void _clipper_do(const ClipperLib::ClipType clipType, const Slic3r::Polylines &subject, 
    const Slic3r::Polygons &clip, ClipperLib::PolyTree* retval, const ClipperLib::PolyFillType fillType,
    const bool safety_offset_)
{
    PROFILE_BLOCK(_clipper_do_polylines);

    // read input
    ClipperLib::Paths input_subject, input_clip;
    Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
    Slic3rMultiPoints_to_ClipperPaths(clip,    &input_clip);
    
    // perform safety offset
    if (safety_offset_) safety_offset(&input_clip);
    
    // init Clipper
    ClipperLib::Clipper clipper;
    clipper.Clear();
    
    // add polygons
    {
        PROFILE_BLOCK(_clipper_do_polylines_AddPaths);
        clipper.AddPaths(input_subject, ClipperLib::ptSubject, false);
        clipper.AddPaths(input_clip,    ClipperLib::ptClip,    true);
    }
    
    // perform operation
    {
        PROFILE_BLOCK(_clipper_do_polylines_Execute);
        clipper.Execute(clipType, *retval, fillType, fillType);
    }
}

polygon polygon::createUnion(const std::vector<polygon>& data)
{
	base_int maxDenom = 1;
	for(auto poly : data)
	{
		maxDenom = lcm(maxDenom, poly.highestDenominator());
	}

	maxDenom = std::min(maxDenom, base_int(1000000000L));
	//std::cout << "-----" << std::endl;
	//std::cout << maxDenom << std::endl;
	polygon base = data[0];
		
	for(unsigned int i = 1; i < data.size(); i++)
	{
		ClipperLib::Clipper clipper;
		clipper.AddPath(base.path(maxDenom), ClipperLib::PolyType::ptSubject, true);
		clipper.AddPath(data[i].path(maxDenom), ClipperLib::PolyType::ptClip, true);
		
		ClipperLib::Paths returnedPaths;
		clipper.Execute(ClipperLib::ClipType::ctUnion, returnedPaths, ClipperLib::pftNonZero, ClipperLib::pftNonZero);

		base = polygon::from(returnedPaths, maxDenom)[0];

	}

	return base;
}

ClipperLib::PolyTree
_clipper_do(const ClipperLib::ClipType clipType, const Polylines &subject, 
    const Polygons &clip, const ClipperLib::PolyFillType fillType,
    const bool safety_offset_)
{
    // read input
    ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
    ClipperLib::Paths input_clip    = Slic3rMultiPoints_to_ClipperPaths(clip);
    
    // perform safety offset
    if (safety_offset_) safety_offset(&input_clip);
    
    // init Clipper
    ClipperLib::Clipper clipper;
    clipper.Clear();
    
    // add polygons
    clipper.AddPaths(input_subject, ClipperLib::ptSubject, false);
    clipper.AddPaths(input_clip,    ClipperLib::ptClip,    true);
    
    // perform operation
    ClipperLib::PolyTree retval;
    clipper.Execute(clipType, retval, fillType, fillType);
    return retval;
}

void _clipper_do(const ClipperLib::ClipType clipType, const Slic3r::Polygons &subject, 
    const Slic3r::Polygons &clip, T &retval, const ClipperLib::PolyFillType fillType, const bool safety_offset_)
{
    // read input
    ClipperLib::Paths* input_subject = new ClipperLib::Paths();
    ClipperLib::Paths* input_clip    = new ClipperLib::Paths();
    Slic3rMultiPoints_to_ClipperPaths(subject, *input_subject);
    Slic3rMultiPoints_to_ClipperPaths(clip,    *input_clip);
    
    // perform safety offset
    if (safety_offset_) {
        if (clipType == ClipperLib::ctUnion) {
            safety_offset(input_subject);
        } else {
            safety_offset(input_clip);
        }
    }
    
    // init Clipper
    ClipperLib::Clipper clipper;
    clipper.Clear();
    
    // add polygons
    clipper.AddPaths(*input_subject, ClipperLib::ptSubject, true);
    delete input_subject;
    clipper.AddPaths(*input_clip, ClipperLib::ptClip, true);
    delete input_clip;
    
