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/OpenMesh/Tools/Decimater/DecimaterT.cc

@@ -136,13 +136,13 @@ void DecimaterT<Mesh>::heap_vertex(VertexHandle _vh) {
     mesh_.property(priority_, _vh) = -1;
   }
 }
-
-//-----------------------------------------------------------------------------
-template<class Mesh>
-size_t DecimaterT<Mesh>::decimate(size_t _n_collapses) {
-
-  if (!this->is_initialized())
-    return 0;
+
+//-----------------------------------------------------------------------------
+template<class Mesh>
+size_t DecimaterT<Mesh>::decimate(size_t _n_collapses) {
+
+  if (!this->is_initialized())
+    return 0;
 
   typename Mesh::VertexIter v_it, v_end(mesh_.vertices_end());
   typename Mesh::VertexHandle vp;
@@ -212,12 +212,16 @@ size_t DecimaterT<Mesh>::decimate(size_t _n_collapses) {
 
     // update heap (former one ring of decimated vertex)
     for (s_it = support.begin(), s_end = support.end(); s_it != s_end; ++s_it) {
-      assert(!mesh_.status(*s_it).deleted());
-      heap_vertex(*s_it);
-    }
-  }
-
-  // delete heap
+      assert(!mesh_.status(*s_it).deleted());
+      heap_vertex(*s_it);
+    }
+
+    // notify observer and stop if the observer requests it
+    if (!this->notify_observer(n_collapses))
+        return n_collapses;
+  }
+
+  // delete heap
   heap_.reset();
 
 
@@ -226,13 +230,13 @@ size_t DecimaterT<Mesh>::decimate(size_t _n_collapses) {
   return n_collapses;
 }
 
-//-----------------------------------------------------------------------------
-
-template<class Mesh>
-size_t DecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
-
-  if (!this->is_initialized())
-    return 0;
+//-----------------------------------------------------------------------------
+
+template<class Mesh>
+size_t DecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
+
+  if (!this->is_initialized())
+    return 0;
 
   if (_nv >= mesh_.n_vertices() || _nf >= mesh_.n_faces())
     return 0;
@@ -313,12 +317,16 @@ size_t DecimaterT<Mesh>::decimate_to_faces(size_t _nv, size_t _nf) {
 
     // update heap (former one ring of decimated vertex)
     for (s_it = support.begin(), s_end = support.end(); s_it != s_end; ++s_it) {
-      assert(!mesh_.status(*s_it).deleted());
-      heap_vertex(*s_it);
-    }
-  }
-
-  // delete heap
+      assert(!mesh_.status(*s_it).deleted());
+      heap_vertex(*s_it);
+    }
+
+    // notify observer and stop if the observer requests it
+    if (!this->notify_observer(n_collapses))
+        return n_collapses;
+  }
+
+  // delete heap
   heap_.reset();