I'm trying to continuously update matlibplots in tkinter GUI while being able to click on buttons to pause/continue/stop updating the plots. I've tried using threads, but they don't seem to be executing parallelly (e.g. data thread is being executed but the plots don't get updated clicking on buttons is ignored). Why doesn't it work?
# Import Modules
import tkinter as tk
from threading import *
import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)
from scipy.fft import fft
import numpy as np
import time
import random
# global variables
state = 1 # 0 starting state; 1 streaming; 2 pause; -1 end and save
x = [0]*12
y = [0]*12
# Thread buttons and plots separately
def threading():
state = 1
t_buttons = Thread(target = buttons)
t_plots = Thread(target = plots)
t_data = Thread(target = data)
t_buttons.start()
t_plots.start()
t_data.start()
def hex_to_dec(x, y):
for i in range(0, 12):
for j in range(0, len(y)):
x[i][j] = int(str(x[i][j]), 16)
y[i][j] = int(str(y[i][j]), 16)
def data():
fig1, axs1 = main_plot()
fig2, axs2 = FFT_plot()
# To be replaced with actual Arduino data
while(state!=-1):
for i in range(0, 12):
x[i] = [j for j in range(101)]
y[i] = [random.randint(0, 10) for j in range(-50, 51)]
for i in range(0, 12):
for j in range(0, len(y)):
x[i][j] = int(str(x[i][j]), 16)
y[i][j] = int(str(y[i][j]), 16)
# create buttons
def stream_clicked():
state = 1
print("clicked")
def pause_clicked():
state = 2
print("state")
def finish_clicked():
state = -1
def buttons():
continue_button = tk.Button(window, width = 30, text = "Stream data" ,
fg = "black", bg = '#98FB98', command = stream_clicked)
continue_button.place(x = window.winfo_screenwidth()*0.2, y = 0)
pause_button = tk.Button(window, width = 30, text = "Pause streaming data" ,
fg = "black", bg = '#FFA000', command = pause_clicked)
pause_button.place(x = window.winfo_screenwidth()*0.4, y = 0)
finish_button = tk.Button(window, width = 30, text = "End session and save",
fg = 'black', bg = '#FF4500', command = finish_clicked())
finish_button.place(x = window.winfo_screenwidth()*0.6, y = 0)
def plots():
fig1, axs1 = main_plot()
fig2, axs2 = FFT_plot()
if state==1:
print("update")
for i in range(0, 12):
axs1[i].plot(x[i], y[i], 'blue')
axs1[i].axes.get_yaxis().set_ticks([0], labels = ["channel " str(i 1)])
axs1[i].grid(True)
axs1[i].margins(x = 0)
fig1.canvas.draw()
fig1.canvas.flush_events()
for i in range(0, 12):
axs1[i].clear()
for i in range(0, 12):
axs2.plot(x[i], fft(y[i]))
plt.title("FFT of all 12 channels", x = 0.5, y = 1)
fig2.canvas.draw()
fig2.canvas.flush_events()
axs2.clear()
def main_plot():
plt.ion()
fig1, axs1 = plt.subplots(12, figsize = (10, 9), sharex = True)
fig1.subplots_adjust(hspace = 0)
# Add fixed values for axis
canvas = FigureCanvasTkAgg(fig1, master = window)
canvas.draw()
canvas.get_tk_widget().pack()
canvas.get_tk_widget().place(x = 0, y = 35)
return fig1, axs1
def update_main_plot(fig1, axs1):
if state==1:
for i in range(0, 12):
axs1[i].plot(x[i], y[i], 'blue')
axs1[i].axes.get_yaxis().set_ticks([0], labels = ["channel " str(i 1)])
axs1[i].grid(True)
axs1[i].margins(x = 0)
axs1[0].set_title("Plot recordings", x = 0.5, y = 1)
fig1.canvas.draw()
fig1.canvas.flush_events()
for i in range(0, 12):
axs1[i].clear()
def FFT_plot():
# Plot FFT figure
plt.ion()
fig2, axs2 = plt.subplots(1, figsize = (7, 9))
# Add fixed values for axis
canvas = FigureCanvasTkAgg(fig2, master = window)
