python - 为什么 Python Tkinter Canvas 绘制会导致冻结？

Question

我写了一段代码，其中有一个带有画布的简单 gui。在这个画布上我画了一个matplot。matplot 每秒更新一次，其中的数据来自我在 SQLite DB 中创建的假传感器数据（目前仅用于测试）。

我的问题是画布的重绘导致我的窗口/gui每秒都滞后。

我什至试图在另一个线程中更新情节。但即使在那里我也有滞后。

这里没有线程的想法：

from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import tkinter as tk
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
import sqlite3
from datetime import datetime
from random import randint

class MainApplication(tk.Frame):
    def __init__(self, parent, *args, **kwargs):
        tk.Frame.__init__(self, parent, *args, **kwargs)
        self.parent = parent

        root.update_idletasks()

        f = Figure(figsize=(5,5), dpi=100)        
        x=1
        ax = f.add_subplot(111)        
        line = ax.plot(x, np.sin(x))        

        def animate(i):
            # Open Database
            conn = sqlite3.connect('Sensor_Data.db')
            c = conn.cursor()
            # Create some fake Sensor Data    
            NowIs = datetime.now()
            Temperature = randint(0, 100)
            Humidity = randint(0, 100)
            # Add Data to the Database
            c = conn.cursor()
            # Insert a row of data
            c.execute("insert into Sensor_Stream_1 (Date, Temperature, Humidity) values (?, ?, ?)",
                        (NowIs, Temperature, Humidity))
            # Save (commit) the changes
            conn.commit()
            # Select Data from the Database
            c.execute("SELECT Temperature FROM Sensor_Stream_1 LIMIT 10 OFFSET (SELECT COUNT(*) FROM Sensor_Stream_1)-10") 
            # Gives a list of all temperature values 
            x = 1
            Temperatures = []

            for record in c.fetchall():    
                Temperatures.append(str(x)+','+str(record[0]))
                x+=1
            # Setting up the Plot with X and Y Values
            xList = []
            yList = []

            for eachLine in Temperatures:
                if len(eachLine) > 1:
                    x, y = eachLine.split(',')
                    xList.append(int(x))
                    yList.append(int(y))

            ax.clear()

            ax.plot(xList, yList) 

            ax.set_ylim(0,100)
            ax.set_xlim(1,10)
            ax.grid(b=None, which='major', axis='both', **kwargs)


        label = tk.Label(root,text="Temperature / Humidity").pack(side="top", fill="both", expand=True)

        canvas = FigureCanvasTkAgg(f, master=root)
        canvas.get_tk_widget().pack(side="left", fill="both", expand=True)

        root.ani = animation.FuncAnimation(f, animate, interval=1000)            

if __name__ == "__main__":
    root = tk.Tk()
    MainApplication(root).pack(side="top", fill="both", expand=True)
    root.mainloop()

在这里我尝试另一个线程：

import tkinter as tk
from tkinter import messagebox

import numpy as np

from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import matplotlib.pyplot as plt
import matplotlib.animation as animation

import sqlite3

from datetime import datetime
from random import randint

#
from concurrent import futures
from time import sleep, time
#

class MainApplication(tk.Frame):
    def __init__(self, parent, *args, **kwargs):
        tk.Frame.__init__(self, parent, *args, **kwargs)
        self.parent = parent

        root.geometry('1280x720')
        root.update_idletasks()       

        #GUI
        x = 1
        f = Figure(figsize=(5,5), dpi=100)
        ax = f.add_subplot(111)        
        line = ax.plot(x, np.sin(x))

        label = tk.Label(root,text="Temperature / Humidity").pack(side="top", fill="both", expand=True)

        canvas = FigureCanvasTkAgg(f, master=root)
        canvas.get_tk_widget().pack(side="left", fill="both", expand=True)

        def animate(i):
            print("hello")
            # Open Database
            conn = sqlite3.connect('Sensor_Data.db')
            c = conn.cursor()
            # Create some fake Sensor Data    
            NowIs = datetime.now()
            Temperature = randint(0, 100)
            Humidity = randint(0, 100)
            # Add Data to the Database
            c = conn.cursor()
            # Insert a row of data
            c.execute("insert into Sensor_Stream_1 (Date, Temperature, Humidity) values (?, ?, ?)",
                        (NowIs, Temperature, Humidity))
            # Save (commit) the changes
            conn.commit()
            # Select Data from the Database
            c.execute("SELECT Temperature FROM Sensor_Stream_1 LIMIT 10 OFFSET (SELECT COUNT(*) FROM Sensor_Stream_1)-10") 
            # Gives a list of all temperature values 
            x = 1

            Temperatures = []

            for record in c.fetchall():    
                Temperatures.append(str(x)+','+str(record[0]))
                x+=1
#                
            # Setting up the Plot with X and Y Values
            xList = []
            yList = []

            for eachLine in Temperatures:
                if len(eachLine) > 1:
                    x, y = eachLine.split(',')
                    xList.append(int(x))
                    yList.append(int(y))

            ax.clear()

            ax.plot(xList, yList) 

            ax.set_ylim(0,100)
            ax.set_xlim(1,10)
            ax.grid(b=None, which='major', axis='both', **kwargs)

            canvas.draw()

            root.after(1000, animate, 1000) 


        e = futures.ThreadPoolExecutor(max_workers=1)

        e.submit(animate, 1000)           

def on_closing():
    if messagebox.askokcancel("Quit", "Do you want to quit?"):
        root.destroy()

if __name__ == "__main__":
    root = tk.Tk()
    MainApplication(root).pack(side="top", fill="both", expand=True)
    root.protocol("WM_DELETE_WINDOW", on_closing)
    root.mainloop() 

标签： pythonpython-3.xuser-interfacecanvastkinter