Resetting a view

[pazars]

Hello!

I'm trying to understand how to reset/replace an existing view using just VTK in an asynchronous task. Basically an automatic paraview.simple.ReloadFiles, but in my case using the paraview module is not an option. There is a replace_view function in all the vtk view classes, and I figured that could be used. In this simple example the goal is to continously switch between a cone and a sphere, but upon the first switch from cone to sphere the window simply freezes. What am I missing?

import asyncio
import os

from trame.app import get_server, asynchronous

from trame.ui.vuetify import VAppLayout
from trame.widgets import vtk, vuetify

from vtkmodules.vtkRenderingCore import (
    vtkActor,
    vtkPolyDataMapper,
    vtkRenderer,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
)

from vtkmodules.vtkFiltersSources import vtkConeSource, vtkSphereSource
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleTrackballCamera


# Required for interactor initialization
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleSwitch  # noqa

# Required for rendering initialization, not necessary for
# local rendering, but doesn't hurt to include it
import vtkmodules.vtkRenderingOpenGL2  # noqa


# -----------------------------------------------------------------------------
# VTK pipeline
# -----------------------------------------------------------------------------


colors = vtkNamedColors()


def cone():

    cone = vtkConeSource()
    cone.SetResolution(60)

    # Create a mapper and actor
    mapper = vtkPolyDataMapper()
    mapper.SetInputConnection(cone.GetOutputPort())

    actor = vtkActor()
    actor.SetMapper(mapper)
    actor.GetProperty().SetDiffuseColor(colors.GetColor3d('bisque'))

    # Visualize
    renderer = vtkRenderer()
    renderWindow = vtkRenderWindow()
    renderWindow.AddRenderer(renderer)
    renderWindowInteractor = vtkRenderWindowInteractor()
    interactor_style = vtkInteractorStyleTrackballCamera()
    renderWindowInteractor.SetInteractorStyle(interactor_style)
    renderWindowInteractor.SetRenderWindow(renderWindow)

    renderer.AddActor(actor)
    renderer.SetBackground(colors.GetColor3d('Salmon'))
    renderer.ResetCamera()

    renderWindow.SetSize(640, 480)
    renderWindow.SetWindowName('Cone')

    return renderWindow


def sphere():

    sphere = vtkSphereSource()

    # Create a mapper and actor
    mapper = vtkPolyDataMapper()
    mapper.SetInputConnection(sphere.GetOutputPort())

    actor = vtkActor()
    actor.SetMapper(mapper)
    actor.GetProperty().SetDiffuseColor(colors.GetColor3d('bisque'))

    # Visualize
    renderer = vtkRenderer()
    renderWindow = vtkRenderWindow()
    renderWindow.AddRenderer(renderer)
    renderWindowInteractor = vtkRenderWindowInteractor()
    interactor_style = vtkInteractorStyleTrackballCamera()
    renderWindowInteractor.SetInteractorStyle(interactor_style)
    renderWindowInteractor.SetRenderWindow(renderWindow)

    renderer.AddActor(actor)
    renderer.SetBackground(colors.GetColor3d('Salmon'))
    renderer.ResetCamera()

    renderWindow.SetSize(640, 480)
    renderWindow.SetWindowName('Sphere')

    return renderWindow


cone_window = cone()
sphere_window = sphere()

# -----------------------------------------------------------------------------
# Trame setup
# -----------------------------------------------------------------------------

server = get_server()
state, ctrl = server.state, server.controller

# Initial VTK window width and height values
state.vtk_window_width = 300
state.vtk_window_height = 300


# -----------------------------------------------------------------------------
# Background thread
# -----------------------------------------------------------------------------


@asynchronous.task
async def refresh_function(**kwargs):
    counter = 1
    while True:
        with state:
            if counter % 2 == 0:
                ren_win = sphere_window
            else:
                ren_win = cone_window

            view.replace_view(ren_win)
            ctrl.view_update()

            counter += 1

        await asyncio.sleep(5)


# -----------------------------------------------------------------------------
# GUI
# -----------------------------------------------------------------------------


with VAppLayout(server) as layout:

    with layout.root:
        with vuetify.VContainer(fluid=True, classes="pa-0 fill-height"):
            view = vtk.VtkLocalView(cone_window)
            ctrl.view_update = view.update
            ctrl.on_server_ready.add(refresh_function)


# -----------------------------------------------------------------------------
# Main
# -----------------------------------------------------------------------------

if __name__ == "__main__":
    server.start()

[jourdain]

I haven't tried yet, but controller callback can not be async function.

Try to remove the @asyncronous.task decorator and call ctrl.on_server_ready.add_task(refresh_function) instead.

You may need to run pip install -U trame-server as I've added add_task only a couple days ago.

[pazars]

Tried, but it didn't work.
The replace_view seems to work fine outside async functions.

[pazars]

The view gets replaced but changes show up only once the page is manually refreshed from the browser.
This applies to the original approach, as well as using add_task.

[jourdain]

I'm not forgetting about your question but I haven't got a chance to look into it. Another approach is to create 2 VtkLocalView with a v_if that can be toggle between which one you want to show...

[jourdain]

I finally managed to look at it and it is working as expected for Remote rendering but it does not work for Local Rendering. This is mainly due to how the data handling for synchronization is happening. There is definitely a bug and even when trying with various instances + context of the Vue.js component that does not solve the problem.

Someone needs to dive into the code to handle that specific use case. If it is a priority for you feel free to reach out to Kitware to seek support so we can make our priority.

Thanks for reporting this issue in that use case.

Seb

[jourdain]

I did not try the replace_view but trame-vtk>=2.0.10 should fixed it.

https://github.com/Kitware/trame-vtk/releases/tag/v2.0.10

[zhuoju36]

I've tried the code with the latest trame but it seems that the problem still exists.
timestamp 2023/3/3

[jourdain]

The issue was on the client side and is now fixed

• vue-vtk-js
• trame-vtk>=2.2.3

Thanks for reporting the issue.