protected override void OnRender(DrawingContext dc)
{
Point pos, tangent;
double angleInRadians;
double angleInDegrees;
TransformGroup tg;
Pen pen = new Pen(Stroke, StrokeThickness);
dc.DrawGeometry(null, pen, LinePath);
if (BeginCap != null)
{
LinePath.GetPointAtFractionLength(0.01d, out pos, out tangent);
angleInRadians = Math.Atan2(tangent.Y, tangent.X) + Math.PI;
angleInDegrees = angleInRadians * 180 / Math.PI + 180;
tg = new TransformGroup();
tg.Children.Add(new RotateTransform(angleInDegrees));
LinePath.GetPointAtFractionLength(0.0d, out pos, out tangent);
tg.Children.Add(new TranslateTransform(pos.X, pos.Y));
dc.PushTransform(tg);
dc.DrawGeometry(Brushes.Red, pen, BeginCap);
dc.Pop();
}
if (EndCap != null)
{
LinePath.GetPointAtFractionLength(0.99, out pos, out tangent);
angleInRadians = Math.Atan2(tangent.Y, tangent.X) + Math.PI;
angleInDegrees = angleInRadians * 180 / Math.PI;
tg = new TransformGroup();
tg.Children.Add(new RotateTransform(angleInDegrees));
LinePath.GetPointAtFractionLength(1, out pos, out tangent);
tg.Children.Add(new TranslateTransform(pos.X, pos.Y));
dc.PushTransform(tg);
dc.DrawGeometry(Brushes.Red, pen, EndCap);
}
}