jspdf的基本用法

代码如下：

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

exportPDF () {
  var title = this.htmlTitle
  html2Canvas(document.querySelector('#pdfDom'), {
    allowTaint: true
  }).then((canvas) => {
    console.log(canvas.width, canvas.height)
    const contentWidth = canvas.width
    const contentHeight = canvas.height
    const pageHeight = (contentWidth / 592.28) * 841.89
    let leftHeight = contentHeight
    let position = 0
    const imgWidth = 841.89
    const imgHeight = (841.89 / contentWidth) * contentHeight
    const pageData = canvas.toDataURL('image/jpeg', 1.0)
    const PDF = new JsPDF('l', 'pt', 'a4')
    if (leftHeight < pageHeight) {
      PDF.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight)
    } else {
      while (leftHeight > 0) {
        PDF.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
        leftHeight -= pageHeight
        position -= 841.89
        if (leftHeight > 0) {
          PDF.addPage()
        }
      }
    }
    PDF.save(title + '.pdf')
  })
},