C#图片加水印实例与代码

本文要提供的类可以为图片加文字水印，以及判断是否是图片文件。经过测试可运行，例子请下载：http://hovertree.com/h/bjaf/5qc5eh6y.htm

例子效果图：

以下是HovercWarter类的代码：

 using System.Drawing;
 using System.Drawing.Imaging;
 using System.IO;

 namespace HoverTreeBatch.HovercFrame
 {
 public class HovercWarter
 {
 public static Image AddTextToImg(Image image, string text)
 {
 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 = ;
 float rectY = ;
 float rectWidth = text.Length * (fontSize + );
 float rectHeight = fontSize + ;
 //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);

 Image h_hovercImg = Image.FromStream(ms);

 g.Dispose();
 bitmap.Dispose();

 return h_hovercImg;
 }

 /// <summary>
 /// 根据文件头判断上传的文件类型
 /// </summary>
 /// <param name="filePath">filePath是文件的完整路径 </param>
 /// <returns>返回true或false</returns>
 public static bool IsPicture(string filePath)
 {
 try
 {
 FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
 BinaryReader reader = new BinaryReader(fs);
 string fileClass;
 byte buffer;
 buffer = reader.ReadByte();
 fileClass = buffer.ToString();
 buffer = reader.ReadByte();
 fileClass += buffer.ToString();
 reader.Close();
 fs.Close();
 if (fileClass == "" || fileClass == "" || fileClass == "" || fileClass == "")
 //何问起 hovertree.com
 //255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar
 {
 return true;
 }
 else
 {
 return false;
 }
 }
 catch
 {
 return false;
 }
 }
 }
 }

另外出一道.NET的题目：http://hovertree.com/shortanswer/bjaf/9vqxwuda.htm

开发技术文章收集: http://www.cnblogs.com/sosoft/p/kaifajishu.html