CirclePolygon.py

import cv2
import numpy as np
import matplotlib.pyplot as plt

def ShowWithMatplotlib(img, title):
    imgRGB = img[:, :, ::-1]
    plt.imshow(imgRGB)
    plt.title(title)
    plt.show()

colors = {'blue': (255, 0, 0), 'green': (0, 255, 0), 'red': (0, 0, 255), 'yellow': (0, 255, 255),
          'magenta': (255, 0, 255), 'cyan': (255, 255, 0), 'white': (255, 255, 255), 'black': (0, 0, 0),
          'gray': (125, 125, 125), 'rand': np.random.randint(0, high=256, size=(3,)).tolist(),
          'dark_gray': (50, 50, 50), 'light_gray': (220, 220, 220)}

image = np.zeros((640, 640, 3), dtype="uint8")
image.fill(255)
pts = np.array([(600, 320), (563, 460), (460, 562), (320, 600), (180, 563), (78, 460), (40, 320), (77, 180), (179, 78), (319, 40),
                (459, 77), (562, 179)])
pts = pts.reshape((-1, 1, 2))

cv2.polylines(image, [pts], True, colors['green'], 5)
ShowWithMatplotlib(image, 'polygon with the shape of a circle using 12 points')