I'm currently writing a simple board game in Python and I just realized that garbage collection doesn't purge the discarded bitmap data from memory when images are reloaded. It happens only when game is started or loaded or the resolution changes but it multiples the memory consumed so I can't let this problem unsolved.
When images are reloaded all references are transferred to the new image data since it is binded to the same variable as the original image data was binded to. I tried to force the garbage collection by using collect() but it didn't help.
I wrote a small sample to demonstrate my problem.
from tkinter import Button, DISABLED, Frame, Label, NORMAL, Tk
from PIL.Image import open
from PIL.ImageTk import PhotoImage
class App(Tk):
def __init__(self):
Tk.__init__(self)
self.text = Label(self, text = "Please check the memory usage. Then push button #1.")
self.text.pack()
self.btn = Button(text = "#1", command = lambda : self.buttonPushed(1))
self.btn.pack()
def buttonPushed(self, n):
"Cycle to open the Tab module n times."
self.btn.configure(state = DISABLED) # disable to prevent paralell cycles
if n == 100:
self.text.configure(text = "Overwriting the bitmap with itself 100 times...\n\nCheck the memory usage!\n\nUI may seem to hang but it will finish soon.")
self.update_idletasks()
for i in range(n): # creates the Tab frame whith the img, destroys it, then recreates them to overwrite the previous Frame and prevous img
b = Tab(self)
b.destroy()
if n == 100:
print(i+1,"percent of processing finished.")
if n == 1:
self.text.configure(text = "Please check the memory usage now.\nMost of the difference is caused by the bitmap opened.\nNow push button #100.")
self.btn.configure(text = "#100", command = lambda : self.buttonPushed(100))
self.btn.configure(state = NORMAL) # starting cycles is enabled again
class Tab(Frame):
"""Creates a frame with a picture in it."""
def __init__(self, master):
Frame.__init__(self, master = master)
self.a = PhotoImage(open("map.png")) # img opened, change this to a valid one to test it
self.b = Label(self, image = self.a)
self.b.pack() # Label with img appears in Frame
self.pack() # Frame appears
if __name__ == '__main__':
a = App()
To run the code above you will need a PNG image file. My map.png's dimensions are 1062×1062. As a PNG it is 1.51 MB and as bitmap data it is about 3-3.5 MB. Use a large image to see the memory leak easily.
Expected result when you run my code: python's process eats up memory cycle by cycle. When it consumes approximately 500 MB it collapses but starts to eat up the memory again.
Please give me some advice how to solve this issue. I'm grateful for every help. Thank you. in advance.
