--- a/OrthancStone/Resources/CMake/OrthancStoneConfiguration.cmake	Fri Aug 07 15:00:52 2020 +0200
+++ b/OrthancStone/Resources/CMake/OrthancStoneConfiguration.cmake	Fri Aug 07 15:55:59 2020 +0200
@@ -338,12 +338,14 @@
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/FloatTextureSceneLayer.h
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/GrayscaleStyleConfigurator.cpp
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/GrayscaleStyleConfigurator.h
+  ${ORTHANC_STONE_ROOT}/Sources/Scene2D/GrayscaleWindowingSceneTracker.cpp
+  ${ORTHANC_STONE_ROOT}/Sources/Scene2D/GrayscaleWindowingSceneTracker.h
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/ICompositor.h
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/ILayerStyleConfigurator.h
+  ${ORTHANC_STONE_ROOT}/Sources/Scene2D/IPointerTracker.h
+  ${ORTHANC_STONE_ROOT}/Sources/Scene2D/ISceneLayer.h
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/InfoPanelSceneLayer.cpp
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/InfoPanelSceneLayer.h
-  ${ORTHANC_STONE_ROOT}/Sources/Scene2D/IPointerTracker.h
-  ${ORTHANC_STONE_ROOT}/Sources/Scene2D/ISceneLayer.h
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/LookupTableStyleConfigurator.cpp
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/LookupTableStyleConfigurator.h
   ${ORTHANC_STONE_ROOT}/Sources/Scene2D/LookupTableTextureSceneLayer.cpp

--- a/OrthancStone/Sources/Scene2D/FloatTextureSceneLayer.cpp	Fri Aug 07 15:00:52 2020 +0200
+++ b/OrthancStone/Sources/Scene2D/FloatTextureSceneLayer.cpp	Fri Aug 07 15:55:59 2020 +0200
@@ -31,7 +31,10 @@
 {
   FloatTextureSceneLayer::FloatTextureSceneLayer(const Orthanc::ImageAccessor& texture) :
     inverted_(false),
-    applyLog_(false)
+    applyLog_(false),
+    isRangeComputed_(false),
+    minValue_(0),
+    maxValue_(0)
   {
     {
       std::unique_ptr<Orthanc::ImageAccessor> t(
@@ -107,11 +110,11 @@
   void FloatTextureSceneLayer::FitRange()
   {
     float minValue, maxValue;
-    Orthanc::ImageProcessing::GetMinMaxFloatValue(minValue, maxValue, GetTexture());
+    GetRange(minValue, maxValue);
+    assert(minValue <= maxValue);
 
     float width;
 
-    assert(minValue <= maxValue);
     if (LinearAlgebra::IsCloseToZero(maxValue - minValue))
     {
       width = 1;
@@ -125,6 +128,22 @@
   }
 
     
+  void FloatTextureSceneLayer::GetRange(float& minValue,
+                                        float& maxValue)
+  {
+    if (!isRangeComputed_)
+    {
+      Orthanc::ImageProcessing::GetMinMaxFloatValue(minValue_, maxValue_, GetTexture());
+      isRangeComputed_ = true;
+    }
+
+    assert(minValue_ <= maxValue_);
+
+    minValue = minValue_;
+    maxValue = maxValue_;
+  }
+
+
   ISceneLayer* FloatTextureSceneLayer::Clone() const
   {
     std::unique_ptr<FloatTextureSceneLayer> cloned
@@ -136,6 +155,9 @@
     cloned->customWidth_ = customWidth_;
     cloned->inverted_ = inverted_;
     cloned->applyLog_ = applyLog_;
+    cloned->isRangeComputed_ = isRangeComputed_;
+    cloned->minValue_ = minValue_;
+    cloned->maxValue_ = maxValue_;
 
     return cloned.release();
   }

--- a/OrthancStone/Sources/Scene2D/FloatTextureSceneLayer.h	Fri Aug 07 15:00:52 2020 +0200
+++ b/OrthancStone/Sources/Scene2D/FloatTextureSceneLayer.h	Fri Aug 07 15:55:59 2020 +0200
@@ -33,6 +33,9 @@
     float            customWidth_;
     bool             inverted_;
     bool             applyLog_;
+    bool             isRangeComputed_;
+    float            minValue_;
+    float            maxValue_;
 
   public:
     // The pixel format must be convertible to "Float32"
@@ -68,6 +71,9 @@
       return applyLog_;
     }
 
