一、前情提要

1. 需求

仿照e签宝，实现pdf电子签章 => 拿到pdf链接，移动章的位置，获取章的坐标

技术 : 使用fabric + pdfjs-dist + vuedraggable

2. 借鉴

一位大佬的代码仓亏 : 地址

一位大佬写的文章 ：地址

3. 优化

在大佬的代码基础上，进行了些许优化，变的更像e签宝

二、下载

ps : 怕版本不同，导致无法运行，请下载指定版本

1. fabric

fabric : 是一个功能强大且操作简单的 Javascript HTML5 canvas 工具库

npm install fabric@5.3.0

2. pdfjs-dist

npm install pdfjs-dist@2.5.207

问题一

注意 : 最好配置一下babel，因为打包的时候可能会报错

因为babel默认不会转化node_modules中的包，但是pdfjs-dist用了es6的东东

// 安装包
npm install babel-loader @babel/core @babel/preset-env -D

在webpack.config.js中配置

{
  test: /\.js$/,
  loader: 'babel-loader',
  include: [
    resolve('src'),
    // 转化pdfjs-dist，之所以分开写，是因为pdfjs-dist里面有很多es6的语法，但是我们只需要转化pdfjs-dist里面的web文件夹下的js文件
    resolve('node_modules/pdfjs-dist/web/pdf_viewer.js'),
    resolve('node_modules/pdfjs-dist/build/pdf.js'),
    resolve('node_modules/pdfjs-dist/build/pdf.worker.js'),
    resolve('node_modules/pdfjs-dist/build/pdf.worker.entry.js')        ]
},

问题二 

pdf.js文件过大，可以给 .babelrc 加上属性，"compact": false

3. vuedraggable

npm install vuedraggable@2.24.3

三、代码

1. 准备pdf文件

text.pdf 可放置在 src/static 文件夹中

ps : 线上最好让后端返回pdf链接，因为存在pdf跨域问题

2. 大佬的代码

<!-- //?模块说明 =>  合同签章模块 -->
<template>
  <div id="elesign" class="elesign">
    <el-row>
      <el-col :span="4" style="margin-top: 1%">
        <div class="left-title">我的印章</div>
        <draggable
          v-model="mainImagelist"
          :group="{ name: 'itext', pull: 'clone' }"
          :sort="false"
          @end="end"
        >
          <transition-group type="transition">
            <li v-for="item in mainImagelist" :key="item" class="item" style="text-align: center">
              <img :src="item" width="100%;" height="100%" class="imgstyle" />
            </li>
          </transition-group>
        </draggable>
      </el-col>
      <el-col :span="16" style="text-align: center" class="pCenter">
        <div class="page">
          <!-- <el-button class="btn-outline-dark" @click="zoomIn">-</el-button>
          <span style="color: red">{{ (percentage * 100).toFixed(0) + '%' }}</span>
          <el-button class="btn-outline-dark" @click="zoomOut">+</el-button> -->
          <el-button class="btn-outline-dark" @click="prevPage">上一页</el-button>
          <el-button class="btn-outline-dark" @click="nextPage">下一页</el-button>
          <el-button class="btn-outline-dark">{{ pageNum }}/{{ numPages }}页</el-button>
          <el-input-number
            style="margin: 0 5px; border-radius: 5px"
            class="btn-outline-dark"
            v-model="pageNum"
            :min="1"
            :max="numPages"
            label="输入页码"
          ></el-input-number>
          <el-button class="btn-outline-dark" @click="cutover">跳转</el-button>
        </div>
        <canvas id="the-canvas" />
        <!-- 盖章部分 -->
        <canvas id="ele-canvas"></canvas>
        <div class="ele-control" style="margin-bottom: 2%">
          <el-button class="btn-outline-dark" @click="removeSignature">删除签章</el-button>
          <el-button class="btn-outline-dark" @click="clearSignature">清除所有签章</el-button>
          <el-button class="btn-outline-dark" @click="submitSignature">提交所有签章信息</el-button>
        </div>
      </el-col>
      <el-col :span="4" style="margin-top: 1%">
        <div class="left-title">任务信息</div>
        <div style="text-align: center">
          <div>
            <div class="right-item">
              <div class="right-item-title">文件主题</div>
              <div class="detail-item-desc">{{ taskInfo.title }}</div>
            </div>
            <div class="right-item">
              <div class="right-item-title">发起方</div>
              <div class="detail-item-desc">{{ taskInfo.uname }}</div>
            </div>
            <div class="right-item">
              <div class="right-item-title">截止时间</div>
              <div class="detail-item-desc">{{ taskInfo.endtime }}</div>
            </div>
          </div>
        </div>
      </el-col>
    </el-row>
  </div>
</template>
<script>
import draggable from 'vuedraggable';
import { fabric } from 'fabric';
import workerSrc from 'pdfjs-dist/es5/build/pdf.worker.entry';
import * as pdfjsViewer from 'pdfjs-dist/web/pdf_viewer';
const pdfjsLib = require('pdfjs-dist/es5/build/pdf.js');
pdfjsLib.GlobalWorkerOptions.workerSrc = workerSrc;
export default {
  components: { draggable },
  data() {
    return {
      // pdf预览
      pdfUrl: '',
      pdfDoc: null,
      numPages: 1,
      pageNum: 1,
      scale: 2.2,
      pageRendering: false,
      pageNumPending: null,
      sealUrl: '',
      signUrl: '',
      canvas: null,
      ctx: null,
      canvasEle: null,
      whDatas: null,
      mainImagelist: [],
      taskInfo: {}
      // percentage: 1
    };
  },
  computed: {
    hasSigna() {
      if (this.canvasEle && this.canvasEle.getObjects()[0]) {
        return true;
      } else {
        return false;
      }
    }
  },
  created() {
    var that = this;
    that.mainImagelist = [require('@/assets/img/projectCenter/sign.png'), require('@/assets/img/projectCenter/seal.png')];
    that.taskInfo = { title: '测试盖章', uname: '张三', endtime: '2021-09-01 17:59:59' };
    this.setPdfArea();
  },
  mounted() {
    // this.showpdf(this.pdfUrl);
    if (!pdfjsLib.getDocument || !pdfjsViewer.PDFViewer) {
      // eslint-disable-next-line no-alert
      alert('Please build the pdfjs-dist library using\n  `gulp dist-install`');
    }
  },
  methods: {
    // pdf预览
    // zoomIn() {
    //   console.log('缩小');
    //   if (this.scale <= 0.5) {
    //     this.$message.error('已经显示最小比例');
    //   } else {
    //     this.scale -= 0.1;
    //     this.percentage -= 0.1;
    //     this.renderPage(this.pageNum);
    //     this.renderFabric();
    //   }
    // },
    // zoomOut() {
    //   console.log('放大');
    //   if (this.scale >= 2.2) {
    //     this.$message.error('已经显示最大比例');
    //   } else {
    //     this.scale += 0.1;
    //     this.percentage += 0.1;
    //     this.renderPage(this.pageNum);
    //     this.renderFabric();
    //   }
    // },
    renderPage(num) {
      let _this = this;
      this.pageRendering = true;
      return this.pdfDoc.getPage(num).then((page) => {
        let viewport = page.getViewport({ scale: _this.scale }); // 设置视口大小
        _this.canvas.height = viewport.height;
        _this.canvas.width = viewport.width;

