//新建原始普通大小的bmp

     Bitmap bmCanvas = new Bitmap(imgSrc.Width, imgSrc.Height, PixelFormat.Format24bppRgb);

     Graphics gCanvas = Graphics.FromImage(bmCanvas);

     gCanvas.Clear(Color.White);

     gCanvas.SmoothingMode = SmoothingMode.HighQuality;

     gCanvas.InterpolationMode = InterpolationMode.High;

     //将原始图片加载入画布

     gCanvas.DrawImage(imgSrc, , , imgSrc.Width, imgSrc.Height);

     //计算图片对角线长度

     double diagonal = Math.Sqrt(Math.Pow(width, ) + Math.Pow(height, ));

     //计算对角线倾角

     double angle = Math.Asin(height / Math.Sqrt(Math.Pow(width, ) + Math.Pow(height, ))) / Math.PI * ;

     // 确定水印文字的字体大小

     int[] sizes = new int[]

     {

         , , , , , , , , , , , , , , , , , , ,

         , , , , , , , , , , , , , , , , , , ,

         , , , , , , , , , , , , , , , , , , , , , ,

         , , , , , , , , ,

     };

     Font crFont = null;

     SizeF crSize = new SizeF();

     for (int i = ; i < sizes.Length; i++)

     {

         crFont = new Font("微软雅黑", sizes[i], FontStyle.Bold);

         crSize = gCanvas.MeasureString(watermarkText, crFont);

         if ((int)crSize.Width < (int)diagonal * 0.9)

         {

             break;

         }

     }

     // 生成水印图片（将文字写到图片中）

     //Bitmap bmWaterMark = new Bitmap((int)crSize.Width + 3, (int)crSize.Height + 3, PixelFormat.Format32bppArgb);

     Bitmap bmWaterMark = new Bitmap(width, height, PixelFormat.Format32bppArgb);

     Graphics gWaterMark = Graphics.FromImage(bmWaterMark);

     gWaterMark.TranslateTransform(width / , height / );

     gWaterMark.RotateTransform(-(int)angle);

     gWaterMark.TranslateTransform(-crSize.Width / , -crSize.Height / );

     PointF pt = new PointF(, );

     // 画阴影文字

     Brush transparentBrush0 = new SolidBrush(Color.FromArgb(, Color.Black));

     Brush transparentBrush1 = new SolidBrush(Color.FromArgb(, Color.Black));

     gWaterMark.DrawString(watermarkText, crFont, transparentBrush0, pt.X, pt.Y + );

     gWaterMark.DrawString(watermarkText, crFont, transparentBrush0, pt.X + , pt.Y);

     gWaterMark.DrawString(watermarkText, crFont, transparentBrush1, pt.X + , pt.Y + );

     gWaterMark.DrawString(watermarkText, crFont, transparentBrush1, pt.X, pt.Y + );

     gWaterMark.DrawString(watermarkText, crFont, transparentBrush1, pt.X + , pt.Y);

     transparentBrush0.Dispose();

     transparentBrush1.Dispose();

     // 画文字

     gWaterMark.SmoothingMode = SmoothingMode.HighQuality;

     //Brush SolidBrush3 = new SolidBrush(Color.White);

     Brush solidBrush3 = new SolidBrush(Color.FromArgb(, Color.White));

     gWaterMark.DrawString(watermarkText, crFont, solidBrush3, pt.X, pt.Y, StringFormat.GenericDefault);

     solidBrush3.Dispose();

     // 保存刚才的操作

     gWaterMark.Save();

     gWaterMark.Dispose();

     bmWaterMark.Save(_wmImgSavePath, ImageFormat.Jpeg);

     //// 将水印图片加到原图中

     //AddWatermarkImage(gCanvas, new Bitmap(bmWaterMark), "WM_TOP_LEFT", width, height);

     using (var imageAttr = new ImageAttributes())

     {

         ColorMap colorMap = new ColorMap();

         colorMap.OldColor = Color.FromArgb(, , , );

         colorMap.NewColor = Color.FromArgb(, , , );

         ColorMap[] remapTable = { colorMap };

         imageAttr.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

         float[][] colorMatrixElements =

         {

             new float[] {1.0f, 0.0f, 0.0f, 0.0f, 0.0f},

             new float[] {0.0f, 1.0f, 0.0f, 0.0f, 0.0f},

             new float[] {0.0f, 0.0f, 1.0f, 0.0f, 0.0f},

             new float[] {0.0f, 0.0f, 0.0f, 0.3f, 0.0f},

             new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}

         };

         ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);

         imageAttr.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);

         gCanvas.DrawImage(bmWaterMark, new Rectangle(, , bmWaterMark.Width, bmWaterMark.Height), , ,

             bmWaterMark.Width, bmWaterMark.Height, GraphicsUnit.Pixel, imageAttr);

         gCanvas.Dispose();

     }

     bmWaterMark.Dispose();