cgal/GraphicsView/demo/Triangulation_2/Constrained_Delaunay_triangulation_2.cpp

//#define CGAL_USE_BOOST_BIMAP
#define CGAL_MESH_2_OPTIMIZER_VERBOSE
#define CGAL_MESH_2_OPTIMIZERS_DEBUG

#include <fstream>
#include <vector>
#include <list>
#include <boost/config.hpp>
#include <boost/version.hpp>

// CGAL headers
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Constrained_Delaunay_triangulation_2.h>
#include <CGAL/Delaunay_mesher_2.h>
#include <CGAL/Delaunay_mesh_face_base_2.h>
#include <CGAL/Delaunay_mesh_vertex_base_2.h>
#include <CGAL/Delaunay_mesh_size_criteria_2.h>
#include <CGAL/Mesh_2/Lipschitz_sizing_field_2.h>
#include <CGAL/Lipschitz_sizing_field_criteria_2.h>
#include <CGAL/Constrained_voronoi_diagram_2.h>
#include <CGAL/Triangulation_conformer_2.h>
#include <CGAL/lloyd_optimize_mesh_2.h>
#include <CGAL/IO/File_poly.h>
#include <CGAL/Random.h>
#include <CGAL/point_generators_2.h>
#include <CGAL/Timer.h>
#include <CGAL/IO/write_VTU.h>
#include <CGAL/IO/WKT.h>

// Qt headers
#include <QtGui>
#include <QString>
#include <QActionGroup>
#include <QFileDialog>
#include <QInputDialog>
#include <QDragEnterEvent>
#include <QDropEvent>
#include <QMessageBox>

// GraphicsView items and event filters (input classes)
#include "TriangulationCircumcircle.h"
#include "DelaunayMeshInsertSeeds.h"
#include <CGAL/Qt/GraphicsViewPolylineInput.h>
#include <CGAL/Qt/DelaunayMeshTriangulationGraphicsItem.h>
#include <CGAL/Qt/Converter.h>
// the two base classes
#include "ui_Constrained_Delaunay_triangulation_2.h"
#include <CGAL/Qt/DemosMainWindow.h>

// for viewportsBbox(QGraphicsScene*)
#include <CGAL/Qt/utility.h>

typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::Point_2 Point_2;
typedef K::Segment_2 Segment_2;
typedef K::Iso_rectangle_2 Iso_rectangle_2;
typedef CGAL::Delaunay_mesh_vertex_base_2<K>  Vertex_base;
typedef CGAL::Delaunay_mesh_face_base_2<K> Face_base;

typedef Face_base Fb;
typedef CGAL::Triangulation_data_structure_2<Vertex_base, Fb>  TDS;
typedef CGAL::Exact_predicates_tag              Itag;
typedef CGAL::Constrained_Delaunay_triangulation_2<K, TDS, Itag> CDT;
typedef CGAL::Constrained_voronoi_diagram_2<CDT> CVD;
typedef CGAL::Delaunay_mesh_size_criteria_2<CDT> Criteria;

typedef CGAL::Lipschitz_sizing_field_2<CDT> Lipschitz_sizing_field;
typedef CGAL::Lipschitz_sizing_field_criteria_2<CDT, Lipschitz_sizing_field> Lipschitz_criteria;
typedef CGAL::Delaunay_mesher_2<CDT, Lipschitz_criteria> Lipschitz_mesher;

typedef CDT::Vertex_handle Vertex_handle;
typedef CDT::Face_handle Face_handle;
typedef CDT::All_faces_iterator All_faces_iterator;

using namespace CGAL::parameters;

void
discoverInfiniteComponent(const CDT & ct)
{
  //when this function is called, all faces are set "in_domain"
  Face_handle start = ct.infinite_face();
  std::list<Face_handle> queue;
  queue.push_back(start);

  while(! queue.empty())
  {
    Face_handle fh = queue.front();
    queue.pop_front();
    fh->set_in_domain(false);

    for(int i = 0; i < 3; i++)
    {
      Face_handle fi = fh->neighbor(i);
      if(fi->is_in_domain()
         && !ct.is_constrained(CDT::Edge(fh,i)))
        queue.push_back(fi);
    }
  }
}

template<typename SeedList>
void
discoverComponents(const CDT & ct,
                   const SeedList& seeds)
{
  if (ct.dimension() != 2)
    return;

