/// <summary>
        /// 获取值
        /// </summary>
        /// <param name="brush">画刷</param>
        /// <returns>画刷</returns>
        public static Brush GetValue(this ISVGBrush brush)
        {
            if (brush == null)
            {
                return(null);
            }

            return(brush.Value);
        }
        /// <summary>
        /// 尝试从url中获取画刷
        /// </summary>
        /// <param name="svg">SVG</param>
        /// <param name="value">颜色</param>
        /// <returns>画刷</returns>
        private Brush Get_URL(SVG svg, string value)
        {
            value = value.Replace(" ", "").Replace("\t", "");
            value = value.Replace("url(#", "").Replace(")", "");

            if (!svg.Resource.ContainsKey(value))
            {
                return(null);
            }

            ISVGBrush brush = svg.Resource[value] as ISVGBrush;

            if (brush == null || brush.Value == null)
            {
                return(null);
            }

            return(brush.Value.Clone());
        }