HilbertEncoder.h
/**********************************************************************
*
* GEOS - Geometry Engine Open Source
* http://geos.osgeo.org
*
* Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>
*
* This is free software; you can redistribute and/or modify it under
* the terms of the GNU Lesser General Public Licence as published
* by the Free Software Foundation.
* See the COPYING file for more information.
*
**********************************************************************/
#pragma once
#include <geos/export.h>
#include <geos/geom/Geometry.h>
#include <string>
#include <vector>
#include <cstdint>
// Forward declarations
namespace geos {
namespace geom {
class Coordinate;
}
}
namespace geos {
namespace shape { // geos.shape
namespace fractal { // geos.shape.fractal
class GEOS_DLL HilbertEncoder {
public:
HilbertEncoder(uint32_t p_level, geom::Envelope& extent);
uint32_t encode(const geom::Envelope* env);
static void sort(std::vector<geom::Geometry*>& geoms);
template<typename T>
static geom::Envelope getEnvelope(T begin, T end) {
geom::Envelope extent;
for (auto it = begin; it != end; ++it) {
const auto* g = *it;
if (extent.isNull())
extent = *(g->getEnvelopeInternal());
else
extent.expandToInclude(*(g->getEnvelopeInternal()));
}
return extent;
}
template<typename T>
static void sort(T begin, T end) {
auto extent = getEnvelope(begin, end);
HilbertEncoder encoder(12, extent);
HilbertComparator hilbertCompare(encoder);
std::sort(begin, end, hilbertCompare);
}
private:
uint32_t level;
double minx;
double miny;
double strideX;
double strideY;
struct HilbertComparator {
HilbertEncoder& enc;
HilbertComparator(HilbertEncoder& e)
: enc(e) {};
bool
operator()(const geom::Geometry* a, const geom::Geometry* b)
{
return enc.encode(a->getEnvelopeInternal()) > enc.encode(b->getEnvelopeInternal());
}
};
};
} // namespace geos.shape.fractal
} // namespace geos.shape
} // namespace geos
geos::geom::Coordinate
Coordinate is the lightweight class used to store coordinates.
Definition Coordinate.h:217
geos::geom
Definition Angle.h:26
geos
Basic namespace for all GEOS functionalities.
Definition geos.h:38