应用场景:做个投票活动，将参赛者的信息转化成图片截图分享。用户上传图片上传到腾讯云cos桶中，html2canvas只能转换本地资源的图片，涉及跨域的图片无法转换、

解决方法：通过nginx代理转发，

假设你的网站是   http://www.helloworld.com  

把 https://dingzi-1258648408.cos.ap-chengdu.myqcloud.com/upload/f49a6da3-73ea-422a-9b63-7a3e522130e2.png

换成 http://www.helloworld.com/cosImageUrl/upload/f49a6da3-73ea-422a-9b63-7a3e522130e2.png 

这样访问http://www.helloworld.com/cosImageUrl就代理成https://dingzi-1258648408.cos.ap-chengdu.myqcloud.com/

1. 配置nginx,在80端口下的localtion中添加一条配置

   location /cosImageUrl/ { proxy_http_version 1.1; proxy_pass https://dingzi-1258648408.cos.ap-chengdu.myqcloud.com/; add_header Access-Control-Allow-Origin *; add_header Access-Control-Allow-Methods "POST, GET, OPTIONS"; add_header Access-Control-Allow-Headers "Origin, Authorization, Accept"; add_header Access-Control-Allow-Credentials true; }

   　　

2. 图片地址换成http://www.helloworld.com/cosImageUrl/upload/f49a6da3-73ea-422a-9b63-7a3e522130e2.png 
3. vue文件中

    <div ref="imageWrapper" v-if="firstFlag"></div><div class="show_img"> <img :src="dataURL" v-if="!firstFlag" style="width: 100%"></div>

   　　

   import html2canvas from "html2canvas"export default { name: "share", data() { return { firstFlag: true, dataURL: ‘‘, } }, methods: { toImg() { html2canvas(this.$refs.imageWrapper,{useCORS: true}).then(canvas => { let imgUrl = canvas.toDataURL(‘image/png‘); this.dataURL = imgUrl; this.firstFlag = false; }).catch(error => { }) }, }, mounted() { const that = this; that.$nextTick(function () { that.toImg(); }); },