Figure 3: Pie Chart

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. Data. sqlclient;
Using system. drawing;
Using system. Drawing. drawing2d;
Using system. collections;

Public partial class _ default: system. Web. UI. Page
{
Protected void page_load (Object sender, eventargs E)
{
Createimage ();
}
Private void createimage ()
{
// Specify the connection string as a constant.
Sqlconnection con = new sqlconnection ("Server = (local); database = db_05; uid = sa; Pwd = eesoft ");
Con. open ();
String cmdtxt = "select * From tb_13_54"; // read type of books, number of books of each type
// Sqlcommand COM = new sqlcommand (cmdtxt, con );
Dataset DS = new dataset ();
Sqldataadapter da = new sqldataadapter (cmdtxt, con );
Da. Fill (DS );
Con. Close ();
Float Total = 0.0f, TMP;

For (INT I = 0; I <Ds. Tables [0]. Rows. Count; I ++)
{
// Convert to single precision. You can also write it as convert. toint32.
TMP = convert. tosingle (Ds. Tables [0]. Rows [I] ["quantity"]);
Total + = TMP;
}

// Set the fonttitle as the title Font
Font fontlegend = new font ("verdana", 9 );
Font fonttitle = new font ("verdana", 10, fontstyle. Bold );

// Background width
Int width = 230;
Int bufferspace = 15;
Int legendheight = fontlegend. Height * (Ds. Tables [0]. Rows. Count + 1) + bufferspace;
Int titleheight = fonttitle. height + bufferspace;
Int Height = width + legendheight + titleheight + bufferspace; // the white background height.
Int pieheight = width;
Rectangle pierect = new rectangle (0, titleheight, width, pieheight );

// Add various random colors
Arraylist colors = new arraylist ();
Random RND = new random ();
For (INT I = 0; I <Ds. Tables [0]. Rows. Count; I ++)
Colors. Add (New solidbrush (color. fromargb (RND. Next (255), RND. Next (255), RND. Next (255 ))));

// Create a bitmap instance
Bitmap objbitmap = new Bitmap (width, height );
Graphics objgraphics = graphics. fromimage (objbitmap );

// Draw a white background
Objgraphics. fillrectangle (New solidbrush (color. White), 0, 0, width, height );

// Draw a bright yellow background
Objgraphics. fillrectangle (New solidbrush (color. Beige), pierect );

// The following is a pie chart (several rows of rows are drawn)
Float currentdegree = 0.0f;
For (INT I = 0; I <Ds. Tables [0]. Rows. Count; I ++)
{
Objgraphics. fillpie (solidbrush) colors [I], pierect, currentdegree,
Convert. tosingle (Ds. Tables [0]. Rows [I] ["quantity"])/Total * 360 );
Currentdegree + = convert. tosingle (Ds. Tables [0]. Rows [I] ["quantity"])/Total * 360;
}
// Generate the main title as follows
Solidbrush blackbrush = new solidbrush (color. Black );
String title = "sales ratio survey of various types of books ";
Stringformat = new stringformat ();
Stringformat. Alignment = stringalignment. Center;
Stringformat. linealignment = stringalignment. Center;

Objgraphics. drawstring (title, fonttitle, blackbrush,
New rectangle (0, 0, width, titleheight), stringformat );
// List the fields and numbers
Objgraphics. drawrectangle (new pen (color. Black, 2), 0, height-legendheight, width, legendheight );
For (INT I = 0; I <Ds. Tables [0]. Rows. Count; I ++)
{
Objgraphics. fillrectangle (solidbrush) colors [I], 5, height-legendheight + fontlegend. Height * I + 5, 10, 10 );

Objgraphics. drawstring (string) ds. tables [0]. rows [I] ["bookkind"] + "---" + convert. tostring (convert. tosingle (Ds. tables [0]. rows [I] ["quantity"]) * 100/total ). substring (0, 5) + "%", fontlegend, blackbrush, 20, height-legendheight + fontlegend. height * I + 1 );

}
// The total height of the image-the height of a row of font, that is, the height of the row of the base row (height-fontlegend. Height)
Objgraphics. drawstring ("Total number of books sold:" + convert. tostring (total) + "", fontlegend, blackbrush, 5, height-fontlegend. Height );
Response. contenttype = "image/JPEG ";
Objbitmap. Save (response. outputstream, system. Drawing. imaging. imageformat. JPEG );
Objgraphics. Dispose ();
Objbitmap. Dispose ();
}
}