• html,vue转换成PDF


    1,先看html的,直接上代码

    <!DOCTYPE html>
    <html lang="en">
    <head>
      <meta charset="UTF-8">
      <title>Document</title>
      <style>
        #demo{
          background-color: yellow;
           1000px;
          height: 2000px;
          /* margin: auto; */
        }
        .red{
          background-color: red;
           50px;
          height: 50px;
        }
      </style>
    </head>
    <body>
      <div class="demo-container">
        <div id="demo">
          <div class="red"></div>
        </div>    
      </div>
      <button>
        下载简历
      </button>
    </body>
    <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.0.272/jspdf.debug.js"></script>
    <script src="https://cdn.bootcss.com/html2canvas/0.5.0-beta4/html2canvas.js"></script>
    <script>
       function download(){
         window.scrollTo(0,0);   //解决有滚动条的情况图片或者pdf展示不完全
         var element = $("#demo");    // 这个dom元素是要导出pdf的div容器
         var w = element.width();    // 获得该容器的宽
         var h = element.height();    // 获得该容器的高
         var offsetTop = element.offset().top;    // 获得该容器到文档顶部的距离
         var offsetLeft = element.offset().left;    // 获得该容器到文档最左的距离
         var canvas = document.createElement("canvas");
         var abs = 0;
         var win_i = $(window).width();    // 获得当前可视窗口的宽度(不包含滚动条)
         var win_o = window.innerWidth;    // 获得当前窗口的宽度(包含滚动条)
         if(win_o>win_i){
           abs = (win_o - win_i)/2;    // 获得滚动条长度的一半
         }
         canvas.width = w * 2;    // 将画布宽&&高放大两倍
         canvas.height = h * 2;
         var context = canvas.getContext("2d");
         context.scale(2, 2);
         context.translate(-offsetLeft-abs,-offsetTop);    
         // 这里默认横向没有滚动条的情况,因为offset.left(),有无滚动条的时候存在差值,因此        
         // translate的时候,要把这个差值去掉
         html2canvas(element).then(function(canvas) {
          var contentWidth = canvas.width;
          var contentHeight = canvas.height;
          //一页pdf显示html页面生成的canvas高度;
          var pageHeight = contentWidth / 592.28 * 841.89;
          //未生成pdf的html页面高度
          var leftHeight = contentHeight;
          //页面偏移
          var position = 0;
          //a4纸的尺寸[595.28,841.89],html页面生成的canvas在pdf中图片的宽高
          var imgWidth = 595.28;
          var imgHeight = 592.28/contentWidth * contentHeight;
          var pageData = canvas.toDataURL('image/jpeg', 1.0);
          console.log(pageData);
          var pdf = new jsPDF('', 'pt', 'a4');
          //有两个高度需要区分,一个是html页面的实际高度,和生成pdf的页面高度(841.89)
          //当内容未超过pdf一页显示的范围,无需分页
          if (leftHeight < pageHeight) {
          pdf.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight);
          } else {    // 分页
              while(leftHeight > 0) {
                  pdf.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
                  leftHeight -= pageHeight;
                  position -= 841.89;
                  //避免添加空白页
                  if(leftHeight > 0) {
                    pdf.addPage();
                  }
              }
          }
          pdf.save('我的简历.pdf');        
        })
      }
      $("button").click(function(){
        download();
      })
    </script>
    </html>

      2,vue项目中使用

    ①先安装依赖

    第一个.将页面html转换成图片
    npm install --save html2canvas 
    第二个.将图片生成pdf
    npm install jspdf --save

    ②定义工具文件

    /* eslint-disable */
    //不使用JQuery版的
    import html2canvas from 'html2canvas';
    import JsPDF from 'jspdf';
    
    /**
     * @param  ele          要生成 pdf 的DOM元素(容器)
     * @param  padfName     PDF文件生成后的文件名字
     * */
    
    function downloadPDF(ele, pdfName) {
      window.scrollTo(0, 0);
      let eleW = ele.offsetWidth;// 获得该容器的宽
      let eleH = ele.offsetHeight;// 获得该容器的高
      let eleOffsetTop = ele.offsetTop;  // 获得该容器到文档顶部的距离
      let eleOffsetLeft = ele.offsetLeft; // 获得该容器到文档最左的距离
    
      var canvas = document.createElement("canvas");
      var abs = 0;
    
      let win_in = document.documentElement.clientWidth || document.body.clientWidth; // 获得当前可视窗口的宽度(不包含滚动条)
      let win_out = window.innerWidth; // 获得当前窗口的宽度(包含滚动条)
    
      if (win_out > win_in) {
        // abs = (win_o - win_i)/2;    // 获得滚动条长度的一半
        abs = (win_out - win_in) / 2;    // 获得滚动条宽度的一半
        // console.log(a, '新abs');
      }
      canvas.width = eleW * 2;    // 将画布宽&&高放大两倍
      canvas.height = eleH * 2;
    
      var context = canvas.getContext("2d");
      context.scale(2, 2);
      context.translate(-eleOffsetLeft - abs, -eleOffsetTop);
      // 这里默认横向没有滚动条的情况,因为offset.left(),有无滚动条的时候存在差值,因此
      // translate的时候,要把这个差值去掉
    
      // html2canvas(element).then( (canvas)=>{ //报错
      // html2canvas(element[0]).then( (canvas)=>{
      html2canvas(ele, {
        dpi: 300,
        // allowTaint: true,  //允许 canvas 污染, allowTaint参数要去掉,否则是无法通过toDataURL导出canvas数据的
        useCORS: true  //允许canvas画布内 可以跨域请求外部链接图片, 允许跨域请求。
      }).then((canvas) => {
        var contentWidth = canvas.width;
        var contentHeight = canvas.height;
        //一页pdf显示html页面生成的canvas高度;
        var pageHeight = contentWidth / 592.28 * 841.89;
        //未生成pdf的html页面高度
        var leftHeight = contentHeight;
        //页面偏移
        var position = 0;
        //a4纸的尺寸[595.28,841.89],html页面生成的canvas在pdf中图片的宽高
        var imgWidth = 595.28;
        var imgHeight = 595.28 / contentWidth * contentHeight;
        var pageData = canvas.toDataURL('image/jpeg', 1.0);
        var pdf = new JsPDF('', 'pt', 'a4');
        //有两个高度需要区分,一个是html页面的实际高度,和生成pdf的页面高度(841.89)
        //当内容未超过pdf一页显示的范围,无需分页
        if (leftHeight < pageHeight) {
          //在pdf.addImage(pageData, 'JPEG', 左,上,宽度,高度)设置在pdf中显示;
          pdf.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight);
          // pdf.addImage(pageData, 'JPEG', 20, 40, imgWidth, imgHeight);
        } else {    // 分页
          while (leftHeight > 0) {
            pdf.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight);
            leftHeight -= pageHeight;
            position -= 841.89;
            //避免添加空白页
            if (leftHeight > 0) {
              pdf.addPage();
            }
          }
        }
        //可动态生成
        pdf.save(pdfName);
      })
    }
    
    async function previewImg(ele) { // 返回图片base64格式
      window.scrollTo(0, 0);
      let eleW = ele.offsetWidth;// 获得该容器的宽
      let eleH = ele.offsetHeight;// 获得该容器的高
      let eleOffsetTop = ele.offsetTop;  // 获得该容器到文档顶部的距离
      let eleOffsetLeft = ele.offsetLeft; // 获得该容器到文档最左的距离
    
      var canvas = document.createElement("canvas");
      var abs = 0;
    
      let win_in = document.documentElement.clientWidth || document.body.clientWidth; // 获得当前可视窗口的宽度(不包含滚动条)
      let win_out = window.innerWidth; // 获得当前窗口的宽度(包含滚动条)
    
      if (win_out > win_in) {
        abs = (win_out - win_in) / 2;    // 获得滚动条宽度的一半
      }
      canvas.width = eleW * 2;
      canvas.height = eleH * 2;
    
      var context = canvas.getContext("2d");
      context.scale(2, 2);
      context.translate(-eleOffsetLeft - abs, -eleOffsetTop);
      var baseSrc = ''
      await html2canvas(ele, { //等待函数执行完成
        dpi: 300,
        useCORS: true  //允许canvas画布内 可以跨域请求外部链接图片, 允许跨域请求。
      }).then((canvas) => {
        var pageData = canvas.toDataURL('image/jpeg', 1.0);
        baseSrc = pageData
      })
    
      return baseSrc;
    }
    
    export default {
      downloadPDF,
      previewImg
    }

    ③在项目中使用

    <div style="padding: 10px;">
         <el-button type="primary" @click="handlePreview()">预览</el-button>
         <el-button type="primary" @click="handleDown()">下载</el-button>
    </div>
    import htmlToPdf from '@/assets/js/toPdf'
    export default {
      methods: {
         handleDown () {
    htmlToPdf.downloadPDF(document.querySelector('#demo'), '离职申请表')
    },

    handlePreview () {
    htmlToPdf.previewImg(document.querySelector('#demo')).then( res => {
    this.previewUrl = res
    })
    }
      }
    }
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  • 原文地址:https://www.cnblogs.com/mk2016/p/11821794.html
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