在Asp.net中为图像加入水印信息并保存为Jpg类型

using System.Drawing;using System.IO;using System.Drawing.Imaging;private void AddTextToImg(string fileName,string text){if(!File.Exists(MapPath(fileName))){throw new FileNotFoundException("The file don't exist!");}if( text == string.Empty ){return;}//还需要判断文件类型是否为图像类型，这里就不赘述了System.Drawing.Image image = System.Drawing.Image.FromFile(MapPath(fileName));Bitmap bitmap = new Bitmap(image,image.Width,image.Height);Graphics g = Graphics.FromImage(bitmap);float fontSize = 12.0f; //字体大小float textWidth = text.Length*fontSize; //文本的长度//下面定义一个矩形区域，以后在这个矩形里画上白底黑字float rectX = 0; float rectY = 0;float rectWidth = text.Length*(fontSize+8);float rectHeight = fontSize+8;//声明矩形域RectangleF textArea = new RectangleF(rectX,rectY,rectWidth,rectHeight);Font font = new Font("宋体",fontSize); //定义字体Brush whiteBrush = new SolidBrush(Color.White); //白笔刷，画文字用Brush blackBrush = new SolidBrush(Color.Black); //黑笔刷，画背景用g.FillRectangle(blackBrush,rectX,rectY,rectWidth,rectHeight); g.DrawString(text,font,whiteBrush,textArea);MemoryStream ms = new MemoryStream( );//保存为Jpg类型bitmap.Save(ms,ImageFormat.Jpeg);//输出处理后的图像，这里为了演示方便，我将图片显示在页面中了Response.Clear();Response.ContentType = "image/jpeg";Response.BinaryWrite( ms.ToArray() );g.Dispose();bitmap.Dispose();image.Dispose();}

AddTextToImg("me.jpg","武林网http://www.vevb.com/");