/// <summary>
/// Gets the point on this line that is closest to a specified position.
/// </summary>
/// <param name="p">The position to search from.</param>
/// <param name="tol">Maximum distance from line to the search position</param>
/// <returns>The closest position (null if the line is further away than the specified
/// max distance)</returns>
internal override IPosition GetClosest(IPointGeometry p, ILength tol)
{
// Get the perpendicular point (or closest end)
IPointGeometry s = Start;
IPointGeometry e = End;
double xp, yp;
BasicGeom.GetPerpendicular(p.X, p.Y, s.X, s.Y, e.X, e.Y, out xp, out yp);
// Ignore if point is too far away
double t = tol.Meters;
double dx = p.X - xp;
if (dx > t)
{
return(null);
}
double dy = p.Y - yp;
if (dy > t)
{
return(null);
}
double dsq = (dx * dx + dy * dy);
if (dsq > t * t)
{
return(null);
}
return(new Position(xp, yp));
}
public static ILength GetDistance(ILineSegmentGeometry g, IPosition point)
{
double xp, yp;
BasicGeom.GetPerpendicular(point.X, point.Y, g.Start.X, g.Start.Y, g.End.X, g.End.Y, out xp, out yp);
double d = BasicGeom.Distance(new Position(xp, yp), point);
return(new Length(d));
}