Calculating distance from point to voronoi cell with boost - c++

Question

Good night. Has anyone encountered a similar problem?
Constructing Voronoi diagram has not caused problems. Voronoi cell is a polygon, at least for me. The library also allows you to find the distance from a point to a polygon. But the library function does not want to work with the cell. The compiler produces something in Elvish. Joke. In short, the compiler output can not help me.
Is there a way to make a polygon from the cell?
Voronoi diagram is constructed on vpoints. The program should calculate the distance from the qpoints element to the corresponding cell.
Here is my code:
#include <iostream>
#include <vector>
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/polygon.hpp>
#include <boost/polygon/voronoi.hpp>
namespace bg = boost::geometry;
using boost::polygon::voronoi_diagram;
typedef voronoi_diagram<double>::cell_type cell_type;
typedef voronoi_diagram<double>::edge_type edge_type;
typedef voronoi_diagram<double>::vertex_type vertex_type;
typedef boost::polygon::point_data<double> point_type;
using namespace std;
int main() {
vector< point_type > vpoints;
vpoints.push_back(point_type(0.0, 0.0));
vpoints.push_back(point_type(0.0, 4.0));
vpoints.push_back(point_type(4.0, 4.0));
vpoints.push_back(point_type(4.0, 0.0));
vpoints.push_back(point_type(2.0, 2.0));
vector< point_type > qpoints;
qpoints.push_back(point_type(0.0, 0.0));
qpoints.push_back(point_type(0.0, 2.0));
qpoints.push_back(point_type(3.0, 3.0));
qpoints.push_back(point_type(5.0, 5.0));
qpoints.push_back(point_type(5.0, 5.0));
voronoi_diagram<double> vd;
construct_voronoi(vpoints.begin(), vpoints.end(), &vd);
for (int i = 0; i < qpoints.size(); i++) {
for (voronoi_diagram<double>::const_cell_iterator it = vd.cells().begin();
it != vd.cells().end(); ++it) {
if (i == it->source_index()) {
cout << "v[i]=(" << vpoints[i].x() << "," << vpoints[i].y() << ")\t";
cout << "q[i]=(" << qpoints[i].x() << "," << qpoints[i].y() << ")\t";
cout << "Distance=";
cout << bg::distance(qpoints[i], *it) << endl;
cout << endl;
break;
}
}
}
return 0;
}

Answer 1

The message is
boost_1_57_0/boost/geometry/core/geometry_id.hpp|37 col 5| error: no matching function for call to ‘assertion_failed(mpl_::failed************ (boost::geometry::core_dispatch::geometry_id<void>::NOT_IMPLEMENTED_FOR_THIS_GEOMETRY_TYPE::************)(mpl_::assert_::types<void, mpl_::na, mpl_::na, mpl_::na>))’
Which is the NOT_IMPLEMENTED_FOR_THIS_GEOMETRY_TYPE assert. It happens doing geometry_id for reverse_dispatch:
/*!
\brief Meta-function returning the id of a geometry type
\details The meta-function geometry_id defines a numerical ID (based on
boost::mpl::int_<...> ) for each geometry concept. A numerical ID is
sometimes useful, and within Boost.Geometry it is used for the
reverse_dispatch metafuntion.
\note Used for e.g. reverse meta-function
\ingroup core
*/
template <typename Geometry>
struct geometry_id : core_dispatch::geometry_id<typename tag<Geometry>::type>
{};
The same warning is triggered when you do
cout << distance(qpoints[i], qpoints[i]) << endl;
So the problem is that your point type is not a reqistered geometry. Including
#include <boost/geometry/geometries/adapted/boost_polygon.hpp>
makes that compile, but of course
cout << distance(qpoints[i], *it) << endl;
still fails, this time because const boost::polygon::voronoi_cell<double> isn't a known geometry type to Boost Geometry.
I'd suggest not mixing the libraries unless you know why you want to.
It looks to me that a voronoi cell can be more than just a single thing (contains_segment() and contains_point() are indications). You may have to write some switching logic to handle the possible cases separately, and perhaps use euclidean_distance from Boost Polygon in the process (as opposed to boost::geometry::distance`)