        // Render PDF page into canvas context
        let renderContext = {
          canvasContext: _this.ctx,
          viewport: viewport
        };
        let renderTask = page.render(renderContext);
        // Wait for rendering to finish
        renderTask.promise.then(() => {
          _this.pageRendering = false;
          if (_this.pageNumPending !== null) {
            // New page rendering is pending
            this.renderPage(_this.pageNumPending);
            _this.pageNumPending = null;
          }
        });
      });
    },
    queueRenderPage(num) {
      if (this.pageRendering) {
        this.pageNumPending = num;
      } else {
        this.renderPage(num);
      }
    },
    prevPage() {
      this.confirmSignature();
      if (this.pageNum <= 1) {
        return;
      }
      this.pageNum--;
    },
    nextPage() {
      this.confirmSignature();
      if (this.pageNum >= this.numPages) {
        return;
      }
      this.pageNum++;
    },
    cutover() {
      this.confirmSignature();
    },
    // 渲染pdf，到时还会盖章信息，在渲染时，同时显示出来，不应该在切换页码时才显示印章信息
    showpdf(pdfUrl) {
      let caches = JSON.parse(localStorage.getItem('signs')); // 获取缓存字符串后转换为对象
      // console.log(caches);

      if (caches != null) {
        let datas = caches[this.pageNum];
        if (datas != null && datas != undefined) {
          for (let index in datas) {
            this.addSeal(
              datas[index].sealUrl,
              datas[index].left,
              datas[index].top,
              datas[index].index
            );
          }
        }
      }

      this.canvas = document.getElementById('the-canvas');
      this.ctx = this.canvas.getContext('2d');
      pdfjsLib
        .getDocument({ url: pdfUrl, rangeChunkSize: 65536, disableAutoFetch: false })
        .promise.then((pdfDoc_) => {
          this.pdfDoc = pdfDoc_;
          this.numPages = this.pdfDoc.numPages;
          this.renderPage(this.pageNum).then(() => {
            this.renderPdf({
              width: this.canvas.width,
              height: this.canvas.height
            });
          });
          this.commonSign(this.pageNum, true);
        });
    },
    /**
     *  盖章部分开始
     */
    // 设置绘图区域宽高
    renderPdf(data) {
      this.whDatas = data;
      // document.querySelector("#elesign").style.width = data.width + "px";
    },
    // 生成绘图区域
    renderFabric() {
      let canvaEle = document.querySelector('#ele-canvas');
      let pCenter = document.querySelector('.pCenter');
      canvaEle.width = pCenter.clientWidth;
      // canvaEle.height = (this.whDatas.height)*(this.scale);
      canvaEle.height = this.whDatas.height;

