Example of interactive rectangular selection

Once all the cells below have been executed, you will be able to press the Select button, drag a rectangle enclosing the sources you wish to select and see their names in the table at the right of the ipyaladin view.

from ipyaladin import Aladin
from ipywidgets import Layout, Box, widgets

from astroquery.simbad import Simbad
import astropy.units as u

aladin = Aladin(
    layout=Layout(width="50%"),
    target="M 1",
    fov=0.2,
    show_projection_control=False,
    show_fullscreen_control=False,
)
button = widgets.Button(description="Select")


def on_button_clicked(_: any) -> None:
    """Button click event callback.

    It will trigger the rectangular selection in the Aladin widget.

    Parameters
    ----------
    _: any
        The button widget that triggered the event.
    """
    aladin.selection("rectangle")


button.on_click(on_button_clicked)
table_info = widgets.HTML(layout=Layout(height="auto", overflow="auto"))

box_layout = Layout(
    display="flex",
    flex_flow="row",
    align_items="stretch",
    width="100%",
    position="relative",
)
box = Box(children=[aladin, button, table_info], layout=box_layout)
box

table = Simbad.query_region("M 1", radius=0.1 * u.deg)
aladin.add_table(table)


def process_result(sources: dict) -> None:
    """Process the sources selected in the Aladin widget and display them in the table.

    Parameters
    ----------
    sources: dict
        The sources selected in the Aladin widget.
    """
    s = '<table border="1">'
    s += "<tr><th>MAIN_ID</th><th>RA</th><th>DEC</th></tr>"
    for source in sources:
        s += "<tr><td>%s</td><td>%s</td><td>%s</td></tr>" % (
            source["data"]["MAIN_ID"],
            source["data"]["RA"],
            source["data"]["DEC"],
        )
    s += "</table>"
    table_info.value = s


aladin.set_listener("select", process_result)