example_action.py

import argparse
import webbrowser

import neuroglancer
import neuroglancer.cli

if __name__ == "__main__":
    ap = argparse.ArgumentParser()
    neuroglancer.cli.add_server_arguments(ap)
    args = ap.parse_args()
    neuroglancer.cli.handle_server_arguments(args)

    viewer = neuroglancer.Viewer()
    with viewer.txn() as s:
        s.layers["image"] = neuroglancer.ImageLayer(
            source="precomputed://gs://neuroglancer-public-data/flyem_fib-25/image",
        )

    def my_action(s):
        print("Got my-action")
        print(f"  Mouse position: {s.mouse_voxel_coordinates}")
        print(f"  Layer selected values: {s.selected_values}")

    viewer.actions.add("my-action", my_action)
    with viewer.config_state.txn() as s:
        s.input_event_bindings.viewer["keyt"] = "my-action"
        s.status_messages["hello"] = "Welcome to this example"

    print(viewer)
    webbrowser.open_new(viewer.get_viewer_url())