Generate graph using Nplot

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using NPlot;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;

public partial class PointGraph : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        CreatePointGraph();
    }

    private void CreatePointGraph()
    {
        NPlot.Bitmap.PlotSurface2D npSurface = new NPlot.Bitmap.PlotSurface2D(700, 500);

        NPlot.PointPlot npPlot1 = new PointPlot();
        NPlot.PointPlot npPlot2 = new PointPlot();
        NPlot.PointPlot npPlot3 = new PointPlot();

        //Font definitions:
        Font TitleFont=new Font("Arial", 12);
        Font AxisFont=new Font("Arial", 10);
        Font TickFont=new Font("Arial", 8);



        //Legend definition:
        NPlot.Legend npLegend = new NPlot.Legend();

        DateTime[] X1 = new DateTime[50];
        DateTime[] X2 = new DateTime[50];
        int[] Y1 = new int[50];
        int[] Y2 = new int[50];

        Random r1 = new Random();
        Random r2 = new Random();



        for (int i = 0; i < 50; i++)
        {
            X1[i] = DateTime.Now.Date.AddDays(i);
            X2[i] = DateTime.Now.Date.AddDays(i);
            Y1[i] = r1.Next(100);
            Y2[i] = r2.Next(300);
        }


        //Prepare PlotSurface:
        npSurface.Clear();
        npSurface.Title = "Point Graph";
        npSurface.BackColor = System.Drawing.Color.White;


        //Left Y axis grid:
        NPlot.Grid p = new Grid();
        npSurface.Add(p, NPlot.PlotSurface2D.XAxisPosition.Bottom, NPlot.PlotSurface2D.YAxisPosition.Left);


        
        //Weight:
        npPlot1.AbscissaData = X1;
        npPlot1.DataSource = Y1;
        npPlot1.Label = "Weight (kg.)";
        npPlot1.Marker.Color = System.Drawing.Color.Blue;

        //Height
        npPlot2.AbscissaData = X2;
        npPlot2.DataSource = Y2;
        npPlot2.Label = "Height (cm)";
        npPlot2.Marker.Color = System.Drawing.Color.Green;


        npSurface.Add(npPlot1, NPlot.PlotSurface2D.XAxisPosition.Bottom, NPlot.PlotSurface2D.YAxisPosition.Left);
        npSurface.Add(npPlot2, NPlot.PlotSurface2D.XAxisPosition.Bottom, NPlot.PlotSurface2D.YAxisPosition.Left);



        //X axis
        npSurface.XAxis1.Label = "Date";
        npSurface.XAxis1.NumberFormat = "yyyy-MM-dd";
        npSurface.XAxis1.TicksLabelAngle = 90;
        npSurface.XAxis1.TickTextNextToAxis = true;
        npSurface.XAxis1.FlipTicksLabel = true;
        npSurface.XAxis1.LabelOffset = 110;
        npSurface.XAxis1.LabelOffsetAbsolute = true;
        npSurface.XAxis1.LabelFont = AxisFont;
        npSurface.XAxis1.TickTextFont = TickFont;
        

        //Y axis
        npSurface.YAxis1.Label = "Value";
        npSurface.YAxis1.NumberFormat = "{0:####0.0}";
        npSurface.YAxis1.LabelFont = AxisFont;
        npSurface.YAxis1.TickTextFont = TickFont;

        //Add legend:
        npLegend.AttachTo(NPlot.PlotSurface2D.XAxisPosition.Top, NPlot.PlotSurface2D.YAxisPosition.Right);
        npLegend.VerticalEdgePlacement = NPlot.Legend.Placement.Inside;
        npLegend.HorizontalEdgePlacement = NPlot.Legend.Placement.Outside;
        npLegend.BorderStyle = NPlot.LegendBase.BorderType.Line;
        npSurface.Legend = npLegend;


        //Update PlotSurface:
        npSurface.Refresh();


        //Save PlotSurface to MemoryStream, stream output as GIF file:
        Response.Buffer = true;
        Response.ContentType = "image/gif";

        MemoryStream memStream = new MemoryStream();

        npSurface.Bitmap.Save(memStream, System.Drawing.Imaging.ImageFormat.Gif);
        memStream.WriteTo(Response.OutputStream);
        Response.End();
    }


}