      this.canvasEle = new fabric.Canvas(canvaEle);
      let container = document.querySelector('.canvas-container');
      container.style.position = 'absolute';
      container.style.top = '50px';
      // container.style.left = "30%";
    },
    // 相关事件操作哟
    canvasEvents() {
      // 拖拽边界 不能将图片拖拽到绘图区域外
      this.canvasEle.on('object:moving', function (e) {
        var obj = e.target;
        // if object is too big ignore
        if (obj.currentHeight > obj.canvas.height || obj.currentWidth > obj.canvas.width) {
          return;
        }
        obj.setCoords();
        // top-left  corner
        if (obj.getBoundingRect().top < 0 || obj.getBoundingRect().left < 0) {
          obj.top = Math.max(obj.top, obj.top - obj.getBoundingRect().top);
          obj.left = Math.max(obj.left, obj.left - obj.getBoundingRect().left);
        }
        // bot-right corner
        if (
          obj.getBoundingRect().top + obj.getBoundingRect().height > obj.canvas.height ||
          obj.getBoundingRect().left + obj.getBoundingRect().width > obj.canvas.width
        ) {
          obj.top = Math.min(
            obj.top,
            obj.canvas.height - obj.getBoundingRect().height + obj.top - obj.getBoundingRect().top
          );
          obj.left = Math.min(
            obj.left,
            obj.canvas.width - obj.getBoundingRect().width + obj.left - obj.getBoundingRect().left
          );
        }
      });
    },
    // 添加公章
    addSeal(sealUrl, left, top, index) {
      fabric.Image.fromURL(sealUrl, (oImg) => {
        oImg.set({
          left: left,
          top: top,
          // angle: 10,
          scaleX: 0.8,
          scaleY: 0.8,
          index: index
        });
        // oImg.scale(0.5); //图片缩小一
        this.canvasEle.add(oImg);
      });
    },
    // 删除签章
    removeSignature() {
      this.canvasEle.remove(this.canvasEle.getActiveObject());
    },
    // 翻页展示盖章信息
    commonSign(pageNum, isFirst = false) {
      if (isFirst == false) this.canvasEle.remove(this.canvasEle.clear()); // 清空页面所有签章
      let caches = JSON.parse(localStorage.getItem('signs')); // 获取缓存字符串后转换为对象
      // console.log(caches);
      if (caches == null) return false;
      let datas = caches[this.pageNum];
      if (datas != null && datas != undefined) {
        for (let index in datas) {
          this.addSeal(
            datas[index].sealUrl,
            datas[index].left,
            datas[index].top,
            datas[index].index
          );
        }
      }
    },
    // 确认签章位置并保存到缓存
    confirmSignature() {
      let data = this.canvasEle.getObjects(); // 获取当前页面内的所有签章信息
      let caches = JSON.parse(localStorage.getItem('signs')); // 获取缓存字符串后转换为对象

      let signDatas = {}; // 存储当前页的所有签章信息
      let i = 0;
      // let sealUrl = '';
      for (var val of data) {
        signDatas[i] = {
          width: val.width,
          height: val.height,
          top: val.top,
          left: val.left,
          angle: val.angle,
          translateX: val.translateX,
          translateY: val.translateY,
          scaleX: val.scaleX,
          scaleY: val.scaleY,
          pageNum: this.pageNum,
          sealUrl: this.mainImagelist[val.index],
          index: val.index
        };
        i++;
      }
      if (caches == null) {
        caches = {};
        caches[this.pageNum] = signDatas;
      } else {
        caches[this.pageNum] = signDatas;
      }
      localStorage.setItem('signs', JSON.stringify(caches)); // 对象转字符串后存储到缓存
    },
    // 提交数据
    submitSignature() {
      this.confirmSignature();
      // let caches = localStorage.getItem('signs');
      // console.log(JSON.parse(caches));
      return false;
    },
    // 清空数据
    clearSignature() {
      this.canvasEle.remove(this.canvasEle.clear()); // 清空页面所有签章
      localStorage.removeItem('signs'); // 清除缓存
    },
    end(e) {
      this.addSeal(
        this.mainImagelist[e.newDraggableIndex],
        e.originalEvent.layerX,
        e.originalEvent.layerY,
        e.newDraggableIndex
      );
    },
    // 设置PDF预览区域高度
    setPdfArea() {
      this.pdfUrl = './static/text.pdf';
      // this.pdfurl = res.data.data.pdfurl;
      this.$nextTick(() => {
        this.showpdf(this.pdfUrl); // 接口返回的应该还有盖章信息，不只是pdf
      });
    }
  },
  watch: {
    whDatas: {
      handler() {
        const loading = this.$loading({
          lock: true,
          text: 'Loading',
          spinner: 'el-icon-loading',
          background: 'rgba(0, 0, 0, 0.7)'
        });
        if (this.whDatas) {
          // console.log(this.whDatas);
          loading.close();
          this.renderFabric();
          this.canvasEvents();
          let eleCanvas = document.querySelector('#ele-canvas');
          eleCanvas.style = 'border:1px solid #5ea6ef;margin-top: 10px;';
        }
      }
    },
    pageNum: function () {
      this.commonSign(this.pageNum);
      this.queueRenderPage(this.pageNum);
    }
  }
};
</script>
<style lang="scss" scoped>
/*pdf部分*/
#the-canvas {
  margin-top: 10px;
}

