在App_Code類中定義一個全局的類文件
using System;
using System.Web;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
/// <summary>
/// 映射文件後綴名方式的數字水印
/// </summary>
public class CoverHandler : IHttpHandler
{
private const string WATERMARK_URL = "~/Images/watermark.jpg"; //水印圖片
private const string DEFAULTIMAGE_URL = "~/Images/default.jpg"; //默認圖片
public CoverHandler()
{
}
public void ProcessRequest(HttpContext context)
{
System.Drawing.Image Cover;
//判斷請求的物理路徑中,是否存在文件
if (File.Exists(context.Request.PhysicalPath))
{
//加載文件
Cover = Image.FromFile(context.Request.PhysicalPath);
//加載水印圖片
Image watermark = Image.FromFile(context.Request.MapPath(WATERMARK_URL));
//實例化畫布
Graphics g = Graphics.FromImage(Cover);
//在image上繪製水印
g.DrawImage(watermark, new Rectangle(Cover.Width - watermark.Width, Cover.Height - watermark.Height, watermark.Width, watermark.Height), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel);
//釋放畫布
g.Dispose();
//釋放水印圖片
watermark.Dispose();
}
else
{
//加載默認圖片
Cover = Image.FromFile(context.Request.MapPath(DEFAULTIMAGE_URL));
}
//設置輸出格式
context.Response.ContentType = "image/jpeg";
//將圖片存入輸出流
Cover.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
Cover.Dispose();
context.Response.End();
}
public bool IsReusable
{
get
{
return false;
}
}
}
WebConfig文件中的代碼:
<system.web>
<httpHandlers>
<add verb="*" path="Images/BookCovers/*.jpg" type="CoverHandler"/>
</httpHandlers>
</system.web>
這樣在你調用在web.config中的Path屬性中設置的所有圖片時,水印會自動添加!