使用ASP.NET Image Generation生成图片缩略图及水印

接ASP.NET Image Generation介绍

ASP.NET Image Generation内置了ImageResizeTransform类，可以实现图片大小调整功能。

也可以扩展ImageTransform实现自己的图片变换类。

下面使用ASP.NET Image Generation生成图片缩略图及水印的代码：

数据库

CREATE TABLE t_images

(

image_id INT,

image_data IMAGE,

last_modified_date, DATETIME

)

Default.aspx

Code

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using Microsoft.Web;

using System.Collections.Specialized;

using System.Data.SqlClient;

using System.Drawing;

namespace NET35Lab.GeneratedImage.Web

{

public class ImageHandler1 : ImageHandler

{

public ImageHandler1()

{

this.ImageTransforms.Add(new ImageResizeTransform { Width = 320, Mode = ImageResizeMode.Fit });

this.ImageTransforms.Add(new CopyrightTransform { Text = "Guushuuse .NET" });

this.EnableClientCache = true;

this.EnableServerCache = true;

}

public override ImageInfo GenerateImage(NameValueCollection parameters)

{

int imageID = int.Parse(parameters["imageid"]);

SqlConnection connection = new SqlConnection(

@"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database.mdf;Integrated Security=True;User Instance=True;");

connection.Open();

SqlCommand command = new SqlCommand("select image_data from t_images where image_id=" + imageID, connection);

SqlDataReader dr = command.ExecuteReader();

dr.Read();

return new ImageInfo((Byte[])dr[0]);

}

}

public class CopyrightTransform : ImageTransform

{

private const int VERTICAL_PADDING = 5;

private const int HORIZONAL_PADDING = 5;

public string Text { get; set; }

public Font Font { get; set; }

public Color FontColor { get; set; }

public CopyrightTransform()

{

//Assign Defaults

FontColor = Color.FromArgb(128, 255, 0, 0);

Font = new Font("Courier", 13);

}

public override System.Drawing.Image ProcessImage(System.Drawing.Image img)

{

Graphics gra = Graphics.FromImage(img);

SizeF sz = gra.MeasureString(Text, Font);

gra.DrawString(Text, Font, new SolidBrush(FontColor), img.Width - sz.Width - HORIZONAL_PADDING, img.Height - sz.Height - VERTICAL_PADDING);

return img;

}

public override string UniqueString

{

get

{

return base.UniqueString + Text + FontColor.ToString() + Font.ToString();

}

}

}

}

运行效果