canvas.draw()
canvas.get_tk_widget().pack()
canvas.get_tk_widget().place(x = window.winfo_screenwidth()*0.55, y = 35)
return fig2, axs2
def update_FFT_plot(fig2, axs2):
# Update FFT plot
for i in range(0, 12):
axs2.plot(x[i], fft(y[i]))
plt.title("FFT", x = 0.5, y = 1)
fig2.canvas.draw()
fig2.canvas.flush_events()
axs2.clear()
# create root window and set its properties
window = tk.Tk()
window.title("Data Displayer")
window.geometry("%dx%d" % (window.winfo_screenwidth(), window.winfo_screenheight()))
window.configure(background = 'white')
threading()
window.mainloop()
*** Sometimes it just doesn't work without any message and sometimes I also get "RuntimeError: main thread is not in main loop" ***
CodePudding user response:
to be fair all functions in your code are very likely to cause a segmentation fault, and other functions that don't result in a segmentation fault simply don't work, it's hard to explain what's wrong.
- define global variables as
global
if you are going to modify them - update GUI in your main thread by using the
window.after
method repeatedly. - only reading from your microcontroller should be done in separate thread.
- creation of Tkinter objects should be done in the main thread, only updates are allowed in other threads, but it is not thread-safe, so while it may work it can lead to some weird behavior or errors sometimes.
- calling matplotlib functions such as
ion
andflush_events
causes errors because these are for matplotlib interactive canvas, not for tkinter canvas. - threading has a very tough learning curve so ask yourself "do i really need threads in here" and "is there any way to not use threads" before you attempt to use them as once you start using threads you are no longer using python's "safe code", despite all the efforts, threads are not safe to use for any task, it's up to you to make them safe, and to be honest threads are not needed here unless you are reading 1 GB/s from your microcontroller.
- don't use numbers for states, it's not pythonic, and it confuses the readers, and it has no performance benefit over using Enums.
- programs are built incrementally, not copy-paste from multiple working snippets, as it is harder to track where the error comes from when multiple parts of the code weren't verified to be working.
# Import Modules
import tkinter as tk
from threading import *
import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)
from scipy.fft import fft
import numpy as np
import time
import random
from enum import Enum,auto
UPDATE_INTERVAL_MS = 300
class States(Enum):
STREAM = auto()
PAUSE = auto()
SAVE = auto()
START = auto()
# global variables
state = States.START # check States Enum
x = [[0]]*12
y = [[0]]*12
# Thread buttons and plots separately
def threading():
global state
global window
state = States.STREAM
buttons()
plots()
data()
t_grab_data = Thread(target=grab_data_loop,daemon=True)
t_grab_data.start()
# t_buttons = Thread(target=buttons)
# t_plots = Thread(target=plots)
# t_data = Thread(target=data)
#
# t_buttons.start()
# t_plots.start()
# t_data.start()
def hex_to_dec(x, y):
for i in range(0, 12):
for j in range(0, len(y)):
x[i][j] = int(str(x[i][j]), 16)
y[i][j] = int(str(y[i][j]), 16)
def data():
global fig1,axs1,fig2,axs2
fig1, axs1 = main_plot()
fig2, axs2 = FFT_plot()
# To be replaced with actual Arduino data
window.after(UPDATE_INTERVAL_MS,draw_data_loop)
