I created a radar chart that displays data called zones. I am not able to make a callback function that returns the legends visible currently by user’s action on the legend. When user deselects legend item(s) the plot hides it well, but I need to capture what remains.

Essentially I am printing names of zones in display, later using it for data frame filters to display some analytics.

def create_radar_chart(metrics: Dict[str, List[float]], categories: List[str]) -> go.Figure:
    fig = go.Figure()
    fig.add_trace(go.Scatterpolar(
        r=metrics['Baseline'],
        theta=categories,
        fill='toself',
        name='Baseline',
        line=dict(color='#808080'),
        fillcolor='rgba(128, 128, 128, 0.2)'
    ))

    colors = ['#00FFB8', '#4A9DFF', '#FF6B6B', '#FFD93D', '#6C63FF']
    for i, (zone, values) in enumerate(metrics.items()):
        if zone != 'Baseline':
            color = colors[i % len(colors)]
            fig.add_trace(go.Scatterpolar(
                r=values,
                theta=categories,
                fill='toself',
                name=zone,
                line=dict(color=color),
                fillcolor=f'rgba{tuple(list(int(color.lstrip("#")[i:i+2], 16) for i in (0, 2, 4)) + [0.4])}'
            ))

    fig.update_layout(
        width=500,
        height=500,
        polar=dict(
            radialaxis=dict(
                visible=True,
                range=[0, max([max(vals) for vals in metrics.values()]) * 1.1]
            ),
            bgcolor='rgba(0,0,0,0)'
        ),
        showlegend=True,
        paper_bgcolor='rgba(0,0,0,0)',
        plot_bgcolor='rgba(0,0,0,0)',
        font_color = '#7A7F8C',
        legend_font_color = '#7A7F8C',
    )

    return fig

Metrics are the values for the plot by zone, Categories are the names

Here is a sample to reproduce:

import streamlit as st
import pandas as pd
from typing import Dict, List
import plotly.graph_objects as go
metrics = {
"Baseline": [60, 70, 80, 65, 90],
"Zone A": [75, 85, 70, 80, 95],
"Zone B": [65, 60, 75, 70, 85],
"Zone C": [55, 65, 85, 60, 80],
"Zone D": [80, 90, 70, 85, 88]
}

categories = ["Safety", "Infrastructure", "Resources", "Response Time", "Efficiency"]

def create_radar_chart(metrics: Dict[str, List[float]], categories: List[str]) -> go.Figure:
    """Create radar chart."""
    fig = go.Figure()
    fig.add_trace(go.Scatterpolar(
    r=metrics['Baseline'],
    theta=categories,
    fill='toself',
    name='Baseline',
    line=dict(color='#808080'),
    fillcolor='rgba(128, 128, 128, 0.2)'
    ))

    colors = ['#00FFB8', '#4A9DFF', '#FF6B6B', '#FFD93D', '#6C63FF']
    for i, (zone, values) in enumerate(metrics.items()):
        if zone != 'Baseline':
            color = colors[i % len(colors)]
            fig.add_trace(go.Scatterpolar(
            r=values,
            theta=categories,
            fill='toself',
            name=zone,
            line=dict(color=color),
            fillcolor=f'rgba{tuple(list(int(color.lstrip("#")[i:i+2], 16) for i in (0, 2, 4)) + [0.4])}'
            ))

    fig.update_layout(
    width=500,
    height=500,
    polar=dict(
        radialaxis=dict(
            visible=True,
            range=[0, max([max(vals) for vals in metrics.values()]) * 1.1]
        ),
        bgcolor='rgba(0,0,0,0)'
    ),
    showlegend=True,
    paper_bgcolor='rgba(0,0,0,0)',
    plot_bgcolor='rgba(0,0,0,0)',
    font_color = '#7A7F8C',
    legend_font_color = '#7A7F8C',
    )

    return fig


fig = create_radar_chart(metrics, categories)
fig.show()