爲什麼Tkinter中的這個形狀更新緩慢？

Question

試圖做在Tkinter的簡單的動作：

import tkinter as tk 

class GameApp(object): 
    """ 
    An object for the game window. 

    Attributes: 
     master: Main window tied to the application 
     canvas: The canvas of this window 
    """ 

    def __init__(self, master): 
     """ 
     Initialize the window and canvas of the game. 
     """ 

     self.master = master 
     self.master.title = "Game" 
     self.master.geometry('{}x{}'.format(500, 500)) 

     self.canvas = tk.Canvas(self.master) 
     self.canvas.pack(side="top", fill="both", expand=True) 

     self.start_game() 

    #----------------------------------------------# 


    def start_game(self): 
     """ 
     Actual loading of the game. 
     """ 

     player = Player(self) 

    #----------------------------------------------# 

#----------------------------------------------# 


class Player(object): 
    """ 
    The player of the game. 

    Attributes: 
     color: color of sprite (string) 
     dimensions: dimensions of the sprite (array) 
     canvas: the canvas of this sprite (object) 
     window: the actual game window object (object) 
     momentum: how fast the object is moving (array) 
    """ 


    def __init__(self, window): 

     self.color = "" 
     self.dimensions = [225, 225, 275, 275] 
     self.window = window 
     self.properties() 

    #----------------------------------------------# 

    def properties(self): 
     """ 
     Establish the properties of the player. 
     """ 

     self.color = "blue" 
     self.momentum = [5, 0] 

     self.draw() 
     self.mom_calc() 

    #----------------------------------------------# 

    def draw(self): 
     """ 
     Draw the sprite. 
     """ 

     self.sprite = self.window.canvas.create_rectangle(*self.dimensions, fill=self.color, outline=self.color) 

    #----------------------------------------------# 


    def mom_calc(self): 
     """ 
     Calculate the actual momentum of the thing 
     """ 

     self.window.canvas.move(self.sprite, *self.momentum) 
     self.window.master.after(2, self.mom_calc) 

    #----------------------------------------------# 

#----------------------------------------------# 


root = tk.Tk() 

game_window = GameApp(root) 

哪裏self.momentum是含有2個整數的數組：一個用於x運動，和另一個用於y運動。但是，矩形的實際移動非常緩慢（每秒大約5次移動），而self.window.master.after()時間似乎沒有效果。

以前在另一個tkinter項目中，我設法得到了真正響應的tkinter運動，所以我只是想知道是否有辦法在這種情況下最小化運動更新時間，方法是使用不同風格的OOP，或者完全不同的代碼。

UPDATE：原來在.after()方法中的時間確實很重要，它實際上會疊加到方法的實時上。使用timeit時間調用該方法後，我得到了這樣的輸出：

>>> print(timeit.timeit("(self.window.master.after(2, self.mom_calc))", number=10000, globals={"self":self})) 
0.5395521819053108 

所以我想真正的問題是：爲什麼.after()方法要花這麼長時間？

更新2：在多臺計算機上測試過，任何平臺上的移動仍然很慢。 「

Answer 1

我在使用Python 3.6的Windows 10中至少沒有看到您報告的問題。我按照所示測試了該程序，並在最後添加了root.mainloop()。這沒有顯示矩形，因爲對象已經從畫布上移開得太快而看不到。

所以我修改了這個以在牆壁之間反彈，並添加了一個計數器來打印每秒呼叫數量mom_calc。如果將後超時設置爲20ms，我會按預期每秒獲得50個動作調用。設置爲2ms，因爲在你的文章中，我每秒獲得約425個，所以這裏有一個小小的錯誤，每次調用大約需要2.3或2.4毫秒。這是有點可變的，因爲其他進程可能會佔用這個粒度的一些時間。

這裏是（略）修改後的代碼：

import tkinter as tk 

class GameApp(object): 
    """ 
    An object for the game window. 

    Attributes: 
     master: Main window tied to the application 
     canvas: The canvas of this window 
    """ 

    def __init__(self, master): 
     """ 
     Initialize the window and canvas of the game. 
     """ 

     self.master = master 
     self.master.title = "Game" 
     self.master.geometry('{}x{}'.format(500, 500)) 

     self.canvas = tk.Canvas(self.master, background="white") 
     self.canvas.pack(side="top", fill="both", expand=True) 

     self.start_game() 

    #----------------------------------------------# 


    def start_game(self): 
     """ 
     Actual loading of the game. 
     """ 

     player = Player(self) 

    #----------------------------------------------# 

#----------------------------------------------# 


class Player(object): 
    """ 
    The player of the game. 

    Attributes: 
     color: color of sprite (string) 
     dimensions: dimensions of the sprite (array) 
     canvas: the canvas of this sprite (object) 
     window: the actual game window object (object) 
     momentum: how fast the object is moving (array) 
    """ 


    def __init__(self, window): 

     self.color = "" 
     self.dimensions = [225, 225, 275, 275] 
     self.window = window 
     self.movement = 0 
     self.movement_last = 0 
     self.properties() 

    #----------------------------------------------# 

    def properties(self): 
     """ 
     Establish the properties of the player. 
     """ 

     self.color = "blue" 
     self.momentum = [5, 0] 

     self.draw() 
     self.mom_calc() 
     self.velocity() 

    #----------------------------------------------# 

    def draw(self): 
     """ 
     Draw the sprite. 
     """ 

     self.sprite = self.window.canvas.create_rectangle(*self.dimensions, fill=self.color, outline=self.color) 

    #----------------------------------------------# 


    def mom_calc(self): 
     """ 
     Calculate the actual momentum of the thing 
     """ 

     pos = self.window.canvas.coords(self.sprite) 
     if pos[2] > 500: 
      self.momentum = [-5, 0] 
     elif pos[0] < 2: 
      self.momentum = [5, 0] 

     self.window.canvas.move(self.sprite, *self.momentum) 
     self.window.master.after(2, self.mom_calc) 
     self.movement = self.movement + 1 

    def velocity(self): 
     print(self.movement - self.movement_last) 
     self.movement_last = self.movement 
     self.aid_velocity = self.window.master.after(1000, self.velocity) 

    #----------------------------------------------# 

#----------------------------------------------# 


if __name__ == '__main__': 
    root = tk.Tk() 
    game_window = GameApp(root) 
    root.mainloop() 

Answer 2

」默認的Windows定時器分辨率是〜15ms，每1ms嘗試觸發一個定時器不可能按照你想要的方式工作，而對於一個遊戲來說可能是非常不必要的（一個運行60FPS的顯示器只更新每個〜16ms ）請參閱Why are .NET timers limited to 15 ms resolution?「

在Python - tkinter call to after is too slow處找到解決方案，Andrew Medico給出了一個很好的答案（在評論中）。