--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/Internals/CompositorHelper.h	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,96 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 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 "../Scene2D.h"
+#include "../ScenePoint2D.h"
+#include <boost/noncopyable.hpp>
+
+#include <map>
+
+namespace OrthancStone
+{
+  namespace Internals
+  {
+    class CompositorHelper : protected Scene2D::IVisitor
+    {
+    public:
+      class ILayerRenderer : public boost::noncopyable
+      {
+      public:
+        virtual ~ILayerRenderer()
+        {
+        }
+
+        virtual void Render(const AffineTransform2D& transform,
+                            unsigned int canvasWidth,
+                            unsigned int canvasHeight) = 0;
+
+        // "Update()" is only called if the type of the layer has not changed
+        virtual void Update(const ISceneLayer& layer) = 0;
+      };
+
+      class IRendererFactory : public boost::noncopyable
+      {
+      public:
+        virtual ~IRendererFactory()
+        {
+        }
+
+        virtual ILayerRenderer* Create(const ISceneLayer& layer) = 0;
+      };
+
+    private:
+      class Item;
+
+      typedef std::map<int, Item*>  Content;
+
+      IRendererFactory&  factory_;
+      Content            content_;
+      const Scene2D*     lastScene_;   // This is only a safeguard, don't use it!
+
+      // Only valid during a call to Refresh()
+      AffineTransform2D  sceneTransform_;
+      unsigned int       canvasWidth_;
+      unsigned int       canvasHeight_;
+      
+    protected:
+      virtual void Visit(const Scene2D& scene,
+                         const ISceneLayer& layer,
+                         uint64_t layerIdentifier,
+                         int depth);
+
+    public:
+      CompositorHelper(IRendererFactory& factory) :
+      factory_(factory),
+      lastScene_(NULL)
+      {
+      }
+
+      ~CompositorHelper();
+
+      void Refresh(const Scene2D& scene,
+                   unsigned int canvasWidth,
+                   unsigned int canvasHeight);
+    };
+  }
+}