lsst::afw::geom::ellipses::EllipseHorizontalLineIntersection Class Reference

Public Member Functions
	EllipseHorizontalLineIntersection (Ellipse const &ellipse)
boost::optional< std::pair< double, double > >	xAt (double y) const

Detailed Description

Definition at line 62 of file PixelRegion.cc.

Constructor & Destructor Documentation

EllipseHorizontalLineIntersection()

lsst::afw::geom::ellipses::EllipseHorizontalLineIntersection::EllipseHorizontalLineIntersection ( Ellipse const & ellipse )

inlineexplicit

Definition at line 65 of file PixelRegion.cc.

                                                                       :
        _center(ellipse.getCenter()),
        _p(0.0), _t(0.0), _r(0.0)
    {
        Quadrupole converted(ellipse.getCore());
        converted.normalize();
        auto q = converted.getMatrix();
        if (q(1, 1) < q(0, 0)*std::numeric_limits<double>::epsilon()) {
            _r = q(0, 0);
        } else {
            _p = q(0, 1)/q(1, 1);
            _r = q(0, 0) - q(0, 1)*_p;
            _t = _r/q(1, 1);
        }
    }

Member Function Documentation

xAt()

boost::optional< std::pair< double, double > > lsst::afw::geom::ellipses::EllipseHorizontalLineIntersection::xAt ( double y ) const

inline

Definition at line 81 of file PixelRegion.cc.

                                                               {
        double yc = y - _center.getY();
        double xc = _p*yc + _center.getX();
        double s = _r - _t*yc*yc;
        if (s < 0) {
            return boost::none;
        } else {
            double d = std::sqrt(s);
            return std::make_pair(xc - d, xc + d);
        }
    }

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The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/afw/g5a732f18d5+be83d3ecdb/src/geom/ellipses/PixelRegion.cc