  // tag all faces inside
  for(typename CDT::All_faces_iterator fit = ct.all_faces_begin();
      fit != ct.all_faces_end();
      ++fit)
      fit->set_in_domain(true);

  // mark "outside" infinite component of the object
  discoverInfiniteComponent(ct);

  // mark "outside" components with a seed
  for(typename SeedList::const_iterator sit = seeds.begin();
      sit != seeds.end();
      ++sit)
  {
    typename CDT::Face_handle fh_loc = ct.locate(*sit);

    if(fh_loc == nullptr || !fh_loc->is_in_domain())
      continue;

    std::list<typename CDT::Face_handle> queue;
    queue.push_back(fh_loc);
    while(!queue.empty())
    {
      typename CDT::Face_handle f = queue.front();
      queue.pop_front();
      f->set_in_domain(false);

      for(int i = 0; i < 3; ++i)
      {
        typename CDT::Face_handle ni = f->neighbor(i);
        if(ni->is_in_domain()
          && !ct.is_constrained(typename CDT::Edge(f,i))) //same component
        {
          queue.push_back(ni);
        }
      }
    }
  }
}



class MainWindow :
  public CGAL::Qt::DemosMainWindow,
  public Ui::Constrained_Delaunay_triangulation_2
{
  Q_OBJECT

private:
  CDT cdt;
  QGraphicsScene scene;
  std::list<Point_2> m_seeds;

  CGAL::Qt::DelaunayMeshTriangulationGraphicsItem<CDT> * dgi;

  CGAL::Qt::GraphicsViewPolylineInput<K> * pi;
  CGAL::Qt::TriangulationCircumcircle<CDT> *tcc;
  CGAL::Qt::DelaunayMeshInsertSeeds<CDT> *dms;

public:
  MainWindow();

  void clear();

private:
  template <typename Iterator>
  void insert_polyline(Iterator b, Iterator e)
  {
    Point_2 p, q;
    typename CDT::Vertex_handle vh, wh;
    Iterator it = b;
    vh = cdt.insert(*it);
    p = *it;
    ++it;
    for(; it != e; ++it){
      q = *it;
      if(p != q){
        wh = cdt.insert(*it);
        cdt.insert_constraint(vh,wh);
        vh = wh;
        p = q;
      } else {
        std::cout << "duplicate point: " << p << std::endl;
      }
    }
    Q_EMIT( changed());
  }

public Q_SLOTS:
  void open(QString);

  void processInput(CGAL::Object o);

  void on_actionShowVertices_toggled(bool checked);

  void on_actionShowDelaunay_toggled(bool checked);

  void on_actionShowTriangulationInDomain_toggled(bool checked);

  void on_actionShow_constrained_edges_toggled(bool checked);

  void on_actionShow_voronoi_edges_toggled(bool checked);

  void on_actionShow_faces_in_domain_toggled(bool checked);

  void on_actionShow_blind_faces_toggled(bool checked);

  void on_actionShow_seeds_toggled(bool checked);

  void on_actionInsertPolyline_toggled(bool checked);

  void on_actionInsertSeeds_OnOff_toggled(bool checked);

  void on_actionCircumcenter_toggled(bool checked);

  void on_actionClear_triggered();

  void on_actionRecenter_triggered();

  void on_actionLoadConstraints_triggered();

  void loadWKT(QString);

  void loadFile(QString);

  void loadPolyConstraints(QString);

  void loadPolygonConstraints(QString);

  void loadEdgConstraints(QString);

  void on_actionSaveConstraints_triggered();

  void saveConstraints(QString);

  void on_actionMakeGabrielConform_triggered();

  void on_actionMakeDelaunayConform_triggered();

  void on_actionMakeDelaunayMesh_triggered();

  void on_actionMakeLipschitzDelaunayMesh_triggered();

  void on_actionInsertRandomPoints_triggered();

  void on_actionTagBlindFaces_triggered();

  void on_actionLloyd_optimization_triggered();

