How to add observer to handle viewport changing(rotate) event?

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1

Hello,I want to recalculate the normal of all actors in the window when view port changing(rotating) by dragging or left key pressing.Below approaches have been tried:

class Callback:

    def __init__(self):
          pass

    def __call__(self, caller, ev):
         print("rotating...")

interactor.AddObserver(vtk.vtkCommand.RotateEvent, Callback())
renwin.AddObserver(vtk.vtkCommand.RotateEvent, Callback())
renderer.GetActiveCamera().AddObserver(vtk.vtkCommand.RotateEvent, Callback())

But none of them will print out “rotating”,question is

Where to register which type of event to handle rotate event?

Thanks.

1 Like
2

I have the same problem, somehow OnRotate function is not triggered

here is my custom interactorStyle

class NoRotateStyle(vtk.vtkInteractorStyleTrackballCamera):

def __init__(self):
    self.AddObserver("RotateEvent",self.onRotateEvent)
    self.AddObserver("LeftButtonPressEvent", self.onLeftButtonDown)
    # self.AddObserver("LeftButtonReleaseEvent", self.onLeftButtonUp)
    # self.AddObserver("InteractionEvent",self.onInteract)
    # self.AddObserver("RightButtonPressEvent", self.onRightButtonDown)
    pass

def onLeftButtonDown(self, obj, event) -> None:
    print("left clicked down custom interactor",obj)
    self.OnLeftButtonDown()
    return 

def onRotateEvent(self, obj,event) -> None:
    print("rotating")
    self.OnRotate()
    return

def OnRotate(self) -> None:
    print("rotating")
    return super().OnRotate()

def OnPan(self) -> None:
    print("panning")
    return super().OnPan()

OnPan, OnRotate methods which are original methods are not triggered.
Also if I addobserver for rotate or pan, the custome method “onRotateEvent” method is also not triggered
Am I missing something or is there a bug??
Thanks in advance
Best Regards