--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Samples/Common/CreateLineMeasureTracker.cpp	Fri May 10 16:15:55 2019 +0200
@@ -0,0 +1,83 @@
+/**
+ * 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 "CreateLineMeasureTracker.h"
+#include <Core/OrthancException.h>
+
+using namespace Orthanc;
+
+namespace OrthancStone
+{
+  CreateLineMeasureTracker::CreateLineMeasureTracker(
+    Scene2D&                        scene,
+    std::vector<TrackerCommandPtr>& undoStack,
+    std::vector<MeasureToolPtr>&    measureTools,
+    const PointerEvent&             e)
+    : CreateMeasureTracker(scene, undoStack, measureTools)
+  {
+    command_.reset(
+      new CreateLineMeasureCommand(
+        scene,
+        measureTools,
+        e.GetMainPosition().Apply(scene.GetCanvasToSceneTransform())));
+  }
+
+  CreateLineMeasureTracker::~CreateLineMeasureTracker()
+  {
+
+  }
+
+  void CreateLineMeasureTracker::PointerMove(const PointerEvent& event)
+  {
+    if (!active_)
+    {
+      throw OrthancException(ErrorCode_InternalError,
+        "Internal error: wrong state in CreateLineMeasureTracker::"
+        "PointerMove: active_ == false");
+    }
+
+    ScenePoint2D scenePos = event.GetMainPosition().Apply(
+      scene_.GetCanvasToSceneTransform());
+
+    //LOG(TRACE) << "scenePos.GetX() = " << scenePos.GetX() << "     " <<
+    //  "scenePos.GetY() = " << scenePos.GetY();
+
+    CreateLineMeasureTracker* concreteThis =
+      dynamic_cast<CreateLineMeasureTracker*>(this);
+    assert(concreteThis != NULL);
+    command_->Update(scenePos);
+  }
+
+  void CreateLineMeasureTracker::PointerUp(const PointerEvent& e)
+  {
+    // TODO: the current app does not prevent multiple PointerDown AND
+    // PointerUp to be sent to the tracker.
+    // Unless we augment the PointerEvent structure with the button index, 
+    // we cannot really tell if this pointer up event matches the initial
+    // pointer down event. Let's make it simple for now.
+    active_ = false;
+  }
+
+  void CreateLineMeasureTracker::PointerDown(const PointerEvent& e)
+  {
+    LOG(WARNING) << "Additional touches (fingers, pen, mouse buttons...) "
+      "are ignored when the line measure creation tracker is active";
+  }
+}