Q_SIGNALS:
  void changed();
};


MainWindow::MainWindow()
  : DemosMainWindow()
{
  setupUi(this);

  this->graphicsView->setAcceptDrops(false);

  // Add a GraphicItem for the CDT triangulation
  dgi = new CGAL::Qt::DelaunayMeshTriangulationGraphicsItem<CDT>(&cdt);
  QColor facesColor(::Qt::blue);
  facesColor.setAlpha(150);
  dgi->setFacesInDomainBrush(facesColor);

  QObject::connect(this, SIGNAL(changed()),
                   dgi, SLOT(modelChanged()));
  dgi->setVerticesPen(
    QPen(Qt::red, 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
  dgi->setVoronoiPen(
    QPen(Qt::darkGreen, 0, Qt::DashLine, Qt::RoundCap, Qt::RoundJoin));
  dgi->setSeedsPen(
    QPen(Qt::darkBlue, 0, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));

  dgi->setZValue(-1);
  scene.addItem(dgi);

  // Setup input handlers. They get events before the scene gets them
  // and the input they generate is passed to the triangulation with
  // the signal/slot mechanism
  pi = new CGAL::Qt::GraphicsViewPolylineInput<K>(this, &scene, 0, true); // inputs polylines which are not closed
  QObject::connect(pi, SIGNAL(generate(CGAL::Object)),
                   this, SLOT(processInput(CGAL::Object)));

  tcc = new CGAL::Qt::TriangulationCircumcircle<CDT>(&scene, &cdt, this);
  tcc->setPen(QPen(Qt::red, 0, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));

  dms = new CGAL::Qt::DelaunayMeshInsertSeeds<CDT>(&scene, &cdt, this);//input seeds
  QObject::connect(dms, SIGNAL(generate(CGAL::Object)),
                   this, SLOT(processInput(CGAL::Object)));

  //
  // Manual handling of actions
  //
  QObject::connect(this->actionQuit, SIGNAL(triggered()),
                   this, SLOT(close()));

  // We put mutually exclusive actions in an QActionGroup
  QActionGroup* ag = new QActionGroup(this);
  ag->addAction(this->actionInsertPolyline);

  // Check two actions
  this->actionInsertPolyline->setChecked(true);
  this->actionShowDelaunay->setChecked(true);
  this->actionShowVertices->setChecked(true);
  this->actionShowTriangulationInDomain->setChecked(false);
  this->actionShow_faces_in_domain->setChecked(true);
  this->actionShow_constrained_edges->setChecked(true);
  this->actionShow_voronoi_edges->setChecked(false);
  this->actionShow_seeds->setChecked(false);
  this->actionInsertSeeds_OnOff->setChecked(false);

  //
  // Setup the scene and the view
  //
  scene.setItemIndexMethod(QGraphicsScene::NoIndex);
  scene.setSceneRect(-100, -100, 100, 100);
  this->graphicsView->setScene(&scene);
  this->graphicsView->setMouseTracking(true);

  // Turn the vertical axis upside down
  this->graphicsView->scale(1, -1);

