add observer pattern to all decimaters

closes #2366

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@1197 fdac6126-5c0c-442c-9429-916003d36597

src/Unittests/unittests_mc_decimater.cc

@@ -106,4 +106,58 @@ TEST_F(OpenMeshMultipleChoiceDecimater, DecimateMeshToFaceFaceLimit) {
   EXPECT_EQ(14994u, mesh_.n_edges()) << "The number of edges after decimation is not correct!";
   EXPECT_EQ(9996u, mesh_.n_faces()) << "The number of faces after decimation is not correct!";
 }
+
+class UnittestObserver : public OpenMesh::Decimater::Observer
+{
+    size_t notifies_;
+    size_t all_steps_;
+public:
+    UnittestObserver(size_t _steps) :Observer(_steps), notifies_(0), all_steps_(0) {}
+
+    void notify(size_t _step)
+    {
+        ++notifies_;
+        all_steps_ = _step;
+    }
+    bool abort() const
+    {
+        return all_steps_ >= 2526u;
+    }
+
+    size_t countedNotifies()
+    {
+        return notifies_;
+    }
+};
+
+TEST_F(OpenMeshMultipleChoiceDecimater, DecimateMeshStoppedByObserver) {
+
+    bool ok = OpenMesh::IO::read_mesh(mesh_, "cube1.off");
+
+    ASSERT_TRUE(ok);
+
+    typedef OpenMesh::Decimater::McDecimaterT< Mesh >  Decimater;
+    typedef OpenMesh::Decimater::ModQuadricT< Mesh >::Handle HModQuadric;
+
+    Decimater decimaterDBG(mesh_);
+    HModQuadric hModQuadricDBG;
+    decimaterDBG.add(hModQuadricDBG);
+
+    decimaterDBG.module(hModQuadricDBG).unset_max_err();
+
+    decimaterDBG.initialize();
+    UnittestObserver obs(2);
+    decimaterDBG.set_observer(&obs);
+    size_t removedVertices = 0;
+    removedVertices = decimaterDBG.decimate_to_faces(0, 0);
+    decimaterDBG.mesh().garbage_collection();
+
+    EXPECT_TRUE(obs.abort()) << "Observer did not abort the decimater!";
+    EXPECT_EQ(obs.countedNotifies(), 2526u / 2u) << "Observer did not get the right amount of notifications!";
+
+    EXPECT_EQ(2526u, removedVertices) << "The number of remove vertices is not correct!";
+    EXPECT_EQ(5000u, mesh_.n_vertices()) << "The number of vertices after decimation is not correct!";
+    EXPECT_EQ(14994u, mesh_.n_edges()) << "The number of edges after decimation is not correct!";
+    EXPECT_EQ(9996u, mesh_.n_faces()) << "The number of faces after decimation is not correct!";
+}
 }