asp.net、C#动态添加图片水印

例子1：

web.config

<httpHandlers>

<remove verb="*" path="*.asmx"/>

<add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

<add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

<add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>

<add verb="*" path="images/shangjia/*/*.jpg" type="CoverHandler"/>

<add verb="*" path="images/shangjia/*/*/*.jpg" type="CoverHandler"/>

<add verb="*" path="admin/TotalUpImg/VedioImg/*.jpg" type="CoverHandler1"/>

</httpHandlers>

<httpHandlers>

<remove verb="*" path="*.asmx"/>

<add verb="*" path="*.asmx" validate="false"

type="System.Web.Script.Services.ScriptHandlerFactory,

System.Web.Extensions, Version=1.0.61025.0, Culture=neutral,

PublicKeyToken=31bf3856ad364e35"/>

<add verb="*" path="*_AppService.axd" validate="false"

type="System.Web.Script.Services.ScriptHandlerFactory,

System.Web.Extensions, Version=1.0.61025.0, Culture=neutral,

PublicKeyToken=31bf3856ad364e35"/>

<add verb="GET,HEAD" path="ScriptResource.axd"

type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions,

Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"

validate="false"/>

<add verb="*" path="images/shangjia/*/*.jpg"

type="CoverHandler"/>

<add verb="*" path="images/shangjia/*/*/*.jpg"

type="CoverHandler"/>

<add verb="*" path="admin/TotalUpImg/VedioImg/*.jpg"

type="CoverHandler1"/>

</httpHandlers>

CoverHandler.cs

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.IO;

using System.Drawing;

using System.Drawing.Imaging;

/// <summary>

/// CoverHandler 的摘要说明

/// </summary>

public class CoverHandler : IHttpHandler

{

public CoverHandler()

{

//

// TODO: 在此处添加构造函数逻辑

//

}

private const string WATERMARK_URL = "~/images/WaterMark.png";

private const string DEFAULTIMAGE_URL = "~/images/default.jpg";

#region IHttpHandler 成员

public void ProcessRequest(HttpContext context)

{

System.Drawing.Image Cover;

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

{

Cover = Image.FromFile(context.Request.PhysicalPath);

Image watermark = Image.FromFile(context.Request.MapPath(WATERMARK_URL));

Graphics g = Graphics.FromImage(Cover);

Random r = new Random();

int width = r.Next(10,Cover.Width - watermark.Width);

int height = r.Next(10,Cover.Height - watermark.Height);

g.DrawImage(watermark, new Rectangle(width, height, watermark.Width, watermark.Height), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel);

g.Dispose();

watermark.Dispose();

}

else

{

Cover = Image.FromFile(context.Request.MapPath(DEFAULTIMAGE_URL));

}

context.Response.ContentType = "image/Jpeg";

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

Cover.Dispose();

context.Response.End();

}

public bool IsReusable

{

get

{

return false;

}

}

#endregion

}

例子2:

WaterMarke.cs 类 code

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Drawing;

using System.Drawing.Imaging;

using System.IO;

/// <summary>

/// WaterMarker 的摘要说明

/// </summary>

public class WaterMarker : IHttpHandler

{

public WaterMarker()

{

//

// TODO: 在此处添加构造函数逻辑

//

}

public bool IsReusable

{

get { return true; }

}

public void ProcessRequest(HttpContext context)

{

//获取请求的物理路径

string imagePath = context.Request.PhysicalPath;

System.Drawing.Image image = null;

//判断指定的物理路径是否存在

if (File.Exists(imagePath))

{

//定义水印文字

string text = "本图片来自夏楚枫的博客";

//定义水印文字字体的大小

int fontSize = 12;

//水印文字字体

Font font = new Font("宋体", fontSize);

//根据图片的物理路径加载图片

image = System.Drawing.Image.FromFile(imagePath);

Graphics g = Graphics.FromImage(image);

//获取要绘制水印文字所需要区域的大小

SizeF size = g.MeasureString(text, font);

if (size.Width > image.Width || size.Height > image.Height)

{

//如果要显示图片的尺寸都不足以显示按照指定文字字体来添加水印

//可以减小的字体的大小或者不添加水印（太小了没办法添加嘛）

}

else

{

//添加水印文字

Brush br = Brushes.Red;

g.DrawString(text, font, br, image.Width - size.Width, image.Height - size.Height);

g.Dispose();

}

}

else //如果不存在指定一个默认的图片进行显示http://www.xuehai.net

{

imagePath = context.Server.MapPath("~/image/default.jpg");

image = System.Drawing.Image.FromFile(imagePath);

}

image.Save(context.Response.OutputStream, ImageFormat.Jpeg);//将添加水印的图片输出

}

}

webconfig 中的配置

方法一：在所在文件夹添加一个webconfig文件，然后再在

<system.web>节点中添加下面的代码

<httpHandlers>

<!--对jpg文件添加水印-->

<add path="*" verb="*.jpg" type="WaterMarker"/>

<!--对bmp文件添加水印-->

<add verb="*" path="*.bmp" type="WaterMarker"/>

</httpHandlers>

方法二： 不在图片所在的文件夹下添加webconfig 而是直接在根目录下的webconfig中的配置

不用自动生成的那个<System.web>中配置 而是在<configuration>节点中添加如下代码

<location path="image">

<system.web>

<httpHandlers>

<!--对jpg文件添加水印-->

<add path="*" verb="*.jpg" type="WaterMarker"/>

<!--对bmp文件添加水印-->

<add verb="*" path="*.bmp" type="WaterMarker"/>

</httpHandlers>

</system.web>

</location>