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#include <mbgl/tile/geometry_tile_data.hpp>
#include <mbgl/tile/tile_id.hpp>
#include <mapbox/geometry/wagyu/wagyu.hpp>
namespace mbgl {
static double signedArea(const GeometryCoordinates& ring) {
double sum = 0;
for (std::size_t i = 0, len = ring.size(), j = len - 1; i < len; j = i++) {
const GeometryCoordinate& p1 = ring[i];
const GeometryCoordinate& p2 = ring[j];
sum += (p2.x - p1.x) * (p1.y + p2.y);
}
return sum;
}
static LinearRing<int32_t> toWagyuPath(const GeometryCoordinates& ring) {
LinearRing<int32_t> result;
result.reserve(ring.size());
for (const auto& p : ring) {
result.emplace_back(p.x, p.y);
}
return result;
}
static GeometryCollection toGeometryCollection(MultiPolygon<int16_t>&& multipolygon) {
GeometryCollection result;
for (auto& polygon : multipolygon) {
for (auto& ring : polygon) {
result.emplace_back(std::move(ring));
}
}
return result;
}
GeometryCollection fixupPolygons(const GeometryCollection& rings) {
using namespace mapbox::geometry::wagyu;
wagyu<int32_t> clipper;
for (const auto& ring : rings) {
clipper.add_ring(toWagyuPath(ring));
}
MultiPolygon<int16_t> multipolygon;
clipper.execute(clip_type_union, multipolygon, fill_type_even_odd, fill_type_even_odd);
return toGeometryCollection(std::move(multipolygon));
}
std::vector<GeometryCollection> classifyRings(const GeometryCollection& rings) {
std::vector<GeometryCollection> polygons;
std::size_t len = rings.size();
if (len <= 1) {
polygons.push_back(rings);
return polygons;
}
GeometryCollection polygon;
int8_t ccw = 0;
for (std::size_t i = 0; i < len; i++) {
double area = signedArea(rings[i]);
if (area == 0)
continue;
if (ccw == 0)
ccw = (area < 0 ? -1 : 1);
if (ccw == (area < 0 ? -1 : 1) && !polygon.empty()) {
polygons.push_back(polygon);
polygon.clear();
}
polygon.push_back(rings[i]);
}
if (!polygon.empty())
polygons.push_back(polygon);
return polygons;
}
void limitHoles(GeometryCollection& polygon, uint32_t maxHoles) {
if (polygon.size() > 1 + maxHoles) {
std::nth_element(polygon.begin() + 1,
polygon.begin() + 1 + maxHoles,
polygon.end(),
[] (const auto& a, const auto& b) {
return std::fabs(signedArea(a)) > std::fabs(signedArea(b));
});
polygon.resize(1 + maxHoles);
}
}
static Feature::geometry_type convertGeometry(const GeometryTileFeature& geometryTileFeature, const CanonicalTileID& tileID) {
const double size = util::EXTENT * std::pow(2, tileID.z);
const double x0 = util::EXTENT * tileID.x;
const double y0 = util::EXTENT * tileID.y;
auto tileCoordinatesToLatLng = [&] (const Point<int16_t>& p) {
double y2 = 180 - (p.y + y0) * 360 / size;
return Point<double>(
(p.x + x0) * 360 / size - 180,
360.0 / M_PI * std::atan(std::exp(y2 * M_PI / 180)) - 90.0
);
};
GeometryCollection geometries = geometryTileFeature.getGeometries();
switch (geometryTileFeature.getType()) {
case FeatureType::Unknown: {
assert(false);
return Point<double>(NAN, NAN);
}
case FeatureType::Point: {
MultiPoint<double> multiPoint;
for (const auto& p : geometries.at(0)) {
multiPoint.push_back(tileCoordinatesToLatLng(p));
}
if (multiPoint.size() == 1) {
return multiPoint[0];
} else {
return multiPoint;
}
}
case FeatureType::LineString: {
MultiLineString<double> multiLineString;
for (const auto& g : geometries) {
LineString<double> lineString;
for (const auto& p : g) {
lineString.push_back(tileCoordinatesToLatLng(p));
}
multiLineString.push_back(std::move(lineString));
}
if (multiLineString.size() == 1) {
return multiLineString[0];
} else {
return multiLineString;
}
}
case FeatureType::Polygon: {
MultiPolygon<double> multiPolygon;
for (const auto& pg : classifyRings(geometries)) {
Polygon<double> polygon;
for (const auto& r : pg) {
LinearRing<double> linearRing;
for (const auto& p : r) {
linearRing.push_back(tileCoordinatesToLatLng(p));
}
polygon.push_back(std::move(linearRing));
}
multiPolygon.push_back(std::move(polygon));
}
if (multiPolygon.size() == 1) {
return multiPolygon[0];
} else {
return multiPolygon;
}
}
}
// Unreachable, but placate GCC.
return Point<double>();
}
Feature convertFeature(const GeometryTileFeature& geometryTileFeature, const CanonicalTileID& tileID) {
Feature feature { convertGeometry(geometryTileFeature, tileID) };
feature.properties = geometryTileFeature.getProperties();
feature.id = geometryTileFeature.getID();
return feature;
}
Feature convertFeatureProperties(const GeometryTileFeature& geometryTileFeature) {
Feature feature { Point<double>() };
feature.properties = geometryTileFeature.getProperties();
feature.id = geometryTileFeature.getID();
return feature;
}
} // namespace mbgl
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