对pdfjs-dist进行vue组件封装（svg和canvas两

组件封装

这边以vue-cli3生成的项目为例

1. 安装相关文件

npm install pdfjs-dist@2.4.456 --save

2. 将node_modules中的pdfjs-dist/es5/build，pdfjs-dist/es5/web，pdfjs-dist/cmaps拷贝到public目录下，
   这边也可以将修改好的源码上传到cdn，引用会更加方便。

   
   引入pdfjs-dist

3. (可选) 修改打开电子签章显示的代码
   public/pdfjs-dist/es5/build/pdf.worker.js

   
   pdf.work.js

4. 在components下新建pdf文件夹

   
   pdf

getPdfjsDist代码如下

// src/components/pdf/getPdfjsDist.js
const getJavsScript = (src) => {
  return new Promise((resolve, reject) => {
    const script = document.createElement('script')

    script.onload = resolve
    script.onerror = reject

    script.src = src
    document.body.append(script)
  })
}

const getCss = (href) => {
  return new Promise((resolve, reject) => {
    const link = document.createElement('link')

    link.onload = resolve
    link.onerror = reject

    link.setAttribute('rel', 'stylesheet')
    link.setAttribute('type', 'text/css')
    link.href=href
    document.body.append(link)
  })
}

const getPdfjsDist = (pdfjsDistPath) => {
  return getJavsScript(`${pdfjsDistPath}/pdfjs-dist/es5/build/pdf.js`)
  .then(() => {
    return Promise.all([
      getJavsScript(`${pdfjsDistPath}/pdfjs-dist/es5/web/pdf_viewer.js`),
      getCss(`${pdfjsDistPath}/pdfjs-dist/es5/web/pdf_viewer.css`)
    ])
  })
}

export default getPdfjsDist

index.js代码如下

// src/components/pdf/index.js
import './index.less'
import Pdf from './pdf'

Pdf.install = (Vue) => {
  Vue.component(Pdf.name, Pdf);
};
  

export default Pdf

pdf.js代码如下

// src/components/pdf/pdf.js
import getPdfjsDist from '@/components/pdf/getPdfjsDist'

export default {
  name: 'Pdf',
  props: {
    url: {
      type: String,
      default: ''
    },
    type: {
      type: String,
      default: 'svg'
    },
    pdfjsDistPath: {
      type: String,
      default: '.'
    }
  },
  data() {
    return {
      pdfViewer: null,
      pdfLinkService: null,
      currentScale: 'page-width',
      loadingTask: null
    }
  },

  methods: {
    onPagesInit({source}) {
      source.currentScaleValue = this.currentScale
    },
    async pdfLibInit() {
      let pdfjsLib = window.pdfjsLib;
      let pdfjsViewer = window.pdfjsViewer
      if (!pdfjsLib || !pdfjsViewer) {
        try {
          await getPdfjsDist(this.pdfjsDistPath)
          this.CMAP_URL = `${this.pdfjsDistPath}/pdfjs-dist/cmaps/`
          pdfjsLib = window.pdfjsLib;
          pdfjsLib.GlobalWorkerOptions.workerSrc = `${this.pdfjsDistPath}/pdfjs-dist/es5/build/pdf.worker.js`
          pdfjsViewer = window.pdfjsViewer
        } catch (error) {
          // console.log(error)
          // pdfjs文件获取失败
          return 
        }
      }

      const container = this.$refs.container
      const eventBus = new pdfjsViewer.EventBus();

      // (Optionally) enable hyperlinks within PDF files.
      const pdfLinkService = new pdfjsViewer.PDFLinkService({
        eventBus: eventBus,
      });
      this.pdfLinkService = pdfLinkService
      const pdfViewer = new pdfjsViewer.PDFViewer({
        container: container,
        eventBus: eventBus,
        linkService: pdfLinkService,
        renderer: this.type,
        textLayerMode: 0,
        downloadManager: new pdfjsViewer.DownloadManager({}),
        enableWebGL: true
      });
      this.pdfViewer = pdfViewer
      pdfLinkService.setViewer(pdfViewer);

      eventBus.on("pagesinit", this.onPagesInit);
    },
    renderPdf() {
      if (!this.url) { return }
      // Loading document.
      if (this.pdfViewer === null || this.pdfLinkService === null) {
        return
      }
      if (this.loadingTask !== null) {
        this.loadingTask.destroy()
        this.loadingTask = null
      }
      this.loadingTask = window.pdfjsLib.getDocument({
        cMapUrl: this.CMAP_URL,
        cMapPacked: true,
        url: this.url,
      });
      return this.loadingTask.promise.then((pdfDocument) => {
        if (pdfDocument.loadingTask.destroyed || !this.url) { return }
        this.pdfViewer.setDocument(pdfDocument)
        this.pdfLinkService.setDocument(pdfDocument, null);
        this.loadingTask = null
      }).catch(error => {
        console.log(error)
      });
    }
  },
  mounted() {
    this.pdfLibInit().then(() => {
      this.renderPdf()
    })
  },
  watch: {
    url() {
      // 如果存在pdfViewer则取消渲染
      if(this.pdfViewer) {
        this.pdfViewer._cancelRendering()
      }
      this.renderPdf()
    }
  },
  render() {
    return (
      <div class="pdf-view">
        <div id="viewerContainer" ref="container">
          <div id="viewer" class="pdfViewer" />
        </div>
      </div>
    )
  }
}

最终在组件中使用方式如下：

<div style="width:320px;height:560px">
    <!-- canvas渲染方式 -->
    <pdf url="./helloworld.pdf" type="canvas" />
    <!-- svg渲染方式 -->
    <pdf url="./helloworld.pdf" type="svg" />
</div>

依然未解决的问题

1. 发现使用svg渲染的过程中，依然有部分pdf的电子签章，无法显示出来。暂时也无法解决
2. win10 chrome(版本：62.0.3202.94)
   Funtouch OS PD1803_A_1.20.4 自带浏览器 Mozilla/5.0(Linux;Android 8.1.0;vivo Y83A Build/011019;vw)AppleWebKit/537.36(KHTML, like Gecko)Ghrome/62.0.3202.84 Mobile Safari/537.36 VivoBrowser/8.2.10.0 渲染部分表格会出现黑块