dom-to-image图像失真

dom-to-image.js 修改部分

/**
     * @param {Node} node - The DOM Node object to render
     * @param {Object} options - Rendering options, @see {@link toSvg}
     * @return {Promise} - A promise that is fulfilled with a JPEG image data URL
     * */
    function toJpeg (node, options) {
        options = options || {};
        return draw(node, options)
            .then(function (canvas) {
			// 函数的第二个参数是质量。范围从 0.0 到 1.0
                return canvas.toDataURL('image/jpeg', options.quality || 1.0);
            });
    }

// height: document.getElementById("hwLabelform").scrollHeight,//canvas高
// width: document.getElementById("hwLabelform").scrollWidth, //canvas宽
// scale: 4, //按比例增加分辨率 (2=双倍).
function saveImage(table_id,path_img) {

domtoimage.toPng(document.getElementById(table_id),{height: document.getElementById(table_id).scrollHeight + 20,width: document.getElementById(table_id).scrollWidth + 20,scale: 4,})
            .then(function (dataUrl) {
                var link = document.createElement("a");
                link.download = path_img;
                link.href = dataUrl;
                link.click();
            });
    }