/// <summary>
/// Creates a Loop (Closed Spline) path through a given set of points.
/// </summary>
/// <param name="AppendTo">Spline should be appended to this path. If null, a new path will be created.</param>
/// <param name="Points">Points between which the loop will be created.</param>
/// <returns>Loop path.</returns>
public static SKPath CreateLoop(SKPath AppendTo, params SKPoint[] Points)
{
int i, c = Points.Length;
if (c == 0)
{
throw new ArgumentException("No points provided.", nameof(Points));
}
if (AppendTo is null)
{
AppendTo = new SKPath();
AppendTo.MoveTo(Points[0]);
}
else
{
SKPoint P = AppendTo.LastPoint;
if (P.X != Points[0].X || P.Y != Points[0].Y)
{
AppendTo.LineTo(Points[0]);
}
}
if (c == 1)
{
return(AppendTo);
}
float[] V = new float[c];
for (i = 0; i < c; i++)
{
V[i] = Points[i].X;
}
GetCubicBezierCoefficients(V, out float[] Ax, out float[] Bx);
for (i = 0; i < c; i++)
{
V[i] = Points[i].Y;
}
GetCubicBezierCoefficients(V, out float[] Ay, out float[] By);
for (i = 0; i < c - 1; i++)
{
AppendTo.CubicTo(Ax[i], Ay[i], Bx[i], By[i], Points[i + 1].X, Points[i + 1].Y);
}
AppendTo.CubicTo(Ax[i], Ay[i], Bx[i], By[i], Points[0].X, Points[0].Y);
AppendTo.Close();
return(AppendTo);
}
/// <summary>
/// Creates a Spline path through a given set of points.
/// </summary>
/// <param name="AppendTo">Spline should be appended to this path. If null, a new path will be created.</param>
/// <param name="Points">Points between which the spline will be created.</param>
/// <returns>Spline path.</returns>
public static SKPath CreateSpline(SKPath AppendTo, params SKPoint[] Points)
{
int i, c = Points.Length;
if (c == 0)
{
throw new ArgumentException("No points provided.", nameof(Points));
}
if (AppendTo is null)
{
AppendTo = new SKPath();
AppendTo.MoveTo(Points[0]);
}
else
{
AppendTo.LineTo(Points[0]);
}
if (c == 1)
{
return(AppendTo);
}
if (c == 2)
{
AppendTo.LineTo(Points[1]);
return(AppendTo);
}
double[] V = new double[c];
for (i = 0; i < c; i++)
{
V[i] = Points[i].X;
}
GetCubicBezierCoefficients(V, out double[] Ax, out double[] Bx);
for (i = 0; i < c; i++)
{
V[i] = Points[i].Y;
}
GetCubicBezierCoefficients(V, out double[] Ay, out double[] By);
for (i = 0; i < c - 1; i++)
{
AppendTo.CubicTo((float)Ax[i], (float)Ay[i], (float)Bx[i], (float)By[i],
Points[i + 1].X, Points[i + 1].Y);
}
return(AppendTo);
}