Class SegmentStringExtractor

generative/noding/geometry-noder.cpp:17–91

namespace generative::noding {

class SegmentStringExtractor : public geos::geom::GeometryComponentFilter
{
public:
    SegmentStringExtractor(geos::noding::SegmentString::NonConstVect& to) : m_to(to) {}
    SegmentStringExtractor(const SegmentStringExtractor&) = delete;
    SegmentStringExtractor& operator=(const SegmentStringExtractor&) = delete;

    void filter_ro(const geos::geom::Geometry* geometry) override
    {
        switch (geometry->getGeometryTypeId())
        {
        case geos::geom::GeometryTypeId::GEOS_POINT:
        {
            // HACK: This is gross and dirty, and has the potential to explode in future GEOS
            // releases. Single-coordinate segment strings (which isn't _really_ a **segment**
            // string at all) don't get noded.
            //
            // So bold facedly lie to the noder, by treating POINTs as a "segment" with two
            // duplicate coordinates.
            auto coords = geometry->getCoordinates();
            coords->add(coords->getAt(0), true);
            geos::noding::SegmentString* segment_string =
                new geos::noding::NodedSegmentString(coords.release(), false, false, nullptr);
            m_to.push_back(segment_string);
            break;
        }
        case geos::geom::GeometryTypeId::GEOS_LINESTRING:
        case geos::geom::GeometryTypeId::GEOS_LINEARRING:
        {
            auto coords = geometry->getCoordinates();
            geos::noding::SegmentString* segment_string =
                new geos::noding::NodedSegmentString(coords.release(), false, false, nullptr);
            m_to.push_back(segment_string);
            break;
        }
        // need to get the interior holes too
        case geos::geom::GeometryTypeId::GEOS_POLYGON:
        {
            const auto* poly = dynamic_cast<const geos::geom::Polygon*>(geometry);
            if (poly != nullptr)
            {
                const auto* exterior = poly->getExteriorRing();
                this->filter_ro(exterior);

                for (size_t i = 0; i < poly->getNumInteriorRing(); i++)
                {
                    const auto* interior = poly->getInteriorRingN(i);
                    this->filter_ro(interior);
                }
            }
            break;
        }

        // Intentional fallthrough
        case geos::geom::GeometryTypeId::GEOS_CIRCULARSTRING:
        case geos::geom::GeometryTypeId::GEOS_COMPOUNDCURVE:
        case geos::geom::GeometryTypeId::GEOS_MULTICURVE:
        case geos::geom::GeometryTypeId::GEOS_MULTISURFACE: