private void FillRoundedRect(RectangleF rect, CGContext context)
{
float radius = 10.0f;
context.BeginPath();
context.SetFillColor(0.0f, Opacity);
context.MoveTo(rect.GetMinX() + radius, rect.GetMinY());
context.AddArc(rect.GetMaxX() - radius, rect.GetMinY() + radius, radius, (float)(3 * Math.PI / 2), 0f, false);
context.AddArc(rect.GetMaxX() - radius, rect.GetMaxY() - radius, radius, 0, (float)(Math.PI / 2), false);
context.AddArc(rect.GetMinX() + radius, rect.GetMaxY() - radius, radius, (float)(Math.PI / 2), (float)Math.PI, false);
context.AddArc(rect.GetMinX() + radius, rect.GetMinY() + radius, radius, (float)Math.PI, (float)(3 * Math.PI / 2), false);
context.ClosePath();
context.FillPath();
}