--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/Internals/FixedPointAligner.h	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,49 @@
+/**
+ * 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 "../../Scene2DViewport/PredeclaredTypes.h"
+#include "../../Scene2D/ScenePoint2D.h"
+#include "../../Viewport/IViewport.h"
+
+#include <boost/weak_ptr.hpp>
+
+namespace OrthancStone
+{
+  namespace Internals
+  {
+    // During a mouse event that modifies the view of a scene, keeps
+    // one point (the pivot) at a fixed position on the canvas
+    class FixedPointAligner : public boost::noncopyable
+    {
+    private:
+      boost::shared_ptr<IViewport> viewport_;
+      ScenePoint2D           pivot_;
+      ScenePoint2D           canvas_;
+
+    public:
+      FixedPointAligner(boost::shared_ptr<IViewport> viewport,
+                        const ScenePoint2D& p);
+
+      void Apply();
+    };
+  }
+}