    // perform operation
    clipper.Execute(clipType, retval, fillType, fillType);
}

void simplify_polygons(const Slic3r::Polygons &subject, Slic3r::ExPolygons* retval, bool preserve_collinear)
{
    PROFILE_FUNC();

    if (!preserve_collinear) {
        Polygons polygons;
        simplify_polygons(subject, &polygons, preserve_collinear);
        union_(polygons, retval);
        return;
    }
    
    // convert into Clipper polygons
    ClipperLib::Paths input_subject;
    Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
    
    ClipperLib::PolyTree polytree;
    
    ClipperLib::Clipper c;
    c.PreserveCollinear(true);
    c.StrictlySimple(true);
    c.AddPaths(input_subject, ClipperLib::ptSubject, true);
    c.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    
    // convert into ExPolygons
    PolyTreeToExPolygons(polytree, retval);
}

Vector<Vector2> expand(const Vector<Vector2> &points, const Rect2i &rect, float epsilon = 2.0) {
	int size = points.size();
	ERR_FAIL_COND_V(size < 2, Vector<Vector2>());

	ClipperLib::Path subj;
	ClipperLib::PolyTree solution;
	ClipperLib::PolyTree out;

	for (int i = 0; i < points.size(); i++) {

		subj << ClipperLib::IntPoint(points[i].x * PRECISION, points[i].y * PRECISION);
	}
	ClipperLib::ClipperOffset co;
	co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
	co.Execute(solution, epsilon * PRECISION);

	ClipperLib::PolyNode *p = solution.GetFirst();

	ERR_FAIL_COND_V(!p, points);

	while (p->IsHole()) {
		p = p->GetNext();
	}

	//turn the result into simply polygon (AKA, fix overlap)

	//clamp into the specified rect
	ClipperLib::Clipper cl;
	cl.StrictlySimple(true);
	cl.AddPath(p->Contour, ClipperLib::ptSubject, true);
	//create the clipping rect
	ClipperLib::Path clamp;
	clamp.push_back(ClipperLib::IntPoint(0, 0));
	clamp.push_back(ClipperLib::IntPoint(rect.size.width * PRECISION, 0));
	clamp.push_back(ClipperLib::IntPoint(rect.size.width * PRECISION, rect.size.height * PRECISION));
	clamp.push_back(ClipperLib::IntPoint(0, rect.size.height * PRECISION));
	cl.AddPath(clamp, ClipperLib::ptClip, true);
	cl.Execute(ClipperLib::ctIntersection, out);

	Vector<Vector2> outPoints;
	ClipperLib::PolyNode *p2 = out.GetFirst();
	ERR_FAIL_COND_V(!p2, points);

	while (p2->IsHole()) {
		p2 = p2->GetNext();
	}

	int lasti = p2->Contour.size() - 1;
	Vector2 prev = Vector2(p2->Contour[lasti].X / PRECISION, p2->Contour[lasti].Y / PRECISION);
	for (unsigned int i = 0; i < p2->Contour.size(); i++) {

		Vector2 cur = Vector2(p2->Contour[i].X / PRECISION, p2->Contour[i].Y / PRECISION);
		if (cur.distance_to(prev) > 0.5) {
			outPoints.push_back(cur);
			prev = cur;
		}
	}
	return outPoints;
}

std::vector<Vec2> AutoPolygon::expand(const std::vector<Vec2>& points, const cocos2d::Rect &rect, const float& epsilon)
{
    auto size = points.size();
    // if there are less than 3 points, then we have nothing
    if(size<3)
    {
        log("AUTOPOLYGON: cannot expand points for %s with less than 3 points, e: %f", _filename.c_str(), epsilon);
        return std::vector<Vec2>();
    }
    ClipperLib::Path subj;
    ClipperLib::PolyTree solution;
    ClipperLib::PolyTree out;
    for(std::vector<Vec2>::const_iterator it = points.begin(); it<points.end(); it++)
    {
        subj << ClipperLib::IntPoint(it-> x* PRECISION, it->y * PRECISION);
    }
    ClipperLib::ClipperOffset co;
    co.AddPath(subj, ClipperLib::jtMiter, ClipperLib::etClosedPolygon);
    co.Execute(solution, epsilon * PRECISION);
    
    ClipperLib::PolyNode* p = solution.GetFirst();
    if(!p)
    {
        log("AUTOPOLYGON: Clipper failed to expand the points");
        return points;
    }
    while(p->IsHole()){
        p = p->GetNext();
    }

