vue.js 实现图片本地预览 裁剪 压缩 上传功能

<div id="wrap">
 <label>
  点我上传图片
  <input type='file' @change="change" ref="input">
 </label>
 <img :src="src" ref="img">
</div>
new Vue({
 el: '#wrap',
 data: {
  // 一张透明的图片
  src:'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7', 
  elInput: null
 },
 methods: {
  change(e){
   // ...
  }
 }
})

function getSize(e){
 return e.target.files[0].size;
}

const refs = this.$refs
const elInput = refs.input
const elImg = refs.img

function getSrc(){
 const reader = new FileReader();
 reader.onload = (e) => {
  const src = e.target.result;
  elImg.src = src;
 };
 if (elInput.files && elInput.files[0]) {
  reader.readAsDataURL(elInput.files[0]);
 }
}

function getSrc(){
 elInput.select();
 elInput.blur();
 const src = document.selection.createRange().text;
 document.selection.empty();
 elImg.style.filter = `progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='${src}')`;
}

label{
 overflow:hidden;
}
label input[type='file']{
 position:absolute;
 top:9999px;
 left:9999px;
}

let tempEl;
const getSizeIncompatible = (src, callback) => {
 if (!tempEl) {
  tempEl = document.createElement('div');
  tempEl.style.position = 'absolute';
  tempEl.style.width = '1px';
  tempEl.style.height = '1px';
  tempEl.style.left = '-9999px';
  tempEl.style.top = '-9999px';
  tempEl.style.filter = 'progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=image)';
  document.body.insertBefore(tempEl, document.body.firstChild);
 }
 tempEl.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
 callback(tempEl.offsetWidth, tempEl.offsetHeight);
};

const getSize = (src, callback) => {
 const image = new Image();
 image.onload = () => {
  callback(image.width, image.height);
 };
 image.src = src;
};