no error when closing

.gitignore

@@ -1 +1,7 @@
 .DS_Store
+*.png
+*.jpg
+*.xml
+.idea/
+venv/
+__pycache__/

graphics.py

@@ -1,6 +1,6 @@
 import time
 from tkinter import *
-
+import sys
 import cv2
 from PIL import Image, ImageTk
 
@@ -49,7 +49,10 @@ def __init__(self):
         self.button_1.grid(row=1, column=0)
         self.button_2.grid(row=1, column=1)
         self.button_3.grid(row=1, column=2)
-
+        self.win.protocol("WM_DELETE_WINDOW", self.close_window)
+        self.running = True
+    def close_window(self):
+        self.running = False
     def high(self):
         self.selected_sensitivity = 2
         self.then()

main.py

@@ -17,6 +17,7 @@ def dist(a, b, c, d):
     return math.sqrt((a - c) ** 2 + (b - d) ** 2)
 
 
+
 detected = False
 upright = False
 cap = cv2.VideoCapture(0)
@@ -27,6 +28,8 @@ def dist(a, b, c, d):
 
 # main loop
 while cap.isOpened():
+    if not graphics.running:
+        break
     # updating the tkinter window and text
     graphics.update(detected, upright)
     ret, img_orig = cap.read()
@@ -149,4 +152,5 @@ def dist(a, b, c, d):
     else:
         print("No camera input")
 
+
 cap.release()