private void UpdateAnchorPosition()
{
Point point, tangent;
var path = this.PathGeometry;
path.GetPointAtFractionLength(0, out point, out tangent);
this.SourceAnchorAngle = ModelingHelper.ToAngle(-tangent.Y, -tangent.X);
this.SourceAnchorPosition = point;
path.GetPointAtFractionLength(1, out point, out tangent);
this.SinkAnchorAngle = ModelingHelper.ToAngle(tangent.Y, tangent.X);
this.SinkAnchorPosition = point;
path.GetPointAtFractionLength(0.5, out point, out tangent);
this.LabelPosition = this.CenterPoint = point;
}
/// <summary>
/// 计算某个点到矩形中点的角度。
/// </summary>
/// <param name="center"></param>
/// <param name="point"></param>
/// <returns></returns>
private static double AngleFromCenter(Point center, Point point)
{
return(ModelingHelper.ToAngle(point.Y - center.Y, point.X - center.X));
}
