protected void DrawCircle(Graphics canvas, ICloudLayouter layouter)
{
var centerPoint = layouter.GetCloudCenter();
var radius = (int)Math.Ceiling(CalculateСircumcircleRadius(layouter.GetCurrentLayout(), centerPoint));
canvas.DrawEllipse(new Pen(Color.ForestGreen, 2), centerPoint.X - radius, centerPoint.Y - radius, 2 * radius, 2 * radius);
}