Python OpenCV – cv2.polylines() method

15 Jun, 2022
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() 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. 
ncontours: 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 cv2import numpy as np # pathpath = gfg.jpeg' # Reading an image in default# modeimage = cv2.imread(path) # Window name in which image is# displayedwindow_name = 'Image' # Polygon corner points coordinatespts = 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 BGRcolor = (255, 0, 0) # Line thickness of 2 pxthickness = 2 # Using cv2.polylines() method# Draw a Blue polygon with# thickness of 1 pximage = cv2.polylines(image, [pts],                      isClosed, color, thickness) # Displaying the imagewhile(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 cv2import numpy as np # pathpath = r'gfg.jpeg' # Reading an image in default# modeimage = cv2.imread(path) # Window name in which image is# displayedwindow_name = 'Image' # Polygon corner points coordinatespts = 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 BGRcolor = (0, 255, 0) # Line thickness of 8 pxthickness = 8 # Using cv2.polylines() method# Draw a Green polygon with# thickness of 1 pximage = cv2.polylines(image, [pts],                      isClosed, color,                      thickness) # Displaying the imagewhile(1):         cv2.imshow('image', image)    if cv2.waitKey(20) & 0xFF == 27:                 breakcv2.destroyAllWindows()
Output:
 
miktw0d
Python-OpenCV
Python
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