vue使用pdfjs显示PDF可复制的实现方法

npm install pdfjs-dist

import PDFJS from 'pdfjs-dist';

PDFJS.GlobalWorkerOptions.workerSrc = 'pdfjs-dist/build/pdf.worker.js';

<template>
  <!--<button @click="scalBig">放大</button>-->
  <!--<button @click="scalSmall">缩小</button>-->
  <!--<p>页码{{`${pageNo}/${totals.length}`}}</p>-->
  <div class="drag-box" id="dragBox" @scroll="scrollfun($event)">
   <el-scrollbar style="height: 100%;overflow-y: hidden;">
   <div class="wrapper" id="pdf-container">
    <div v-for="item in totals" :id="`page-${item}`" :key="item" class="pdf-box">
     <canvas :id="'canvas-pdf-' + item" class="canvas-pdf"></canvas>
    </div>
   </div>
   </el-scrollbar>
  </div>
</template>

<script>
import PDFJS from 'pdfjs-dist'
import { TextLayerBuilder } from 'pdfjs-dist/web/pdf_viewer'
import 'pdfjs-dist/web/pdf_viewer.css'
export default {
 name: 'showPdf',
 props: ['pdfUrl'],
 data () {
  return {
   scale: 1.4,
   totals: [],
   pageNo: 1,
   viewHeight: 0
  }
 },
 mounted () {
  this.renderPdf(this.scale)
 },
 watch: {
  scale (val) {
   this.totals = []
   this.renderPdf(val)
  }
 },
 methods: {
  renderPdf (scale) {
   PDFJS.workerSrc = require('pdfjs-dist/build/pdf.worker.min')
   // 当 PDF 地址为跨域时，pdf 应该已流的形式传输，否则会出现pdf损坏无法展示
   PDFJS.getDocument(this.pdfUrl).then(pdf => {
    // 得到PDF的总的页数
    let totalPage = pdf.numPages
    let idName = 'canvas-pdf-'
    // 根据总的页数创建相同数量的canvas
    this.createCanvas(totalPage, idName)
    for (let i = 1; i <= totalPage; i++) {
     pdf.getPage(i).then((page) => {
      let pageDiv = document.getElementById(`page-${i}`)
      let viewport = page.getViewport(scale)
      let canvas = document.getElementById(idName + i)
      let context = canvas.getContext('2d')
      canvas.height = viewport.height
      canvas.width = viewport.width
      this.viewHeight = viewport.height
      let renderContext = {
       canvasContext: context,
       viewport
      }
      // 如果你只是展示pdf而不需要复制pdf内容功能，则可以这样写render
      // page.render(renderContext) 如果你需要复制则像狼蚁网站SEO优化那样写利用text-layer
      page.render(renderContext).then(() => {
       return page.getTextContent()
      }).then((textContent) => {
       // 创建文本图层div
       const textLayerDiv = document.createElement('div')
       textLayerDiv.setAttribute('class', 'textLayer')
       // 将文本图层div添加至每页pdf的div中
       pageDiv.appendChild(textLayerDiv)
       // 创建新的TextLayerBuilder实例
       let textLayer = new TextLayerBuilder({
        textLayerDiv: textLayerDiv,
        pageIndex: page.pageIndex,
        viewport: viewport
       })
       textLayer.setTextContent(textContent)
       textLayer.render()
      })
     })
    }
   })
  },
  createCanvas (totalPages) {
   for (let i = 1; i <= totalPages; i++) {
    this.totals.push(i)
   }
  },
  // 分页
  scrollfun (e) {
   let scrollTop = e.target.scrollTop
   if (scrollTop === 0) {
    this.pageNo = 1
   } else {
    this.pageNo = Math.ceil(scrollTop / this.viewHeight)
   }
  },
  // 放大
  scalBig () {
   this.scale = this.scale + 0.1
  },
  // 缩小
  scalSmall () {
   if (this.scale > 1.2) {
    this.scale = this.scale - 0.1
   }
  }
 }
}
</script>

<style scoped lang="scss">
 .drag-box {
  height: 800px;
 }
 .pdf-box {
  position: relative;
 }
 .el-scrollbar__wrap {
  overflow-x: hidden;
 }
</style>