js 导出pdf

首先需要两个插件：

html2canvas：http://html2canvas.hertzen.com/documentation

jsPDF：http://www.rotisedapsales.com/snr/cloud2/website/jsPDF-master/docs/jsPDF.html  

导出代码：DOM是要导出的html节点

html2canvas(DOM).then(canvas => {
        // document.body.appendChild(canvas);
        const imageData = canvas.toDataURL("image/jpeg", 1);
        // eslint-disable-next-line new-cap
        const doc = new jsPDF({ userUnit: 2, unit: "px", format: [canvas.width, canvas.height] });
        doc.addImage(imageData, "jpeg", 0, 0, canvas.width, canvas.height);
        doc.save("应对报告.pdf");
      });

 a4纸分页：

// const domList = document.querySelectorAll('.pdf-report .export-pdf-class')
      // console.log(domList)
      // eslint-disable-next-line new-cap
      // const doc = new jsPDF({ orientation: 'p', unit: 'mm', format: 'a4' })
      // domList.forEach(q => {
      //   console.log(q)
      //   html2canvas(q).then(canvas => {
      //     const imageData = canvas.toDataURL('image/jpeg', 1)
      //     doc.addImage(imageData, 'jpeg', 0, 0, canvas.width, canvas.height)
      //   })
      // })
      // doc.save(`${row.surveyObject}.pdf`)
      // const DOM = this.$refs.webReport
      // html2canvas(DOM).then(canvas => {
      //   const contentWidth = canvas.width
      //   const contentHeight = canvas.height
      //   const pageHeight = contentWidth / 595.23 * 841.89
      //   let leftHeight = contentHeight
      //   let position = 0
      //   const imgWidth = 595.23
      //   const imgHeight = 595.23 / contentWidth * contentHeight
      //   // document.body.appendChild(canvas);
      //   const imageData = canvas.toDataURL('image/jpeg', 1)
      //   // eslint-disable-next-line new-cap
      //   const doc = new jsPDF({ unit: 'pt', format: 'a4' })
      //   if (leftHeight < pageHeight) {
      //     doc.addImage(imageData, 'jpeg', 0, 0, imgWidth, imgHeight)
      //   } else {
      //     while (leftHeight > 0) {
      //       doc.addImage(imageData, 'jpeg', 0, position, imgWidth, imgHeight)
      //       leftHeight -= pageHeight
      //       position -= 841.89
      //       if (leftHeight > 0) {
      //         doc.addPage()
      //       }
      //     }
      //   }
      //   // doc.addImage(imageData, 'jpeg', 0, 0, canvas.width, canvas.height)
      //   doc.save(`${row.surveyObject}.pdf`)
      // })

a0: [1189, 841],
a1: [841, 594],
a2: [594, 420],
a3: [420, 297],
a4: [297, 210], // [841.83, 595.23] unit: 'pt'
a5: [210, 148]

1pt=0.3528mm。

1pt=0.35146mm。

记录学习每一天。