Platform Support

megane ships in five distributions. They share the same Rust parser core (compiled to WASM and PyO3), but the host UI and the set of registered file types differ. This page is the single reference for what works on which platform, and it is descriptive of the current state — including known gaps.

Platforms

Platform	Entry	What it is
Standalone web app	src/index.tsx, served by megane serve	Full-featured viewer with pipeline editor, drag-and-drop, file dialogs, and WebSocket trajectory streaming.
Jupyter widget (anywidget)	src/widget.ts + python/megane/widget.py	Embedded viewer in a notebook cell, driven by Python (MolecularViewer).
JupyterLab labextension	jupyterlab-megane/src/index.ts	Document-style viewer launched from the JupyterLab file browser.
VSCode extension	vscode-megane/webview/main.tsx	Custom editor activated when a registered file type is opened in VS Code.
Python package (PyO3)	python/megane/parsers/	Programmatic API for parsing files into Python objects. No viewer.

File-format support

Legend:

• ✓ — openable directly from the platform's native UI (file browser, drag-drop, customEditor, LoadStructure/LoadTrajectory node, etc.)
• API — parser exists and is reachable programmatically, but the platform does not expose a UI opener for this format
• — — not supported

Structure formats

Format	Extensions	Standalone	Jupyter widget	JupyterLab	VSCode	Python
PDB	.pdb	✓	API	✓	✓	✓
GRO	.gro	✓	API	✓	✓	✓
XYZ	.xyz	✓	API	✓	✓	✓
MOL	.mol	✓	API	✓	✓	✓
SDF	.sdf	✓	API	✓	✓	✓
MOL2	.mol2	✓	API	✓	✓	✓
CIF	.cif	✓	API	✓	✓	✓
LAMMPS data	.data, .lammps	✓	API	✓	✓	✓

Trajectory formats

Format	Extensions	Standalone	Jupyter widget	JupyterLab	VSCode	Python
XTC	.xtc	✓	API	✓¹	✓¹	✓
ASE trajectory	.traj	✓	API	—	✓	✓
LAMMPS dump	.lammpstrj, .dump	✓	API	✓¹	✓¹	✓

¹ Trajectory-only formats need a topology already loaded. Opening a .xtc / .lammpstrj / .dump directly surfaces an actionable error; recover by opening a structure file (PDB, GRO, …) first or by wiring a Load Structure node in the always-mounted pipeline editor.

Sources of truth: crates/megane-wasm/src/lib.rs (browser parsers), crates/megane-python/src/lib.rs (Python parsers), src/components/nodes/LoadStructureNode.tsx and src/components/nodes/LoadTrajectoryNode.tsx (standalone accept lists), jupyterlab-megane/src/filetypes.ts (JupyterLab IFileType registrations), vscode-megane/package.json (VSCode customEditors).

UI features

Feature	Standalone	Jupyter widget	JupyterLab	VSCode	Python
Drag-and-drop into viewer	✓	—	—	—	n/a
Built-in file picker	✓	—	host	host	n/a
Visual pipeline editor	✓	—	✓	✓ (.megane.json)	n/a
Trajectory timeline / scrubbing	✓	✓	✓	✓	n/a
WebSocket trajectory streaming	✓	—	—	—	n/a
Multi-layer rendering	✓	✓ (via pipeline)	✓	✓	n/a
frame_change callback	✓ (React prop)	✓ (Python event)	—	—	n/a
selection_change / measurement events	—	✓	—	—	n/a
Programmatic frame seek (frame_index = N)	✓	✓	—	—	n/a

Notes:

• host means the parent app provides the file picker (the JupyterLab file browser, the VS Code explorer); megane itself does not render one.
• The Jupyter widget intentionally does not mount the visual pipeline editor — pipelines are built in Python (megane.Pipeline) and pushed via MolecularViewer.set_pipeline(). Use the standalone app, JupyterLab labextension, or VSCode extension to edit pipelines visually.
• The standalone app is the only platform with megane serve WebSocket streaming; other platforms load full trajectories into memory.
• The standalone React MeganeViewer exposes an onFrameChange?: (frame: number) => void prop that fires on every trajectory frame transition — useful for keeping a host Plotly figure in sync.

Load methods / APIs

How data gets into the viewer on each platform:

Platform	Primary load path	API surface
Standalone	Drag-and-drop, file dialog, megane serve <file>, WebSocket	parseStructureFile(file) (TypeScript), pipeline node LoadStructure / LoadTrajectory
Jupyter widget	Python only — no in-cell file picker	MolecularViewer.load(pdb_path, xtc=, traj=) (deprecated) or MolecularViewer.set_pipeline(Pipeline) (recommended)
JupyterLab	Click a registered file type in the file browser	Internally reads context.model (jupyterlab-megane/src/MeganeDocWidget.tsx)
VSCode	Open a registered file from the explorer; extension host posts loadFile / loadPipeline to the webview	postMessage({ type: "loadFile", … }) (vscode-megane/webview/main.tsx)
Python	from megane.parsers import …	load_pdb, load_cif, load_lammps_data, load_traj, load_trajectory (XTC), and the parse_* PyO3 functions

Known gaps

These are formats or features that the parser layer supports but a given platform does not yet wire into its UI. They are documented here so users do not file bugs against expected-but-absent behaviour.

• Trajectory-only opens require a topology first. On VSCode and JupyterLab, opening a .xtc / .lammpstrj / .dump file before any structure is loaded surfaces a friendly error. The recommended flow is to open the structure first, or to use the pipeline editor (always mounted on these hosts) to wire a Load Structure node.
• Jupyter widget has no in-cell file picker or drag-and-drop. This is intentional — the widget is Python-driven. Use set_pipeline() with a Pipeline to load any supported format.
• Jupyter widget has no visual pipeline editor. The editor's React surface relies on host chrome (drag handles, side panel layout) that the anywidget cell cannot reliably render, so it is only shipped on the standalone app, JupyterLab labextension, and VSCode extension. Build pipelines in Python with megane.Pipeline and push them via MolecularViewer.set_pipeline().
• selection_change / measurement events are widget-only. Other platforms do not emit these to a host. The standalone React component does expose onFrameChange (see UI features table).