app.py

import streamlit as st
from PIL import Image, ImageDraw

from streamlit_image_coordinates import streamlit_image_coordinates

with Image.open("kitty.jpeg") as img:
    draw = ImageDraw.Draw(img)

    def get_ellipse_coords(point):# tuple[int, int]) -> tuple[int, int, int, int]):
        center = point
        radius = 10
        return (
            center[0] - radius,
            center[1] - radius,
            center[0] + radius,
            center[1] + radius,
        )


    # Draw an ellipse at each coordinate in points
    for point in st.session_state["points"]:
        coords = get_ellipse_coords(point)
        draw.ellipse(coords, fill="red")

    value = streamlit_image_coordinates(img, key="pil")

    if value is not None:
        point = value["x"], value["y"]

        if point not in st.session_state["points"]:
            st.session_state["points"].append(point)
            st.experimental_rerun()