html部分：

//外面最好加个div，这样就可以控制显示在页面上绘制出来的图片的大小
<div style="width:400px">
      <img :src="image" class="img" alt=""/>
      <canvas id="mycanvas" width='750' height='530' class="my-canvas"></canvas>
</div>

js部分：

export default {
data() {
    return {
      image: "",
      nane:'张三',
      zhengshu:'3333333'
    };
  },
  mounted() {
     this.drawPhoto();
  },
  methods: {
    drawPhoto() {
      let canvas = document.getElementById("mycanvas");//创建canvas
      let context = canvas.getContext("2d"); //创建画布
      let img = new Image(); //因为拿不到图片静态资源，所以创建图片标签
      img.setAttribute("crossOrigin", "anonymous"); //解决图片跨域问题,也要放到赋值前，否ze大部分浏览器会报错
      img.src = require("xxx.jpg");
      //加载图片
      img.onload = () => {
        canvas.setAttribute("width",img.width)
        canvas.setAttribute("height",img.height)
        //绘制图片
        context.drawImage(img,0,0,img.width,img.height);
        //字体大小
        context.font = "90px Arial";
        //字体文字，显示位置  图片上需要n个文字就写n个context.fillText(文字,上下,左右);
        context.fillText(this.nane, 420, 1150);
        context.fillText(this.zhengshu, 2700, 1020);
        //合成图片
        this.image = canvas.toDataURL("image/jpg", 1.0);
      };
    },
  }
}

css部分：

<style  scoped>
  .my-canvas{
        position: fixed;
        top: -99999999999px;
        left: -99999999999px;
        z-index: -99999999999;
        opacity: 0;
   }
   .img{
		width: 100%;
		height: auto;
   }
</style>