图片添加水印字符串，二进制流添加水印字符串

/// <summary>
        /// 文字水印
        /// </summary>
        /// <param name="imgPath">服务器图片相对路径</param>
        /// <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="quality">附加水印图片质量,0-100</param>
        /// <param name="fontsize">字体大小</param>
        /// <param name="fontname">字体</param>
        public void ImageAddWaterMarkStr(string imgPath, string filename, string watermarkText,
            int watermarkStatus, int quality, int fontsize, string fontname = "微软雅黑")
        {
            byte[] _ImageBytes = File.ReadAllBytes(imgPath);
            Image img = Image.FromStream(new System.IO.MemoryStream(_ImageBytes));

            Graphics g = Graphics.FromImage(img);
            Font drawFont = new Font(fontname, fontsize, FontStyle.Regular, GraphicsUnit.Pixel);
            SizeF crSize;
            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;
            }

            g.DrawString(watermarkText, drawFont, new SolidBrush(Color.White), xpos + 1, ypos + 1);
            g.DrawString(watermarkText, drawFont, new SolidBrush(Color.Black), xpos, ypos);

            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
            ImageCodecInfo ici = null;
            foreach (ImageCodecInfo codec in codecs)
            {
                if (codec.MimeType.IndexOf("jpeg") > -1) ici = codec;
            }
            EncoderParameters encoderParams = new EncoderParameters();
            long[] qualityParam = new long[1];
            if (quality < 0 || quality > 100) quality = 80;

            qualityParam[0] = quality;

            EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);
            encoderParams.Param[0] = encoderParam;

            if (ici != null) img.Save(filename, ici, encoderParams);
            else img.Save(filename);

            g.Dispose();
            img.Dispose();
        }

//测试代码
private void 添加水印_Click(object sender, EventArgs e)
        {
            string img = Application.StartupPath + "\app.ico";
            string waterImg = Application.StartupPath + "\waterApp.ico";
            
            ImageAddWaterMarkStr(img, waterImg, "app", 2, 50, 10);
            this.pbWater.Image = Image.FromFile(waterImg);
        }
/// <summary>
        /// 文字水