Add polygon set drawing functionality.

Boolean_set_operations_2/doc/Boolean_set_operations_2/CGAL/draw_polygon_set_2.h

@@ -0,0 +1,14 @@
+namespace CGAL {
+
+/*!
+\ingroup PkgDrawPolygonSet2
+
+opens a new window and draws `aps`, an instance of the `CGAL::Polygon_set_2` class. A call to this function is blocking, that is the program continues as soon as the user closes the window. This function requires CGAL_Qt5, and is only available if the flag CGAL_USE_BASIC_VIEWER is defined at compile time.
+\tparam PS an instance of the `CGAL::Polygon_set_2` class.
+\param aps the polygon set to draw.
+
+*/
+template<class PS>
+void draw(const PS& aps);
+
+} /* end namespace CGAL */

Boolean_set_operations_2/doc/Boolean_set_operations_2/PackageDescription.txt

@@ -6,6 +6,14 @@
 /// The namespace containing concepts specific to 2D Boolean Set Operations.
 namespace ArrDirectionalTraits {}
 
+/*!
+  \code
+  #include <CGAL/draw_polygon_set_2.h>
+  \endcode
+*/
+/// \defgroup PkgDrawPolygonSet2 Draw a 2D Polygon Set
+/// \ingroup PkgBooleanSetOperations2Ref
+
 /*!
 \addtogroup PkgBooleanSetOperations2Ref
 \todo check generated documentation
@@ -62,4 +70,7 @@ containment predicates.
 - \link boolean_oriented_side `CGAL::oriented_side()` \endlink
 - \link boolean_connect_holes `CGAL::connect_holes()` \endlink
 
+\cgalCRPSection{Draw a Polygon_set_2}
+- \link  PkgDrawPolygonSet2 CGAL::draw<PS>() \endlink
+
 */

Boolean_set_operations_2/doc/Boolean_set_operations_2/examples.txt

@@ -5,6 +5,7 @@
 \example Boolean_set_operations_2/conic_traits_adapter.cpp
 \example Boolean_set_operations_2/connect_polygon.cpp
 \example Boolean_set_operations_2/do_intersect.cpp
+\example Boolean_set_operations_2/draw_polygon_set.cpp
 \example Boolean_set_operations_2/dxf_union.cpp
 \example Boolean_set_operations_2/sequence.cpp
 \example Boolean_set_operations_2/set_union.cpp

Boolean_set_operations_2/examples/Boolean_set_operations_2/draw_polygon_set.cpp

@@ -0,0 +1,47 @@
+/*! \file draw_polygon_set.cpp
+ * Drawing a polygon set.
+ */
+
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/Polygon_2.h>
+#include <CGAL/Polygon_with_holes_2.h>
+#include <CGAL/Polygon_set_2.h>
+#include <CGAL/draw_polygon_set_2.h>
+
+typedef CGAL::Exact_predicates_exact_constructions_kernel K;
+typedef CGAL::Polygon_2<K>                                Polygon_2;
+typedef CGAL::Polygon_with_holes_2<K>                     Polygon_with_holes_2;
+typedef CGAL::Polygon_set_2<K>                            Polygon_set_2;
+typedef CGAL::Point_2<K>                                  Point_2;
+
+Polygon_2 rectangle(int l)
+{
+  // Create a rectangle with given side length.
+  Polygon_2 P;
+  P.push_back(Point_2(-l,-l));
+  P.push_back(Point_2(l,-l));
+  P.push_back(Point_2(l,l));
+  P.push_back(Point_2(-l,l));
+
+  return P;
+}
+
+int main()
+{
+  // Create a large rectangle A, with a hole and a smaller rectangle
+  // B inside A's hole.
+  Polygon_with_holes_2 A(rectangle(3));
+  Polygon_2 H(rectangle(2));
+  H.reverse_orientation();
+  A.add_hole(H);
+  Polygon_2 B(rectangle(1));
+
+  // Add them to a polygon set and draw it.
+  Polygon_set_2 S;
+  S.insert(A);
+  S.insert(B);
+
+  CGAL::draw(S);
+
+  return 0;
+}

