Description
Bug summary
I'm trying to update a plot in tkinter by destroying the frame where the FigureCanvasTkAgg tk widget is packed and creating another instance of FigureCanvasTkAgg, but the memory of the script only goes up after repeating the process several times.
Code for reproduction
import tkinter as tk
from tkinter import ttk
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import numpy as np
class Main_Program(tk.Tk):
def __init__(self, *args, **kwargs):
tk.Tk.__init__(self, *args, **kwargs)
self.geometry("500x500")
# ---------------------------------------- TOP FRAME (Button)
self.top_frame = tk.Frame(self)
ttk.Button(self.top_frame,text="Update graph",command=self.update_graph).pack()
self.top_frame.pack()
# ---------------------------------------- BOTTOM FRAME (Graph)
self.bottom_frame = tk.Frame(self)
DisplayGraph(self.bottom_frame,
x_limit= (-10, 10) ,
delta_x= 0.1 ,
y_input= "2*x+2" )
self.bottom_frame.pack()
def update_graph(self):
# ----------------------------- CLEAR
for widget in self.bottom_frame.winfo_children():
widget.destroy()
# ----------------------------- DISPLAY NEW GRAPH
DisplayGraph(self.bottom_frame,
x_limit= (-10, 10) ,
delta_x= 0.1 ,
y_input= "2*x+2" )
class DisplayGraph:
def __init__(self,passed_frame,
x_limit=(), # TUPLE (-10,10)
delta_x=0.0, # FLOAT 0.1
y_input='', # STRING 2*x+2
figsize_x=6,
figsize_y=5):
self.x_limit = x_limit
self.delta_x = delta_x
self.y_input = y_input
# ---------------------------------------------------------- CREATE FIGURE AND SUBPLOT
self.fig = Figure(figsize=(figsize_x,figsize_y),dpi=100)
self.ax = self.fig.add_subplot(111)
self.ax.grid()
# ---------------------------------------------------------- PLOT
self.plot_input()
# ---------------------------------------------------------- PACK AND DRAW
self.canvas_frame = tk.Frame(passed_frame,bg="black")
self.canvas_mat = FigureCanvasTkAgg(self.fig, master=self.canvas_frame)
self.canvas_mat.get_tk_widget().pack(anchor="center", expand=True,padx=2,pady=2)
self.canvas_frame.pack(side=tk.LEFT,anchor="center", expand=True)
self.canvas_mat.draw()
# ----------------------------------------------------------
def plot_input(self):
x = np.arange(self.x_limit[0],self.x_limit[1],self.delta_x)
y = eval(self.y_input)
self.ax.plot(x,y)
App = Main_Program()
App.mainloop()Actual outcome
Memory after running the script for the first time
Memory after clicking the button 20 times:
I've seen that some of the memory is freed after a while but not immediately after updating the frame.
Expected outcome
I would expect that destroying the frame where the FigureCanvasTkAgg widget is located would allow me to create another instance of FigureCanvasTkAgg without increasing the memory (or at least too much).
Additional information
I've seen posts as far back as 13 years ago reporting the issue in different places, but I have not been able to find a way to solve it. I know that you can create only one instance of the FigureCanvasTkAgg object and clear/plot each time, but I'm working on a project that involves several figures at the same time and closing the tkinter toplevel window does not seem to clear the memory.
Operating system
Windows
Matplotlib Version
3.6.2
Matplotlib Backend
TkAgg
Python version
3.11.0
Jupyter version
No response
Installation
pip