cgal/Polygon/include/CGAL/draw_polygon_with_holes_2.h

// 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>
//                 Mostafa Ashraf <mostaphaashraf1996@gmail.com>

#ifndef CGAL_DRAW_POLYGON_WITH_HOLES_2_H
#define CGAL_DRAW_POLYGON_WITH_HOLES_2_H

#include <CGAL/Qt/Basic_viewer.h>
#include <CGAL/Graphics_scene.h>
#include <CGAL/Graphics_scene_options.h>
#include <CGAL/Polygon_with_holes_2.h>

#ifdef DOXYGEN_RUNNING
namespace CGAL {

/*!
 * \ingroup PkgDrawPolygonWithHoles2
 *
 * opens a new window and draws `aph`, an instance of the
 * `CGAL::Polygon_with_holes_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_Qt6`, and is only available if the macro
 * `CGAL_USE_BASIC_VIEWER` is defined.  Linking with the cmake target
 * `CGAL::CGAL_Basic_viewer` will link with `CGAL_Qt6` and add the definition
 * `CGAL_USE_BASIC_VIEWER`.
 * \tparam PH an instance of the `CGAL::Polygon_with_holes_2` class.
 * \param aph the polygon with holes to draw.
 */

template <typename PH>
void draw(const PH& aph);

} /* namespace CGAL */

#endif

namespace CGAL
{

namespace draw_function_for_ph2_with_holes {

template <class P2, class GSOptions>
void compute_one_loop_elements(const P2& ap2,
                               const typename P2::General_polygon_2& aloop,
                               Graphics_scene &graphics_scene,
                               bool hole,
                               const GSOptions& gs_options)
{
  if (hole && gs_options.are_faces_enabled())
  { graphics_scene.add_point_in_face(aloop.vertex(aloop.size()-1)); }

  typename P2::General_polygon_2::Vertex_const_iterator prev;
  for(typename P2::General_polygon_2::Vertex_const_iterator i=aloop.vertices_begin();
      i!=aloop.vertices_end(); ++i)
  {
    if(gs_options.are_vertices_enabled() &&
       gs_options.draw_vertex(ap2, i))
    { // Add vertex
      if(gs_options.colored_vertex(ap2, i))
      { graphics_scene.add_point(*i, gs_options.vertex_color(ap2, i)); }
      else
      { graphics_scene.add_point(*i); }
    }

    if(i!=aloop.vertices_begin() &&
       gs_options.are_edges_enabled() && gs_options.draw_edge(ap2, prev))
    { // Add segment with previous point
      if(gs_options.colored_edge(ap2, prev))
      { graphics_scene.add_segment(*prev, *i, gs_options.edge_color(ap2, prev)); }
      else
      { graphics_scene.add_segment(*prev, *i); }
    }

    if(gs_options.are_faces_enabled())
    { graphics_scene.add_point_in_face(*i); } // Add point in face

    prev=i;
  }

  // Add the last segment between the last point and the first one
  if(gs_options.are_edges_enabled() &&
     gs_options.draw_edge(ap2, aloop.vertices_begin()))
  {
    if(gs_options.colored_edge(ap2, prev))
    { graphics_scene.add_segment(*prev, *(aloop.vertices_begin()),
                                 gs_options.edge_color(ap2, prev)); }
    else
    { graphics_scene.add_segment(*prev, *(aloop.vertices_begin())); }
  }
}

template <class P2, class GSOptions>
void compute_elements(const P2& p2, Graphics_scene &graphics_scene,
                      const GSOptions& gs_options)
{
  if (p2.outer_boundary().is_empty()) return;

  if (gs_options.are_faces_enabled())
  {
    if(gs_options.colored_face(p2, nullptr))
    { graphics_scene.face_begin(gs_options.face_color(p2, nullptr)); }
    else
    { graphics_scene.face_begin(); }
  }

  compute_one_loop_elements<P2>(p2, p2.outer_boundary(), graphics_scene,
                                false, gs_options);

  for (typename P2::Hole_const_iterator it=p2.holes_begin(); it!=p2.holes_end(); ++it)
  {
    compute_one_loop_elements<P2>(p2, *it, graphics_scene,
                                  true, gs_options);
    if (gs_options.are_faces_enabled())
    { graphics_scene.add_point_in_face(p2.outer_boundary().vertex
                                       (p2.outer_boundary().size()-1));
    }
  }

 if (gs_options.are_faces_enabled())
 { graphics_scene.face_end(); }
}

} // draw_function_for_ph2

#define CGAL_P2_WITH_HOLES_TYPE CGAL::Polygon_with_holes_2<T, C>

template <class T, class C, class GSOptions>
void add_to_graphics_scene(const CGAL_P2_WITH_HOLES_TYPE& p2,
                           CGAL::Graphics_scene& graphics_scene,
                           const GSOptions &gs_options)
{
  draw_function_for_ph2_with_holes::compute_elements(p2, graphics_scene,
                                                     gs_options);
}

template <class T, class C>
void add_to_graphics_scene(const CGAL_P2_WITH_HOLES_TYPE& p2,
                           CGAL::Graphics_scene& graphics_scene)
{
  Graphics_scene_options<CGAL_P2_WITH_HOLES_TYPE,
                  typename CGAL_P2_WITH_HOLES_TYPE::General_polygon_2::Vertex_const_iterator,
                  typename CGAL_P2_WITH_HOLES_TYPE::General_polygon_2::Vertex_const_iterator,
                  void*> gs_options;

  add_to_graphics_scene(p2, graphics_scene, gs_options);
}

#ifdef CGAL_USE_BASIC_VIEWER

// Specialization of draw function.
template<class T, class C, class GSOptions>
void draw(const CGAL_P2_WITH_HOLES_TYPE& ap2, const GSOptions &gs_options,
          const char* title="Polygon with Holes Basic Viewer")
{
  CGAL::Graphics_scene buffer;
  add_to_graphics_scene(ap2, buffer, gs_options);
  draw_graphics_scene(buffer, title);
}

template<class T, class C>
void draw(const CGAL_P2_WITH_HOLES_TYPE& ap2,
          const char* title="Polygon with Holes Basic Viewer")
{
  CGAL::Graphics_scene buffer;
  add_to_graphics_scene(ap2, buffer);
  draw_graphics_scene(buffer, title);
}

#endif // CGAL_USE_BASIC_VIEWER

#undef CGAL_P2_WITH_HOLES_TYPE

} // End namespace CGAL

#endif // CGAL_DRAW_POLYGON_WITH_HOLES_2_H