解决canvas导出图片模糊问题

 // 解决导出图片模糊的方法
        toBeCanvas() {
            var copyDom = $("#canvasQR");
            var width = copyDom.offsetWidth; //dom宽
            var height = copyDom.offsetHeight; //dom高
            var scale = 2; //放大倍数
            html2canvas(this.$refs['order'], {
                dpi: window.devicePixelRatio * 2,
                scale: scale,
                width: width,
                heigth: height,
            }).then(canvas => {
                const context = canvas.getContext('2d');
                // 【重要】关闭抗锯齿
                context.mozImageSmoothingEnabled = false;
                context.webkitImageSmoothingEnabled = false;
                context.msImageSmoothingEnabled = false;
                context.imageSmoothingEnabled = false;
                var url = canvas.toDataURL();

                var triggerDownload = $("").attr("href", url).attr("download", "详情.png").appendTo("body");
                triggerDownload[0].click();
                triggerDownload.remove();
            });
        },