js生成带log的二维码(qrcodejs)

github: qrcodejs

cdn: http://static.runoob.com/assets/qrcode/qrcode.min.js

#qrcode

#qrcode
	margin: 20px

// 生成二维码图片
let tmp = document.createElement('div');
let qrcode = new QRCode(tmp, {
   text: "https://cn.vuejs.org/v2/guide/",
    128,
   height: 128,
   colorDark : "#000000",
   colorLight : "#ffffff",
   useCanvas: true,
   correctLevel : QRCode.CorrectLevel.H
});
// 加载logo
let logo = new Image();
//logo.crossOrigin = 'Anonymous';
//logl.src = 'https://cn.vuejs.org/images/logo.png';
logo.src = 'data:image/png;base64,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';

logo.onload = function () {
   let container = document.getElementById('qrcode');
   let qrImg = qrcode._el.getElementsByTagName('img')[0];
   let canvas = qrcode._el.getElementsByTagName('canvas')[0];
   var ctx = canvas.getContext("2d");
   ctx.drawImage(logo, 128 * 0.5 - 20, 128 * 0.5 - 20, 40, 40);
   qrImg.src = canvas.toDataURL();
   container.appendChild(qrcode._el);
   // 销毁临时dom
   tmp = null;
   qrcode = null;
   logo = null;
}

Canvas画图加载远程图片报错

pen.js:26 Uncaught DOMException: Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.
       at Image.logo.onload (pen.js:33:22)

没有跨域CORS授权也可以在 canvas 中使用图像, 但这样做就会污染(taints)画布。 只要 canvas 被污染, 就不能再从画布中提取数据, 也就是说不能再调用 toBlob(), toDataURL() 和 getImageData() 等方法, 否则会抛出安全错误(security error).
这实际上是为了保护用户的个人信息,避免未经许可就从远程web站点加载用户的图像信息,造成隐私泄漏。

解决方案：

1. 允许远程服务器Access-Control-Allow-Origin开启跨域
2. 图片服务放在同一域名