How to make an animated button in C# winforms

[ToolboxBitmap(typeof(Button))]
public class SButton : Button
{
    int bra = 20;
    StringAlignment ha = StringAlignment.Center;
    StringAlignment va = StringAlignment.Center;
    public StringAlignment HorizontalAlignment
    {
        get { return ha; }
        set { ha = value; Invalidate(); }
    }
    public StringAlignment VerticalAlignment
    {
        get { return va; }
        set { va = value; Invalidate(); }
    }
    public int BorderRadius
    {
        get { return bra; }
        set { bra = value; this.Invalidate(); }
    }
    public SButton() { BackColor = Color.White; ForeColor = Color.Black; Font = new Font("Segoe UI", 13, FontStyle.Bold); }
    static int GetFontWidth(int textlength, Font font)
    {
        return textlength * (int)font.Size;
    }
    protected override void OnPaint(PaintEventArgs e)
    {
        // Draw default button
        base.OnPaint(e);
        // High quality smoothing mode
        e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
        //Clear the Windows button graphics
        e.Graphics.Clear(Parent.BackColor);
        if (bra < 2)
        {
            SolidBrush s = new SolidBrush(BackColor);
            e.Graphics.FillRectangle(s, ClientRectangle);
        }
        else
        {
            GraphicsPath path = new GraphicsPath();
            path.AddArc(new Rectangle(0, 0, bra, bra), 180, 90);
            path.AddArc(new Rectangle(Width - bra, 0, bra, bra), -90, 90);
            path.AddArc(new Rectangle(Width - bra, Height - bra, bra, bra), 0, 90);
            path.AddArc(new Rectangle(0, Height - bra, bra, bra), 90, 90);
            e.Graphics.FillPath(new SolidBrush(BackColor), path);
        }
        // Draw text with his font
        e.Graphics.DrawString(Text, Font, new SolidBrush(ForeColor),ClientRectangle, new StringFormat() { LineAlignment = ha, Alignment = va } );
        // If Image property is not null, draw image with his align
        if (Image != null)
        {
            if (ImageAlign == ContentAlignment.TopLeft)
            {
                e.Graphics.DrawImage(Image, new Point(16, 16));
            }else if (ImageAlign == ContentAlignment.TopCenter)
            {
                e.Graphics.DrawImage(Image, new Point(this.Width / 2 - Image.Width / 2, 16));
            }else if (ImageAlign == ContentAlignment.TopRight)
            {
                e.Graphics.DrawImage(Image, new Point(this.Width - Image.Width - 16, 16));
            }else if (ImageAlign == ContentAlignment.MiddleLeft)
            {
                e.Graphics.DrawImage(Image, new Point(16, this.Height / 2 - Image.Height / 2));
            }else if (ImageAlign == ContentAlignment.MiddleCenter)
            {
                e.Graphics.DrawImage(Image, new Point(this.Width / 2 - Image.Width / 2, this.Height / 2 - Image.Height / 2));
            }else if (ImageAlign == ContentAlignment.MiddleRight)
            {
                e.Graphics.DrawImage(Image, new Point(this.Width - Image.Width - 16, this.Height / 2 - Image.Height / 2));
            }else if (ImageAlign == ContentAlignment.BottomLeft)
            {
                e.Graphics.DrawImage(Image, new Point(16, this.Height - Image.Height - 16));
            }
            else if (ImageAlign == ContentAlignment.BottomCenter)
            {
                e.Graphics.DrawImage(Image, new Point(this.Width / 2 - Image.Width / 2, this.Height - Image.Height - 16));
            }
            else if (ImageAlign == ContentAlignment.BottomRight)
            {
                e.Graphics.DrawImage(Image, new Point(this.Width - Image.Width - 16, this.Height - Image.Height - 16));
            }
        }
    }
}