  // The navigation adds zooming and translation functionality to the
  // QGraphicsView
  this->addNavigation(this->graphicsView);

  this->setupStatusBar();
  this->setupOptionsMenu();
  this->addAboutDemo(":/cgal/help/about_Constrained_Delaunay_triangulation_2.html");
  this->addAboutCGAL();
  this->setupExportSVG(this->actionExport_SVG, this->graphicsView);

  this->addRecentFiles(this->menuFile, this->actionQuit);
  connect(this, SIGNAL(openRecentFile(QString)),
          this, SLOT(open(QString)));
}


void
MainWindow::processInput(CGAL::Object o)
{
  // Polygon
  std::list<Point_2> points;
  if(CGAL::assign(points, o))
  {
    if(points.size() == 1)
      cdt.insert(points.front());
    else
      insert_polyline(points.begin(), points.end());
    }
  else
  {
    // Seed (from Shift + left clic)
    Point_2 p;
    if(CGAL::assign(p, o))
    {
      m_seeds.push_back(p);
      if(actionShow_seeds->isChecked())
        dgi->setVisibleSeeds(true, m_seeds.begin(), m_seeds.end());
    }
  }

  discoverComponents(cdt, m_seeds);
  Q_EMIT( changed());
}


/*
 *  Qt Automatic Connections
 *  https://doc.qt.io/qt-5/designer-using-a-ui-file.html#automatic-connections
 *
 *  setupUi(this) generates connections to the slots named
 *  "on_<action_name>_<signal_name>"
 */
void
MainWindow::on_actionInsertPolyline_toggled(bool checked)
{
  if(checked){
    scene.installEventFilter(pi);
  } else {
    scene.removeEventFilter(pi);
  }
}

void
MainWindow::on_actionInsertSeeds_OnOff_toggled(bool checked)
{
  if(checked){
    std::cout << "Insert seeds with Shift + Left click" << std::endl;
    scene.installEventFilter(dms);
  } else {
    scene.removeEventFilter(dms);
  }
}

void
MainWindow::on_actionShowDelaunay_toggled(bool checked)
{
  dgi->setVisibleEdges(checked);
  if(checked)
  {
    dgi->setVisibleInsideEdges(false);
    actionShowTriangulationInDomain->setChecked(false);
  }
  update();
}

void
MainWindow::on_actionShowVertices_toggled(bool checked)
{
  dgi->setVisibleVertices(checked);
  update();
}

void
MainWindow::on_actionShowTriangulationInDomain_toggled(bool checked)
{
  dgi->setVisibleInsideEdges(checked);
  if(checked)
  {
    dgi->setVisibleEdges(false);
    actionShowDelaunay->setChecked(false);
  }
  update();
}

void
MainWindow::on_actionShow_constrained_edges_toggled(bool checked)
{
  dgi->setVisibleConstraints(checked);
  update();
}

void
MainWindow::on_actionShow_voronoi_edges_toggled(bool checked)
{
  dgi->setVisibleVoronoiEdges(checked);
  update();
}

void
MainWindow::on_actionShow_faces_in_domain_toggled(bool checked)
{
  dgi->setVisibleFacesInDomain(checked);
  update();
}

void
MainWindow::on_actionShow_blind_faces_toggled(bool checked)
{
  dgi->setVisibleBlindFaces(checked);
  update();
}

void
MainWindow::on_actionShow_seeds_toggled(bool checked)
{
  dgi->setVisibleSeeds(checked, m_seeds.begin(), m_seeds.end());
  update();
}

void
MainWindow::on_actionCircumcenter_toggled(bool checked)
{
  if(checked){
    scene.installEventFilter(tcc);
    tcc->show();
  } else {
    scene.removeEventFilter(tcc);
    tcc->hide();
  }
}


void
MainWindow::on_actionClear_triggered()
{
  clear();
  Q_EMIT( changed());
}

void
MainWindow::clear()
{
  cdt.clear();
  m_seeds.clear();

  if(actionShow_seeds->isChecked())
    dgi->setVisibleSeeds(true, m_seeds.end(), m_seeds.end());
}

