using System;

using System.Drawing;

using System.Windows.Forms;

 

namespace Example3_1

{

    public partial class Form1 : Form

    {

        // Define the drawing area

        private Rectangle PlotArea;

        // Unit defined in world coordinate system :

        private float xMin = 0f;

        private float xMax = 6;

        private float yMin = -1.1f;

        private float yMax = 1.1f;

        private int nPoints = 61;

        // Unit in pixel:

        private int offset = 30;

 

        public Form1()

        {

            InitializeComponent();

            This.BackColor = Color.White;

            this.SetStyle(ControlStyles.ResizeRedraw, true);

        }

 

        protected override void OnPaint(PaintEventArgs e)

        {

            Graphics g = e.Graphics;

 

            // Calculate the location and size of the plot area

            // within which we want to draw the graphics:

            Rectangle ChartArea = ClientRectangle;

            PlotArea = new Rectangle(ChartArea.Location,

                          ChartArea.Size);

            PlotArea.Inflate(-offset, -offset);

 

            //Draw PlotArea:

            g.DrawRectangle(Pens.Black, PlotArea);

 

            // Generate Sine and Cosine data points to plot:

            PointF[] pt1 = new PointF[nPoints];

            PointF[] pt2 = new PointF[nPoints];

            for (int i = 0; i < nPoints; i++)

            {

                pt1[i] = new PointF(i / 5.0f, (float)Math.Sin(i/5.0f));

                pt2[i] = new PointF(i / 5.0f, (float)Math.Cos(i/5.0f));

            }

 

             // Draw Sine and Cosine lines:

            for (int i = 1; i < nPoints; i++)

            {

                g.DrawLine(Pens.Blue, Point2D(pt1[i - 1]),

                                      Point2D(pt1[i]));

                g.DrawLine(Pens.Red, Point2D(pt2[i - 1]),

                                     Point2D(pt2[i]));

            }

            g.Dispose();

        }

 

        private PointF Point2D(PointF ptf)

        {

            PointF aPoint = new PointF();

            if (ptf.X < xMin || ptf.X > xMax ||

                ptf.Y < yMin || ptf.Y > yMax)

            {

                ptf.X = Single.NaN;

                ptf.Y = Single.NaN;

            }        

            aPoint.X = PlotArea.X + (ptf.X - xMin) *

                PlotArea.Width / (xMax - xMin);

            aPoint.Y = PlotArea.Bottom - (ptf.Y - yMin) *

                PlotArea.Height / (yMax - yMin);

            return aPoint;

        }

    }

}