/// <summary>
/// Render a plum colored circle at pre-render tick label time
/// </summary>
/// <param name="sender">KnobControl</param>
/// <param name="e">PreRenderEventArgs</param>
private void PreRenderTickLabel(object sender, PreRenderEventArgs e)
{
KnobControl kc = sender as KnobControl;
if (kc != null)
{
// Locate where the current "value label" is located,
// and then render our circle accordingly
Point pt = GetLabelPoint(kc, e);
e.Graphics.FillEllipse(Brushes.Plum,
new Rectangle(pt.X, pt.Y, 20, 20));
}
}
/// <summary>
/// Returns tick label point
/// </summary>
/// <returns>Upper left tick label rect of the control</returns>
private Point GetLabelPoint(KnobControl kc, PreRenderEventArgs e)
{
decimal count = kc.MaxValue - kc.MinValue;
double rad = GetRadians(
(float)((kc.SweepAngle * kc.Value) / count + kc.StartAngle));
int x = e.Bounds.X + e.Bounds.Width / 2;
int dx = e.Bounds.Width / 2;
Point pt = new Point();
pt.X = (int)(Math.Cos(rad) * dx + x - 10);
pt.Y = (int)(Math.Sin(rad) * dx + x - 10);
return(pt);
}
