/// <summary>
/// Returns the position of the intersection that is closest to a specific position.
/// </summary>
/// <param name="posn">The position to search for.</param>
/// <param name="xsect">The closest intersection.</param>
/// <param name="tolsq">The smallest allowable distance (squared) between the
/// search position and the closest intersection (default=0.0).</param>
/// <returns>TRUE if the position was found.</returns>
internal bool GetClosest(IPosition posn, out IPosition xsect, double tolsq)
{
xsect = null;
// Go through each intersection, looking for the closest
// intersection that is not TOO close.
double mindsq = Double.MaxValue;
double dsq;
foreach (IntersectionData d in m_Data)
{
dsq = BasicGeom.DistanceSquared(posn, d.P1);
if (dsq < mindsq && dsq > tolsq)
{
mindsq = dsq;
xsect = d.P1;
}
// If the intersection is a graze, check the 2nd
// intersection too.
if (d.IsGraze)
{
dsq = BasicGeom.DistanceSquared(posn, d.P2);
if (dsq < mindsq && dsq > tolsq)
{
mindsq = dsq;
xsect = d.P2;
}
}
}
return(xsect != null);
}
/// <summary>
/// Checks if a position is coincident with a line segment
/// </summary>
/// <param name="p">The position to test</param>
/// <param name="start">The start of the segment.</param>
/// <param name="end">The end of the segment.</param>
/// <param name="tolsq">The tolerance (squared) to use. Default is XYTOLSQ.</param>
/// <returns>True if the test position lies somewhere along the segment.</returns>
public static bool IsCoincidentWith(IPointGeometry p, IPointGeometry start, IPointGeometry end, double tolsq)
{
// Check whether there is exact coincidence at either end.
if (p.IsCoincident(start) || p.IsCoincident(end))
{
return(true);
}
// Get the distance squared of a perpendicular dropped from
// the test position to the segment (or the closest end if the
// perpendicular does not fall ON the segment).
return(BasicGeom.DistanceSquared(p.X, p.Y, start.X, start.Y, end.X, end.Y) < tolsq);
}
private PointGeometry[] CheckMultiSegmentEnds(PointGeometry[] pts)
{
if (pts.Length <= 2)
{
return(pts);
}
//double tol = (Constants.XYRES * Constants.XYRES);
double tol = (0.001 * 0.001);
PointGeometry[] res = pts;
bool doCheck = true;
while (doCheck && res.Length > 2)
{
doCheck = false;
// If the start position coincides with the second segment, strip out
// the second position.
if (BasicGeom.DistanceSquared(res[0].X, res[0].Y, res[1].X, res[1].Y, res[2].X, res[2].Y) < tol)
{
PointGeometry[] tmp = new PointGeometry[res.Length - 1];
tmp[0] = res[0];
Array.Copy(res, 2, tmp, 1, res.Length - 2);
res = tmp;
doCheck = true;
}
}
// If the end position coincides with the second last segment, strip out
// the second last position.
doCheck = true;
while (doCheck && res.Length > 2)
{
doCheck = false;
int last = res.Length - 1;
if (BasicGeom.DistanceSquared(res[last].X, res[last].Y, res[last - 1].X, res[last - 1].Y, res[last - 2].X, res[last - 2].Y) < tol)
{
PointGeometry[] tmp = new PointGeometry[res.Length - 1];
Array.Copy(res, 0, tmp, 0, res.Length - 2);
tmp[tmp.Length - 1] = res[last];
res = tmp;
doCheck = true;
}
}
return(res);
}
static double MinDistanceSquared(ICircularArcGeometry g, IPosition p)
{
// If the position lies in the arc sector, the minimum distance
// is given by the distance to the circle. Otherwise the minimum
// distance is the distance to the closest end of the arc.
if (IsInSector(g, p, 0.0))
{
double dist = BasicGeom.Distance(p, g.Circle.Center);
double radius = g.Circle.Radius;
return((dist - radius) * (dist - radius));
}
else
{
double d1 = BasicGeom.DistanceSquared(p, g.BC);
double d2 = BasicGeom.DistanceSquared(p, g.EC);
return(Math.Min(d1, d2));
}
}
/// <summary>
/// Checks whether a position is coincident with a line segment, using a tolerance that's
/// consistent with the resolution of data.
/// </summary>
/// <param name="testX">The position to test</param>
/// <param name="testY"></param>
/// <param name="xs">Start of line segment.</param>
/// <param name="ys"></param>
/// <param name="xe">End of line segment.</param>
/// <param name="ye"></param>
/// <param name="tsq">The tolerance (squared) to use for checking whether the test point is
/// coincident with the segment.</param>
/// <returns>True if the distance from the test position to the line segment is less
/// than the specified tolerance.</returns>
private static bool IsCoincident(double testX, double testY, double xs, double ys, double xe, double ye, double tsq)
{
return(BasicGeom.DistanceSquared(testX, testY, xs, ys, xe, ye) < tsq);
}