C# 给图片添加文字水印

        /// <summary>
        /// 文字水印
        /// </summary>
        /// <param name="filename">保存文件名</param>
        /// <param name="watermarkText">水印文字</param>
        /// <param name="watermarkStatus">图片水印位置 0=不使用 1=左上 2=中上 3=右上 4=左中  9=右下</param>
        /// <param name="fontsize">字体大小</param>
        public static void AddImageSignText(string fileName, string watermarkText, int watermarkStatus, Font drawFont, SolidBrush brush)
        {
            System.Drawing.Image img = System.Drawing.Image.FromFile(fileName);
            Bitmap map = new Bitmap(img);
            Graphics g = Graphics.FromImage(map);
            SizeF crSize = g.MeasureString(watermarkText, drawFont);

            float xpos = 0;
            float ypos = 0;

            switch (watermarkStatus)
            {
                case 1:
                    xpos = (float)img.Width * (float).01;
                    ypos = (float)img.Height * (float).01;
                    break;
                case 2:
                    xpos = ((float)img.Width * (float).50) - (crSize.Width / 2);
                    ypos = (float)img.Height * (float).01;
                    break;
                case 3:
                    xpos = ((float)img.Width * (float).99) - crSize.Width;
                    ypos = (float)img.Height * (float).01;
                    break;
                case 4:
                    xpos = (float)img.Width * (float).01;
                    ypos = ((float)img.Height * (float).50) - (crSize.Height / 2);
                    break;
                case 5:
                    xpos = ((float)img.Width * (float).50) - (crSize.Width / 2);
                    ypos = ((float)img.Height * (float).50) - (crSize.Height / 2);
                    break;
                case 6:
                    xpos = ((float)img.Width * (float).99) - crSize.Width;
                    ypos = ((float)img.Height * (float).50) - (crSize.Height / 2);
                    break;
                case 7:
                    xpos = (float)img.Width * (float).01;
                    ypos = ((float)img.Height * (float).99) - crSize.Height;
                    break;
                case 8:
                    xpos = ((float)img.Width * (float).50) - (crSize.Width / 2);
                    ypos = ((float)img.Height * (float).99) - crSize.Height;
                    break;
                case 9:
                    xpos = ((float)img.Width * (float).99) - crSize.Width;
                    ypos = ((float)img.Height * (float).99) - crSize.Height;
                    break;
            }
            img.Dispose();
            g.DrawString(watermarkText, drawFont, brush, xpos + 1, ypos + 1);
            g.InterpolationMode = InterpolationMode.HighQualityBilinear;
            map.Save(fileName);
            drawFont.Dispose();
            g.Dispose();

        }

调用的代码：

 　　　　　　 string path = "D:\\images";
            SolidBrush brush = new SolidBrush(Color.Yellow);
            Font font = new Font("宋体", 42, System.Drawing.FontStyle.Bold);
            string datastr = $"天气:晴朗\n紫外线:强\n时间:{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")}";
            //判断是否存在
            if (Directory.Exists(path))
            {
                System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(path);
                var files = di.GetFiles();
                if (files != null)
                {
                    foreach (var item in files.ToList())
                    {
                        AddImageSignText(item.FullName, datastr, 3, font, brush);
                    }
                }
            }