移动端图片缩放（包括滑动查看）

上一篇文章中的移动端图片缩放是不包括同时左右滑动查看图片，但是有些场景需要我们去实现类似于微信朋友圈的点击查看图片的效果。

弊端：photoswipe暂时只能实现iOS端长按出现保存图片到本地的功能，但是在安卓上却没有办法，暂时还未发现解决，后续会找办法。如果有找到解决办法的帅哥美女，可以留言告诉我一下吗，谢谢！

所需要引入的样式和js可以到这里下载，也可简单查看页面展示：

链接：https://pan.baidu.com/s/1y1kqfBVyER8_ldSgHpcgVQ
提取码：8q0p

style样式：

* {margin: 0;padding: 0;}
.clearfix::before, .clearfix::after {
display: block;
content: '';
visibility: hidden;
height: 100%;
clear: both;
}
body {padding-top: 2%;}
.my-gallery {80%;margin: 0 auto;}
.my-gallery .img-dv {100%;margin-bottom: 1%;}
.my-gallery .img-dv a {display:block;100%;text-align: center}
.my-gallery .img-dv a img {100%;}
.pswp__caption{display: none;}

body体代码：

<!--如果有多个data-pswp-uid 它的值是不能重复的-->
<div class="my-gallery" data-pswp-uid="1">
<figure>
<div class="img-dv"><a href="img/img1.png" data-size=""><img src="img/img1.png"></a></div>
<figcaption style="display:none;">在这里可增加图片描述</figcaption>
</figure>
<figure>
<div class="img-dv"><a href="img/img2.png" data-size=""><img src="img/img2.png"></a></div>
<figcaption style="display:none;">在这里可增加图片描述2</figcaption>
</figure>
<figure>
<div class="img-dv"><a href="img/img3.png" data-size=""><img src="img/img3.png"></a></div>
<figcaption style="display:none;">在这里可增加图片描述3</figcaption>
</figure>
<figure>
<div class="img-dv"><a href="img/img4.png" data-size=""><img src="img/img4.png"></a></div>
<figcaption style="display:none;">在这里可增加图片描述4</figcaption>
</figure>
<figure>
<div class="img-dv"><a href="img/img5.png" data-size=""><img src="img/img5.png"></a></div>
<figcaption style="display:none;">在这里可增加图片描述5在这里可增加图片描述5在这里可增加图片描述5</figcaption>
</figure>
</div>

<div class="pswp" tabindex="-1" role="dialog" aria-hidden="true">
<div class="pswp__bg"></div>
<div class="pswp__scroll-wrap">
<div class="pswp__container">
<div class="pswp__item"></div>
<div class="pswp__item"></div>
<div class="pswp__item"></div>
</div>
<div class="pswp__ui pswp__ui--hidden">
<div class="pswp__top-bar">
<div class="pswp__counter"></div>
<button class="pswp__button pswp__button--close" title="Close (Esc)"></button>
<button class="pswp__button pswp__button--fs" title="Toggle fullscreen"></button>
<button class="pswp__button pswp__button--zoom" title="Zoom in/out"></button>
<div class="pswp__preloader">
<div class="pswp__preloader__icn">
<div class="pswp__preloader__cut">
<div class="pswp__preloader__donut"></div>
</div>
</div>
</div>
</div>
<div class="pswp__share-modal pswp__share-modal--hidden pswp__single-tap">
<div class="pswp__share-tooltip"></div>
</div>
<button class="pswp__button pswp__button--arrow--left" title="Previous (arrow left)">
</button>
<button class="pswp__button pswp__button--arrow--right" title="Next (arrow right)">
</button>
<div class="pswp__caption">
<div class="pswp__caption__center"></div>
</div>
</div>
</div>
</div>

script代码：

$(function(){
imgs();// 根据不同屏幕分辨率设置放大之后的图片宽高
})

// 根据不同屏幕分辨率设置放大之后的图片宽高
function imgs(){
var img_list = $(".img-dv img");
var widthN = document.body.clientWidth;//放在图片之后的宽度
for(var i=0;i<img_list.length;i++){
var widthO = $(img_list[i]).width();
var heightO = $(img_list[i]).height();
var heightN = parseInt(widthN*heightO/widthO);
var data_size = widthN+"x"+heightN
$(img_list[i]).parent().attr("data-size",data_size);
if(i==img_list.length-1){
photoSwiperInit();//初始化图片缩放和滑动查看
}
}
}

