/// <summary>
/// Get Closed Bezier Spline Control Points.
/// </summary>
/// <param name="knots">Input Knot Bezier spline points.</param>
/// <param name="firstControlPoints">Output First Control points array of the same
/// length as the <paramref name="knots"/> array.</param>
/// <param name="secondControlPoints">Output Second Control points array of of the same
/// length as the <paramref name="knots"/> array.</param>
public static void GetCurveControlPoints(
IList <ILocation> knots,
out ILocationCollection firstControlPoints,
out ILocationCollection secondControlPoints)
{
firstControlPoints = MilSymFactory.LocationCollection();
secondControlPoints = MilSymFactory.LocationCollection();
int n = knots.Count;
if (n <= 2)
{
return;
}
// Calculate first Bezier control points
// The matrix.
var a = new double[n];
var b = new double[n];
var c = new double[n];
for (int i = 0; i < n; ++i)
{
a[i] = 1;
b[i] = 4;
c[i] = 1;
}
// Right hand side vector for points X coordinates.
var rhs = new double[n];
for (int i = 0; i < n; ++i)
{
int j = (i == n - 1) ? 0 : i + 1;
rhs[i] = (4 * knots[i].Longitude) + (2 * knots[j].Longitude);
}
// Solve the system for X.
double[] x = Cyclic.Solve(a, b, c, 1, 1, rhs);
// Right hand side vector for points Y coordinates.
for (int i = 0; i < n; ++i)
{
int j = (i == n - 1) ? 0 : i + 1;
rhs[i] = (4 * knots[i].Latitude) + (2 * knots[j].Latitude);
}
// Solve the system for Y.
double[] y = Cyclic.Solve(a, b, c, 1, 1, rhs);
// Fill output arrays.
for (int i = 0; i < n; ++i)
{
// First control point.
firstControlPoints.Add(MilSymFactory.Location(Order.LatLon, y[i], x[i]));
// Second control point.
secondControlPoints.Add(
MilSymFactory.Location(Order.LatLon, (2 * knots[i].Latitude) - y[i], (2 * knots[i].Longitude) - x[i]));
}
}
/// <summary>
/// Get the curve control points.
/// </summary>
/// <param name="count">
/// The point count.
/// </param>
/// <param name="knots">
/// The knots.
/// </param>
/// <param name="firstControlPoints">
/// The first set of control points.
/// </param>
/// <param name="secondControlPoints">
/// The second set of control points.
/// </param>
public static void GetCurveControlPoints(
int count,
IList <Point> knots,
out IList <Point> firstControlPoints,
out IList <Point> secondControlPoints)
{
firstControlPoints = new List <Point>(count);
secondControlPoints = new List <Point>(count);
if (count <= 2)
{
return;
}
// Calculate first Bezier control points
// The matrix.
var a = new double[count];
var b = new double[count];
var c = new double[count];
for (int i = 0; i < count; ++i)
{
a[i] = 1;
b[i] = 4;
c[i] = 1;
}
// Right hand side vector for points X coordinates.
var rhs = new double[count];
for (int i = 0; i < count; ++i)
{
int j = (i == count - 1) ? 0 : i + 1;
rhs[i] = (4 * knots[i].X) + (2 * knots[j].X);
}
// Solve the system for X.
double[] x = Cyclic.Solve(a, b, c, 1, 1, rhs);
// Right hand side vector for points Y coordinates.
for (int i = 0; i < count; ++i)
{
int j = (i == count - 1) ? 0 : i + 1;
rhs[i] = (4 * knots[i].Y) + (2 * knots[j].Y);
}
// Solve the system for Y.
double[] y = Cyclic.Solve(a, b, c, 1, 1, rhs);
// Fill output arrays.
for (int i = 0; i < count; ++i)
{
// First control point.
firstControlPoints.Add(new Point(x[i], y[i]));
// Second control point.
secondControlPoints.Add(new Point(
(2 * knots[i].X) - x[i],
(2 * knots[i].Y) - y[i]));
}
}