def grab_data_loop():
while state != States.SAVE:
for i in range(0, 12):
x[i] = [j for j in range(101)]
y[i] = [random.randint(0, 10) for j in range(-50, 51)]
for i in range(0, 12):
for j in range(0, len(y)):
x[i][j] = int(str(x[i][j]), 16)
y[i][j] = int(str(y[i][j]), 16)
time.sleep(0.1) # because we are not reading from a microcontroller
def draw_data_loop():
if state == States.STREAM:
update_main_plot(fig1, axs1)
update_FFT_plot(fig2, axs2)
window.after(UPDATE_INTERVAL_MS,draw_data_loop)
# create buttons
def stream_clicked():
global state
state = States.STREAM
print("clicked")
def pause_clicked():
global state
state = States.PAUSE
print("state")
def finish_clicked():
global state
state = States.SAVE
window.destroy()
def buttons():
continue_button = tk.Button(window, width=30, text="Stream data",
fg="black", bg='#98FB98', command=stream_clicked)
continue_button.place(x=window.winfo_screenwidth() * 0.2, y=0)
pause_button = tk.Button(window, width=30, text="Pause streaming data",
fg="black", bg='#FFA000', command=pause_clicked)
pause_button.place(x=window.winfo_screenwidth() * 0.4, y=0)
finish_button = tk.Button(window, width=30, text="End session and save",
fg='black', bg='#FF4500', command=finish_clicked)
finish_button.place(x=window.winfo_screenwidth() * 0.6, y=0)
def plots():
global state
fig1, axs1 = main_plot()
fig2, axs2 = FFT_plot()
if state == States.STREAM:
print("update")
for i in range(0, 12):
axs1[i].plot(x[i], y[i], 'blue')
axs1[i].axes.get_yaxis().set_ticks([0], labels=["channel " str(i 1)])
axs1[i].grid(True)
axs1[i].margins(x=0)
# fig1.canvas.draw()
# fig1.canvas.flush_events()
# for i in range(0, 12):
# axs1[i].clear()
for i in range(0, 12):
axs2.plot(x[i], np.abs(fft(y[i])))
plt.title("FFT of all 12 channels", x=0.5, y=1)
# fig2.canvas.draw()
# fig2.canvas.flush_events()
# axs2.clear()
def main_plot():
# plt.ion()
global canvas1
fig1, axs1 = plt.subplots(12, figsize=(10, 9), sharex=True)
fig1.subplots_adjust(hspace=0)
# Add fixed values for axis
canvas1 = FigureCanvasTkAgg(fig1, master=window)
# canvas.draw()
canvas1.get_tk_widget().pack()
canvas1.get_tk_widget().place(x=0, y=35)
return fig1, axs1
def update_main_plot(fig1, axs1):
if state == States.STREAM:
for i in range(0, 12):
axs1[i].clear()
for i in range(0, 12):
axs1[i].plot(x[i], y[i], 'blue')
axs1[i].axes.get_yaxis().set_ticks([0], labels=["channel " str(i 1)])
axs1[i].grid(True)
axs1[i].margins(x=0)
axs1[0].set_title("Plot recordings", x=0.5, y=1)
canvas1.draw()
# fig1.canvas.draw()
# fig1.canvas.flush_events()
def FFT_plot():
# Plot FFT figure
# plt.ion()
global canvas2
fig2, axs2 = plt.subplots(1, figsize=(7, 9))
# Add fixed values for axis
canvas2 = FigureCanvasTkAgg(fig2, master=window)
# canvas.draw()
canvas2.get_tk_widget().pack()
canvas2.get_tk_widget().place(x=window.winfo_screenwidth() * 0.55, y=35)
return fig2, axs2
def update_FFT_plot(fig2, axs2):
# Update FFT plot
if state == States.STREAM:
axs2.clear()
for i in range(0, 12):
axs2.plot(x[i], np.abs(fft(y[i])))
plt.title("FFT", x=0.5, y=1)
canvas2.draw()
# fig2.canvas.draw()
# fig2.canvas.flush_events()
# axs2.clear()
# create root window and set its properties
window = tk.Tk()
window.title("Data Displayer")
window.geometry("%dx%d" % (window.winfo_screenwidth(), window.winfo_screenheight()))
window.configure(background='white')
threading()
window.mainloop()
# put saving logic here