/// <summary>
/// Finds, provided it exists, the intersection point with the specified <see cref="Line2D"/>.
/// </summary>
///
/// <param name="other"><see cref="Line2D"/> to find intersection with.</param>
///
/// <returns>Returns intersection point with the specified <see cref="Line2D"/>, or <see langword="null"/>, if
/// the line does not intersect with this segment.</returns>
///
/// <remarks><para>If the line and the segment do not intersect, the method returns <see langword="null"/>. If the line
/// and the segment share multiple points, the method throws an <see cref="OverlappingLinesException"/>.
/// </para></remarks>
///
/// <exception cref="OverlappingLinesException">Thrown if this segment is a portion of
/// <paramref name="other"/> line.</exception>
///
public Vector2?GetIntersectionWith(Line2D other)
{
Vector2?result;
if ((_line.Slope == other.Slope) || (_line.IsVertical && other.IsVertical))
{
if (_line.Intercept == other.Intercept)
{
throw new OverlappingLineLineSegmentException(this, other, "Segment is a portion of the specified line.");
}
// unlike Line.GetIntersectionWith(Line), this does not throw on parallel distinct lines
result = null;
}
else
{
result = _line.GetIntersectionWith(other);
}
if ((result.HasValue) && (LocateProjection(result.Value) != ProjectionLocation.SegmentAB))
{
// the intersection is on this segment's extended line, but not on the segment itself
result = null;
}
return(result);
}
private static void Line2DTest()
{
Line2D line1 = new Line2D(1, 1, 1);
Line2D line2 = new Line2D(1, 1, 0);
Line2D line3 = new Line2D(1, -1, -3);
Console.WriteLine("Line1: {0}", line1);
Console.WriteLine("Line2: {0}", line2);
Console.WriteLine("Line3: {0}", line3);
Point2D intersection = line1.GetIntersectionWith(line2);
if (intersection == null)
{
Console.WriteLine("No intersection between line1 and line2.");
}
else
{
Console.WriteLine("Intersection: {0}", intersection);
}
intersection = line1.GetIntersectionWith(line3);
if (intersection == null)
{
Console.WriteLine("No intersection between line1 and line3.");
}
else
{
Console.WriteLine("Intersection: {0}", intersection);
}
Point2D p1 = new Point2D(1, 5);
Point2D p2 = new Point2D(2, 4);
Line2D line4 = new Line2D(p1, p2);
Console.WriteLine("Line4: {0}", line4);
Line2D line5 = new Line2D(0, 1, -3);
Console.WriteLine("line5: {0}", line5);
}
