private void Init()
{
if (radiusDEG > 90)
{
//--spans more than half the globe
Debug.Assert(enclosingBox.GetWidth() == 360);
double backDistDEG = 180 - radiusDEG;
if (backDistDEG > 0)
{
double backRadius = 180 - radiusDEG;
double backX = DistanceUtils.NormLonDEG(GetCenter().GetX() + 180);
double backY = DistanceUtils.NormLatDEG(GetCenter().GetY() + 180);
//Shrink inverseCircle as small as possible to avoid accidental overlap.
// Note that this is tricky business to come up with a value small enough
// but not too small or else numerical conditioning issues become a problem.
backRadius -= Math.Max(Ulp(Math.Abs(backY) + backRadius), Ulp(Math.Abs(backX) + backRadius));
if (inverseCircle != null)
{
inverseCircle.Reset(backX, backY, backRadius);
}
else
{
inverseCircle = new GeoCircle(ctx.MakePoint(backX, backY), backRadius, ctx);
}
}
else
{
inverseCircle = null; //whole globe
}
horizAxisY = GetCenter().GetY(); //although probably not used
}
else
{
inverseCircle = null;
double _horizAxisY = ctx.GetDistCalc().CalcBoxByDistFromPt_yHorizAxisDEG(GetCenter(), radiusDEG, ctx);
//some rare numeric conditioning cases can cause this to be barely beyond the box
if (_horizAxisY > enclosingBox.GetMaxY())
{
horizAxisY = enclosingBox.GetMaxY();
}
else if (_horizAxisY < enclosingBox.GetMinY())
{
horizAxisY = enclosingBox.GetMinY();
}
else
{
horizAxisY = _horizAxisY;
}
//Debug.Assert(enclosingBox.Relate_yRange(horizAxis, horizAxis, ctx).Intersects());
}
}
