Frontend Python Callbacks¶

Most layers in pyglobegl are driven entirely by typed data models. A few globe.gl accessors, though, are computed per-datum in the browser — the hex bin layer is the main example. Rather than make you write JavaScript, pyglobegl lets you decorate a Python function with @frontend_python and run it on the frontend.

from pyglobegl import frontend_python


@frontend_python
def hex_altitude(hexbin):
    return hexbin["sumWeight"] * 0.01

Pass the decorated function wherever an accessor callback is accepted (for example hex_altitude=, hex_top_color=, hex_label=).

How it works¶

• @frontend_python returns a FrontendPythonFunction. The function's source is shipped to the widget and executed in the browser via MicroPython, so it runs client-side without a Python round-trip per datum.
• Callback arguments are normalised to plain Python values (dict / list / str / float / bool / None) when they are JSON-serializable, so dict methods like .get(...) work inside the callback.