html:fullscreen {
  background: white;
}
.elesign {
  display: flex;
  flex: 1;
  flex-direction: column;
  position: relative;
  /* padding-left: 180px; */
  margin: auto;
  /* width:600px; */
}
.page {
  text-align: center;
  margin: 0 auto;
  margin-top: 1%;
}
#ele-canvas {
  /* border: 1px solid #5ea6ef; */
  overflow: hidden;
}
.ele-control {
  text-align: center;
  margin-top: 3%;
}
#page-input {
  width: 7%;
}

@keyframes ani-demo-spin {
  from {
    transform: rotate(0deg);
  }
  50% {
    transform: rotate(180deg);
  }
  to {
    transform: rotate(360deg);
  }
}
/* .loadingclass{
    position: absolute;
    top:30%;
    left:49%;
    z-index: 99;
} */
.left {
  position: absolute;
  top: 42px;
  left: -5px;
  padding: 5px 5px;
  /*border: 1px solid #eee;*/
  /*border-radius: 4px;*/
}
.left-title {
  text-align: center;
  padding-bottom: 10px;
  border-bottom: 1px solid #eee;
}
li {
  list-style-type: none;
  padding: 10px;
}
.imgstyle {
  vertical-align: middle;
  width: 130px;
  border: solid 1px #e8eef2;
  background-image: url('~@/assets/img/projectCenter/tuo.png');
  background-repeat: no-repeat;
}
.right {
  position: absolute;
  top: 7px;
  right: -177px;
  margin-top: 34px;
  padding-top: 10px;
  padding-bottom: 20px;
  width: 152px;
  /*border: 1px solid #eee;*/
  /*border-radius: 4px;*/
}
.right-item {
  margin-bottom: 15px;
  margin-left: 10px;
}
.right-item-title {
  color: #777;
  height: 20px;
  line-height: 20px;
  font-size: 12px;
  font-weight: 400;
  text-align: left !important;
}
.detail-item-desc {
  color: #333;
  line-height: 20px;
  width: 100%;
  font-size: 12px;
  display: inline-block;
  text-align: left;
}
.btn-outline-dark {
  color: #0f1531;
  background-color: transparent;
  background-image: none;
  border: 1px solid #3e4b5b;
}

.btn-outline-dark:hover {
  color: #fff;
  background-color: #3e4b5b;
  border-color: #3e4b5b;
}
</style>

3. 优化后的代码 

<!-- //?模块说明 =>  合同签章模块 addToTab-->
<template>
  <div class="contract-signature-view">
    <div class="title-operation">
      <h2 class="title">合同签章</h2>
      <div class="operation">
        <el-button type="danger" @click="removeSignature">删除签章</el-button>
        <el-button type="danger" @click="clearSignature">清空签章</el-button>
        <el-button type="primary" @click="submitSignature">提交签章</el-button>
      </div>
    </div>
    <div class="section-box">
      <!-- 签章图片 -->
      <aside class="signature-img">
        <div class="info">
          <h3 class="name">印章</h3>
          <p class="text">将示例印章标识拖到文件相应区域即可获取签章位置</p>
        </div>
        <!-- 拖拽 -->
        <draggable
          v-model="mainImagelist"
          :group="{ name: 'itext', pull: 'clone' }"
          :sort="false"
          @end="end"
        >
          <transition-group type="transition">
            <li
              v-for="item in mainImagelist"
              :key="item.img"
              class="item"
              style="text-align: center"
            >
              <img :src="item.img" width="100%;" height="100%" class="img" />
            </li>
          </transition-group>
        </draggable>
      </aside>
      <!-- 主体区域 -->
      <section class="main-layout" :class="{ 'is-first': isFirst }">
        <!-- 操作 -->
        <div class="operate-box">
          <div class="slider-box">
            <el-slider
              class="slider"
              v-model="scale"
              :min="0.5"
              :max="2"
              :step="0.1"
              :show-tooltip="false"
              @change="sliderChange"
            />
            <span class="scale-value">{{ (scale * 100).toFixed(0) + '%' }}</span>
          </div>
          <div class="page-change">
            <i class="icon el-icon-arrow-left" @click="prevPage" />
            <!-- :min="1" -->
            <el-input
              class="input-box"
              v-model.number="pageNum"
              :max="defaultNumPages"
              @change="cutover"
            />
            <span class="default-text">/{{ defaultNumPages }}</span>
            <i class="icon el-icon-arrow-right" @click="nextPage" />
          </div>
        </div>
        <!-- 画图 -->
        <div class="out-view" :class="{ 'is-show': isShowPdf }">
          <div class="canvas-layout" v-for="item in numPages" :key="item">
            <!-- pdf部分 -->
            <canvas class="the-canvas" />
            <!-- 盖章部分 -->
            <canvas class="ele-canvas"></canvas>
          </div>
        </div>
        <i class="loading" v-loading="!isShowPdf" />
      </section>
      <!-- 位置信息 -->
      <div class="position-info">
        <h3 class="title">位置信息</h3>
        <ul class="nav">
          <li class="item" v-for="(item, index) in coordinateList" :key="index">
            <span>{{ item.name }}</span>
            <span>{{ item.page }}</span>
            <span>{{ item.left }}</span>
            <span>{{ item.top }}</span>
          </li>
        </ul>
      </div>
    </div>
  </div>
</template>
<script>
// 拖拽插件
import draggable from 'vuedraggable';
// pdf插件
import { fabric } from 'fabric';
import workerSrc from 'pdfjs-dist/es5/build/pdf.worker.entry';
const pdfjsLib = require('pdfjs-dist/es5/build/pdf.js');
pdfjsLib.GlobalWorkerOptions.workerSrc = workerSrc;

