qr.js

    drawQr: function(content) {
        var that = this,
            scale = 750/500,
            w = this.sysinfo.windowWidth / scale;
        qr.api.draw(content, "qrcode", w, w, function (ctx) {
            setTimeout(function () {
                wx.canvasToTempFilePath({
                    canvasId: ctx.canvasId,
                    success: res => {
                        that.setData({
                            qrSrc: res.tempFilePath,
                        });
                        setTimeout(function() {
                            // that.qrShowing = false;
                            that.animation
                                .rotate(10).step()
                                .rotate(25).step()
                                .rotate(0).top("-550rpx").step({ duration: 250 });
                            that.setData({qrAnimation: that.animation.export()});
                        }, 1000);
                    }
                })
            }, 500);
        });
    },