void
MainWindow::open(QString fileName)
{
  if(! fileName.isEmpty()){
    if(cdt.number_of_vertices() > 0)
    {
      QMessageBox msgBox(QMessageBox::Warning,
        "Open new polygon",
        "Do you really want to clear the current mesh?",
        (QMessageBox::Yes | QMessageBox::No),
        this);
      int ret = msgBox.exec();
      if(ret == QMessageBox::Yes)
        clear();
      else
        return;
    }
    if(fileName.endsWith(".polygons.cgal")){
      loadPolygonConstraints(fileName);
    } else if(fileName.endsWith(".cpts.cgal")){
      loadFile(fileName);
    } else if(fileName.endsWith(".edg")){
      loadEdgConstraints(fileName);
    } else if(fileName.endsWith(".poly")){
      loadPolyConstraints(fileName);
    } else if(fileName.endsWith(".wkt")){
      loadWKT(fileName);
    }
    this->addToRecentFiles(fileName);
  }
  Q_EMIT(changed());
  actionRecenter->trigger();
}

void
MainWindow::on_actionLoadConstraints_triggered()
{
  QString fileName = QFileDialog::getOpenFileName(this,
                                                  tr("Open Constraint File"),
                                                  ".",
                                                  tr("Edge files (*.edg);;"
                                                     "Polyline files (*.polygons.cgal);;"
                                                     "Poly files (*.poly);;"
                                                     "Plg files (*.plg);;"
                                                     "CGAL files (*.cpts.cgal);;"
                                                     "WKT files (*.WKT *.wkt);;"
                                                     "All (*)"));
  open(fileName);
}

void
MainWindow::loadWKT(QString filename)
{
  std::ifstream ifs(qPrintable(filename));

  typedef CGAL::Polygon_with_holes_2<K> Polygon;
  typedef CGAL::Point_2<K> Point;

  std::deque<Point> points;
  std::deque<std::vector<Point>> linestrings;
  std::deque<Polygon> polygons;

  CGAL::IO::read_WKT(ifs, points, linestrings, polygons);

  cdt.insert(points.begin(),points.end());

  for(const std::vector<Point>& line : linestrings){
    cdt.insert_constraint(line.begin(), line.end());
  }

  for(const Polygon& p : polygons){
    if(p.outer_boundary().is_empty())
      continue;

    cdt.insert_constraint(p.outer_boundary().vertices_begin(), p.outer_boundary().vertices_end(),true);

    for(Polygon::Hole_const_iterator h_it = p.holes_begin(); h_it != p.holes_end(); ++h_it){
      cdt.insert_constraint(h_it->vertices_begin(), h_it->vertices_end(),true);
    }
  }

  discoverComponents(cdt, m_seeds);
  Q_EMIT( changed());
  actionRecenter->trigger();
}

void
MainWindow::loadFile(QString fileName)
{
  std::ifstream ifs(qPrintable(fileName));
  ifs >> cdt;
  if(!ifs) abort();
  discoverComponents(cdt, m_seeds);
  Q_EMIT( changed());
  actionRecenter->trigger();
}

void
MainWindow::loadPolyConstraints(QString fileName)
{
  std::ifstream ifs(qPrintable(fileName));
  CGAL::IO::read_triangle_poly_file(cdt,ifs);
  discoverComponents(cdt, m_seeds);
  Q_EMIT( changed());
  actionRecenter->trigger();
}


void
MainWindow::loadPolygonConstraints(QString fileName)
{
  K::Point_2 p,q, first;
  CDT::Vertex_handle vp, vq, vfirst;
  std::ifstream ifs(qPrintable(fileName));
  int n;
  // int counter = 0;
  while(ifs >> n){
    int poly_size = n;
    ifs >> first;
    p = first;
    vfirst = vp = cdt.insert(p);
    n--;
    while(n--){
      ifs >> q;
      vq = cdt.insert(q, vp->face());
      if(vp != vq) {
        cdt.insert_constraint(vp,vq);
        // std::cerr << "inserted constraint #" << counter++ << std::endl;
      }
      p = q;
      vp = vq;
    }
    if(poly_size != 2 && vp != vfirst) {
      cdt.insert_constraint(vp, vfirst);
    }
  }

  discoverComponents(cdt, m_seeds);
  Q_EMIT( changed());
  actionRecenter->trigger();
}


void
MainWindow::loadEdgConstraints(QString fileName)
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);
  CGAL::Timer tim;
  tim.start();
  std::ifstream ifs(qPrintable(fileName));
  bool first=true;
  int n;
  ifs >> n;

