annotate.py 文件源码

def annotate(event, x, y, flags, param):
    """Callback for function 'annotate_tracks'.
    Tracks cursor and detects if mouse position is to be saved as
    a trackpoint. Track points are saved once per frame if the 
    left mouse button is held down.
    """

    global is_read
    global px, py

    if event == cv2.EVENT_MOUSEMOVE:
        px, py = x, y

    if event == cv2.EVENT_LBUTTONDOWN:
        is_read = 1

    if event == cv2.EVENT_LBUTTONUP:
        is_read = 0