+    void GetRange(float& minValue,
+                  float& maxValue);
+
     virtual ISceneLayer* Clone() const;
 
     virtual Type GetType() const

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/GrayscaleWindowingSceneTracker.cpp	Fri Aug 07 15:55:59 2020 +0200
@@ -0,0 +1,161 @@
+/**
+ * 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/>.
+ **/
+
+
+#include "GrayscaleWindowingSceneTracker.h"
+
+#include "../Scene2DViewport/ViewportController.h"
+#include "FloatTextureSceneLayer.h"
+
+#include <OrthancException.h>
+
+namespace OrthancStone
+{
+  namespace
+  {
+    class GrayscaleLayerAccessor : public boost::noncopyable
+    {
+    private:
+      std::unique_ptr<IViewport::ILock>   lock_;
+      FloatTextureSceneLayer*             layer_;
+
+    public:
+      GrayscaleLayerAccessor(boost::shared_ptr<IViewport> viewport,
+                             int layerIndex) :
+        layer_(NULL)
+      {
+        if (viewport != NULL)
+        {
+          lock_.reset(viewport->Lock());
+
+          if (lock_->GetController().GetScene().HasLayer(layerIndex))
+          {
+            ISceneLayer& layer = lock_->GetController().GetScene().GetLayer(layerIndex);
+            if (layer.GetType() == ISceneLayer::Type_FloatTexture)
+            {
+              layer_ = &dynamic_cast<FloatTextureSceneLayer&>(layer);
+            }
+          }
+        }
+      }
+
+      bool IsValid() const
+      {
+        return layer_ != NULL;
+      }
+
+      FloatTextureSceneLayer& GetLayer() const
+      {
+        if (layer_ == NULL)
+        {
+          throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+        }
+        else
+        {
+          return *layer_;
+        }
+      }
+
+      void Invalidate()
+      {
+        if (lock_.get() != NULL)
+        {
+          lock_->Invalidate();
+        }
+      }
+    };
+  }
+  
+  void GrayscaleWindowingSceneTracker::SetWindowing(float center,
+                                                    float width)
+  {
+    if (active_)
+    {
+      GrayscaleLayerAccessor accessor(viewport_, layerIndex_);
+      
+      if (accessor.IsValid())
+      {
+        accessor.GetLayer().SetCustomWindowing(center, width);
+        accessor.Invalidate();
+      }
+    }      
+  }
+    
+
+  GrayscaleWindowingSceneTracker::GrayscaleWindowingSceneTracker(boost::shared_ptr<IViewport> viewport,
+                                                                 int layerIndex,
+                                                                 const PointerEvent& event,
+                                                                 unsigned int canvasWidth,
+                                                                 unsigned int canvasHeight) :
+    OneGesturePointerTracker(viewport),
+    layerIndex_(layerIndex),
+    clickX_(event.GetMainPosition().GetX()),
+    clickY_(event.GetMainPosition().GetY())
+  {
+    active_ = false;
+
+    if (canvasWidth > 3 &&
+        canvasHeight > 3)
+    {
+      GrayscaleLayerAccessor accessor(viewport_, layerIndex_);
+      
+      if (accessor.IsValid())
+      {
+        FloatTextureSceneLayer& layer = accessor.GetLayer();
+        
+        layer.GetWindowing(originalCenter_, originalWidth_);
+        
+        float minValue, maxValue;
+        layer.GetRange(minValue, maxValue);
+        
+        normalization_ = (maxValue - minValue) / static_cast<double>(std::min(canvasWidth, canvasHeight) - 1);
+        active_ = true;
+      }
+      else
+      {
+        LOG(INFO) << "Cannot create GrayscaleWindowingSceneTracker on a non-float texture";
+      }
+    }
+  }
+  
+  void GrayscaleWindowingSceneTracker::PointerMove(const PointerEvent& event)
+  {
+    if (active_)
+    {
+      const double x = event.GetMainPosition().GetX();
+      const double y = event.GetMainPosition().GetY();
+
+      float center = originalCenter_ + (x - clickX_) * normalization_;
+      float width = originalWidth_ + (y - clickY_) * normalization_;
+
+      if (width <= 1)
+      {
+        width = 1;
+      }
+      
+      SetWindowing(center, width);
+    }
+  }
+
+  void GrayscaleWindowingSceneTracker::Cancel()
+  {
+    SetWindowing(originalCenter_, originalWidth_);
+  }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/GrayscaleWindowingSceneTracker.h	Fri Aug 07 15:55:59 2020 +0200
@@ -0,0 +1,58 @@
+/**
+ * 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/OneGesturePointerTracker.h"
+#include "../Viewport/IViewport.h"
+#include "Internals/FixedPointAligner.h"
+
+#include <boost/weak_ptr.hpp>
+
+namespace OrthancStone
+{
+  class GrayscaleWindowingSceneTracker : public OneGesturePointerTracker
+  {
+  private:
+    bool    active_;
+    int     layerIndex_;
+    double  normalization_;
+    float   originalCenter_;
+    float   originalWidth_;
+    double  clickX_;
+    double  clickY_;
+
+    void SetWindowing(float center,
+                      float width);
+    
+  public:
+    GrayscaleWindowingSceneTracker(boost::shared_ptr<IViewport> viewport,
+                                   int layerIndex,
+                                   const PointerEvent& event,
+                                   unsigned int canvasWidth,
+                                   unsigned int canvasHeight);
+
+    virtual void PointerMove(const PointerEvent& event) ORTHANC_OVERRIDE;
+    
+    virtual void Cancel() ORTHANC_OVERRIDE;
+  };
+}

