vue项目中pdf文件如何使用print.js导出

// 打印类属性、方法定义
/* eslint-disable */
const Print = function (dom, options) {
 if (!(this instanceof Print)) return new Print(dom, options);

 this.options = this.extend({
  'noPrint': '.no-print'
 }, options);

 if ((typeof dom) === "string") {
  this.dom = document.querySelector(dom);
 } else {
  this.isDOM(dom)
  this.dom = this.isDOM(dom) ? dom : dom.$el;
 }

 this.init();
};
Print.prototype = {
 init: function () {
  var content = this.getStyle() + this.getHtml();
  this.writeIframe(content);
 },
 extend: function (obj, obj2) {
  for (var k in obj2) {
   obj[k] = obj2[k];
  }
  return obj;
 },

 getStyle: function () {
  var str = "",
   styles = document.querySelectorAll('style,link');
  for (var i = 0; i < styles.length; i++) {
   str += styles[i].outerHTML;
  }
  str += "<style>" + (this.options.noPrint &#63; this.options.noPrint : '.no-print') + "{display:none;}</style>";
  str += "<style>html,body,div,#preview-main,.report{width:100%!important;height: auto!important;font-size:14px}</style>";

  return str;
 },

 getHtml: function () {
  var inputs = document.querySelectorAll('input');
  var textareas = document.querySelectorAll('textarea');
  var selects = document.querySelectorAll('select');
  var canvass = document.querySelectorAll('canvas');

  for (var k = 0; k < inputs.length; k++) {
   if (inputs[k].type == "checkbox" || inputs[k].type == "radio") {
    if (inputs[k].checked == true) {
     inputs[k].setAttribute('checked', "checked")
    } else {
     inputs[k].removeAttribute('checked')
    }
   } else if (inputs[k].type == "text") {
    inputs[k].setAttribute('value', inputs[k].value)
   } else {
    inputs[k].setAttribute('value', inputs[k].value)
   }
  }

  for (var k2 = 0; k2 < textareas.length; k2++) {
   if (textareas[k2].type == 'textarea') {
    textareas[k2].innerHTML = textareas[k2].value
   }
  }

  for (var k3 = 0; k3 < selects.length; k3++) {
   if (selects[k3].type == 'select-one') {
    var child = selects[k3].children;
    for (var i in child) {
     if (child[i].tagName == 'OPTION') {
      if (child[i].selected == true) {
       child[i].setAttribute('selected', "selected")
      } else {
       child[i].removeAttribute('selected')
      }
     }
    }
   }
  }

  //canvass echars图表转为图片
  for (var k4 = 0; k4 < canvass.length; k4++) {
   var imageURL = canvass[k4].toDataURL("image/png");
   var img = document.createElement("img");
   img.src = imageURL;
   img.setAttribute('style', 'max-width: 100%;');
   img.className = 'isNeedRemove'
   // canvass[k4].style.display = 'none'
   // canvass[k4].parentNode.style.width = '100%'
   // canvass[k4].parentNode.style.textAlign = 'center'
   canvass[k4].parentNode.insertBefore(img,canvass[k4].nextElementSibling);
  }

  return this.dom.outerHTML;
 },

 writeIframe: function (content) {
  var w, doc, iframe = document.createElement('iframe'),
   f = document.body.appendChild(iframe);
  iframe.id = "myIframe";
  //iframe.style = "position:absolute;width:0;height:0;top:-10px;left:-10px;";
  iframe.setAttribute('style', 'position:absolute;width:0;height:0;top:-10px;left:-10px;');
  w = f.contentWindow || f.contentDocument;
  doc = f.contentDocument || f.contentWindow.document;
  doc.open();
  doc.write(content);
  doc.close();
  
  // 避免重复打印echarts
  var removes = document.querySelectorAll('.isNeedRemove');
  for (var k = 0; k < removes.length; k++) {
   removes[k].parentNode.removeChild(removes[k]);
  }

  var _this = this
  iframe.onload = function(){
   _this.toPrint(w);
   setTimeout(function () {
    document.body.removeChild(iframe)
   }, 100)
  }
 },

 toPrint: function (frameWindow) {
  try {
   setTimeout(function () {
    frameWindow.focus();
    try {
     if (!frameWindow.document.execCommand('print', false, null)) {
      frameWindow.print();
     }
    } catch (e) {
     frameWindow.print();
    }
    frameWindow.close();
   }, 10);
  } catch (err) {
   console.log('err', err);
  }
 },
 isDOM: (typeof HTMLElement === 'object') &#63;
  function (obj) {
   return obj instanceof HTMLElement;
  } :
  function (obj) {
   return obj && typeof obj === 'object' && obj.nodeType === 1 && typeof obj.nodeName === 'string';
  }
};
const MyPlugin = {}
MyPlugin.install = function (Vue, options) {
 // 4. 添加实例方法
 Vue.prototype.$print = Print
}
export default MyPlugin

img.className = 'isNeedRemove'


canvass[k4].parentNode.insertBefore(img,canvass[k4].nextElementSibling);


var removes = document.querySelectorAll('.isNeedRemove');

//调用系统打印机
print () {
  this.$print(this.$refs.print) // 使用
},

 <!-- 预览 -->
<Modal v-model="previewModal" fullscreen :mask-closable="false" :closable="false">
  <preview ref="print" :previewEditOldForm="previewEditForm"></preview>
  <div slot="footer" class="btn">
    <Button type="text" @click="closePreview">关闭</Button>
    <Button type="primary" @click="print">打印</Button>
  </div>
</Modal> 

import Preview from '../operation_report/Preview'
export default {
 components: {
     Preview
  }
}

export default {
 data() {
 return{
  previewEditForm: {},
 }
  }
}

// 父组件向子组件传值
 on: {
   click: () => {
     // 父组件向子组件传值
     this.previewEditForm = params.row;
     setTimeout(() => {
       this.$refs.print.queryById();
       this.$refs.print.eventOverviews();
       this.previewModal=true;
     }, 2000)
   }
 }

<style scoped>
  @media print {
    .btn{
      display: none;
    }
  }
</style>