Drawing Line Charts In asp.net

LineChart.cs

import the following namespaces

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Collections;


public class LineChart
{
public Bitmap Bitmapb;
public string strTitle = "Default Title";
public ArrayList ArrayListchartValues = new ArrayList();
public float ftXorigin = 0, ftYorigin = 0;
public float ftScaleX, ftScaleY;
public float ftXdivs = 2, ftYdivs = 2;
private int intWidth, intHeight;
private Graphics Graphicsg;
private Page Pagep;

struct datapoint
{
public float ftx;
public float fty;
public bool bolvalid;
}
//initialize

public LineChart(int intmyWidth, int intmyHeight, Page myPage)
{
intWidth = intmyWidth; intHeight = intmyHeight;
ftScaleX = intmyWidth; ftScaleY = intmyHeight;
Bitmapb = new Bitmap(intmyWidth, intmyHeight);
Graphicsg = Graphics.FromImage(Bitmapb);
Pagep = myPage;
}
public void AddValue(int intx, int inty)
{
datapoint myPoint;
myPoint.ftx = intx;
myPoint.fty = inty;
myPoint.bolvalid = true;
ArrayListchartValues.Add(myPoint);

}
public void Draw()

{

int inti;
float ftx, fty, ftx0, fty0;
string strmyLabel;
Pen penblackPen = new Pen(Color.Black,1);
Brush BrushblackBrush = new SolidBrush(Color.Black);
Font FontaxesFont = new Font("arial",10);

//first establish working area

Pagep.Response.ContentType="image/jpeg";
Graphicsg.FillRectangle(new
SolidBrush(Color.LightYellow),0,0,intWidth,intHeight);
int intChartInset = 50;
int intChartWidth = intWidth-(2*intChartInset);
int intChartHeight = intHeight-(2*intChartInset);
Graphicsg.DrawRectangle(new Pen(Color.Black,1),intChartInset,intChartInset,intChartWidth,intChartHeight);
//must draw all text items before doing the rotate below
Graphicsg.DrawString(strTitle, new Font("arial",14), BrushblackBrush, intWidth/3, 10);
//draw X axis labels
for(inti=0; inti<=ftXdivs; inti++)

{

ftx=intChartInset+(inti*intChartWidth)/ftXdivs;
fty=intChartHeight+intChartInset;
strmyLabel = (ftXorigin + (ftScaleX*inti/ftXdivs)).ToString();
Graphicsg.DrawString(strmyLabel, FontaxesFont, BrushblackBrush, ftx-4, fty+10);
Graphicsg.DrawLine(penblackPen, ftx, fty+2, ftx, fty-2);
}

//draw Y axis labels
for(inti=0; inti<=ftYdivs; inti++)

{

ftx=intChartInset;
fty=intChartHeight+intChartInset-(inti*intChartHeight/ftYdivs);
strmyLabel = (ftYorigin + (ftScaleY*inti/ftYdivs)).ToString();
Graphicsg.DrawString(strmyLabel, FontaxesFont, BrushblackBrush, 5, fty-6);
Graphicsg.DrawLine(penblackPen, ftx+2, fty, ftx-2, fty);

}



//transform drawing coords to lower-left (0,0)

Graphicsg.RotateTransform(180);
Graphicsg.TranslateTransform(0,-intHeight);
Graphicsg.TranslateTransform(-intChartInset,intChartInset);
Graphicsg.ScaleTransform(-1, 1);



//draw chart data

datapoint datapointprevPoint = new datapoint();
datapointprevPoint.bolvalid=false;

foreach(datapoint myPoint in ArrayListchartValues)

{

if(datapointprevPoint.bolvalid==true)

{

ftx0=intChartWidth*(datapointprevPoint.ftx-ftXorigin)/ftScaleX;
fty0=intChartHeight*(datapointprevPoint.fty-ftYorigin)/ftScaleY;
ftx=intChartWidth*(myPoint.ftx-ftXorigin)/ftScaleX;
fty=intChartHeight*(myPoint.fty-ftYorigin)/ftScaleY;
Graphicsg.DrawLine(penblackPen,ftx0,fty0,ftx,fty);
Graphicsg.FillEllipse(BrushblackBrush,ftx0-2,fty0-2,4,4);
Graphicsg.FillEllipse(BrushblackBrush,ftx-2,fty-2,4,4);

}

datapointprevPoint = myPoint;

}

//finally send graphics to browser
Bitmapb.Save(Pagep.Response.OutputStream, ImageFormat.Jpeg);

}
LineChart()

{

Graphicsg.Dispose();

Bitmapb.Dispose();

}

}

-----------------------------------------------------------

add a default.aspx and add the following code in page load


default.aspx.cs
-----------------
protected void Page_Load(object sender, EventArgs e)
{
LineChart c = new LineChart(640, 480, Page);
c.strTitle = "My Line Chart";
c.ftXorigin = 0;
c.ftScaleX = 500;
c.ftXdivs = 5;
c.ftYorigin = 0;
c.ftScaleY = 1000;
c.ftYdivs = 5;
c.AddValue(50, 50);
c.AddValue(100, 100);
c.AddValue(200, 150);
c.AddValue(450, 450);
c.Draw();


}