图片水印

 

 1 public class WaterImgHandler:IHttpHandler

 2     {

 3 

 4         public bool IsReusable

 5         {

 6             get { return false; }

 7         }

 8 

 9         public void ProcessRequest(HttpContext context)

10         {

11                  // 指定水印图片

12             string water_Url = "~/wImages/logo.gif";

13             // 指定默认图片

14             string default_Url = "~/wImages/error.jpg";

15             // 创建图片对象，用于存放用户读取的图片

16             System.Drawing.Image g;

17             // 判断所请求的图片是否存在，存在就给图片加水印

18             if (File.Exists(context.Request.PhysicalPath))

19             {

20                 g = System.Drawing.Image.FromFile(context.Request.PhysicalPath);

21                 // 加载水印图片

22                 System.Drawing.Image waterImg = System.Drawing.Image.FromFile(context.Request.MapPath(water_Url));

23                 Graphics gh = Graphics.FromImage(g);

24                 gh.DrawImage(waterImg, new RectangleF(0, g.Height - waterImg.Height, 100, 20));

25 

26                 // 加载水印字符串

27                 Font font = new System.Drawing.Font("Arial", 6, System.Drawing.FontStyle.Bold);

28                 gh.DrawString("abcdefg", font, Brushes.White, 2, 2);

29                 gh.Dispose();

30                 waterImg.Dispose();

31             }

32             else { 

33                 // 图片不存在，显示默认图片

34                 g = System.Drawing.Image.FromFile(context.Request.MapPath(default_Url));

35             }

36             context.Request.ContentType = "image/jpeg";

37             g.Save(context.Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);

38             g.Dispose();

39             context.Response.End();

40 

41         }

42     }

43         // 最后在配置文件Web.config中写

44       <httpHandlers>

45          <add verb="*" path="*.jpg" type="Picture.WaterImgHandler"/>

46      </httpHandlers>