--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Framework/Scene2DViewport/LayerHolder.cpp	Wed May 22 11:55:52 2019 +0200
@@ -0,0 +1,137 @@
+/**
+ * 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/>.
+ **/
+
+#include "LayerHolder.h"
+#include "../Scene2D/TextSceneLayer.h"
+#include "../Scene2D/PolylineSceneLayer.h"
+#include "../Scene2D/Scene2D.h"
+#include "../Scene2DViewport/ViewportController.h"
+#include "../StoneException.h"
+
+using namespace Orthanc;
+
+namespace OrthancStone
+{
+  LayerHolder::LayerHolder(
+    ViewportControllerWPtr controllerW,
+    int                    polylineLayerCount,
+    int                    textLayerCount)
+    : textLayerCount_(textLayerCount)
+    , polylineLayerCount_(polylineLayerCount)
+    , controllerW_(controllerW)
+    , baseLayerIndex_(-1)
+  {
+
+  }
+
+  void LayerHolder::CreateLayers()
+  {
+    assert(baseLayerIndex_ == -1);
+
+    baseLayerIndex_ = GetScene()->GetMaxDepth() + 100;
+
+    for (int i = 0; i < polylineLayerCount_; ++i)
+    {
+      std::auto_ptr<PolylineSceneLayer> layer(new PolylineSceneLayer());
+      GetScene()->SetLayer(baseLayerIndex_ + i, layer.release());
+    }
+
+    for (int i = 0; i < textLayerCount_; ++i)
+    {
+      std::auto_ptr<TextSceneLayer> layer(new TextSceneLayer());
+      GetScene()->SetLayer(
+        baseLayerIndex_ + polylineLayerCount_ + i,
+        layer.release());
+    }
+
+  }
+
+  void LayerHolder::CreateLayersIfNeeded()
+  {
+    if (baseLayerIndex_ == -1)
+      CreateLayers();
+  }
+
+  bool LayerHolder::AreLayersCreated() const
+  {
+    return (baseLayerIndex_ != -1);
+  }
+
+  OrthancStone::Scene2DPtr LayerHolder::GetScene()
+  {
+    ViewportControllerPtr controller = controllerW_.lock();
+    ORTHANC_ASSERT(controller.get() != 0, "Zombie attack!");
+    return controller->GetScene();
+  }
+
+  void LayerHolder::DeleteLayers()
+  {
+    for (int i = 0; i < textLayerCount_ + polylineLayerCount_; ++i)
+    {
+      ORTHANC_ASSERT(GetScene()->HasLayer(baseLayerIndex_ + i), "No layer");
+      GetScene()->DeleteLayer(baseLayerIndex_ + i);
+    }
+    baseLayerIndex_ = -1;
+  }
+
+  PolylineSceneLayer* LayerHolder::GetPolylineLayer(int index /*= 0*/)
+  {
+    ORTHANC_ASSERT(baseLayerIndex_ != -1);
+    ORTHANC_ASSERT(GetScene()->HasLayer(GetPolylineLayerIndex(index)));
+    ISceneLayer* layer =
+      &(GetScene()->GetLayer(GetPolylineLayerIndex(index)));
+
+    PolylineSceneLayer* concreteLayer =
+      dynamic_cast<PolylineSceneLayer*>(layer);
+
+    ORTHANC_ASSERT(concreteLayer != NULL);
+    return concreteLayer;
+  }
+
+  TextSceneLayer* LayerHolder::GetTextLayer(int index /*= 0*/)
+  {
+    ORTHANC_ASSERT(baseLayerIndex_ != -1);
+    ORTHANC_ASSERT(GetScene()->HasLayer(GetTextLayerIndex(index)));
+    ISceneLayer* layer =
+      &(GetScene()->GetLayer(GetTextLayerIndex(index)));
+
+    TextSceneLayer* concreteLayer =
+      dynamic_cast<TextSceneLayer*>(layer);
+
+    ORTHANC_ASSERT(concreteLayer != NULL);
+    return concreteLayer;
+  }
+
+  int LayerHolder::GetPolylineLayerIndex(int index /*= 0*/)
+  {
+    ORTHANC_ASSERT(index < polylineLayerCount_);
+    return baseLayerIndex_ + index;
+  }
+
+
+  int LayerHolder::GetTextLayerIndex(int index /*= 0*/)
+  {
+    ORTHANC_ASSERT(index < textLayerCount_);
+
+    // the text layers are placed right after the polyline layers
+    // this means they are drawn ON TOP
+    return baseLayerIndex_ + polylineLayerCount_ + index;
+  }
+}