Merge pull request #636 from Kitware/fix-piece-wise-widget

fix(PiecewiseGaussianWidget): Don't grab color if no color available

Author: jourdain

Sources/Interaction/Widgets/PiecewiseGaussianWidget/index.js

@@ -867,7 +867,7 @@ function vtkPiecewiseGaussianWidget(publicAPI, model) {
     });
 
     // Draw color function if any
-    if (model.colorTransferFunction) {
+    if (model.colorTransferFunction && model.colorTransferFunction.getSize()) {
       const rangeToUse =
         model.dataRange || model.colorTransferFunction.getMappingRange();
       if (