OpenCV polygon roi

import cv2
import imutils
import numpy as np
import joblib
 
pts = []  # for storing points
 
 
def draw_roi(event, x, y, flags, param):
    img2 = img.copy()
 
    if event == cv2.EVENT_LBUTTONDOWN:  # Left click, select point
        pts.append((x, y))
 
    if event == cv2.EVENT_RBUTTONDOWN:  # Right click to cancel the last selected point
        pts.pop()
 
    if event == cv2.EVENT_MBUTTONDOWN:
        mask = np.zeros(img.shape, np.uint8)
        points = np.array(pts, np.int32)
        points = points.reshape((-1, 1, 2))
 
        mask = cv2.polylines(mask, [points], True, (255, 255, 255), 2)
        mask2 = cv2.fillPoly(mask.copy(), [points], (255, 255, 255))  # for ROI
        mask3 = cv2.fillPoly(mask.copy(), [points], (0, 255, 0))  # for displaying images on the desktop
 
        show_image = cv2.addWeighted(src1=img, alpha=0.8, src2=mask3, beta=0.2, gamma=0)
 
        cv2.imshow("mask", mask2)
        cv2.imshow("show_img", show_image)
 
        ROI = cv2.bitwise_and(mask2, img)
        cv2.imshow("ROI", ROI)
        cv2.waitKey(0)
 
    if len(pts) > 0:
        # Draw the last point in pts
        cv2.circle(img2, pts[-1], 3, (0, 0, 255), -1)
 
    if len(pts) > 1:
        #
        for i in range(len(pts) - 1):
            cv2.circle(img2, pts[i], 5, (0, 0, 255), -1)  # x ,y is the coordinates of the mouse click place
        cv2.line(img=img2, pt1=pts[i], pt2=pts[i + 1], color=(255, 0, 0), thickness=2)
 
    cv2.imshow('image', img2)
 
 
# Create images and windows and bind windows to callback functions
img = cv2.imread("1.PNG")
img = imutils.resize(img, width=500)
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_roi)
print("[INFO] Click the left button: select the point, right click: delete the last selected point, click the middle button: determine the ROI area")
print("[INFO] Press ‘S’ to determine the selection area and save it")
print("[INFO] Press ESC to quit")
 
while True:
    key = cv2.waitKey(1) & 0xFF
    if key == 27:
        break
    if key == ord("s"):
        saved_data = {
            "ROI": pts
        }
        joblib.dump(value=saved_data, filename="config.pkl")
        print("[INFO] ROI coordinates have been saved to local.")
        # break
cv2.destroyAllWindows()

import cv2
import numpy as np
import copy
 
 
def crop_img(image, coords):
    mask = np.zeros(image.shape, dtype=np.uint8)
    roi_corners = np.array([coords], dtype=np.int32)
 
    channel_count = image.shape[2]
    ignore_mask_color = (255,) * channel_count
    cv2.fillPoly(mask, roi_corners, ignore_mask_color)
    masked_image = cv2.bitwise_and(image, mask)
    return masked_image
 
 
def on_EVENT_LBUTTONDOWN(event, x, y, flags, param):
    if event == cv2.EVENT_LBUTTONDOWN:
        cv2.circle(img, (x, y), 3, (255, 0, 0), thickness=5)
        cv2.imshow("image", img)
        coord.append((x, y))
 
 
img = cv2.imread("1.jpg")
img_new = copy.copy(img)
coord = []
 
cv2.namedWindow("image")
cv2.setMouseCallback("image", on_EVENT_LBUTTONDOWN)
 
 
while True:
    img_show = cv2.imshow("image", img)
 
    key = cv2.waitKey(1) & 0xFF
    if key == ord("s"):
        img = crop_img(img_new, coord)
 
    if key == ord("r"):
        coord = []
        img = cv2.imread("1.jpg")
 
    if key == ord("q"):
        break