Rounded Rectangle

/// <summary>
/// Generate a curved path from a rectangle
/// </summary>
/// <param name="rec">The Rectangle to base the shape on</param>
/// <param name="gp">The GraphicsPath to modify</param>
/// <param name="radius">A float value to set the radius of the curve</param>
/// <param name="inflate">The amount to inflate the Rectangle by (negative values will deflate)</param>
public void makeCurve(RectangleF rec, ref GraphicsPath gp, float radius, float inflate)
{
    radius += inflate;
    if (radius < 1)
        radius = 1;

    inflate = inflate / 2;
    rec.Width += inflate;
    rec.Height += inflate;
    rec.X -= inflate;
    rec.Y -= inflate;

    gp.AddArc(new RectangleF(rec.Location, new SizeF(radius, radius)), 180, 90); // Left-Top
    gp.AddLine(gp.GetLastPoint(), new PointF(rec.Width - radius, rec.Y)); // Top
    gp.AddArc(new RectangleF(gp.GetLastPoint(), new SizeF(radius, radius)), -90, 90); // Right-Top
    gp.AddLine(gp.GetLastPoint(), new PointF(rec.Width, rec.Height - radius)); // Right
    gp.AddArc(new RectangleF(new PointF(gp.GetLastPoint().X - radius, gp.GetLastPoint().Y), new SizeF(radius, radius)), 0, 90); // Right-Bottom
    gp.AddLine(gp.GetLastPoint(), new PointF(rec.X + radius, rec.Height)); // Bottom
    gp.AddArc(new RectangleF(new PointF(rec.X, gp.GetLastPoint().Y - radius), new SizeF(radius, radius)), 90, 90); // Left-Bottom
    gp.AddLine(gp.GetLastPoint(), new PointF(rec.X, rec.Y + radius)); // Left
    gp.CloseFigure();
}