Observing Only Threshold or Window/Level changes of a display node

I have a module where I want to do calculations every time a volume node’s window/level or threshold are changed. Right now my observation is just of the modified event of the display node which is very general:

volume.GetDisplayNode().AddObserver(vtk.vtkCommand.ModifiedEvent, self.onVolumeDisplayNodeModified)

Is there a way to only observe W/L or threshold changes?

You can check the source code, but no, I don’t think there’s a custom event for that. We’d probably accept a PR to add that.