/// <summary>
/// Is the point p on the arc and not on the gap
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
private bool IsPointOnArc(GeoPoint2D p)
{ // we assume that the point is on the (full) ellipse and test here, whether it is on the actual arc
if (Math.Abs(sweepPar - SweepAngle.Full) < 1e-10 || Math.Abs(sweepPar - SweepAngle.FullReverse) < 1e-10)
{
return(true);
}
if (Math.Abs(sweepPar) < 0.1 || Math.Abs(sweepPar) > SweepAngle.Full - 0.1)
{ // if start and endpoint are very close, then we cannot use "IsLeftOf", because it might be imprecise
return(IsParameterOnCurve(PositionOf(p)));
}
else
{
if (sweepPar > 0.0)
{
return(p.IsLeftOf(endPoint, startPoint));
}
else
{
return(p.IsLeftOf(startPoint, endPoint));
}
}
}
private bool crossingZero; // geht über die X-Achse
private void RecalcQuadrant()
{
// Berechnung von start und sweep, wird benötigt für die GDI Darstellung
Angle MajorAngle = majorAxis.Angle;
double s = Math.Sin(MajorAngle);
double c = Math.Cos(MajorAngle);
ModOp2D toCenter = new ModOp2D(c, s, (-c * center.x - s * center.y), -s, c, (s * center.x - c * center.y));
GeoVector2D startVector = toCenter * startPoint - GeoPoint2D.Origin;
GeoVector2D endVector = toCenter * endPoint - GeoPoint2D.Origin;
start = startVector.Angle;
sweep = new SweepAngle(start, endVector.Angle, sweepPar > 0.0);
if (sweep == 0.0)
{
if (sweepPar > 0.0)
{
sweep = Math.PI * 2.0;
}
if (sweepPar < 0.0)
{
sweep = -Math.PI * 2.0;
}
}
// Berechnung der betroffenen Quadranten
startQuad = endQuad = -1;
if (startPoint.IsLeftOf(top, right))
{
startQuad = 0;
}
else if (startPoint.IsLeftOf(left, top))
{
startQuad = 1;
}
else if (startPoint.IsLeftOf(bottom, left))
{
startQuad = 2;
}
else if (startPoint.IsLeftOf(right, bottom))
{
startQuad = 3;
}
if (startQuad == -1)
{ // der Startpunkt muss auf einer Ecke liegen
double dmin, d;
dmin = Geometry.Dist(startPoint, right); startQuad = 0;
d = Geometry.Dist(startPoint, top);
if (d < dmin)
{
startQuad = 1; dmin = d;
}
d = Geometry.Dist(startPoint, left);
if (d < dmin)
{
startQuad = 2; dmin = d;
}
if (Geometry.Dist(startPoint, bottom) < dmin)
{
startQuad = 3;
}
}
if (endPoint.IsLeftOf(top, right))
{
endQuad = 0;
}
else if (endPoint.IsLeftOf(left, top))
{
endQuad = 1;
}
else if (endPoint.IsLeftOf(bottom, left))
{
endQuad = 2;
}
else if (endPoint.IsLeftOf(right, bottom))
{
endQuad = 3;
}
if (endQuad == -1)
{
double dmin, d;
dmin = Geometry.Dist(endPoint, right); endQuad = 0;
d = Geometry.Dist(endPoint, top);
if (d < dmin)
{
endQuad = 1; dmin = d;
}
d = Geometry.Dist(endPoint, left);
if (d < dmin)
{
endQuad = 2; dmin = d;
}
if (Geometry.Dist(endPoint, bottom) < dmin)
{
endQuad = 3;
}
}
if ((sweepPar > 0.0) == (GeoVector2D.Orientation(majorAxis, minorAxis) > 0))
{
// crossingZero = right.IsLeftOf(endPoint,startPoint);
// if (Precision.IsEqual(right,endPoint) && endQuad==0) crossingZero = true;
// if (Precision.IsEqual(right,startPoint) && startQuad==3) crossingZero = true;
crossingZero = (endQuad < startQuad);
if (endQuad == startQuad)
{
crossingZero = sweepPar > Math.PI;
}
}
else
{
// crossingZero = right.IsLeftOf(startPoint,endPoint);
crossingZero = (startQuad < endQuad);
if (endQuad == startQuad)
{
crossingZero = sweepPar < -Math.PI;
}
}
}