vue2.0全局组件之pdf

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 http://mozilla.github.io/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> &nbsp; &nbsp;
                        <span>Page: <span v-text="page_num"></span> / <span v-text="page_count"></span></span>
                        &nbsp; &nbsp;
                        <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：