Boolean_set_operations_2/include/CGAL/draw_polygon_set_2.h

@@ -0,0 +1,94 @@
+// Copyright (c) 1997
+// Utrecht University (The Netherlands),
+// ETH Zurich (Switzerland),
+// INRIA Sophia-Antipolis (France),
+// Max-Planck-Institute Saarbruecken (Germany),
+// and Tel-Aviv University (Israel).  All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org)
+//
+// $URL$
+// $Id$
+// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
+//
+//
+// Author(s)     : Guillaume Damiand <guillaume.damiand@liris.cnrs.fr>
+
+#ifndef CGAL_DRAW_POLYGON_SET_2_H
+#define CGAL_DRAW_POLYGON_SET_2_H
+
+#include <CGAL/draw_polygon_with_holes_2.h>
+
+#ifdef DOXYGEN_RUNNING
+namespace CGAL {
+
+/*!
+\ingroup PkgDrawPolygonSet2
+
+opens a new window and draws `aps`, an instance of the `CGAL::Polygon_set_2` class. A call to this function is blocking, that is the program continues as soon as the user closes the window. This function requires CGAL_Qt5, and is only available if the flag CGAL_USE_BASIC_VIEWER is defined at compile time.
+\tparam PS an instance of the `CGAL::Polygon_set_2` class.
+\param aps the polygon set to draw.
+
+*/
+template<class PS>
+void draw(const PS& aps);
+
+} /* namespace CGAL */
+#endif
+
+#ifdef CGAL_USE_BASIC_VIEWER
+#include <CGAL/Polygon_set_2.h>
+
+namespace CGAL
+{
+
+template<class PS2>
+class SimplePolygonSet2ViewerQt :
+  public SimplePolygonWithHoles2ViewerQt<typename PS2::Polygon_with_holes_2>
+{
+  typedef SimplePolygonWithHoles2ViewerQt<typename PS2::Polygon_with_holes_2> Base;
+
+public:
+  SimplePolygonSet2ViewerQt(QWidget* parent, const PS2& aps2,
+                            const char* title="Basic Polygon_set_2 Viewer") :
+    Base(parent, title)
+  {
+    const int n = aps2.number_of_polygons_with_holes();
+    typename PS2::Polygon_with_holes_2 polygons[n];
+    aps2.polygons_with_holes(polygons);
+
+    for (typename PS2::Polygon_with_holes_2& P: polygons) {
+      Base::compute_elements(P);
+    }
+  }
+};
+
+// Specialization of draw function.
+template<class T, class C>
+void draw(const CGAL::Polygon_set_2<T, C>& aps2,
+          const char* title="Polygon_set_2 Basic Viewer")
+{
+#if defined(CGAL_TEST_SUITE)
+  bool cgal_test_suite=true;
+#else
+  bool cgal_test_suite=qEnvironmentVariableIsSet("CGAL_TEST_SUITE");
+#endif
+
+  if (!cgal_test_suite)
+  {
+    CGAL::Qt::init_ogl_context(4,3);
+    int argc=1;
+    const char* argv[2]={"t2_viewer","\0"};
+    QApplication app(argc,const_cast<char**>(argv));
+    SimplePolygonSet2ViewerQt<CGAL::Polygon_set_2<T, C> >
+      mainwindow(app.activeWindow(), aps2, title);
+    mainwindow.show();
+    app.exec();
+  }
+}
+
+} // End namespace CGAL
+
+#endif // CGAL_USE_BASIC_VIEWER
+
+#endif // CGAL_DRAW_POLYGON_SET_2_H

Polygon/include/CGAL/draw_polygon_with_holes_2.h

@@ -44,7 +44,7 @@ void draw(const PH& aph);
 namespace CGAL
 {
 
-// Viewer class for Polygon_2
+// Viewer class for Polygon_with_holes_2
 template<class P2>
 class SimplePolygonWithHoles2ViewerQt : public Basic_viewer_qt
 {
@@ -52,16 +52,25 @@ class SimplePolygonWithHoles2ViewerQt : public Basic_viewer_qt
   typedef typename P2::General_polygon_2::Point_2 Point;
 
 public:
+  /// Construct the viewer without drawing anything.
+  /// @param title the title of the window
+  SimplePolygonWithHoles2ViewerQt(QWidget* parent,
+                                  const char* title="Basic Polygon_with_holes_2 Viewer") :
+    Base(parent, title, true, true, true, false, false)
+  {
+      clear();
+  }
+
   /// Construct the viewer.
   /// @param ap2 the polygon to view
   /// @param title the title of the window
   SimplePolygonWithHoles2ViewerQt(QWidget* parent, const P2& ap2,
                                   const char* title="Basic Polygon_with_holes_2 Viewer") :
     // First draw: vertices; edges, faces; multi-color; no inverse normal
-    Base(parent, title, true, true, true, false, false),
-    p2(ap2)
+    Base(parent, title, true, true, true, false, false)
   {
-    compute_elements();
+    clear();
+    compute_elements(ap2);
   }
 
 protected:
@@ -85,10 +94,8 @@ protected:
     add_segment(*prev, *(p.vertices_begin()));
   }
 
-  void compute_elements()
+  void compute_elements(const P2& p2)
   {
-    clear();
-
     if (p2.outer_boundary().is_empty()) return;
 
     CGAL::IO::Color c(75,160,255);
@@ -120,9 +127,6 @@ protected:
     // Call the base method to process others/classicals key
     Base::keyPressEvent(e);
   }
-
-protected:
-  const P2& p2;
 };
 
 // Specialization of draw function.