VTK widgets for trame

Warnings

• breaking With the release of `trame` v3, `trame-vtk` (along with `trame-vuetify` and other widget sets) is no longer an implicit dependency of the core `trame` package. Applications must now explicitly install `trame-vtk` and other required widget packages.
  Fix: Ensure your project's `pip install` commands explicitly list `trame-vtk` and any other required widget libraries (e.g., `trame-vuetify`). Example: `pip install trame trame-vuetify trame-vtk`.
• breaking Starting January 2024, `trame` v3 began defaulting to a Vue3 client. Existing applications built with Vue2-based widgets might experience breakage. While `trame` aims for backward compatibility, it's safer to explicitly declare the client type.
  Fix: For applications intended to use Vue2, explicitly set the client type during server initialization: `server.client_type = "vue2"`. For new applications, consider migrating to Vue3 compatible widgets and layouts, or ensure `trame-vuetify3` is used instead of `trame-vuetify`.
• gotcha Web browser caches can cause issues when switching between Vue2 and Vue3-based trame applications, leading to unexpected rendering or behavior.
  Fix: When developing or testing, open browser developer tools and enable 'Disable cache' in the Network tab. Then, reload the web page. This option usually only works while the developer tools are open.
• gotcha The `vue-vtk-js` library (used by `trame-vtk`) uses `Math.round` for setting view sizes, which rounds half to the nearest even integer. Python's built-in `round()` function might behave differently depending on the Python version (e.g., Python 3's `round()` also rounds half to even, but custom implementations or older Python versions might vary).
  Fix: Be aware of potential subtle differences in rounding behavior if you are implementing custom view size calculations in Python that need to precisely match the client-side `Math.round` behavior. For most direct usage of `trame-vtk` components, this is handled internally.
• deprecated Kitware is actively developing `trame-vtklocal` as the default implementation for local rendering using VTK.wasm, replacing the older `vtk.js` based local rendering in `trame-vtk`. While `trame-vtk` still supports `vtk.js`, `trame-vtklocal` offers a more robust solution.
  Fix: For new applications or when aiming for advanced client-side rendering capabilities, consider using `trame-vtklocal`. It provides a `VtkLocalView` component similar to `trame-vtk`'s, but leverages VTK.wasm for improved fidelity and performance. Note that `trame-vtklocal>=1` is compatible with VTK 10, while `trame-vtklocal>=0.16,<1` supports VTK 9.4-9.6.

Install

• pip install trame-vtk Install trame-vtk
• pip install trame trame-vuetify trame-vtk vtk Recommended install for trame v3 and VTK

Imports

• vtk

  from trame.widgets import vtk

  Imports the trame-vtk widgets module.
• VtkRemoteView

  from trame.widgets.vtk import VtkRemoteView

  VtkRemoteView is part of the 'vtk' submodule within trame.widgets. In trame v3, widgets like VtkRemoteView are no longer implicitly available directly under `trame.widgets` without explicit sub-module import.
• VtkLocalView

  from trame.widgets.vtk import VtkLocalView

  For client-side rendering using vtk.js or VTK.wasm.
• vtkConeSource

  from vtkmodules.vtkFiltersSources import vtkConeSource

  Example of importing a specific VTK class. Other VTK objects should be imported from their respective `vtkmodules`.

Quickstart

This quickstart demonstrates a basic trame-vtk application displaying a VTK cone. It sets up a simple VTK pipeline, integrates it with a `VtkRemoteView` widget within a trame `VAppLayout`, and adds a slider to control the cone's resolution. It explicitly sets `server.client_type = "vue3"` for compatibility with recent `trame` versions.

import vtk
from trame.app import get_server
from trame.ui.vuetify3 import VAppLayout
from trame.widgets import vuetify3 as v3
from trame.widgets.vtk import VtkRemoteView
from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkRenderingCore import (vtkActor, vtkPolyDataMapper, vtkRenderer, vtkRenderWindow)

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

cone = vtkConeSource()
mapper = vtkPolyDataMapper()
mapper.SetInputConnection(cone.GetOutputPort())
actor = vtkActor()
actor.SetMapper(mapper)

renderer = vtkRenderer()
renderer.AddActor(actor)
renderer.ResetCamera()

render_window = vtkRenderWindow()
render_window.AddRenderer(renderer)

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

server = get_server('trame_vtk_cone')
server.client_type = "vue3" # Explicitly set for trame v3 and above
state, ctrl = server.state, server.controller

with VAppLayout(server, full_height=True) as layout:
    with v3.VContainer(fluid=True, classes='fill-height'):
        with VtkRemoteView(render_window) as view:
            ctrl.view_update = view.update
            ctrl.view_reset_camera = view.reset_camera

@state.change('resolution')
def update_resolution(resolution, **kwargs):
    cone.SetResolution(resolution)
    ctrl.view_update()

@ctrl.add('reset_camera')
def reset_camera():
    ctrl.view_reset_camera()

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