function photoSwiperInit(){

var initPhotoSwipeFromDOM = function(gallerySelector) {
// 解析来自DOM元素幻灯片数据（URL，标题，大小...）
var parseThumbnailElements = function(el) {
var thumbElements = el.childNodes,
numNodes = thumbElements.length,
items = [],
figureEl,
linkEl,
size,
item,
divEl;
for(var i = 0; i < numNodes; i++) {
figureEl = thumbElements[i]; // <figure> element
// 仅包括元素节点
if(figureEl.nodeType !== 1) {
continue;
}
divEl = figureEl.children[0];
linkEl = divEl.children[0]; // <a> element
size = linkEl.getAttribute('data-size').split('x');
// 创建幻灯片对象
item = {
src: linkEl.getAttribute('href'),
w: parseInt(size[0], 10),
h: parseInt(size[1], 10)
};
if(figureEl.children.length > 1) {
item.title = figureEl.children[1].innerHTML;
}
if(linkEl.children.length > 0) {
// <img> 缩略图节点, 检索缩略图网址
item.msrc = linkEl.children[0].getAttribute('src');
}
item.el = figureEl; // 保存链接元素 for getThumbBoundsFn
items.push(item);
}
return items;
};

// 查找最近的父节点
var closest = function closest(el, fn) {
return el && ( fn(el) ? el : closest(el.parentNode, fn) );
};

// 当用户点击缩略图触发
var onThumbnailsClick = function(e) {
e = e || window.event;
e.preventDefault ? e.preventDefault() : e.returnValue = false;
var eTarget = e.target || e.srcElement;
var clickedListItem = closest(eTarget, function(el) {
return (el.tagName && el.tagName.toUpperCase() === 'FIGURE');
});
if(!clickedListItem) {
return;
}
var clickedGallery = clickedListItem.parentNode,
childNodes = clickedListItem.parentNode.childNodes,
numChildNodes = childNodes.length,
nodeIndex = 0,
index;
for (var i = 0; i < numChildNodes; i++) {
if(childNodes[i].nodeType !== 1) {
continue;
}
if(childNodes[i] === clickedListItem) {
index = nodeIndex;
break;
}
nodeIndex++;
}
if(index >= 0) {
openPhotoSwipe( index, clickedGallery );
}
return false;
};

var photoswipeParseHash = function() {
var hash = window.location.hash.substring(1),
params = {};
if(hash.length < 5) {
return params;
}
var vars = hash.split('&');
for (var i = 0; i < vars.length; i++) {
if(!vars[i]) {
continue;
}
var pair = vars[i].split('=');
if(pair.length < 2) {
continue;
}
params[pair[0]] = pair[1];
}
if(params.gid) {
params.gid = parseInt(params.gid, 10);
}
return params;
};

var openPhotoSwipe = function(index, galleryElement, disableAnimation, fromURL) {
var pswpElement = document.querySelectorAll('.pswp')[0],
gallery,
options,
items;
items = parseThumbnailElements(galleryElement);
// 这里可以定义参数
options = {
barsSize: {
top: 100,
bottom: 100
},
fullscreenEl : false,
tapToClose: true,//可以进行点击关闭当前图片
shareButtons: [
{id:'wechat', label:'分享微信', url:'#'},
{id:'weibo', label:'新浪微博', url:'#'},
{id:'download', label:'保存图片', url:'{{raw_image_url}}', download:true}
],
galleryUID: galleryElement.getAttribute('data-pswp-uid'),
getThumbBoundsFn: function(index) {
var thumbnail = items[index].el.getElementsByTagName('img')[0], // find thumbnail
pageYScroll = window.pageYOffset || document.documentElement.scrollTop,
rect = thumbnail.getBoundingClientRect();
console.log(thumbnail)
return {x:rect.left, y:rect.top + pageYScroll, w:rect.width};
}
};


if(fromURL) {
if(options.galleryPIDs) {
for(var j = 0; j < items.length; j++) {
if(items[j].pid == index) {
options.index = j;
break;
}
}
} else {
options.index = parseInt(index, 10) - 1;
}
} else {
options.index = parseInt(index, 10);
}
if( isNaN(options.index) ) {
return;
}
if(disableAnimation) {
options.showAnimationDuration = 0;
}
gallery = new PhotoSwipe( pswpElement, PhotoSwipeUI_Default, items, options);
gallery.init();
};

var galleryElements = document.querySelectorAll( gallerySelector );
for(var i = 0, l = galleryElements.length; i < l; i++) {
galleryElements[i].setAttribute('data-pswp-uid', i+1);
galleryElements[i].onclick = onThumbnailsClick;
}
var hashData = photoswipeParseHash();
if(hashData.pid && hashData.gid) {
openPhotoSwipe( hashData.pid , galleryElements[ hashData.gid - 1 ], true, true );
}
};

initPhotoSwipeFromDOM('.my-gallery');
}