public void DD_trim()
{
var dd = new DisplayData();
var p1 = new System.Drawing.PointF(-10, -10);
dd.Add(p1);
dd.Add(new System.Drawing.PointF(10, 10));
dd.Add(new System.Drawing.PointF(1, 2));
dd.Add(new System.Drawing.PointF(4, 3));
var p2 = new System.Drawing.PointF(5, 5);
dd.Add(p2);
var r = new System.Drawing.RectangleF((float)-5.5, (float)-5.5, 11, 11);
var trimmed = dd.TrimToWindow(r);
Assert.AreEqual(3, trimmed.Count);
Assert.IsFalse(trimmed.Contains(p1));
}