maybe polygon_set resize is ERROR always. supplied: images and COMPLETE code.

Reproduce the issue with the complete code in offsetTest(), focusing on boost::polygon::set_points and the result = mpol + buffer_distance operation. Compare its output with bufferTest() and determine why polygon_set produces an outside polygon; done means the supplied case produces the expected empty result.

maybe polygon_set resize is ERROR always.
When use boost::geometry::buffer, the result is right;
but use polygon_set, the result is ERROR.
right result: empty

geometryBufferRight

error result: exist an polygon outside

polygonResizeError

all code is as follow:
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/adapted/boost_polygon.hpp>
#include <boost/polygon/polygon.hpp>

using namespace std;
namespace gtl = boost::polygon;
using namespace boost::polygon::operators;

vector srcData = {
688672, 1590035,
688438, 1592394,
688091, 1595907,
687859, 1598266,
687209, 1600398,
687545, 1597000,
687795, 1594459,
688032, 1592042,
687795, 1589625,
687545, 1587084,
687306, 1584666,
686722, 1582740,
686159, 1580883,
686159, 1578528,
686159, 1576209,
687170, 1579536,
687859, 1581805,
688091, 1584163,
688438, 1587676,
688672, 1590035,
};

auto sz = srcData.size() / 2;
const int buffer_distance = -1000;

//bufferTest
int bufferTest()
{
typedef int coordinate_type;
typedef boost::geometry::model::d2::point_xy<coordinate_type> point;
typedef boost::geometry::model::polygon polygon;

polygon poly;
// CW Closed
for (int i = sz - 1; i >= 0; --i)
boost::geometry::append(poly.outer(), point(srcData[i * 2], srcData[i * 2 + 1]));

boost::geometry::model::multi_polygon mpol;
mpol.emplace_back(move(poly));

// Declare strategies
const int points_per_circle = 36;
boost::geometry::strategy::buffer::distance_symmetric<coordinate_type> distance_strategy(buffer_distance);
boost::geometry::strategy::buffer::join_round join_strategy(points_per_circle);
boost::geometry::strategy::buffer::end_round end_strategy(points_per_circle);
boost::geometry::strategy::buffer::point_circle circle_strategy(points_per_circle);
boost::geometry::strategy::buffer::side_straight side_strategy;

// Declare output
boost::geometry::model::multi_polygon result;

// Create the buffer of a multi polygon
boost::geometry::buffer(mpol, result,
distance_strategy, side_strategy,
join_strategy, end_strategy, circle_strategy);

return 0;
}

int offsetTest() {
//lets declare ourselves a polygon set
using namespace gtl; //because of operators
typedef boost::polygon::polygon_with_holes_data polygon;
typedef boost::polygon::polygon_traits::point_type point;
typedef boost::polygon::polygon_with_holes_traits::hole_type hole;
typedef std::vector polygonset;

vector pts;
// CW closed
//for (int i = sz - 1; i >= 0; --i)
// pts.emplace_back(point(srcData[i * 2], srcData[i * 2 + 1]));
// CCW open
for (int i = 0; i < sz - 1; ++i)
pts.emplace_back(point(srcData[i * 2], srcData[i * 2 + 1]));

polygon poly;
boost::polygon::set_points(poly, pts.begin(), pts.end());

polygonset mpol, result;
mpol.emplace_back(move(poly));

result = mpol + buffer_distance;

return 0;
}

int main() {

bufferTest();

// ERROR!!!
offsetTest();

return 0;
}