--- a/OrthancStone/Sources/Scene2DViewport/ViewportController.cpp	Fri Aug 07 15:00:52 2020 +0200
+++ b/OrthancStone/Sources/Scene2DViewport/ViewportController.cpp	Fri Aug 07 15:55:59 2020 +0200
@@ -23,10 +23,11 @@
 #include "UndoStack.h"
 #include "MeasureCommands.h"
 
-#include "../StoneException.h"
+#include "../Scene2D/GrayscaleWindowingSceneTracker.h"
 #include "../Scene2D/PanSceneTracker.h"
 #include "../Scene2D/RotateSceneTracker.h"
 #include "../Scene2D/ZoomSceneTracker.h"
+#include "../StoneException.h"
 
 #include <boost/make_shared.hpp>
 
@@ -41,22 +42,16 @@
     switch (event.GetMouseButton())
     {
       case MouseButton_Left:
-        return new RotateSceneTracker(viewport, event);
+        //return new RotateSceneTracker(viewport, event);
+
+        // Assumes that the layer whose windowing is controlled, is the one with index "0"
+        return new GrayscaleWindowingSceneTracker(viewport, 0, event, viewportWidth, viewportHeight);
 
       case MouseButton_Middle:
         return new PanSceneTracker(viewport, event);
       
       case MouseButton_Right:
-      {
-        if (viewportWidth != 0)
-        {
-          return new ZoomSceneTracker(viewport, event, viewportWidth);
-        }
-        else
-        {
-          return NULL;
-        }
-      }
+        return new ZoomSceneTracker(viewport, event, viewportHeight);
 
       default:
         return NULL;