createTrackbar
createTrackbar is a function in OpenCV's HighGUI module that adds a trackbar, or slider, to a named window. The slider lets users adjust a parameter in real time, either by updating a bound variable (in C++) or by triggering a callback function when the position changes.
Usage notes: The target window must exist before creating a trackbar; the usual sequence is to create
Examples: In C++: createTrackbar("Brightness", "Image", &brightness, 255, onBrightnessChange); In Python: cv2.createTrackbar("Brightness", "Image", brightness, 255, on_brightness_change). The
Behavior: The function itself does not render output; it creates the UI control in the existing window.
Notes: Trackbars are commonly used for interactive parameter tuning, calibration, and demonstrations. They are associated with