PYTHON

waitkey in opencv

cv2.waitKey() 
# function store 'key' that you press during output windows open, 
# also wait for certain amount of time

#if yoy press 'q' then cv2.waitKey(1) replace with ASCII value which is 113
if cv2.waitKey(1000) & 0xFF == ord('q'): # wait for 1000 millisecond
  break

# now your code will look like this
if 113 & 0xFF == ord('q'):
  break

opencv waitkey example

    if cv2.waitKey(1) & 0xFF == ord('q'): # wait for 1 millisecond
        break

openCV waitKey

import numpy as np
import cv2

im = np.zeros((100, 300), np.uint8)
cv2.imshow('Keypressed', im)
while True:
  key = cv2.waitKey(0)
  im_c = im.copy()
  cv2.putText(
    im_c,
    f'{chr(key)} -> {key}',
    (10, 60), 
    cv2.FONT_HERSHEY_SIMPLEX, 
    1,
    (255,255,255),
    2)
  cv2.imshow('Keypressed', im_c)
  if key == 27: break # 'ESC'