From f2ca8973dcbd27d9e8d7897c60d307d79f28bfec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sloriot.ml@gmail.com>
Date: Tue, 13 Dec 2011 15:50:34 +0000
Subject: [PATCH] add an example to print a cropped Voronoi diagram

---
 .gitattributes                                |  1 +
 .../Triangulation_2/draw_cropped_voronoi.cpp  | 53 +++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 Triangulation_2/examples/Triangulation_2/draw_cropped_voronoi.cpp

diff --git a/.gitattributes b/.gitattributes
index 3d2ed5d0659..58a3c44ceb4 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -4281,6 +4281,7 @@ Triangulation_2/doc_tex/Triangulation_2_ref/insert3.gif -text svneol=unset#image
 Triangulation_2/doc_tex/Triangulation_2_ref/neighbors.gif -text svneol=unset#image/gif
 Triangulation_2/doc_tex/Triangulation_2_ref/remove.gif -text svneol=unset#image/gif
 Triangulation_2/doc_tex/Triangulation_2_ref/walk.gif -text svneol=unset#image/gif
+Triangulation_2/examples/Triangulation_2/draw_cropped_voronoi.cpp -text
 Triangulation_2/examples/Triangulation_2/info_insert_with_pair_iterator_2.cpp -text
 Triangulation_2/examples/Triangulation_2/info_insert_with_pair_iterator_regular_2.cpp -text
 Triangulation_2/examples/Triangulation_2/info_insert_with_transform_iterator_2.cpp -text
diff --git a/Triangulation_2/examples/Triangulation_2/draw_cropped_voronoi.cpp b/Triangulation_2/examples/Triangulation_2/draw_cropped_voronoi.cpp
new file mode 100644
index 00000000000..037ad68035e
--- /dev/null
+++ b/Triangulation_2/examples/Triangulation_2/draw_cropped_voronoi.cpp
@@ -0,0 +1,53 @@
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/Delaunay_triangulation_2.h>
+#include <iterator>
+
+typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
+typedef K::Point_2 Point_2;
+typedef K::Iso_rectangle_2 Iso_rectangle_2;
+typedef K::Segment_2 Segment_2;
+typedef K::Ray_2 Ray_2;
+typedef K::Line_2 Line_2;
+typedef CGAL::Delaunay_triangulation_2<K>  Delaunay_triangulation_2;
+
+//A class to recover Voronoi diagram from stream.
+//Rays, lines and segments are cropped to a rectangle
+//so that only segments are stored
+struct Cropped_voronoi_from_delaunay{
+  std::list<Segment_2> m_cropped_vd;
+  Iso_rectangle_2 m_bbox;
+  
+  Cropped_voronoi_from_delaunay(const Iso_rectangle_2& bbox):m_bbox(bbox){}
+  
+  template <class RSL>
+  void crop_and_extract_segment(const RSL& rsl){
+    CGAL::Object obj = CGAL::intersection(rsl,m_bbox);
+    const Segment_2* s=CGAL::object_cast<Segment_2>(&obj);
+    if (s) m_cropped_vd.push_back(*s);
+  }
+  
+  void operator<<(const Ray_2& ray)    { crop_and_extract_segment(ray); }
+  void operator<<(const Line_2& line)  { crop_and_extract_segment(line); }
+  void operator<<(const Segment_2& seg){ crop_and_extract_segment(seg); }
+};
+
+int main(){
+  //consider some points
+  std::vector<Point_2> points;
+  points.push_back(Point_2(0,0));
+  points.push_back(Point_2(1,1));
+  points.push_back(Point_2(0,1));
+  
+  Delaunay_triangulation_2 dt2;
+  //insert points into the triangulation
+  dt2.insert(points.begin(),points.end());
+  //construct a rectangle
+  Iso_rectangle_2 bbox(-1,-1,2,2);
+  Cropped_voronoi_from_delaunay vor(bbox);
+  //extract the cropped Voronoi diagram
+  dt2.draw_dual(vor);
+  //print the cropped Voronoi diagram as segments
+  std::copy(vor.m_cropped_vd.begin(),vor.m_cropped_vd.end(),
+    std::ostream_iterator<Segment_2>(std::cout,"\n"));
+}
+