TEXTAREA|BUTTON|SELECT)$/ },
HWCompositing: true,
// 默认使用transition，transform
useTransition: true,
useTransform: true,
// 把事件mousedown绑定在
// wrapper上
bindToWrapper: typeof window.onmousedown === "undefined"
};
for ( var i in options ) {
// 扩展传进来的参数配置
this.options[i] = options[i];
}
//
// options
// 保存translateZ的样式
this.translateZ = this.options.HWCompositing && utils.hasPerspective ? ' translateZ(0)' : '';
// 重新计算transition,transform属性是否存在
this.options.useTransition = utils.hasTransition && this.options.useTransition;
this.options.useTransform = utils.hasTransform && this.options.useTransform;
// 重新计算方向
// 传入true - > 'vertical'
// 重新计算是否开启阻止默认事件
// 如果方向为‘vertical’，就阻止默认事件触发
// 否则不用
this.options.eventPassthrough = this.options.eventPassthrough === true ? 'vertical' : this.options.eventPassthrough;
this.options.preventDefault = !this.options.eventPassthrough && this.options.preventDefault;
// If you want eventPassthrough I have to lock one of the axes
// 锁定某个方向
this.options.scrollY = this.options.eventPassthrough == 'vertical' ? false : this.options.scrollY;
this.options.scrollX = this.options.eventPassthrough == 'horizontal' ? false : this.options.scrollX;
// With eventPassthrough we also need lockDirection mechanism
this.options.freeScroll = this.options.freeScroll && !this.options.eventPassthrough;
// 锁定方向的时间
this.options.directionLockThreshold = this.options.eventPassthrough ? 0 : this.options.directionLockThreshold;
// 设置缓动函数
this.options.bounceEasing = typeof this.options.bounceEasing == 'string' ? utils.ease[this.options.bounceEasing] || utils.ease.circular : this.options.bounceEasing;
// 窗口改变大小
// 重新计算
this.options.resizePolling = this.options.resizePolling === undefined ? 60 : this.options.resizePolling;
if ( this.options.tap === true ) {
// 设置tap事件
this.options.tap = 'tap';
}
// https://github.com/cubiq/iscroll/issues/1029
if (!this.options.useTransition && !this.options.useTransform) {
// 判断定位
if(!(/relative|absolute/i).test(this.scrollerStyle.position)) {
this.scrollerStyle.position = "relative";
}
}
if ( this.options.shrinkScrollbars == 'scale' ) {
// 如果是伸缩的话
// 就不使用transition 属性
this.options.useTransition = false;
}
// 授予鼠标滚动方向
this.options.invertWheelDirection = this.options.invertWheelDirection ? -1 : 1;
// INSERT POINT: NORMALIZATION
// Some defaults
this.x = 0;
this.y = 0;
this.directionX = 0;
this.directionY = 0;
this._events = {};
// INSERT POINT: DEFAULTS
this._init();
this.refresh();
this.scrollTo(this.options.startX, this.options.startY);
this.enable();
}
IScroll.prototype = {
version: '5.2.0-snapshot',
_init: function () {
this._initEvents();
if ( this.options.scrollbars || this.options.indicators ) {
// 滚动条，和那个指示器，
this._initIndicators();
}
if ( this.options.mouseWheel ) {
// 初始化滚轮事件
this._initWheel();
}
if ( this.options.snap ) {
//
this._initSnap();
}
if ( this.options.keyBindings ) {
// 键盘事件绑定
this._initKeys();
}
// INSERT POINT: _init
},
// 销毁滚动事件
destroy: function () {
this._initEvents(true);
clearTimeout(this.resizeTimeout);
this.resizeTimeout = null;
this._execEvent('destroy');
},
_transitionEnd: function (e) {
// 动画过渡结束之后
//
if ( e.target != this.scroller || !this.isInTransition ) {
return;
}
this._transitionTime();
if ( !this.resetPosition(this.options.bounceTime) ) {
this.isInTransition = false;
// 执行滚动结束事件
this._execEvent('scrollEnd');
}
},
_start: function (e) {
// 相当于onmousedown
// ontouchstart
// React to left mouse button only
// 获取只按下左键
if ( utils.eventType[e.type] != 1 ) {