  K::Point_2 p,q, qold(0,0); // initialize to avoid maybe-uninitialized warning from GCC6

  CDT::Vertex_handle vp, vq, vqold;
  while(ifs >> p) {
    ifs >> q;
    if(p == q){
      continue;
    }
    if((!first) && (p == qold)){
      vp = vqold;
    } else {
      vp = cdt.insert(p);
    }
    vq = cdt.insert(q, vp->face());
    if(vp != vq) {
      cdt.insert_constraint(vp,vq);
    }
    qold = q;
    vqold = vq;
    first = false;
  }


  tim.stop();
  statusBar()->showMessage(QString("Insertion took %1 seconds").arg(tim.time()), 2000);
  discoverComponents(cdt, m_seeds);
  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT( changed());
  actionRecenter->trigger();
}

void
MainWindow::on_actionRecenter_triggered()
{
  this->graphicsView->setSceneRect(dgi->boundingRect());
  this->graphicsView->fitInView(dgi->boundingRect(), Qt::KeepAspectRatio);
}


void
MainWindow::on_actionSaveConstraints_triggered()
{
  QString fileName = QFileDialog::getSaveFileName(this,

                                                  tr("Save Constraints"),
                                                  ".",
                                                  tr("CGAL files (*.cpts.cgal);;"
                                                     "VTU files (*.vtu);;"
                                                     "All (*)"));
  if(! fileName.isEmpty()){
      saveConstraints(fileName);
  }
}


void
MainWindow::saveConstraints(QString fileName)
{
  std::ofstream output(qPrintable(fileName));

  if(!fileName.endsWith("vtu") && output)
    output << cdt;
  else if (output)
  {
    CGAL::IO::write_VTU(output, cdt);
  }
}


void
MainWindow::on_actionMakeGabrielConform_triggered()
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);
  std::size_t nv = cdt.number_of_vertices();
  CGAL::make_conforming_Gabriel_2(cdt);
  nv = cdt.number_of_vertices() - nv;
  discoverComponents(cdt, m_seeds);
  statusBar()->showMessage(QString("Added %1 vertices").arg(nv), 2000);
  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT( changed());
}


void
MainWindow::on_actionMakeDelaunayConform_triggered()
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);
  std::size_t nv = cdt.number_of_vertices();
  CGAL::make_conforming_Delaunay_2(cdt);
  discoverComponents(cdt, m_seeds);
  nv = cdt.number_of_vertices() - nv;
  statusBar()->showMessage(QString("Added %1 vertices").arg(nv), 2000);
   // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT( changed());
}


void
MainWindow::on_actionMakeDelaunayMesh_triggered()
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);
  CGAL::Timer timer;
  timer.start();
  discoverComponents(cdt, m_seeds);
  timer.stop();
  QApplication::restoreOverrideCursor();

  bool ok;
  double shape = QInputDialog::getDouble(this, tr("Shape criterion"),
    tr("B = "), 0.125, 0.005, 100, 4, &ok);
  if(!ok) return;

  double edge_len = QInputDialog::getDouble(this, tr("Size criterion"),
    tr("S = "), 0., 0., (std::numeric_limits<double>::max)(), 5, &ok);
  if(!ok) return;

  QApplication::setOverrideCursor(Qt::WaitCursor);
  std::size_t nv = cdt.number_of_vertices();
  timer.start();

