ocp-viewer-core

The shared half of the OCP viewer ecosystem: one show suite, one tessellation, one set of config semantics, used by four viewers that each keep their own transport and their own settings storage.

Currently supported hosts (viewers):

• ocp_vscode — the VS Code extension
• ocp_viewer — the standalone viewer, python -m ocp_viewer
• Jupyter CadQuery — The viewer for Jupyter Lab through cad-viewer-widget
• build123d Studio — The standalone app based on neutralinojs

The user-facing documentation of the shared behavior — the show commands, the config system, the viewer window and its tools — lives in docs/. Each host documents only its own specifics and refers there for the rest.

Published as one project to two registries: ocp-viewer-core on PyPI for the Python half, ocp-viewer-core on npm for the JavaScript half. Their major.minor is the contract and must match; the patch level is each half's own, so a one-sided fix ships without an artificial release of the other half. See Development.md.

The idea

Each host provides a Comms — a Python encoder and a JavaScript decoder, shipped as a pair — and a settings source. Everything above that is shared and knows nothing about which host it is running in.

Per-host imports stay per host:

• from ocp_vscode import * or from ocp_vscode import show, set_defaults, ...
• from build123d_studio import * or from build123d_studio import show, set_defaults, ...
• from jupyter_cadquery import * or from jupyter_cadquery import show, set_defaults, ...
• from ocp_viewer import * or from ocp_viewer import show, set_defaults, ...

Layout

ocp_viewer_core/__init__.py is import-free by design: hosts import the submodule they need, so that importing the package never pulls in the tessellator or OCP.

Use

A host writes one class and supplies one list. exclude_keys names the keywords it may not be told, because its surface decides them - the show signature is the superset of every host's, so a keyword one host owns is a keyword another has to refuse by name rather than ignore.

comms = MyComms()
session = Session(comms)                        # sets session cache to None
config = Config(session, ("cad_width", "height"))
show(objects)

What a host persists between sessions is its own business and needs no key list here: it answers with values, from Comms.workspace_config(). Which of the viewer's reported state counts as configuration - and so survives into the next show - is keys.CONFIG, derived from the vocabulary, because that set is a property of three-cad-viewer's state and not of any host's settings.

Dependencies

• The Python package ocp-tessellate for tessellation of OCP based CAD objects
• The Javascript package three-cad-viewer, the actual viewer component.

No OCP provider is declared — the same OCP namespace is supplied by cadquery_ocp, cadquery_ocp_novtk and conda's OCP, and naming one would break users of the other two. The host or the user chooses.

Licence

Apache-2.0.