vue2.0全局组件之pdf详解

目的：像elementui那样注册全局组件 预览pdf文件

技术支持：使用火狐的pdf.js

准备：新建一个cpdf.vue文件，把火狐demo里面的build里面的pdf.js下载来,并且依赖了elementui开发的其实就是用了<el-button>

编写：

template

<template>
  <div class="cpdf">
   <div class="center">
     <div class="contor">
      <el-button @click="prev">上一页</el-button>
      <el-button @click="next">下一页</el-button>    
      <span>page: <span v-text="page_num"></span> / <span v-text="page_count"></span></span>
         
      <el-button @click="addscale" icon="plus"></el-button>
      <el-button @click="minus" icon="minus"></el-button>
      <el-button id="prev" @click="closepdf">关闭</el-button>
     </div>
     <canvas class="canvasstyle" id="the-canvas"></canvas>
   </div>
  </div>
</template>

js

 import pdfjs from '../../../static/pdf/pdf.js'
  import {
   mapactions,
   mapgetters
  } from 'vuex';
  export default {
   name: 'c-pdf',
   props: ['pdfurl'],
   data() {

     return {
      pdfdoc: null, //pdfjs 生成的对象
      pagenum: 1,//
      pagerendering: false,
      pagenumpending: null,
      scale: 1.2,//放大倍数
      page_num: 0,//当前页数
      page_count: 0,//总页数
      maxscale: 2,//最大放大倍数
      minscale: 0.8//最小放大倍数
     }
   },
   methods: {
     renderpage(num) { //渲染pdf
      let vm = this
      this.pagerendering = true;
      let canvas = document.getelementbyid('the-canvas')
      // using promise to fetch the page
      this.pdfdoc.getpage(num).then(function(page) {
        var viewport = page.getviewport(vm.scale);
        //alert(vm.canvas.height)
        canvas.height = viewport.height;
        canvas.width = viewport.width;

        // render pdf page into canvas context
        var rendercontext = {
         canvascontext: vm.ctx,
         viewport: viewport
        };
        var rendertask = page.render(rendercontext);

        // wait for rendering to finish
        rendertask.promise.then(function() {
         vm.pagerendering = false;
         if(vm.pagenumpending !== null) {
           // new page rendering is pending
           vm.renderpage(vm.pagenumpending);
           vm.pagenumpending = null;
         }
        });
      });
      vm.page_num = vm.pagenum;

     },
     addscale() {//放大
      if(this.scale >= this.maxscale) {
        return
      }
      this.scale += 0.1;
      this.queuerenderpage(this.pagenum)
     },
     minus() {//缩小
      if(this.scale <= this.minscale) {
        return
      }
      this.scale -= 0.1;
      this.queuerenderpage(this.pagenum)
     },
     prev() {//上一页
      let vm = this
      if(vm.pagenum <= 1) {
        return;
      }
      vm.pagenum--;
      vm.queuerenderpage(vm.pagenum);
     },
     next() {//下一页
      let vm = this
      if(vm.pagenum >= vm.page_count) {
        return;
      }
      vm.pagenum++;
      vm.queuerenderpage(vm.pagenum);
     },
     closepdf() {//关闭pdf
      this.$emit('closepdf')
     },
     queuerenderpage(num) {
      if(this.pagerendering) {
        this.pagenumpending = num;
      } else {
        this.renderpage(num);
      }
     }
   },
   computed: {
     ctx() {
      let id = document.getelementbyid('the-canvas')
      return id.getcontext('2d');
     }
   },
   mounted() {
     let vm = this
     pdfjs.getdocument(vm.pdfurl).then(function(pdfdoc_) { //初始化pdf
      vm.pdfdoc = pdfdoc_;
      vm.page_count = vm.pdfdoc.numpages
      vm.renderpage(vm.pagenum);
     });
   }
  }

style less

 .cpdf {
   position: fixed;
   top: 0;
   left: 0;
   background-color: rgba(0, 0, 0, .5);
   width: 100%;
   height: 100%;
   z-index: 99999;
   display: flex;
   justify-content: center;
   align-items: center;
   .center {
     text-align: center;
     height: 100%;
     overflow: auto;
     padding-top: 20px;
     .contor {
      margin-bottom: 10px;
     }
   }
  }

注册到全局：在main.js 引入cpdf.vue

vue.component(cpdf.name, cpdf)

使用：在想预览pdf文件的组件里面

<c-pdf @closepdf="closepdf" v-show="isshowpdf" :pdfurl="testpdfurl"></c-pdf>

data() {
     return {
      
      isshowpdf:false,
      testpdfurl:'//cdn.mozilla.net/pdfjs/tracemonkey.pdf'
     }
   },
methods: {

     closepdf(){
      this.isshowpdf=false
     },
}

效果：

 

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