// for button property
// http://unixpapa.com/js/mouse.html
var button;
if (!e.which) {
/* IE case */
// 兼容IE
button = (e.button < 2) ? 0 :
((e.button == 4) ? 1 : 2);
} else {
/* All others */
button = e.button;
}
if ( button !== 0 ) {
return;
}
}
if ( !this.enabled || (this.initiated && utils.eventType[e.type] !== this.initiated) ) {
return;
}
if ( this.options.preventDefault && !utils.isBadAndroid && !utils.preventDefaultException(e.target, this.options.preventDefaultException) ) {
// 阻止默认事件
e.preventDefault();
}
// 获取触摸点
var point = e.touches ? e.touches[0] : e,
pos;
// 初始化事件类型
this.initiated = utils.eventType[e.type];
// 这个时候没有move事件
// 只有左键按下这一个操作
this.moved = false;
// 初始化位置
this.distX = 0;
this.distY = 0;
this.directionX = 0;
this.directionY = 0;
this.directionLocked = 0;
// 左键按钮按下的初始时间
this.startTime = utils.getTime();
// 动画结束时
// 如果当我们鼠标左键按下之前有动画执行时
// 把动画结束掉
// 还原到原来的位置
if ( this.options.useTransition && this.isInTransition ) {
this._transitionTime();
this.isInTransition = false;
pos = this.getComputedPosition();
this._translate(Math.round(pos.x), Math.round(pos.y));
this._execEvent('scrollEnd');
} else if ( !this.options.useTransition && this.isAnimating ) {
this.isAnimating = false;
this._execEvent('scrollEnd');
}
// 保存初始位置
this.startX = this.x;
this.startY = this.y;
this.absStartX = this.x;
this.absStartY = this.y;
this.pointX = point.pageX;
this.pointY = point.pageY;
this._execEvent('beforeScrollStart');
},
_move: function (e) {
// 移动事件
// onmousemove
// ontouchmove
if ( !this.enabled || utils.eventType[e.type] !== this.initiated ) {
return;
}
if ( this.options.preventDefault ) { // increases performance on Android? TODO: check!
e.preventDefault();
}
// 获取滑动时的点
var point = e.touches ? e.touches[0] : e,
// 求出滑动差
deltaX = point.pageX - this.pointX,
deltaY = point.pageY - this.pointY,
// 获取滑动当前时间戳
timestamp = utils.getTime(),
newX, newY,
absDistX, absDistY;
// 保存当前
// pageX
// pageY
this.pointX = point.pageX;
this.pointY = point.pageY;
// 滑动的距离
this.distX += deltaX;
this.distY += deltaY;
absDistX = Math.abs(this.distX);
absDistY = Math.abs(this.distY);
// We need to move at least 10 pixels for the scrolling to initiate
// 时间间隔300ms 和 位置小于10
// 什么都不做
if ( timestamp - this.endTime > 300 && (absDistX < 10 && absDistY < 10) ) {
return;
}
// If you are scrolling in one direction lock the other
// 锁定方向判断
if ( !this.directionLocked && !this.options.freeScroll ) {
// directionLockThreshold方向误差
if ( absDistX > absDistY + this.options.directionLockThreshold ) {
this.directionLocked = 'h'; // lock horizontally
} else if ( absDistY >= absDistX + this.options.directionLockThreshold ) {
this.directionLocked = 'v'; // lock vertically
} else {
this.directionLocked = 'n'; // no lock
}
}
if ( this.directionLocked == 'h' ) {
if ( this.options.eventPassthrough == 'vertical' ) {
// 阻止默认事件触发
e.preventDefault();
} else if ( this.options.eventPassthrough == 'horizontal' ) {
this.initiated = false;
return;
}
//
deltaY = 0;
} else if ( this.directionLocked == 'v' ) {
if ( this.options.eventPassthrough == 'horizontal' ) {
e.preventDefault();
} else if ( this.options.eventPassthrough == 'vertical' ) {
this.initiated = false;
return;
}
deltaX = 0;
}
deltaX = this.hasHorizontalScroll ? deltaX : 0;
deltaY = this.hasVerticalScroll ? deltaY : 0;
// 计算出新的位置
newX = this.x + deltaX;
newY = this.y + deltaY;
// Slow down if outside of the boundaries
// 滑出边界的话
if ( newX > 0 || newX < this.maxScrollX ) {
// 左边界=>0