    //turn the result into simply polygon (AKA, fix overlap)
    
    //clamp into the specified rect
    ClipperLib::Clipper cl;
    cl.StrictlySimple(true);
    cl.AddPath(p->Contour, ClipperLib::ptSubject, true);
    //create the clipping rect
    ClipperLib::Path clamp;
    clamp.push_back(ClipperLib::IntPoint(0, 0));
    clamp.push_back(ClipperLib::IntPoint(rect.size.width/_scaleFactor * PRECISION, 0));
    clamp.push_back(ClipperLib::IntPoint(rect.size.width/_scaleFactor * PRECISION, rect.size.height/_scaleFactor * PRECISION));
    clamp.push_back(ClipperLib::IntPoint(0, rect.size.height/_scaleFactor * PRECISION));
    cl.AddPath(clamp, ClipperLib::ptClip, true);
    cl.Execute(ClipperLib::ctIntersection, out);
    
    std::vector<Vec2> outPoints;
    ClipperLib::PolyNode* p2 = out.GetFirst();
    while(p2->IsHole()){
        p2 = p2->GetNext();
    }
    auto end = p2->Contour.end();
    for(std::vector<ClipperLib::IntPoint>::const_iterator pt = p2->Contour.begin(); pt < end; pt++)
    {
        outPoints.push_back(Vec2(pt->X/PRECISION, pt->Y/PRECISION));
    }
    return outPoints;
}

// This is a safe variant of the polygon offset, tailored for a single ExPolygon:
// a single polygon with multiple non-overlapping holes.
// Each contour and hole is offsetted separately, then the holes are subtracted from the outer contours.
ClipperLib::Paths _offset(const Slic3r::ExPolygon &expolygon, const float delta,
    ClipperLib::JoinType joinType, double miterLimit)
{
//    printf("new ExPolygon offset\n");
    // 1) Offset the outer contour.
    const float delta_scaled = delta * float(CLIPPER_OFFSET_SCALE);
    ClipperLib::Paths contours;
    {
        ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath(expolygon.contour);
        scaleClipperPolygon(input);
        ClipperLib::ClipperOffset co;
        if (joinType == jtRound)
            co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
        else
            co.MiterLimit = miterLimit;
        co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
        co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
        co.Execute(contours, delta_scaled);
    }

    // 2) Offset the holes one by one, collect the results.
    ClipperLib::Paths holes;
    {
        holes.reserve(expolygon.holes.size());
        for (Polygons::const_iterator it_hole = expolygon.holes.begin(); it_hole != expolygon.holes.end(); ++ it_hole) {
            ClipperLib::Path input = Slic3rMultiPoint_to_ClipperPath_reversed(*it_hole);
            scaleClipperPolygon(input);
            ClipperLib::ClipperOffset co;
            if (joinType == jtRound)
                co.ArcTolerance = miterLimit * double(CLIPPER_OFFSET_SCALE);
            else
                co.MiterLimit = miterLimit;
            co.ShortestEdgeLength = double(std::abs(delta_scaled * CLIPPER_OFFSET_SHORTEST_EDGE_FACTOR));
            co.AddPath(input, joinType, ClipperLib::etClosedPolygon);
            ClipperLib::Paths out;
            co.Execute(out, - delta_scaled);
            holes.insert(holes.end(), out.begin(), out.end());
        }
    }

    // 3) Subtract holes from the contours.
    ClipperLib::Paths output;
    if (holes.empty()) {
        output = std::move(contours);
    } else {
        ClipperLib::Clipper clipper;
        clipper.Clear();
        clipper.AddPaths(contours, ClipperLib::ptSubject, true);
        clipper.AddPaths(holes, ClipperLib::ptClip, true);
        clipper.Execute(ClipperLib::ctDifference, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    }
    
    // 4) Unscale the output.
    unscaleClipperPolygons(output);
    return output;
}

bool BooleanTool::executeForObjects(PathObject* subject, PathObjects& in_objects, PathObjects& out_objects)
{
	// Convert the objects to Clipper polygons and
	// create a hash map, mapping point positions to the PathCoords.
	// These paths are to be regarded as closed.
	PolyMap polymap;
	
	ClipperLib::Paths subject_polygons;
	pathObjectToPolygons(subject, subject_polygons, polymap);
	
