Python OpenCV – cv2.polylines() method
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:
![](https://media.geeksforgeeks.org/wp-content/uploads/20200403171144/geeks141.png)
Image used for all the below examples:
Example #1:
Python3
import cv2
import numpy as np
path = gfg.jpeg'
image = cv2.imread(path)
window_name = 'Image'
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
color = ( 255 , 0 , 0 )
thickness = 2
image = cv2.polylines(image, [pts],
isClosed, color, thickness)
while ( 1 ):
cv2.imshow( 'image' , image)
if cv2.waitKey( 20 ) & 0xFF = = 27 :
break
cv2.destroyAllWindows()
|
Output:
Example #2:
Python3
import cv2
import numpy as np
path = r 'gfg.jpeg'
image = cv2.imread(path)
window_name = 'Image'
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
color = ( 0 , 255 , 0 )
thickness = 8
image = cv2.polylines(image, [pts],
isClosed, color,
thickness)
while ( 1 ):
cv2.imshow( 'image' , image)
if cv2.waitKey( 20 ) & 0xFF = = 27 :
break
cv2.destroyAllWindows()
|
Output:
![cv2.polylines()](https://media.geeksforgeeks.org/wp-content/uploads/20200403193653/Capture224.jpg)
Last Updated :
20 Jan, 2023
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