JupyterLab : The widget returned by plotter.show(return_viewer=True) isn't updated when the plotter is

[leilakany]

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

I am trying to have a widget returned by the method plotter.show(return_viewer=True) interact with an ipywidget slider in JupyterLab and pythreejs backend, but the widget scene doesn't get updated when the plotter actors change.

However, I works as expected with the @interact decorator.

Steps to reproduce the bug.

Doesn't work as expect

import pyvista as pv
from ipywidgets import widgets
pv.start_xvfb()
pv.set_jupyter_backend('pythreejs')
from pyvista import examples
from ipywidgets import interact

new_plotter = pv.Plotter()
vol = examples.download_brain()
slice = vol.slice()
new_act = [None]
new_act[0] = new_plotter.add_mesh(slice)

int_range =  widgets.IntSlider(min=0, max=180, step=1, )

widget = new_plotter.show(interactive_update=True, return_viewer=True, auto_close=False)

def update_slice(change):
    x = change["new"]
    new_slice = vol.slice(origin=(x, 0, 0))
    new_plotter.remove_actor(new_act[0], render=False, reset_camera=False)
    new_act[0] = new_plotter.add_mesh(new_slice, render=False, reset_camera=False)
    new_plotter.update()
    new_plotter.show()

int_range.observe(update_slice, names=['value'])

display(int_range, widget)
 

Works as expected

import pyvista as pv
from ipywidgets import widgets
pv.start_xvfb()
pv.set_jupyter_backend('pythreejs')
from pyvista import examples
from ipywidgets import interact

vol = examples.download_brain()
p = pv.Plotter()
slice = vol.slice()
actors = [None]
actors[0] = p.add_mesh(slice)
p.show(interactive_update=True, return_viewer=True, auto_close=False)

@interact(x=(0.0,180.0,1.0), continuous_update=False)
def update_slice(x):
    slice = vol.slice(origin=(x, 0, 0))
    p.remove_actor(actors[0], render=False, reset_camera=False)
    actors[0] = p.add_mesh(slice, render=False, reset_camera=False)
    p.show(interactive_update=True, auto_close=False)

System Information

--------------------------------------------------------------------------------
  Date: Mon Jul 04 16:53:41 2022 UTC

                OS : Linux
            CPU(s) : 8
           Machine : x86_64
      Architecture : 64bit
               RAM : 54.9 GiB
       Environment : Jupyter
        GPU Vendor : VMware, Inc.
      GPU Renderer : llvmpipe (LLVM 10.0.0, 256 bits)
       GPU Version : 3.3 (Core Profile) Mesa 20.0.8

  Python 3.8.0 (default, Dec  9 2021, 17:53:27)  [GCC 8.4.0]

           pyvista : 0.33.2
               vtk : 9.0.1
             numpy : 1.19.5
           imageio : 2.9.0
           appdirs : 1.4.4
            scooby : 0.5.7
        matplotlib : 3.3.4
           IPython : 7.16.1
        ipyvtklink : 0.2.2
             scipy : 1.8.1
              tqdm : 4.60.0
            meshio : 4.4.1
--------------------------------------------------------------------------------

Screenshots

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[github-actions]

Hi and welcome! Thanks for posting your first issue in the PyVista project! Someone from @pyvista/developers will chime in before too long. If your question is support related, we may transfer it to the Discussions.

[banesullivan]

Hi @leilakany, this is a great feature request!

At this time, the pythreejs notebook viewer for the Plotter is statically serializing/exporting the scene which is why you aren't seeing the threejs scene in the notebook update after modifying the original Plotter.

Your @interact decorated function is actually re-serializing the scene with the additional p.show() call - this is why it seemingly updates, but this could have very poor performance for many use cases.

At this time, I think the best way to have a reactive and interactive plotter in a notebook is with the ipyvtklink backend though more options and features are definitely on our roadmap, so stay tuned!