	ClipperLib::Paths clip_polygons;
	for (PathObject* object : in_objects)
	{
		if (object != subject)
		{
			pathObjectToPolygons(object, clip_polygons, polymap);
		}
	}
	
	// Do the operation.
	ClipperLib::Clipper clipper;
	clipper.AddPaths(subject_polygons, ClipperLib::ptSubject, true);
	clipper.AddPaths(clip_polygons, ClipperLib::ptClip, true);
	
	ClipperLib::ClipType clip_type;
	ClipperLib::PolyFillType fill_type = ClipperLib::pftNonZero;
	switch (op)
	{
	case Union:         clip_type = ClipperLib::ctUnion;
	                    break;
	case Intersection:  clip_type = ClipperLib::ctIntersection;
	                    break;
	case Difference:    clip_type = ClipperLib::ctDifference;
	                    break;
	case XOr:           clip_type = ClipperLib::ctXor;
	                    break;
	case MergeHoles:    clip_type = ClipperLib::ctUnion;
	                    fill_type = ClipperLib::pftPositive;
	                    break;
	default:            Q_ASSERT(false && "Undefined operation");
	                    return false;
	}

	ClipperLib::PolyTree solution;
	bool success = clipper.Execute(clip_type, solution, fill_type, fill_type);
	if (success)
	{
		// Try to convert the solution polygons to objects again
		polyTreeToPathObjects(solution, out_objects, subject, polymap);
	}
	
	return success;
}

ClipperLib::Polygons NavMesh::_processWalkableObstacleRegions(const ClipperLib::Polygons& walkable, const ClipperLib::Polygons& obstacles)
{
    ClipperLib::Clipper clipper;

    ClipperLib::Polygons solution;

    clipper.AddPolygons(walkable, ClipperLib::ptSubject );

    clipper.AddPolygons(obstacles, ClipperLib::ptClip);

    clipper.Execute(ClipperLib::ctDifference, solution, ClipperLib::PolyFillType::pftNonZero, ClipperLib::PolyFillType::pftNonZero );

    return solution;
}

std::vector<polygon> polygon::subtract(const polygon& subtrahend) const
{
	ClipperLib::Clipper poly;

	auto maxDenom = lcm(this->highestDenominator(), subtrahend.highestDenominator());
	
	poly.AddPath(this->path(maxDenom), ClipperLib::PolyType::ptSubject, true);
	poly.AddPath(subtrahend.path(maxDenom), ClipperLib::PolyType::ptClip, true);

	ClipperLib::Paths returnedPaths;

	poly.Execute(ClipperLib::ClipType::ctDifference, returnedPaths);
	
	return polygon::from(returnedPaths, maxDenom);
}

ExPolygons
ClipperPaths_to_Slic3rExPolygons(const ClipperLib::Paths &input)
{
    // init Clipper
    ClipperLib::Clipper clipper;
    clipper.Clear();
    
    // perform union
    clipper.AddPaths(input, ClipperLib::ptSubject, true);
    ClipperLib::PolyTree polytree;
    clipper.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);  // offset results work with both EvenOdd and NonZero
    
    // write to ExPolygons object
    return PolyTreeToExPolygons(polytree);
}

Polygons top_level_islands(const Slic3r::Polygons &polygons)
{
    // init Clipper
    ClipperLib::Clipper clipper;
    clipper.Clear();
    // perform union
    clipper.AddPaths(Slic3rMultiPoints_to_ClipperPaths(polygons), ClipperLib::ptSubject, true);
    ClipperLib::PolyTree polytree;
    clipper.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd); 
    // Convert only the top level islands to the output.
    Polygons out;
    out.reserve(polytree.ChildCount());
    for (int i = 0; i < polytree.ChildCount(); ++i)
        out.emplace_back(ClipperPath_to_Slic3rPolygon(polytree.Childs[i]->Contour));
    return out;
}

/*
std::vector<Polygon> DecomposePolygonToConvexhulls(const Polygon& polygon) {
  using VHACD::IVHACD;

  TriangleMesh mesh = TriangulatePolygon(polygon);
  std::vector<float> points;
  points.reserve(2 * mesh.vertices.size());
  for (auto& vertex : mesh.vertices) {
    points.emplace_back(vertex(0));
    points.emplace_back(vertex(1));
  }

  std::vector<int> triangle_indices;
  triangle_indices.reserve(mesh.faces.size() * 3);
  for (auto& tr_idx : mesh.faces) {
    triangle_indices.emplace_back(tr_idx[0]);
    triangle_indices.emplace_back(tr_idx[1]);
    triangle_indices.emplace_back(tr_idx[2]);
  }

