canvas 移动端生成海报问题及本次项目总结

1、首先设置html及引入静态文件

<div style="display: none;">
        <img src="@/assets/img/personal/sy.png" class="man man-2" id="man-2" alt="">
        <img src="@/assets/img/personal/bj1.png" id="bg1" alt="">
        <img src="@/assets/img/personal/bj2.png" id="bg2" alt="">
        <img src="@/assets/img/personal/[e-mail]" alt="" id="man-1">
        <img alt="" id="man-1">
        <img alt="" id="qrCode">
</div>

2、canvas绘制方法

createdImageFun ():void {
    const man1:any = document.getElementById('man-1')
    const man2 = document.getElementById('man-2')
    let canvasBg = document.getElementById('bg1')
    if (this.schoolName === '' || !this.schoolName) {
      canvasBg = document.getElementById('bg2')
    }
    const qrcodeImg:any = document.getElementById('qrCode')

    const canvas:any = document.getElementById('myCanvas')
    const ctx = canvas.getContext('2d')
    let qrImage = new Image() // 二维码图片
    canvas.width = 375 // bodyDOM.offsetWidth
    canvas.height = 714
    // 制作背景图
    const patBg = ctx.createPattern(canvasBg, 'repeat')
    ctx.rect(0, 0, 375, 714)
    ctx.fillStyle = patBg
    ctx.fill()
    // 将man1,man2,man3,man4,sen1,btn加入画布
    ctx.drawImage(man1, 0, 92, 375, 375)
    ctx.drawImage(man2, 189, 386, 175, 70)
    ctx.drawImage(qrcodeImg, 250, 595, 100, 100) // x ,y ,w, h
    const schoolname = this.schoolName

    const username = this.studentName
    const userid = 'ID:' + this.studentCode
    const memo = this.declaration
    ctx.font = ' 16px MicrosoftYaHei-Bold'
    ctx.fillStyle = '#FFFFFF'
    ctx.fillText(schoolname, 127, 27, 80, 21)
    ctx.fillStyle = '#4A4A4A'
    ctx.fillText(username, 20, 494, 121, 21)
    ctx.fillStyle = '#4A4A4A'
    ctx.fillText(userid, 270, 494, 121, 21)
    ctx.fillStyle = '#00ACF9'
    ctx.fillText(memo, 20, 547, 324, 17)
    const newImg = new Image()
    newImg.src = canvas.toDataURL('image/png')
    canvas.style = 'display: none';
    (document.querySelector('.lpc-creatImg') as HTMLElement).appendChild(newImg)
    this.canvasImgShow = true
    this.dataLoading = false
  }

使用方法：

this.$nextTick(() => {
            var man1:any = document.getElementById('man-1')
            man1.setAttribute('crossOrigin', 'anonymous') // 配置处理图片跨域问题
            man1.src = this.userImage
            var qrImage:any = document.getElementById('qrCode')
            qrImage.setAttribute('crossOrigin', 'anonymous')
            qrImage.src = this.qrImageHref
            setTimeout(() => {
              this.createdImageFun()
            }, 1000)
          })

问题：

从一开始的使用插件html2canvas绘制开始，遇到绘制一屏问题只能放弃；及QRCode生成二维码，domtoimage绘制在安卓及ios有兼容为题，最后选中还是直接用canvas绘制，遗留问题就是有点模糊；

3、其他问题

1⃣️对于line-height问题在安卓显示会有点偏上的问题，用padding撑开高度并配置line-height：normal;

转载于:https://my.oschina.net/lpcysz/blog/3072289