export default {
  components: { draggable },
  data() {
    return {
      // pdf地址
      pdfUrl: '',
      // 左侧签章列表
      mainImagelist: [],
      // 右侧坐标数据
      coordinateList: [{ name: '名称', page: '所在页面', left: 'x坐标', top: 'Y坐标' }],
      // 总页数
      numPages: 1,
      defaultNumPages: 1,
      // 当前页
      pageNum: 1,
      // 缩放比例
      scale: 1,
      // pdf是否显示
      isFirst: true,
      isShowPdf: false,
      // pdf最外层的out-view
      outViewDom: null,
      // 各页pdf的canvas-layout
      canvasLayoutTopList: [],
      // 用来签章的canvas数组
      canvasEle: [],
      // 绘图区域的宽高
      whDatas: null,
      // pdf渲染的canvas数组
      canvas: [],
      // pdf渲染的canvas的ctx数组
      ctx: [],
      // pdf渲染的canvas的宽高
      pdfDoc: null,
      // 隐藏的input，用来提交数据
      shadowInputValue: ''
    };
  },
  created() {
    this.mainImagelist = [
      { name: '印章', img: require('@/assets/img/projectCenter/contract-sign-img.png') }
      // { name: '印章', img: require('./sign.png') },
      // { name: '红章', img: require('@/assets/img/projectCenter/seal.png') }
    ];
    this.setPdfArea();
  },
  mounted() {},
  methods: {
    /**
     * pdf相关部分
     */
    // 设置PDF地址
    setPdfArea() {
      // // 1. 获取地址栏
      // const urlString = window.location.href;
      // // 2. 截取地址栏
      // const pdfStr = urlString.split('?')[1];
      // // 3. 截取pdf地址并解码
      // this.pdfUrl = decodeURIComponent(pdfStr.split('=')[1]);

      this.pdfUrl = './static/text.pdf';
      this.$nextTick(() => {
        this.showpdf(this.pdfUrl); // 接口返回的应该还有盖章信息，不只是pdf
      });
    },
    // 解析pdf
    showpdf(pdfUrl) {
      pdfjsLib
        .getDocument({ url: pdfUrl, rangeChunkSize: 65536, disableAutoFetch: false })
        .promise.then((pdfDoc_) => {
          this.pdfDoc = pdfDoc_;
          this.numPages = this.pdfDoc.numPages;
          this.defaultNumPages = this.pdfDoc.numPages;
          this.$nextTick(() => {
            this.canvas = document.querySelectorAll('.the-canvas');
            this.canvas.forEach((item) => {
              this.ctx.push(item.getContext('2d'));
            });
            // 循环渲染pdf
            for (let i = 1; i <= this.numPages; i++) {
              this.renderPage(i).then(() => {
                this.renderPdf({
                  width: this.canvas[i - 1].width,
                  height: this.canvas[i - 1].height
                });
              });
            }
            setTimeout(() => {
              this.renderFabric();
              this.canvasEvents();
            }, 1000);
          });
        });
    },
    // 设置pdf宽高，缩放比例，渲染pdf
    renderPage(num) {
      // console.log('this.canvas', this.canvas[num], num);
      return this.pdfDoc.getPage(num).then((page) => {
        const viewport = page.getViewport({ scale: this.scale }); // 设置视口大小
        this.canvas[num - 1].height = viewport.height;
        this.canvas[num - 1].width = viewport.width;
        // Render PDF page into canvas context
        const renderContext = {
          canvasContext: this.ctx[num - 1],
          viewport: viewport
        };
        page.render(renderContext);
      });
    },
    // 设置绘图区域宽高
    renderPdf(data) {
      this.whDatas = data;
    },
    // 生成绘图区域
    renderFabric() {
      // 1. 拿到全部的canvas-layout
      const canvasLayoutDom = document.querySelectorAll('.canvas-layout');
      // 2. 循环遍历
      canvasLayoutDom.forEach((item) => {
        this.canvasLayoutTopList.push({ obj: item, top: item.offsetTop });
        // 3. 设置宽高和居中
        item.style.width = this.whDatas.width + 'px';
        item.style.height = this.whDatas.height + 'px';
        item.style.margin = '0 auto 18px';
        item.style.boxShadow = '4px 4px 4px #e9e9e9';

