plotter.clear() doesnt clear sphere_widgets

Describe the bug, what’s wrong, and what you expected.

My application need to repeatedly create similar 3D scenes with new input data. I’m using Plotter.clear() to clear the scene before building the new one. Plotter.clear() does clears the view of the scene, but doesn’t clear the list of sphere_widgets.

After I clear the scene by using plotter.clear() the list in plotter.sphere_widgets still contains all the previous sphere widgets I added and when I add the new sphere_widgets to the scene it returns the list with all the previous widgets plus the new one.

Steps to reproduce the bug.

import pyvista as pv

plotter = pv.Plotter(notebook=False)

def key_callback(*args, **kwargs):
    print(f"number of sphere_widgets before clearing: {len(plotter.sphere_widgets)}")
    plotter.clear()
    print(f"number of sphere_widgets after clearing: {len(plotter.sphere_widgets)}")

plotter.add_checkbox_button_widget(key_callback, value=True)


def callback(*args, **kwargs):
    pass

coords = [[1,1,1], [2,2,0], [0,3,3]]

stem_widgets_heights = plotter.add_sphere_widget(callback, center=coords, color='red', pass_widget=True, test_callback=False)

plotter.show()

System Information

--------------------------------------------------------------------------------
  Date: Sat Oct 22 22:30:43 2022 +11

                OS : Linux
            CPU(s) : 8
           Machine : x86_64
      Architecture : 64bit
               RAM : 5.7 GiB
       Environment : Python
       File system : ext4
        GPU Vendor : AMD
      GPU Renderer : AMD Radeon Vega 8 Graphics (raven, LLVM 13.0.1, DRM 3.42, 5.15.0-47-generic)
       GPU Version : 4.6 (Core Profile) Mesa 22.0.1

  Python 3.10.4 (main, Jun 29 2022, 12:14:53) [GCC 11.2.0]

           pyvista : 0.36.1
               vtk : 9.2.2
             numpy : 1.21.5
           imageio : 2.22.1
           appdirs : 1.4.4
            scooby : 0.5.12
        matplotlib : 3.5.1
         pyvistaqt : 0.9.0
             PyQt5 : 5.15.6
           IPython : 8.5.0
             scipy : 1.8.0
        jupyterlab : 3.4.8
--------------------------------------------------------------------------------

Screenshots

No response

[mkondratyev85]

@banesullivan Thank you for the help. Calling sphere_widget.Off() before clearing the list solves my issue.

[adam-grant-hendry]

@banesullivan I can confirm the above resolves the issue: first turning the widget Off() before clearing the underlying list.

This needs to be done for all the clear() methods because pyvista crashes with all widget clear() methods when the list is cleared before the widget is turned off.