/// <summary>
/// Gets the points that are furthest apart.
/// </summary>
/// <param name="nIndx1">Ouput. The first index.</param>
/// <param name="nIndx2">Ouput. The second index.</param>
/// <param name="dDist">Ouput. The distance.</param>
public void GetExtremePoints(ref int nIndx1, ref int nIndx2,
ref double dDist)
{
// First take a guess at them.
GetExtremePointsEst(ref nIndx1, ref nIndx2, ref dDist, 0);
// Set up a circle to bound the 2 guesses.
C2DVector Vec = new C2DVector(this[nIndx1], this[nIndx2]);
Vec.Multiply(0.5);
C2DCircle Circle = new C2DCircle(this[nIndx1] + new C2DPoint(Vec), dDist / 2);
// Now, if the guess was wrong, there must be a point outside the circle which is part of
// the right solution. Go through all these, check and reset the result each time.
for (int i = 0; i < Count; i++)
{
if (i != nIndx1 && i != nIndx2)
{
if (!Circle.Contains(this[i]))
{
double dDistCheck = 0;
int nCheck1 = GetFurthestPoint(i, ref dDistCheck);
if (dDistCheck > dDist)
{
nIndx1 = i;
nIndx2 = nCheck1;
dDist = dDistCheck;
}
}
}
}
}
/// <summary>
/// Gets the minimum bounding circle.
/// </summary>
/// <param name="Circle">Ouput. The Circle.</param>
public void GetBoundingCircle(C2DCircle Circle)
{
if (this.Count < 3)
{
if (this.Count == 2)
{
Circle.SetMinimum(this[0], this[1]);
}
else if (this.Count == 1)
{
Circle.Set(this[0], 0);
}
else
{
Debug.Assert(false, "Point set with no points. Cannot calculate bounding circle.");
}
return;
}
int nIndx1 = 0;
int nIndx2 = 0;;
int nIndx3 = 0;;
double dDist = 0;;
// First get the points that are furthest away from each other.
GetExtremePoints(ref nIndx1, ref nIndx2, ref dDist);
// Set the circle to bound these.
Circle.SetMinimum(this[nIndx1], this[nIndx2]);
// Set up a flag to show if we are circumscibed. (Once we are, we always will be).
bool bCircum = false;
// Cycle through and if any points aren't in the circle, then set the circle to be circumscribed.
for (int i = 0; i < Count; i++)
{
if (i != nIndx1 && i != nIndx2)
{
if (!Circle.Contains(this[i]))
{
nIndx3 = i;
Circle.SetCircumscribed(this[nIndx1], this[nIndx2], this[nIndx3]);
bCircum = true;
// Break out and try again.
break;
}
}
}
// If we didn't succeed first time then go through again setting it to be circumscribed every time.
if (bCircum)
{
for (int i = 0; i < Count; i++)
{
if (i != nIndx1 && i != nIndx2 && i != nIndx3)
{
if (!Circle.Contains(this[i]))
{
double Dist1 = this[i].Distance(this[nIndx1]);
double Dist2 = this[i].Distance(this[nIndx2]);
double Dist3 = this[i].Distance(this[nIndx3]);
if (Dist1 < Dist2 && Dist1 < Dist3)
{
// Closest to point 1 so elimitate this
nIndx1 = i;
}
else if (Dist2 < Dist3)
{
// Closest to point 2 so elimitate this
nIndx2 = i;
}
else
{
// Closest to point 3 so elimitate this
nIndx3 = i;
}
Circle.SetCircumscribed(this[nIndx1], this[nIndx2], this[nIndx3]);
}
}
}
}
}