        // 4. 拿到盖章canvas
        const canvasEle = item.querySelector('.ele-canvas');
        // 5. 拿到pdf的canvas
        const pCenter = item.querySelector('.the-canvas');
        // 6. 设置盖章canvas的宽高
        canvasEle.width = pCenter.clientWidth;
        canvasEle.height = this.whDatas.height;
        // 7. 创建fabric对象并存储
        this.canvasEle.push(new fabric.Canvas(canvasEle));
        // 8. 设置盖章canvas的样式
        const container = item.querySelector('.canvas-container');
        container.style.position = 'absolute';
        container.style.left = '50%';
        container.style.transform = 'translateX(-50%)';
        container.style.top = '0px';
      });

      // 现形
      this.isFirst = false;
      this.isShowPdf = true;
      this.outViewDom = document.querySelector('.out-view');
      // 开启监听窗口滚动
      this.outViewScroll();
    },
    // 开启监听窗口滚动
    outViewScroll() {
      this.outViewDom.addEventListener('scroll', this.outViewRun);
    },
    // 关闭监听窗口滚动
    outViewScrollClose() {
      this.outViewDom.removeEventListener('scroll', this.outViewRun);
    },
    // 窗口滚动
    outViewRun() {
      const scrollTop = this.outViewDom.scrollTop;
      const topList = this.canvasLayoutTopList.map((item) => item.top);
      // 增加一个最大值
      topList.push(Number.MAX_SAFE_INTEGER);
      for (let index = 0; index < topList.length; index++) {
        const element = topList[index];
        if (element <= scrollTop && scrollTop < topList[index + 1]) {
          this.pageNum = index + 1;
          break;
        }
      }
    },
    // scale滑块,重新渲染整个pdf
    sliderChange() {
      this.pageNum = 1;
      this.numPages = 0;
      this.canvasLayoutTopList = [];
      this.canvasEle = [];
      this.ctx = [];
      this.canvas = [];
      this.isShowPdf = false;
      // this.outViewScrollClose();
      this.whDatas = null;
      this.coordinateList = [{ name: '名称', page: '所在页面', left: 'x坐标', top: 'Y坐标' }];
      this.getSignatureJson();
      setTimeout(() => {
        this.numPages = this.pdfDoc.numPages;
        this.$nextTick(() => {
          this.canvas = document.querySelectorAll('.the-canvas');
          this.canvas.forEach((item) => {
            this.ctx.push(item.getContext('2d'));
          });
          // 循环渲染pdf
          for (let i = 1; i <= this.numPages; i++) {
            this.renderPage(i).then(() => {
              this.renderPdf({
                width: this.canvas[i - 1].width,
                height: this.canvas[i - 1].height
              });
            });
          }
          setTimeout(() => {
            this.renderFabric();
            this.canvasEvents();
          }, 1000);
        });
      }, 1000);
    },
    /**
     * 签章相关部分
     */
    // 签章拖拽边界处理，不能将图片拖拽到绘图区域外
    canvasEvents() {
      this.canvasEle.forEach((item) => {
        item.on('object:moving', (e) => {
          const obj = e.target;
          // if object is too big ignore
          if (obj.currentHeight > obj.canvas.height || obj.currentWidth > obj.canvas.width) {
            return;
          }
          obj.setCoords();
          // top-left  corner
          if (obj.getBoundingRect().top < 0 || obj.getBoundingRect().left < 0) {
            obj.top = Math.max(obj.top, obj.top - obj.getBoundingRect().top);
            obj.left = Math.max(obj.left, obj.left - obj.getBoundingRect().left);
          }
          // bot-right corner
          if (
            obj.getBoundingRect().top + obj.getBoundingRect().height > obj.canvas.height ||
            obj.getBoundingRect().left + obj.getBoundingRect().width > obj.canvas.width
          ) {
            obj.top = Math.min(
              obj.top,
              obj.canvas.height - obj.getBoundingRect().height + obj.top - obj.getBoundingRect().top
            );
            obj.left = Math.min(
              obj.left,
              obj.canvas.width - obj.getBoundingRect().width + obj.left - obj.getBoundingRect().left
            );
          }
          // console.log('obj.cacheKey',obj.cacheKey);
          const findIndex = this.coordinateList
            .slice(1)
            .findIndex((coord) => coord.cacheKey == obj.cacheKey);
          const keys = ['width', 'height', 'top', 'left', 'angle', 'scaleX', 'scaleY'];
          keys.forEach((item) => {
            this.coordinateList[findIndex + 1][item] = Math.ceil(obj[item] / this.scale);
          });
          this.getSignatureJson();
        });
      });
    },
    // 拖拽结束
    end(e) {
      // 找到当前拖拽到哪一个canvas-layout上
      const currentCanvasLayout = e.originalEvent.target.parentElement.parentElement;
      const findIndex = this.canvasLayoutTopList.findIndex(
        (item) => item.obj == currentCanvasLayout
      );
      if (findIndex == -1) return false;
      // 取整
      const left = e.originalEvent.layerX < 0 ? 0 : Math.ceil(e.originalEvent.layerX / this.scale);