  IVHACD::Parameters params;
  //
  // params.m_maxNumVerticesPerCH = 8;
  params.m_oclAcceleration = false;
  IVHACD* vhacd_interface = VHACD::CreateVHACD();
  bool res = vhacd_interface->Compute(points.data(), 2, mesh.vertices.size(),
                                      triangle_indices.data(), 3,
                                      mesh.faces.size(), params);
  std::vector<Polygon> polygons;
  if (res) {
    size_t num_hulls = vhacd_interface->GetNConvexHulls();
    IVHACD::ConvexHull hull;
    for (size_t p = 0; p < num_hulls; ++p) {
      vhacd_interface->GetConvexHull(p, hull);
      for (size_t v = 0; v < hull.m_nPoints; ++v) {
        std::cout << p << " ";
        std::cout << hull.m_points[3 * v + 0] << " ";
        std::cout << hull.m_points[3 * v + 1] << " ";
        std::cout << hull.m_points[3 * v + 2] << "\n";
      }
    }
  } else {
    std::cerr << "convex hull decomposition not successfull! fall back to "
                 "triangulation!\n";
  }

  vhacd_interface->Clean();
  vhacd_interface->Release();
  exit(0);
  return polygons;
}
*/
std::vector<Polygon2D> ResolveIntersections(const Polygon2D& polygon) {
  // the polygon boundary maybe splitted during this process
  // auto paths = ResolveIntersectionsClosedPath(polygon.path);
  // auto holes = ResolveIntersectionsClosedPaths(polygon.holes);

  ClipperLib::Clipper clipper;
  ClipperLib::Path scaled_path = UScalePathDiaToClipper(polygon.path);
  clipper.AddPath(scaled_path, ClipperLib::ptSubject, true);

  /*
  for (auto& path : paths) {
    ClipperLib::Path scaled_path = UScalePathDiaToClipper(path);
    clipper.AddPath(scaled_path, ClipperLib::ptSubject, true);
  }*/

  for (auto& hole : polygon.holes) {
    ClipperLib::Path scaled_hole = UScalePathDiaToClipper(hole);
    clipper.AddPath(scaled_hole, ClipperLib::ptClip, true);
  }

  ClipperLib::PolyTree path_tree;
  clipper.StrictlySimple(true);
  clipper.Execute(ClipperLib::ctDifference, path_tree, ClipperLib::pftNonZero,
                  ClipperLib::pftNonZero);

  // iterating into the tree
  std::vector<Polygon2D> polygons;
  // only store the pointer to outer polygons
  std::unordered_map<ClipperLib::PolyNode*, size_t> polynode_map;
  for (ClipperLib::PolyNode* node_ptr = path_tree.GetFirst(); node_ptr;
       node_ptr = node_ptr->GetNext()) {
    ClipperLib::PolyNode* poly_ptr = node_ptr;
    while (poly_ptr && poly_ptr->IsHole()) {
      poly_ptr = poly_ptr->Parent;
    }
    if (polynode_map.find(poly_ptr) == polynode_map.end()) {
      polygons.emplace_back(Polygon2D());
      polygons.back().path = DScalePathClipperToDia(poly_ptr->Contour);
      polynode_map[poly_ptr] = polygons.size() - 1;
    } else {
      polygons[polynode_map[poly_ptr]].holes.emplace_back(
          DScalePathClipperToDia(node_ptr->Contour));
    }
  }
  return polygons;
}

void PlaneExt::ConcaveHullJoinCurrent(pcl::PointCloud<pcl::PointXYZ>::Ptr &plane_hull, tVertices &polygon_indices)
{
	// Join new polygon with current
	ClipperLib::ExPolygons newPoly = PolygonizeConcaveHull(plane_hull, polygon_indices);

	ClipperLib::Clipper clipper;
	// insert all existing polygons
	for (unsigned int i = 0; i < planePolygonsClipper.size(); ++i)
		clipper.AddPolygon(planePolygonsClipper[i].outer, ClipperLib::ptSubject);

