// OnPaint event handler.
// in:
// sender object that has sent the event
// e paint event arguments
private void OnPaintHandler(object sender, PaintEventArgs e)
{
// Full redraw: draw complete collection of finished strokes and
// also all the strokes that are currently in drawing.
FinishedStrokes.Draw(e.Graphics);
ActiveStrokes.Draw(e.Graphics);
}