      const top = e.originalEvent.layerY < 0 ? 0 : Math.ceil(e.originalEvent.layerY / this.scale);
      // console.log('e', e, findIndex);
      this.addSeal({
        sealUrl: this.mainImagelist[e.newDraggableIndex].img,
        left,
        top,
        index: e.newDraggableIndex,
        pageNum: findIndex
      });
    },
    // 添加公章
    addSeal({ sealUrl, left, top, index, pageNum }) {
      fabric.Image.fromURL(sealUrl, (oImg) => {
        oImg.set({
          // 距离左边的距离
          left: left,
          // 距离顶部的距离
          top: top,
          // 角度
          // angle: 10,
          // 缩放比例，需要乘以scale
          scaleX: 0.8 * this.scale,
          scaleY: 0.8 * this.scale,
          index,
          // 禁止缩放
          lockScalingX: true,
          lockScalingY: true,
          // 禁止旋转
          lockRotation: true
        });
        this.canvasEle[pageNum].add(oImg);
        // 保存签章信息
        this.saveSignature({ pageNum, index, sealUrl });
      });
      // this.removeActive();
    },
    // 保存签章
    saveSignature({ pageNum, index, sealUrl }) {
      // 1. 拿到当前签章的信息
      let length = 0;
      let pageConfig = this.coordinateList.filter((item) => item.page - 1 == pageNum);
      if (pageConfig) length = pageConfig.length;
      const currentSignInfo = this.canvasEle[pageNum].getObjects()[length];
      // 2. 拼接数据
      const keys = ['width', 'height', 'top', 'left', 'angle', 'scaleX', 'scaleY'];
      const obj = {};
      keys.forEach((item) => {
        obj[item] = Math.ceil(currentSignInfo[item] / this.scale);
      });
      obj.cacheKey = currentSignInfo.cacheKey;
      obj.sealUrl = sealUrl;
      obj.index = index;
      obj.name = `${this.mainImagelist[index].name}${this.coordinateList.length}`;
      obj.page = pageNum + 1;
      this.coordinateList.push(obj);
      this.getSignatureJson();
    },
    // 签章生成json字符串
    getSignatureJson() {
      // 1. 判断是否有签章
      if (this.coordinateList.length <= 1) return (this.shadowInputValue = '');
      // 2. 拿到签章的信息，去除第一条
      const signatureList = this.coordinateList.slice(1);
      // 3. 拼接数据，只要left和top和page
      const keys = ['page', 'left', 'top'];
      const arr = [];
      signatureList.forEach((item) => {
        const obj = {};
        keys.forEach((key) => {
          obj[key] = item[key];
        });
        arr.push(obj);
      });
      // 4. 转成json字符串
      this.shadowInputValue = JSON.stringify(arr);
    },
    /**
     * 操作相关部分
     */
    // 上一页
    prevPage() {
      if (this.pageNum <= 1) return;
      this.pageNum--;
      // 滚动到指定位置
      this.outViewDom.scrollTop = this.canvasLayoutTopList[this.pageNum - 1].top;
    },
    // 下一页
    nextPage() {
      if (this.pageNum >= this.numPages) return;
      this.pageNum++;
      // 滚动到指定位置
      this.outViewDom.scrollTop = this.canvasLayoutTopList[this.pageNum - 1].top;
    },
    // 切换页码
    cutover() {
      this.outViewScrollClose();
      if (this.pageNum < 1) {
        this.pageNum = 1;
      } else if (this.pageNum > this.numPages) {
        this.pageNum = this.numPages;
      }
      // 滚动到指定位置
      this.outViewDom.scrollTop = this.canvasLayoutTopList[this.pageNum - 1].top;
      setTimeout(() => {
        this.outViewScroll();
      }, 500);
    },
    // 删除所有的签章选中状态
    removeActive() {
      this.canvasEle.forEach((item) => {
        item.discardActiveObject().renderAll();
      });
    },
    // 删除签章
    removeSignature() {
      // 1. 判断是否有选中的签章
      const findItem = this.canvasEle.filter((item) => item.getActiveObject());
      // 2. 判断选中签章的个数
      if (findItem.length == 0) return this.$message.error('请选择要删除的签章');
      // 3. 判断选中签章的个数是否大于1
      if (findItem.length > 1) {
        this.removeActive();
        return this.$message.error('只能选择删除一个签章,请重新选择');
      }
      // 4. 拿到选中的签章的cacheKey
      const activeObj = findItem[0].getActiveObject();
      const findIndex = this.coordinateList.findIndex(
        (item) => item.cacheKey == activeObj.cacheKey
      );
      // 5. 删除选中的签章
      findItem[0].remove(activeObj);
      // 6. 删除选中的签章的信息
      this.coordinateList.splice(findIndex, 1);
      this.getSignatureJson();
    },
    // 清空签章
    clearSignature() {
      this.canvasEle.forEach((item) => {
        item.clear();
      });
      this.coordinateList = [{ name: '名称', page: '所在页面', left: 'x坐标', top: 'Y坐标' }];
      this.getSignatureJson();
    },
    // 提交数据
    submitSignature() {
      console.log('this.coordinateList', this.coordinateList);
    }
  }
};
</script>
<style lang="scss" scoped>
.contract-signature-view {
  /*pdf部分*/
  .ele-canvas {
    overflow: hidden;
  }
  .title-operation {
    height: 80px;
    padding: 20px 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    .title {
      font-size: 20px;
      font-weight: 600;
    }
    border-bottom: 1px solid #e4e4e4;
  }
  .section-box {
    position: relative;
    display: flex;
    height: calc(100vh - 60px);