	// insert all new polygons
	for (unsigned int i = 0; i < newPoly.size(); ++i)
		clipper.AddPolygon(newPoly[i].outer, ClipperLib::ptClip);

	// execute join operation
	clipper.Execute(ClipperLib::ctUnion, planePolygonsClipper);
}

GeometryCollection fixupPolygons(const GeometryCollection& rings) {
    ClipperLib::Clipper clipper;
    clipper.StrictlySimple(true);

    for (const auto& ring : rings) {
        clipper.AddPath(toClipperPath(ring), ClipperLib::ptSubject, true);
    }

    ClipperLib::PolyTree polygons;
    clipper.Execute(ClipperLib::ctUnion, polygons, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);
    clipper.Clear();

    GeometryCollection result;
    for (auto * polynode : polygons.Childs) {
        processPolynodeBranch(polynode, result);
    }
    return result;
}

void
ClipperPaths_to_Slic3rExPolygons(const ClipperLib::Paths &input, Slic3r::ExPolygons &output)
{
    // init Clipper
    ClipperLib::Clipper clipper;
    clipper.Clear();
    
    // perform union
    clipper.AddPaths(input, ClipperLib::ptSubject, true);
    ClipperLib::PolyTree* polytree = new ClipperLib::PolyTree();
    clipper.Execute(ClipperLib::ctUnion, *polytree, ClipperLib::pftEvenOdd, ClipperLib::pftEvenOdd);  // offset results work with both EvenOdd and NonZero
    
    // write to ExPolygons object
    output.clear();
    PolyTreeToExPolygons(*polytree, output);
    
    delete polytree;
}

ExPolygons simplify_polygons_ex(const Polygons &subject, bool preserve_collinear)
{
    if (! preserve_collinear)
        return union_ex(simplify_polygons(subject, false));

    // convert into Clipper polygons
    ClipperLib::Paths input_subject = Slic3rMultiPoints_to_ClipperPaths(subject);
    
    ClipperLib::PolyTree polytree;
    
    ClipperLib::Clipper c;
    c.PreserveCollinear(true);
    c.StrictlySimple(true);
    c.AddPaths(input_subject, ClipperLib::ptSubject, true);
    c.Execute(ClipperLib::ctUnion, polytree, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    
    // convert into ExPolygons
    return PolyTreeToExPolygons(polytree);
}

void simplify_polygons(const Slic3r::Polygons &subject, Slic3r::Polygons* retval, bool preserve_collinear)
{
    // convert into Clipper polygons
    ClipperLib::Paths input_subject, output;
    Slic3rMultiPoints_to_ClipperPaths(subject, &input_subject);
    
    if (preserve_collinear) {
        ClipperLib::Clipper c;
        c.PreserveCollinear(true);
        c.StrictlySimple(true);
        c.AddPaths(input_subject, ClipperLib::ptSubject, true);
        c.Execute(ClipperLib::ctUnion, output, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
    } else {
        ClipperLib::SimplifyPolygons(input_subject, output, ClipperLib::pftNonZero);
    }
    
    // convert into Slic3r polygons
    ClipperPaths_to_Slic3rMultiPoints(output, retval);
}

EaglePolygon::EaglePolygon(QPolygonF _vertices, qreal _width, int _layer, qreal _spacing) {
	width = _width; layer = _layer; spacing = _spacing;
	sourcePoly.resize(_vertices.count());
	for (int i = 0; i < _vertices.count(); i++) {
		ClipperLib::long64 x = (ClipperLib::long64)(_vertices.at(i).x()*RES);
		ClipperLib::long64 y = (ClipperLib::long64)(_vertices.at(i).y()*RES);
		sourcePoly[0].push_back(ClipperLib::IntPoint(x,y));
	}

	ClipperLib::Clipper c;
	c.AddPolygons(sourcePoly, ClipperLib::ptSubject);
	c.Execute(ClipperLib::ctUnion,sourcePoly); // only makes sure polys orientation is correct

	ClipperLib::OffsetPolygons(sourcePoly,buffedPoly, width*RES/2, ClipperLib::jtRound); // offset

	for (unsigned int i = 0; i < buffedPoly[0].size(); i++) {
		vertices.append(QPointF(buffedPoly[0].at(i).X/RES, buffedPoly[0].at(i).Y/RES));
	}
}