Last Updated : 12 Jul, 2025
OpenCV is the huge open-source library for computer vision, machine learning, and image processing and it now plays a major role in real-time operations which are very important in today’s systems. By using OpenCV one can process images and videos to identify objects, faces, or even the handwriting of a human. When it is combined with various libraries such as Numpy, Python is capable of processing the OpenCV array structure for analysis.
Note: For more information, refer to OpenCV Python Tutorial
cv2.polylines()cv2.polylines() method is used to draw a polygon on any image.
Syntax: cv2.polylines(image, [pts], isClosed, color, thickness)
Parameters: image: It is the image on which circle is to be drawn.
pts: Array of polygonal curves.
npts: Array of polygon vertex counters.
contours: Number of curves.
isClosed: Flag indicating whether the drawn polylines are closed or not. If they are closed, the function draws a line from the last vertex of each curve to its first vertex.
color: It is the color of polyline to be drawn. For BGR, we pass a tuple.
thickness: It is thickness of the polyline edges.
Return Value: It returns an image.
Image used for all the below examples:
Image used for all the below examples:Example #1:
Python3
# Python program to explain
# cv2.polylines() method
import cv2
import numpy as np
# path
path = gfg.jpeg'
# Reading an image in default
# mode
image = cv2.imread(path)
# Window name in which image is
# displayed
window_name = 'Image'
# Polygon corner points coordinates
pts = np.array([[25, 70], [25, 160],
[110, 200], [200, 160],
[200, 70], [110, 20]],
np.int32)
pts = pts.reshape((-1, 1, 2))
isClosed = True
# Blue color in BGR
color = (255, 0, 0)
# Line thickness of 2 px
thickness = 2
# Using cv2.polylines() method
# Draw a Blue polygon with
# thickness of 1 px
image = cv2.polylines(image, [pts],
isClosed, color, thickness)
# Displaying the image
while(1):
cv2.imshow('image', image)
if cv2.waitKey(20) & 0xFF == 27:
break
cv2.destroyAllWindows()
Output:
Example #2:
Python3
# Python program to explain
# cv2.polylines() method
import cv2
import numpy as np
# path
path = r'gfg.jpeg'
# Reading an image in default
# mode
image = cv2.imread(path)
# Window name in which image is
# displayed
window_name = 'Image'
# Polygon corner points coordinates
pts = np.array([[25, 70], [25, 145],
[75, 190], [150, 190],
[200, 145], [200, 70],
[150, 25], [75, 25]],
np.int32)
pts = pts.reshape((-1, 1, 2))
isClosed = True
# Green color in BGR
color = (0, 255, 0)
# Line thickness of 8 px
thickness = 8
# Using cv2.polylines() method
# Draw a Green polygon with
# thickness of 1 px
image = cv2.polylines(image, [pts],
isClosed, color,
thickness)
# Displaying the image
while(1):
cv2.imshow('image', image)
if cv2.waitKey(20) & 0xFF == 27:
break
cv2.destroyAllWindows()
Output:
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