/// <summary>
/// Determines the orientation of a LineSegment relative to this segment.
/// The concept of orientation is specified as follows:
/// Given two line segments A and L,
/// A is to the left of a segment L if A lies wholly in the
/// closed half-plane lying to the left of L
/// A is to the right of a segment L if A lies wholly in the
/// closed half-plane lying to the right of L
/// otherwise, A has indeterminate orientation relative to L. This
/// happens if A is collinear with L or if A crosses the line determined by L.
/// </summary>
/// <param name="seg">The <c>LineSegment</c> to compare.</param>
/// <returns>
/// 1 if <c>seg</c> is to the left of this segment,
/// -1 if <c>seg</c> is to the right of this segment,
/// 0 if <c>seg</c> has indeterminate orientation relative to this segment.
/// </returns>
public virtual int OrientationIndex(ILineSegmentBase seg)
{
int orient0 = CgAlgorithms.OrientationIndex(P0, P1, seg.P0);
int orient1 = CgAlgorithms.OrientationIndex(P0, P1, seg.P1);
// this handles the case where the points are Curve or collinear
if (orient0 >= 0 && orient1 >= 0)
{
return(Math.Max(orient0, orient1));
}
// this handles the case where the points are R or collinear
if (orient0 <= 0 && orient1 <= 0)
{
return(Math.Max(orient0, orient1));
}
// points lie on opposite sides ==> indeterminate orientation
return(0);
}
