vue前端實現打印下載示例詳解

npm i html2canvas jspdf
或
yarn add html2canvas jspdf

<template>
  <div>
    <h1 ref="toPdf">
      導出區域
    </h1>
    <button @click="toPdfFn">導出pdf</button>
  </div>
</template>
<script>
import html2canvas from "html2canvas"
import JSPDF from "jspdf"
export default {
 methods:{
  toPdfFn(){
   this.htmlToPdf('文件名','時間')
  },
  htmlToPdf(name,time){
      let element = this.$refs.toPdf
      html2canvas(element, {
        logging: false
      }).then(function(canvas) {
        let pdf = new JSPDF("p", "mm", "a4") // A4紙，縱向
        let ctx = canvas.getContext("2d")
        let a4w = 190;
        let a4h = 277 // A4大小，210mm x 297mm，四邊各保留20mm的邊距，顯示區域190x277
        let imgHeight = Math.floor(a4h * canvas.width / a4w) // 按A4顯示比例換算一頁圖像的像素高度
        let renderedHeight = 0
        while (renderedHeight < canvas.height) {
          let page = document.createElement("canvas")
          page.width = canvas.width
          page.height = Math.min(imgHeight, canvas.height - renderedHeight) // 可能內容不足一頁
          // 用getImageData剪裁指定區域，並畫到前面創建的canvas對象中
          page.getContext("2d").putImageData(ctx.getImageData(0, renderedHeight, canvas.width, Math.min(imgHeight,
            canvas.height - renderedHeight)), 0, 0)
          pdf.addImage(page.toDataURL("image/jpeg", 1.0), "JPEG", 10, 10, a4w, Math.min(a4h, a4w * page.height /
            page.width)) // 添加圖像到頁面，保留10mm邊距
          // 如果後面還有內容，添加一個空頁
          renderedHeight += imgHeight
          if (renderedHeight < canvas.height) {
            pdf.addPage()
          }
        }
        pdf.save(name + time)
      })
    }
 }
}
</script>

   // 打印類屬性、方法定義
/* 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 ? this.options.noPrint : '.no-print') + "{display:none;}</style>";
    return str;
  },
  getHtml: function () {
    var inputs = document.querySelectorAll('input');
    var textareas = document.querySelectorAll('textarea');
    var selects = document.querySelectorAll('select');
    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')
            }
          }
        }
      }
    }
    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();
    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') ?
    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. 添加實例方法
  Vue.prototype.$print = Print
}
export default MyPlugin

  import Vue from "vue";
  import print from "./src/utils/print.js";
  Vue.use(print)

<template>
  <div>
    <h1 ref="print">
      <div>打印區域</div>
    </h1>
    <button @click="printFn">打印</button>
  </div>
</template>
<script>
export default {
  methods: {
    printFn() {
      //傳入dom結構即可
      this.$print(this.$refs.print);
    },
  },
};
</script>

<div class="no-print">不要打印我</div>

<div class="do-not-print-me-xxx">不要打印我</div>
this.$print(this.$refs.print,{'no-print':'.do-not-print-me-xxx'}) // 使用