tippecanoe/mapbox/geometry/wagyu/build_result.hpp

#pragma once

#include <mapbox/geometry/wagyu/ring.hpp>
#include <mapbox/geometry/wagyu/ring_util.hpp>

namespace mapbox {
namespace geometry {
namespace wagyu {

template <typename T>
void push_ring_to_polygon(mapbox::geometry::polygon<T>& poly, ring_ptr<T>& r, bool reverse_output) {
    mapbox::geometry::linear_ring<T> lr;
    lr.reserve(r->size + 1);
    auto firstPt = r->points;
    auto ptIt = r->points;
    if (reverse_output) {
        do {
            lr.emplace_back(ptIt->x, ptIt->y);
            ptIt = ptIt->next;
        } while (ptIt != firstPt);
    } else {
        do {
            lr.emplace_back(ptIt->x, ptIt->y);
            ptIt = ptIt->prev;
        } while (ptIt != firstPt);
    }
    lr.emplace_back(firstPt->x, firstPt->y); // close the ring
    poly.push_back(lr);
}

template <typename T>
void build_result_polygons(std::vector<mapbox::geometry::polygon<T>>& solution,
                           ring_list<T>& rings,
                           bool reverse_output) {

    for (auto& r : rings) {
        assert(r->points);
        std::size_t cnt = point_count(r->points);
        if (cnt < 3) {
            continue;
        }
        solution.emplace_back();
        push_ring_to_polygon(solution.back(), r, reverse_output);
        for (auto& c : r->children) {
            assert(c->points);
            cnt = point_count(c->points);
            if (cnt < 3) {
                continue;
            }
            push_ring_to_polygon(solution.back(), c, reverse_output);
        }
        for (auto& c : r->children) {
            if (!c->children.empty()) {
                build_result_polygons(solution, c->children, reverse_output);
            }
        }
    }
}

template <typename T>
void build_result(std::vector<mapbox::geometry::polygon<T>>& solution,
                  ring_manager<T>& rings,
                  bool reverse_output) {
    build_result_polygons(solution, rings.children, reverse_output);
}
}
}
}