SOURCE

import html2Canvas from 'html2canvas';
import JsPDF from 'jspdf';

export default {
  install(Vue, options) {
    Vue.prototype.getPdf = function(elementId, pdfName) {
      const title = this.htmlTitle || pdfName;
      return new Promise((res, rej) => {
        html2Canvas(document.querySelector(elementId), {
          allowTaint: true
        }).then((canvas) => {
          const contentWidth = canvas.width;
          const contentHeight = canvas.height;
          // 一页pdf显示html页面生成的canvas高度;
          const pageHeight = (contentWidth / 592.28) * 841.89;
          // 未生成pdf的html页面高度
          let leftHeight = contentHeight;
          // 页面偏移
          let 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
          // const imgWidth = 595.28;
          const imgWidth = 575.28;
          const imgHeight = (592.28 / contentWidth) * contentHeight;
          const pageData = canvas.toDataURL('image/jpeg', 1.0);
          const 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', 10, 25, imgWidth, imgHeight);
          } else {
            while (leftHeight > 0) {
              PDF.addImage(pageData, 'JPEG', 10, position, imgWidth, imgHeight);
              leftHeight -= pageHeight;
              position -= 841.89;
              // 避免添加空白页
              if (leftHeight > 0) {
                PDF.addPage();
              }
            }
          }
          PDF.save(title + '.pdf');
          res(true);
        });
      });
    };
  }
};