FastPlotPy

FastPlotPy is the Python port of FastPlotJs for renderer-neutral scene generation and browser/Jupyter charts. After its first PyPI publication, install with:

python -m pip install fastplotpy

In Python or Jupyter:

from fastplotpy import createChart

chart = createChart({
    "type": "line",
    "width": 800,
    "height": 400,
    "engine": "auto",
    "data": [{"x": 0, "y": 12}, {"x": 1, "y": 18}],
    "axes": {"show": True},
})
chart  # Jupyter displays the interactive browser view.

The local chart view uses the pinned FastPlotJs browser frontend for Canvas, pointer, and WebGL behavior. Its loopback bridge binds to 127.0.0.1 for the chart session. Python owns scene and state APIs; source frontend callbacks can invoke Python formatters. Browser WebAssembly is separate from the optional Python-host Rust core and is not initialized by initWasmPlotEngine() in CPython. The source-named hasNodePlotEngine() and initNodePlotEngine() are Python compatibility aliases for hasRustPlotEngine() and initRustPlotEngine(); they do not start or require Node.js. getRustPlotEngineStatus() reports host native capabilities. getWasmPlotEngineStatus() reports CPython availability, not the state of the separate browser frontend.

Without a browser, plot() produces a renderer-neutral scene:

from fastplotpy import plot

scene = plot({
    "type": "line",
    "width": 800,
    "height": 400,
    "engine": "ts",  # Source spelling selects the Python fallback geometry.
    "data": [{"x": 0, "y": 12}, {"x": 1, "y": 18}],
})

Current Python geometry covers all eleven source chart families, including source-documented 3D LOD, encodings, lighting, accessibility, and multiple subplots. No chart calculation invokes Node.js at package runtime. Strict engine="rust" uses the optional pinned Rust core for supported 2D families and fails explicitly when unavailable. Pie3D reuses pie datum and presentation options, accepts pie3d.extrusionDepth in (0, 1], and uses the shared scene3d.camera. The native 3D PNG path has Windows validation only. renderToPNG() retains the source placeholder behavior.

The source project is FastPlotJs. The first Python alpha candidate is 0.3.0a1; check PyPI separately for publication status. Python 3.11 or newer is required. Its Windows wheel includes Python code, the pinned frontend, the built Rust ABI library, and the MIT License. The source distribution includes the pinned Rust sources and lockfile for optional native builds. Bundled font attribution is in the packaged assets/native/THIRD_PARTY_NOTICES.md file.

Canvas quality

The pinned browser frontend accepts canvas: { pixelRatio: "auto", resolutionScale: 2 } through createChart. Omitted ratios default to 1; logical sizes, text, and pointer coordinates remain unchanged while the backing bitmap scales. Experimental Pie3D also accepts pie3d: { curveTolerance: 0.1 } (default 1 logical pixel; smaller means more faces, within scene3d.maxPoints). Higher settings use more memory and rendering work. The source browser comparison remains in FastPlotJs. The Python source distribution includes the local Python-backed gallery under examples/gallery/; the installed wheel bundles the interactive frontend but does not install the standalone gallery server.