Graphics Example: Chasing Circles

Introduction

1. Start Microsoft Visual Studio and create a new Windows  Forms Application named ChasingCircles
2. Change the properties of the form as follows:
   BackColor: Black
   FormBorderStyle: None
   WindowState: Maximized
3. Click the middle of the form and, in the Properties window, click the Events button
4. In the Events section of the Properties window, double-click KeyDown
5. Implement the event as follows:

   private void Exercise_KeyDown(object sender, KeyEventArgs e)
   {
       if (e.KeyCode == Keys.Escape)
           Close();
   }

6. Return to the form and add a Timer control to it
7. Set the timer's Enabled to True and its Interval to 50
8. Double-click the timer and change the file as follows:

   using System;
   using System.Collections.Generic;
   using System.ComponentModel;
   using System.Data;
   using System.Drawing;
   using System.Linq;
   using System.Text;
   using System.Windows.Forms;
   
   namespace ChasingCircles
   {
       public partial class Form1 : Form
       {
           int angle1 = 0;
           int angle2 = 15;
           int angle3 = 30;
           int angle4 = 45;
           int angle5 = 60;
   
           public Form1()
           {
               InitializeComponent();
           }
   
           private void timer1_Tick(object sender, EventArgs e)
           {
               Graphics graph = Graphics.FromHwnd(this.Handle);
   
               graph.TranslateTransform((float)(this.ClientSize.Width / 2),
                                        (float)(this.ClientSize.Height / 2));
   
               int radius = 250;
   
               double PI2 = 2 * Math.PI;
   
               int X1 = (int)(radius * Math.Cos(angle1 / PI2));
               int Y1 = (int)(radius * Math.Sin(angle1 / PI2));
               int X2 = (int)(radius * Math.Cos(angle2 / PI2));
               int Y2 = (int)(radius * Math.Sin(angle2 / PI2));
               int X3 = (int)(radius * Math.Cos(angle3 / PI2));
               int Y3 = (int)(radius * Math.Sin(angle3 / PI2));
               int X4 = (int)(radius * Math.Cos(angle4 / PI2));
               int Y4 = (int)(radius * Math.Sin(angle4 / PI2));
               int X5 = (int)(radius * Math.Cos(angle5 / PI2));
               int Y5 = (int)(radius * Math.Sin(angle5 / PI2));
   
               graph.Clear(Color.Black);
   
               graph.DrawEllipse(Pens.Fuchsia, -50, -50, 100, 100);
               graph.DrawEllipse(Pens.Aqua, X1 - 200, Y1 - 200, 400, 400);
               graph.DrawEllipse(Pens.Yellow, X2 - 200, Y2 - 200, 400, 400);
               graph.DrawEllipse(Pens.Blue, X3 - 200, Y3 - 200, 400, 400);
               graph.DrawEllipse(Pens.White, X4 - 200, Y4 - 200, 400, 400);
               graph.DrawEllipse(Pens.Red, X5 - 200, Y5 - 200, 400, 400);
   
               angle1++;
               angle2++;
               angle3++;
               angle4++;
               angle5++;
           }
   
           private void Form1_KeyDown(object sender, KeyEventArgs e)
           {
               if (e.KeyCode == Keys.Escape)
                   Close();
           }
       }
   }

9. Execute the application