public IList <Bezier2> ToBeziers()
{
var expectedIdenticalKnots = Degree + 1;
if (expectedIdenticalKnots != 4)
{
throw new NotSupportedException("Only cubic Bezier curves of 4 points are supported.");
}
var result = new Spline2(Degree, ControlPoints, KnotValues);
for (int offset = 0; ; offset++)
{
// get next set of values
var values = result.KnotValues.Skip(offset * expectedIdenticalKnots).Take(expectedIdenticalKnots).ToList();
if (values.Count == 0 && result.KnotValues.Count() % expectedIdenticalKnots == 0)
{
// done
break;
}
var expectedValue = values[0];
int missingValueCount;
if (values.Count < expectedIdenticalKnots)
{
// not enough values
missingValueCount = expectedIdenticalKnots - values.Count;
}
else if (values.Count < expectedIdenticalKnots || values.Any(v => v != expectedValue))
{
// not all the same
missingValueCount = expectedIdenticalKnots - values.Count(v => v == expectedValue);
}
else
{
missingValueCount = 0;
}
for (int i = 0; i < missingValueCount; i++)
{
result.InsertKnot(expectedValue);
}
}
var points = result.ControlPoints.ToList();
var curves = new List <Bezier2>();
for (int startIndex = 0; startIndex < points.Count; startIndex += expectedIdenticalKnots)
{
var curve = new Bezier2(points[startIndex], points[startIndex + 1], points[startIndex + 2], points[startIndex + 3]);
curves.Add(curve);
}
return(curves);
}
public static XElement ToXElement(this DxfSpline spline)
{
var spline2 = new Spline2(
spline.DegreeOfCurve,
spline.ControlPoints.Select(p => new SplinePoint2(p.Point.X, p.Point.Y)),
spline.KnotValues);
var beziers = spline2.ToBeziers();
var path = beziers.GetSvgPath();
return(new XElement(DxfToSvgConverter.Xmlns + "path",
new XAttribute("d", path.ToString()),
new XAttribute("fill-opacity", 0))
.AddStroke(spline.Color)
.AddStrokeWidth(1.0)
.AddVectorEffect());
}