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Asp.net thumbnails and watermark creation: Image Generation

Source: Internet
Author: User
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Asp.net Image Generation has the built-in ImageResizeTransform class, which allows you to adjust the Image size.
You can also extend ImageTransform to implement your own image conversion class.
The following code uses ASP. NET Image Generation to generate Image thumbnails and Watermarks:

Database
Create table t_images
(
Image_id INT,
Image_data IMAGE,
Last_modified_date, DATETIME
)

Default. aspx

Code
<% @ Page Language = "C #" AutoEventWireup = "true" CodeBehind = "Default. aspx. cs" Inherits = "NET35Lab. GeneratedImage. Web. _ Default" %>

<% @ Register Assembly = "Microsoft. Web. GeneratedImage" Namespace = "Microsoft. Web" TagPRefix = "PC3" %>
<! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<Html xmlns = "http://www.w3.org/1999/xhtml">
<Head runat = "server">
<Title> </title>
</Head>
<Body>
<Form id = "form1" runat = "server">
<Div>
<Asp: DataList ID = "DataList1" runat = "server" performanceid = "sqlperformance1" RepeatColumns = "2"
RepeatDirection = "Horizontal" CellPadding = "4" CellSpacing = "4">
<ItemTemplate>
<PC3: GeneratedImage ID = "GeneratedImage1" runat = "server" ImageHandlerUrl = "~ /ImageHandler1.ashx"
Timestamp = '<% # Eval ("last_modified_date") %>'>
<Parameters>
<PC3: ImageParameter Name = "imageid" Value = '<% # Eval ("image_id") %>'/>
</Parameters>
</PC3: GeneratedImage>
<Br/>
</ItemTemplate>
</Asp: DataList>
</Div>
<Asp: SqlDataSource ID = "SqlDataSource1" runat = "server" ConnectionString = "Data Source =. SQLEXPRESS; AttachDbFilename = | DataDirectory | Database. mdf; Integrated Security = True; User Instance = True ;"
ProviderName = "System. Data. SqlClient" SelectCommand = "SELECT [image_id], [image_data], [last_modified_date] FROM [t_images]">
</Asp: SqlDataSource>
</Form>
</Body>
</Html>

ImageHandler1.ashx

<% @ WebHandler Language = "C #" CodeBehind = "ImageHandler1.ashx. cs" Class = "NET35Lab. GeneratedImage. Web. ImageHandler1" %>

ImageHandler1.ashx. cs

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 {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 ();
}
}
}
}

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