How to create an animated start with C# winform.

Form1.cs

public partial class Form1 : Form
 {
     int radius = 0;
     bool isIncreasing = true;
     public Form1()
     {
         InitializeComponent();
         //set the startup position of star as center of the screen
         this.StartPosition = FormStartPosition.CenterScreen;
         //subscirbe mosue down event so we can move star by mouse move
         this.MouseDown += Form1_MouseDown;
         //subscribe the form load event
         this.Load += Form1_Load;
         //subscribe the form paint event
         this.Paint += Form1_Paint;
         //set the form border styel to hide title bar
         this.FormBorderStyle = FormBorderStyle.None;
     }


     // On mouse down, start moving the form.
     private void Form1_MouseDown(object sender, MouseEventArgs e)
     {
         const int WM_NCLBUTTONDOWN = 0xA1;
         const int HT_CAPTION = 0x2;
         this.Capture = false;
         Message msg = Message.Create(this.Handle,
             WM_NCLBUTTONDOWN, (IntPtr)HT_CAPTION, IntPtr.Zero);
         WndProc(ref msg);
     }
     /// <summary>
     /// Provide the
     /// </summary>
     /// <param name="radius"></param>
     /// <param name="xCenter"></param>
     /// <param name="yCenter"></param>
     /// <returns></returns>
     private PointF[] DrawStar(float radius, float xCenter, float yCenter)
     {
         // r: determines the size of the star.
         // xc, yc: determine the location of the star.
         float sin36 = (float)Math.Sin(36.0 * Math.PI / 180.0);
         float sin72 = (float)Math.Sin(72.0 * Math.PI / 180.0);
         float cos36 = (float)Math.Cos(36.0 * Math.PI / 180.0);
         float cos72 = (float)Math.Cos(72.0 * Math.PI / 180.0);
         float r1 = radius * cos72 / cos36;
         // Fill the star:
         PointF[] pts = new PointF[10];
         pts[0] = new PointF(xCenter, yCenter - radius);
         pts[1] = new PointF(xCenter + r1 * sin36, yCenter - r1 * cos36);
         pts[2] = new PointF(xCenter + radius * sin72, yCenter - radius * cos72);
         pts[3] = new PointF(xCenter + r1 * sin72, yCenter + r1 * cos72);
         pts[4] = new PointF(xCenter + radius * sin36, yCenter + radius * cos36);
         pts[5] = new PointF(xCenter, yCenter + r1);
         pts[6] = new PointF(xCenter - radius * sin36, yCenter + radius * cos36);
         pts[7] = new PointF(xCenter - r1 * sin72, yCenter + r1 * cos72);
         pts[8] = new PointF(xCenter - radius * sin72, yCenter - radius * cos72);
         pts[9] = new PointF(xCenter - r1 * sin36, yCenter - r1 * cos36);
         return pts;
     }

     private void Form1_Load(object sender, EventArgs e)
     {
         //set the Back Color to White
         this.BackColor = Color.White;
         //set Transparency key to White in order to make form fullay Transparent.
         this.TransparencyKey = Color.White;  //as transperency key is white so everything with color white will be transparent.
         
          
         //set height width
         this.Height = 220;
         this.Width = 220;

         //set a timer which will invlidate the form so we can repaint it
         Timer timer = new Timer();
         timer.Interval = 100;
         timer.Tick += Timer_Tick;
         timer.Enabled = true;

     }

     private void Timer_Tick(object sender, EventArgs e)
     {
         //trigger form paint event
         this.Invalidate();
         //if growing then increase radius by 5
         if (isIncreasing)
         {
             radius += 5;
         }
         else  //if reducing then decrease radius by 5 pixel
         {
             radius -= 5;
         }

         //if radius more then 80 then change direction
         if (radius > 80)
         {
             isIncreasing = false;
         }
         //if radius les then 7 then let the start to grow again
         if (radius < 7)
         {
             isIncreasing = true;
         }
     }

     private void Form1_Paint(object sender, PaintEventArgs e)
     {
         //get Star Points
         var pts = DrawStar(radius, 90, 90);
         //creat a BOld Pen and draw blue start..
         //as blue is not our transparent color so start will be visible to us
         Pen p = new Pen(Color.Blue, 5);
         //draw a polygon
         e.Graphics.DrawPolygon(p, pts);

     }
 }