app.py

from shiny import App, ui, render, reactive
from shinywidgets import output_widget, render_widget
import fastf1 as ff1
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection
from matplotlib import cm
import numpy as np
import os

try:    
    script_dir = os.path.dirname(os.path.abspath(__file__))
    print(script_dir)
    cache_folder = 'cache'
    cache_dir = os.path.join(script_dir, cache_folder)
    print(cache_dir)
    ff1.Cache.enable_cache(cache_dir)
except:
    print('Cache error!!')

app_ui = ui.page_fluid(
    ui.div(
        ui.input_select(
            "track", label="Track",
            choices=["Austria", "Hungary", "Spanish Grand Prix"]
        ),
        class_="d-flex gap-3"
    ),
    ui.output_plot("gear")
)

def server(input, output, session):
    @reactive.Calc
    def get_data():
        

        f1_session = ff1.get_session(2023, input.track(), 'R')
        f1_session.load()

        lap = f1_session.laps.pick_fastest()
        tel = lap.get_telemetry()

        #converting data to numpy data tables
        x = np.array(tel['X'].values)
        y = np.array(tel['Y'].values)

        points = np.array([x, y]).T.reshape(-1, 1, 2)
        segments = np.concatenate([points[:-1], points[1:]], axis=1)
        gear = tel['nGear'].to_numpy().astype(float)
        return lap, tel, x, y, points, segments, gear

    @output
    @render.plot
    def gear():
        lap = get_data().lap
        tel = get_data().tel
        points = get_data().points
        segments = get_data().segments

        
        cmap = cm.get_cmap('Paired')
        lc_comp = LineCollection(segments, norm=plt.Normalize(1, cmap.N+1), cmap=cmap)
        lc_comp.set_array(gear)
        lc_comp.set_linewidth(4)

        plt.gca().add_collection(lc_comp)
        plt.axis('equal')
        plt.tick_params(labelleft=False, left=False, labelbottom=False, bottom=False)

        ##title = plt.suptitle(
        ##        f"Fastest Lap Gear Shift Visualization\n"
        ##        f"{lap['Driver']} - {f1_session.event['EventName']} {f1_session.event.year}"
        ##        )

        cbar = plt.colorbar(mappable=lc_comp, label="Gear", boundaries=np.arange(1, 10))
        cbar.set_ticks(np.arange(1.5, 9.5))
        cbar.set_ticklabels(np.arange(1, 9))
            
    return plt


app = App(app_ui, server)