COMP: VisualizationVTKWidgetsPythonQt: Fix build with CTK_USE_CHARTS disabled

This commit ensures associated PythonQt decorators are built only
when needed.

Libs/Visualization/VTK/Widgets/CMakeLists.txt

@@ -134,7 +134,7 @@ if(CTK_LIB_Visualization/VTK/Widgets_USE_TRANSFER_FUNCTION_CHARTS)
   set(CTK_USE_CHARTS 1)
 endif()
 
-IF (${CTK_USE_CHARTS})
+if(${CTK_USE_CHARTS})
   set(KIT_SRCS
       ctkVTKChartView.cpp
       ctkVTKChartView.h

Libs/Visualization/VTK/Widgets/ctkVisualizationVTKWidgetsPythonQtDecorators.h

@@ -48,6 +48,7 @@ public:
 public Q_SLOTS:
 
   // ctkVTKChartView
+#ifdef CTK_USE_CHARTS
   
   QList<double> chartExtent(ctkVTKChartView* view)const
   {
@@ -118,6 +119,7 @@ public Q_SLOTS:
       }
     view->setValidBounds(_bounds);
   }
+#endif
 
 };