  CGAL::refine_Delaunay_mesh_2(cdt,
                               CGAL::parameters::seeds(m_seeds)
                               .criteria(Criteria(shape, edge_len))
                               .seeds_are_in_domain(false));//mesh the subdomains including NO seed

  timer.stop();
  nv = cdt.number_of_vertices() - nv;
  statusBar()->showMessage(QString("Added %1 vertices in %2 seconds").arg(nv).arg(timer.time()), 2000);
  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT( changed());
}

void
MainWindow::on_actionMakeLipschitzDelaunayMesh_triggered()
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);
  std::set<Point_2> points;
  for(CDT::Finite_edges_iterator it = cdt.finite_edges_begin();
      it != cdt.finite_edges_end();
      ++it){
    if(cdt.is_constrained(*it)){
      Segment_2 s = cdt.segment(*it);
      points.insert(s.source());
      points.insert(s.target());
    }
  }

  discoverComponents(cdt, m_seeds);

  bool ok;
  double shape = QInputDialog::getDouble(this, tr("Shape criterion"),
    tr("B = "), 0.125, 0.005, 100, 4, &ok);
  if(!ok) return;
  double klip = QInputDialog::getDouble(this, tr("k-Lipschitz sizing field"),
    tr("k = "), 1., 0.01, 500, 5, &ok);
  if(!ok) return;

  Lipschitz_sizing_field field(points.begin(), points.end(), klip);
  Lipschitz_criteria criteria(shape, &field);
  Lipschitz_mesher mesher(cdt);
  mesher.set_criteria(criteria);

  std::size_t nv = cdt.number_of_vertices();
  mesher.init(true);
  mesher.set_seeds(m_seeds.begin(), m_seeds.end(),
                   false);//mesh the subdomains including NO seed

  mesher.refine_mesh();
  nv = cdt.number_of_vertices() - nv;
  statusBar()->showMessage(QString("Added %1 vertices").arg(nv), 2000);
  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT( changed());
}

void
MainWindow::on_actionInsertRandomPoints_triggered()
{
  QRectF rect = CGAL::Qt::viewportsBbox(&scene);
  CGAL::Qt::Converter<K> convert;
  Iso_rectangle_2 isor = convert(rect);
  CGAL::Random_points_in_iso_rectangle_2<Point_2> pg((isor.min)(), (isor.max)());
  bool ok = false;

  const int number_of_points =
      QInputDialog::getInt(this,
                           tr("Number of random points"),
                           tr("Enter number of random points"),
                           100,
                           0,
                           (std::numeric_limits<int>::max)(),
                           1,
                           &ok);

  if(!ok) {
    return;
  }

  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);
  std::vector<Point_2> points;
  points.reserve(number_of_points);
  for(int i = 0; i < number_of_points; ++i){
    points.push_back(*pg++);
  }
  cdt.insert(points.begin(), points.end());
  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT( changed());
}

void
MainWindow::on_actionTagBlindFaces_triggered()
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);

  CVD voronoi(cdt);
  voronoi.tag_faces_blind();

  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT(changed());
}

void
MainWindow::on_actionLloyd_optimization_triggered()
{
  // wait cursor
  QApplication::setOverrideCursor(Qt::WaitCursor);

  bool ok;
  int nb = QInputDialog::getInt(this, tr("QInputDialog::getInteger()"),
    tr("Number of iterations :"),
    1/*val*/, 0/*min*/, 1000/*max*/, 1/*step*/, &ok);
  if(!ok)
  {
    QApplication::restoreOverrideCursor();
    return;
  }

  CGAL::lloyd_optimize_mesh_2(cdt,
      CGAL::parameters::number_of_iterations(nb).seeds(m_seeds));

  // default cursor
  QApplication::restoreOverrideCursor();
  Q_EMIT(changed());
}

#include "Constrained_Delaunay_triangulation_2.moc"
#include <CGAL/Qt/resources.h>

int main(int argc, char **argv)
{
  QApplication app(argc, argv);

  app.setOrganizationDomain("geometryfactory.com");
  app.setOrganizationName("GeometryFactory");
  app.setApplicationName("Constrained_Delaunay_triangulation_2 demo");

  // Import resources from libCGAL (Qt6).
  CGAL_QT_INIT_RESOURCES;

  MainWindow mainWindow;
  mainWindow.show();

  QStringList args = app.arguments();
  args.removeAt(0);
  Q_FOREACH(QString filename, args) {
    mainWindow.open(filename);
  }

  return app.exec();
}