Tkinter销毁组件未释放内存问题求助

我编写了一段Tkinter代码，通过按钮实现图表更新（销毁后重新绘制）：点击按钮时销毁底部框架内的图表组件，再重新生成图表。代码如下：

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):
        
        # ----------------------------- DESTROY THE FRAME
        
        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()

多次点击按钮后，通过任务管理器观察到Python脚本的内存占用持续增长。我尝试过使用gc.collect()清理未引用对象，以及pack_forget()方法，均无法解决问题。请问该如何避免这种内存增长？不确定问题是否与垃圾回收或destroy方法相关。

核心原因 #

每次点击按钮都会创建新的Figure、FigureCanvasTkAgg对象，但旧对象与Tkinter之间存在未被切断的隐式引用链，导致Python垃圾回收机制无法正确回收这些资源，最终引发内存泄漏。单纯调用widget.destroy()只能销毁Tkinter层面的组件，无法清理matplotlib内部的关联资源。

优化方案 #

方案1：复用已有绘图资源（推荐） #

不需要每次销毁重建整个图表，而是复用已有的Figure和Axes，仅更新绘图数据。这种方式从根源避免了重复创建资源，是最高效的解决方案：

修改后的完整代码：

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")
        
        # 顶部按钮框架
        self.top_frame = tk.Frame(self)  
        ttk.Button(self.top_frame,text="Update graph",command=self.update_graph).pack()
        self.top_frame.pack()
        
        # 底部图表框架
        self.bottom_frame = tk.Frame(self) 
        # 保存DisplayGraph实例，方便后续更新
        self.graph_instance = 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):
        # 直接调用已有实例的更新方法，无需销毁重建
        self.graph_instance.update_plot(
            x_limit=(-10, 10),
            delta_x=0.1,
            y_input="2*x+2"  # 这里可以改成不同的表达式测试，比如"x**2"
        )
        
class DisplayGraph:
    def __init__(self,passed_frame,
                x_limit=(),
                delta_x=0.0,
                y_input='',
                figsize_x=6,
                figsize_y=5):

        self.x_limit = x_limit
        self.delta_x = delta_x
        self.y_input = y_input
        
        # 创建一次Figure和Axes
        self.fig = Figure(figsize=(figsize_x,figsize_y),dpi=100)
        self.ax = self.fig.add_subplot(111)
        self.ax.grid()
        
        # 创建画布并绑定
        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)
        
        # 初次绘图
        self.plot_input()
        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)
        
    def update_plot(self, x_limit, delta_x, y_input):
        # 清空当前Axes的内容
        self.ax.clear()
        self.ax.grid()  # 重新添加网格
        
        # 更新参数并绘图
        self.x_limit = x_limit
        self.delta_x = delta_x
        self.y_input = y_input
        self.plot_input()
        
        # 重新绘制画布
        self.canvas_mat.draw()

App = Main_Program()
App.mainloop()

方案2：手动清理所有关联资源（若必须销毁重建） #

如果坚持使用销毁重建的逻辑，需要手动断开matplotlib画布与Tkinter的绑定，并清理所有相关引用，确保垃圾回收能正常工作：

修改代码如下：

import tkinter as tk
from tkinter import ttk
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import numpy as np
import gc

class Main_Program(tk.Tk):
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)
        
        self.geometry("500x500")
        
        self.top_frame = tk.Frame(self)  
        ttk.Button(self.top_frame,text="Update graph",command=self.update_graph).pack()
        self.top_frame.pack()
        
        self.bottom_frame = tk.Frame(self) 
        # 保存图表实例引用
        self.graph_instance = None
        self.create_graph()
        self.bottom_frame.pack() 
        
    def create_graph(self):
        self.graph_instance = DisplayGraph(self.bottom_frame,
                                          x_limit=(-10, 10),
                                          delta_x=0.1,
                                          y_input="2*x+2")
    
    def update_graph(self):
        # 先手动清理旧图表的资源
        if self.graph_instance:
            # 断开画布与Tkinter的绑定
            self.graph_instance.canvas_mat.get_tk_widget().destroy()
            self.graph_instance.canvas_mat.figure.clear()
            # 清理所有引用
            del self.graph_instance.canvas_mat
            del self.graph_instance.fig
            del self.graph_instance.ax
            del self.graph_instance
            # 强制触发垃圾回收
            gc.collect()
        
        # 销毁框架内剩余组件
        for widget in self.bottom_frame.winfo_children():
            widget.destroy()
        
        # 创建新图表
        self.create_graph()
        
class DisplayGraph:
    def __init__(self,passed_frame,
                x_limit=(),
                delta_x=0.0,
                y_input='',
                figsize_x=6,
                figsize_y=5):

        self.x_limit = x_limit
        self.delta_x = delta_x
        self.y_input = y_input
        
        self.fig = Figure(figsize=(figsize_x,figsize_y),dpi=100)
        self.ax = self.fig.add_subplot(111)
        self.ax.grid()
        
        self.plot_input()

        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()

关键说明 #

• 方案1通过复用资源避免了重复创建对象，内存占用会保持稳定，是优先选择的方案。
• 方案2需要手动清理matplotlib的内部资源并切断引用，同时强制触发垃圾回收，才能有效释放内存。

内容的提问来源于stack exchange，提问作者cenfra