Merge branch 'image-style-winlev-fix-rel' into dgobbi-rollup-rel

Change-Id: I870ddbb823afdfbd37ae8ada7ff08d26587d7bef

Rendering/vtkInteractorStyleImage.cxx

@@ -89,6 +89,10 @@ void vtkInteractorStyleImage::StartWindowLevel()
     return;
     }
   this->StartState(VTKIS_WINDOW_LEVEL);
+
+  // Get the last (the topmost) image
+  this->SetCurrentImageToNthImage(-1);
+
   if (this->HandleObservers &&
       this->HasObserver(vtkCommand::StartWindowLevelEvent))
     {
@@ -96,9 +100,6 @@ void vtkInteractorStyleImage::StartWindowLevel()
     }
   else
     {
-    // Get the last (the topmost) image
-    this->SetCurrentImageToNthImage(-1);
-
     if (this->CurrentImageProperty)
       {
       vtkImageProperty *property = this->CurrentImageProperty;
@@ -642,16 +643,25 @@ void vtkInteractorStyleImage::SetCurrentImageToNthImage(int i)
     int j = 0;
     for (props->InitTraversal(pit); (prop = props->GetNextProp(pit)); )
       {
+      bool foundImageProp = false;
       for (prop->InitPathTraversal(); (path = prop->GetNextPath()); )
         {
         vtkProp *tryProp = path->GetLastNode()->GetViewProp();
         if ( (imageProp = vtkImageSlice::SafeDownCast(tryProp)) != 0 )
           {
-          if (j == i) { break; }
+          if (j == i)
+            {
+            foundImageProp = true;
+            break;
+            }
           imageProp = 0;
           j++;
           }
         }
+      if (foundImageProp)
+        {
+        break;
+        }
       }
     if (i < 0)
       {

Rendering/vtkInteractorStyleImage.h

@@ -156,6 +156,14 @@ public:
   void SetImageOrientation(const double leftToRight[3],
                            const double bottomToTop[3]);
 
+  // Description:
+  // Get the current image property, which is set when StartWindowLevel
+  // is called immediately before StartWindowLevelEvent is generated.
+  // This is the image property of the topmost vtkImageSlice in the
+  // renderer or NULL if no image actors are present.
+  vtkImageProperty *GetCurrentImageProperty() {
+    return this->CurrentImageProperty; }
+
 protected:
   vtkInteractorStyleImage();
   ~vtkInteractorStyleImage();