private double[] GetEllipseParameters(Ellipse ellipse)
{
double atan1;
double atan2;
if (ellipse.IsFullEllipse)
{
atan1 = 0.0;
atan2 = MathHelper.TwoPI;
}
else
{
Vector2 startPoint = new Vector2(ellipse.Center.X, ellipse.Center.Y) + ellipse.PolarCoordinateRelativeToCenter(ellipse.StartAngle);
Vector2 endPoint = new Vector2(ellipse.Center.X, ellipse.Center.Y) + ellipse.PolarCoordinateRelativeToCenter(ellipse.EndAngle);
double a = ellipse.MajorAxis*0.5;
double b = ellipse.MinorAxis*0.5;
double px1 = (startPoint.X - ellipse.Center.X)/a;
double py1 = (startPoint.Y - ellipse.Center.Y)/b;
double px2 = (endPoint.X - ellipse.Center.X)/a;
double py2 = (endPoint.Y - ellipse.Center.Y)/b;
atan1 = Math.Atan2(py1, px1);
atan2 = Math.Atan2(py2, px2);
}
return new[] {atan1, atan2};
}
