opencv实现图片标注

import cv2

dx0 = 0
dy0 = 0
isdown = False

def callback(event, x, y, flags, userdata):
    global dx0,dy0,isdown
    color = 0, 255, 0
    if flags & cv2.EVENT_FLAG_CTRLKEY:
        color = 255, 0, 0
    elif flags & cv2.EVENT_FLAG_SHIFTKEY:
        color = 0, 0, 255
    elif flags & cv2.EVENT_FLAG_ALTKEY:
        color = 128, 255, 50
    if event == cv2.EVENT_LBUTTONDOWN:
        dx0 = x
        dy0 = y
        isdown = True
    if event == cv2.EVENT_LBUTTONUP:
        isdown = False
        cv2.rectangle(userdata, (dx0, dy0), (x, y), (0, 255, 0), 2)
    if event == cv2.EVENT_MOUSEMOVE:
        if isdown:
            temp = userdata.copy()
            cv2.rectangle(temp,(dx0,dy0),(x,y),color,2)
            cv2.imshow("image",temp)

image = cv2.imread("x.jpg")
cv2.namedWindow("image", cv2.WINDOW_FREERATIO)
cv2.setMouseCallback("image", callback,image)
cv2.imshow("image", image)
while True:
    k = cv2.waitKey()
    if k == ord('q'):
        break
cv2.destroyAllWindows()

 

 这样的图片标注