// 右边界=>this.maxScrollX
// 中间 this.x + deltaX / 3
// this.options.bounce 是否还在缓动中
newX = this.options.bounce ? this.x + deltaX / 3 : newX > 0 ? 0 : this.maxScrollX;
}
if ( newY > 0 || newY < this.maxScrollY ) {
// 上边界=>0
// 下边界=>this.maxScrollY
// 中间 this.y + deltaY / 3
// this.options.bounce 是否还在缓动中
newY = this.options.bounce ? this.y + deltaY / 3 : newY > 0 ? 0 : this.maxScrollY;
}
// 判断是往上滑动
// 还是往下滑动
this.directionX = deltaX > 0 ? -1 : deltaX < 0 ? 1 : 0;
this.directionY = deltaY > 0 ? -1 : deltaY < 0 ? 1 : 0;
if ( !this.moved ) {
// 开始滚动
this._execEvent('scrollStart');
}
// 滚动之后设置为true
// 保证触发一次
this.moved = true;
// translate到newX,newY
this._translate(newX, newY);
/* REPLACE START: _move */
if ( timestamp - this.startTime > 300 ) {
// 保存当前时间戳
// 当前位置
this.startTime = timestamp;
this.startX = this.x;
this.startY = this.y;
}
/* REPLACE END: _move */
},
// 滚动结束
_end: function (e) {
if ( !this.enabled || utils.eventType[e.type] !== this.initiated ) {
return;
}
if ( this.options.preventDefault && !utils.preventDefaultException(e.target, this.options.preventDefaultException) ) {
e.preventDefault();
}
var point = e.changedTouches ? e.changedTouches[0] : e,
momentumX,
momentumY,
// 滑动的总时间
duration = utils.getTime() - this.startTime,
// 获取滑动结束时的位置
newX = Math.round(this.x),
newY = Math.round(this.y),
// 计算出滚动的距离
distanceX = Math.abs(newX - this.startX),
distanceY = Math.abs(newY - this.startY),
time = 0,
easing = '';
this.isInTransition = 0;
this.initiated = 0;
this.endTime = utils.getTime();
// reset if we are outside of the boundaries
// 画出边界
// 重新计算
if ( this.resetPosition(this.options.bounceTime) ) {
return;
}
this.scrollTo(newX, newY); // ensures that the last position is rounded
// we scrolled less than 10 pixels
if ( !this.moved ) {
if ( this.options.tap ) {
// 移动端
// 添加点击事件
utils.tap(e, this.options.tap);
}
if ( this.options.click ) {
// pc端
utils.click(e);
}
// 取消滚动
this._execEvent('scrollCancel');
return;
}
if ( this._events.flick && duration < 200 && distanceX < 100 && distanceY < 100 ) {
this._execEvent('flick');
return;
}
// start momentum animation if needed
if ( this.options.momentum && duration < 300 ) {
momentumX = this.hasHorizontalScroll ? utils.momentum(this.x, this.startX, duration, this.maxScrollX, this.options.bounce ? this.wrapperWidth : 0, this.options.deceleration) : { destination: newX, duration: 0 };
momentumY = this.hasVerticalScroll ? utils.momentum(this.y, this.startY, duration, this.maxScrollY, this.options.bounce ? this.wrapperHeight : 0, this.options.deceleration) : { destination: newY, duration: 0 };
newX = momentumX.destination;
newY = momentumY.destination;
time = Math.max(momentumX.duration, momentumY.duration);
this.isInTransition = 1;
}
if ( this.options.snap ) {
var snap = this._nearestSnap(newX, newY);
this.currentPage = snap;
time = this.options.snapSpeed || Math.max(
Math.max(
Math.min(Math.abs(newX - snap.x), 1000),
Math.min(Math.abs(newY - snap.y), 1000)
), 300);
newX = snap.x;
newY = snap.y;
this.directionX = 0;
this.directionY = 0;
easing = this.options.bounceEasing;
}
// INSERT POINT: _end
if ( newX != this.x || newY != this.y ) {
// 超出边界
// change easing function when scroller goes out of the boundaries
if ( newX > 0 || newX < this.maxScrollX || newY > 0 || newY < this.maxScrollY ) {
easing = utils.ease.quadratic;
}
//滚动到新位置
this.scrollTo(newX, newY, time, easing);
return;
}
//执行滚动结束函数
this._execEvent('scrollEnd');
},我也是渐渐在学习中，如果有错误的地方，请广大网友批评指正， 万分感谢