Source code:

[python]
import cv2
import numpy as np

def nothing(x):
pass

cap = cv2.VideoCapture(0)

cv2.namedWindow("frame")
cv2.createTrackbar("test", "frame", 50, 500, nothing)
cv2.createTrackbar("color/gray", "frame", 0, 1, nothing)

while True:
_, frame = cap.read()

test = cv2.getTrackbarPos("test", "frame")
font = cv2.FONT_HERSHEY_COMPLEX
cv2.putText(frame, str(test), (50, 150), font, 4, (0, 0, 255))

s = cv2.getTrackbarPos("color/gray", "frame")
if s == 0:
pass
else:
frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

cv2.imshow("frame", frame)

key = cv2.waitKey(1)
if key == 27:
break

cap.release()
cv2.destroyAllWindows()
[/python]

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