--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Framework/Scene2DViewport/LayerHolder.h	Wed May 22 11:55:52 2019 +0200
@@ -0,0 +1,99 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2019 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#pragma once
+
+#include "PointerTypes.h"
+#include "boost/noncopyable.hpp"
+
+namespace OrthancStone
+{
+  class PolylineSceneLayer;
+  class TextSceneLayer;
+
+  /**
+  This class holds the indices of a set a layer and supplies
+  getters to the concrete layer objects. Sounds very ad hoc, and it is.
+  */
+  class LayerHolder : public boost::noncopyable
+  {
+  public:
+    /**
+    This ctor merely stores the scene and layer counts. No layer creation
+    performed at this time
+    */
+    LayerHolder(
+      ViewportControllerWPtr controllerW,
+      int polylineLayerCount, int textLayerCount);
+
+    /**
+    This actually creates the layers
+    */
+    void CreateLayers();
+
+    /**
+    This creates the layers if they are not created yet. Can be useful in 
+    some scenarios
+    */
+    void CreateLayersIfNeeded();
+
+    /**
+    Whether the various text and polylines layers have all been created or 
+    none at all
+    */
+    bool AreLayersCreated() const;
+
+    /**
+    This removes the layers from the scene
+    */
+    void DeleteLayers();
+
+    /**
+    Please note that the returned pointer belongs to the scene.Don't you dare
+    storing or deleting it, you fool!
+
+    This throws if the index is not valid or if the layers are not created or
+    have been deleted
+    */
+    PolylineSceneLayer* GetPolylineLayer(int index = 0);
+
+    /**
+    Please note that the returned pointer belongs to the scene. Don't you dare
+    storing or deleting it, you fool!
+
+    This throws if the index is not valid or if the layers are not created or
+    have been deleted
+    */
+    TextSceneLayer* GetTextLayer(int index = 0);
+
+  private:
+    int GetPolylineLayerIndex(int index = 0);
+    int GetTextLayerIndex(int index = 0);
+    Scene2DPtr GetScene();
+
+    int textLayerCount_;
+    int polylineLayerCount_;
+    ViewportControllerWPtr controllerW_;
+    int baseLayerIndex_;
+  };
+
+  typedef boost::shared_ptr<LayerHolder> LayerHolderPtr;
+}
+