    .signature-img {
      width: 240px;
      min-width: 240px;
      background-color: #fff;
      padding: 40px 15px;

      border-right: 1px solid #e4e4e4;
      .info {
        margin-bottom: 38px;
        .name {
          font-size: 18px;
          font-weight: 600;
          color: #000000;
          line-height: 25px;
          margin-bottom: 20px;
        }
        .text {
          font-size: 14px;
          color: #000000;
          line-height: 20px;
        }
      }
      .item {
        padding: 10px;
        border: 1px dashed rgba(0, 0, 0, 0.3);
        &:not(:last-child) {
          margin-bottom: 10px;
        }
        .img {
          vertical-align: middle;
          width: 120px;
          background-repeat: no-repeat;
        }
      }
    }
    .main-layout {
      flex: 1;
      background-color: #f7f8fa;
      position: relative;

      &.is-first {
        .operate-box {
          opacity: 0;
        }
      }
      .operate-box {
        opacity: 1;
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 40px;
        background-color: #fff;
        border-bottom: 1px solid #e4e4e4;
        display: flex;
        justify-content: center;
        align-items: center;
        .slider-box {
          width: 230px;
          display: flex;
          justify-content: center;
          align-items: center;
          border-left: 1px solid #e4e4e4;
          border-right: 1px solid #e4e4e4;
          .slider {
            width: 120px;
          }
          .scale-value {
            margin-left: 24px;
            font-size: 16px;
            color: #000000;
            line-height: 22px;
          }
        }
        .page-change {
          display: flex;
          align-items: center;
          margin-left: 30px;
          .icon {
            cursor: pointer;
            padding: 0 5px;
            color: #c1c1c1;
          }
          .input-box {
            border: none;
            /deep/ .el-input__inner {
              width: 34px;
              height: 20px;
              border: none;
              padding: 0;
              text-align: center;
              border-bottom: 1px solid #e4e4e4;
            }
          }
          .default-text {
            display: flex;
            line-height: 22px;
            margin-right: 5px;
          }
        }
      }
      .out-view {
        height: calc(100vh - 100px);
        margin: 40px auto;
        overflow-x: auto;
        overflow-y: auto;
        padding-top: 20px;
        text-align: center;
        opacity: 0;
        transition: all 0.5s;
        &.is-show {
          opacity: 1;
        }
        .canvas-layout {
          position: relative;
          text-align: center;
          margin: 0 auto 18px;
        }
      }
      .loading {
        width: 20px;
        height: 20px;
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        z-index: 999;
        /deep/ .el-loading-mask {
          background-color: transparent;
        }
      }
    }
    .position-info {
      width: 355px;
      min-width: 355px;
      border-left: 1px solid #e4e4e4;
      background-color: #fff;
      padding: 14px 15px;
      .title {
        font-size: 14px;
        font-weight: 400;
        color: #000000;
        line-height: 20px;
        padding-bottom: 18px;
      }
      .nav {
        display: flex;
        flex-direction: column;
        .item {
          display: flex;
          justify-content: space-between;
          padding: 10px 0;
          border-bottom: 1px solid #eee;
          &:first-child {
            background-color: #f7f8fa;
          }
          span {
            flex: 1;
            text-align: center;
            font-size: 12px;
            color: #000000;
            line-height: 20px;
          }
        }
      }
    }
  }
}
</style>