trame-vtklocal

VTK Local Rendering using VTK/WASM to match server side rendering pipeline on the client side. The current code base is still at its infancy but we aim to make it the default implementation for local rendering using VTK/ParaView with trame. This WASM capability is starting to be available with VTK 9.4.

License

This library is OpenSource and follow the Apache Software License

Installation

# to install a compatible version of VTK
pip install "trame-vtklocal[vtk]"

# to install VTK yourself
pip install trame-vtklocal
pip install "vtk>=9.4,<9.5"

Development

Build and install the Vue components

cd vue-components
npm i
npm run build
cd -

Install the library

pip install -e .

Optionally, you can develop with bleeding edge VTK by following these steps. Make sure you've these tools 1. git 2. CMake 3. Ninja 4. Python 5. NodeJS >= 22.0.0: https://nodejs.org/en/download/package-manager 6. Emscripten SDK: See https://emscripten.org/docs/getting_started/downloads.html#download-and-install

# Compile VTK for wasm32 architecture using emscripten. Build artifacts can be found in dev/vtk/build/wasm
./utils/build_vtk.sh -u https://gitlab.kitware.com/vtk/vtk.git -b master -t wasm32 -p RelWithDebInfo

# Compile VTK with python wrappings using system C++ compiler. Build artifacts can be found in dev/vtk/build/py
./utils/build_vtk.sh -u https://gitlab.kitware.com/vtk/vtk.git -b master -t py -p RelWithDebInfo

# Set environment variables
source ./utils/dev_environment.sh -b master -p RelWithDebInfo

Running examples

pip install trame "trame-vtklocal[vtk]" trame-vuetify trame-vtk

# regular trame app
python ./examples/vtk/cone.py

Some example are meant to test and validate WASM rendering. Some will default for remote rendering but if you want to force them to use WASM just run export USE_WASM=1 before executing them.

SharedArrayBuffer

To enable SharedArrayBuffer within trame you can just set the following on the server. This option is not required anymore but still available if needed.

server.http_headers.shared_array_buffer = True

This will download the threaded WASM version. Otherwise, the non-threaded version will be used as it does not require SharedArrayBuffer.

VTK/WASM vs trame-vtklocal

This repository trame-vtklocal focus on providing a web component that is capable of mirroring a vtkRenderWindow defined on the server side. This include a JavaScript section for the browser and a Python section for the server.

The server include a definition of a custom network protocol over our WebSocket (wslink/trame) and some helper class to ease the vtkRenderWindow binding with a web component in the browser. While the Python package include a Vue.js component for a seamless integration with trame, we also publish a npm package. That pure JavaScript library let you still use the trame infrastructure on the server side but with your own stack on the client side. A usage example of that pure JavaScript option is covered here.

For the pure Python trame usage, you can find the documented API here.

By design there is a nice separation between VTK/WASM and trame-vtklocal which should make trame-vtklocal fairly independent of VTK/WASM version. But since we are still building capabilities, when the C++ API expend, we will also expand the Python/JavaScript component properties/methods. Hopefully we should be able to evolve trame-vtklocal with some reasonable fallback when the version of VTK is not in par with what is exposed in trame-vtklocal.

Also most the testing of VTK/WASM is in VTK repository as many validation can be done in pure C++ or Python. Then the WASM module API can be find here with its node/chrome testing.

The documented API can be found here (vtkWasmSceneManager) and here (vtkObjectManager parent of vtkWasmSceneManager)

For the moment we rely on manual testing for when we change the network and/or API at the trame-vtklocal by going over a specific set of examples.

Currently the WASM implementation is used in the following set of projects:

• Pan3D: Pan3D aims to be an utility package for viewing and processing a wide variety of multidimensional datasets. Any dataset that can be interpreted with xarray can be explored and rendered with Pan3D.

Professional Support

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