Fixed the orientation marker widget test for viewport changes

The viewport should be specified in normalized viewport
coordinates with respect to the viewport of the current renderer.

Interaction/Widgets/Testing/Cxx/TestOrientationMarkerWidget2.cxx

@@ -108,7 +108,7 @@ int TestOrientationMarkerWidget2(int argc, char *argv[])
   vtkNew<vtkOrientationMarkerWidget> orientationWidget;
   orientationWidget->SetInteractor(iren.GetPointer());
   orientationWidget->SetDefaultRenderer(smallViewRenderer.GetPointer());
-  orientationWidget->SetViewport(smallViewRenderer->GetViewport());
+  orientationWidget->SetViewport(0, 0, 1, 1);
   orientationWidget->SetOrientationMarker(textActor.GetPointer());
   orientationWidget->On();
 

Interaction/Widgets/vtkOrientationMarkerWidget.h

@@ -112,11 +112,14 @@ public:
 
   // Description:
   // Set/get the viewport to position/size this widget.
+  // Coordinates are expressed as (xmin,ymin,xmax,ymax), where each
+  // coordinate is 0 <= coordinate <= 1.0.
   // Default is bottom left corner (0,0,0.2,0.2).
   // Note that this viewport is scaled with respect to the viewport of the
   // current renderer i.e. if the viewport of the current renderer is
   // (0.5, 0.5, 0.75, 0.75) and Viewport is set to (0, 0, 1, 1), the orientation
-  // marker will be confined to a viewport of (0.5, 0.5, 0.75, 0.75).
+  // marker will be confined to a viewport of (0.5, 0.5, 0.75, 0.75) in the
+  // render window.
   // \sa SetCurrentRenderer()
   vtkSetVector4Macro(Viewport, double);
   vtkGetVector4Macro(Viewport, double);