Python OpenCV | cv2.line() method

10 Jun, 2022
OpenCV-Python is a library of Python bindings designed to solve computer vision problems.cv2.line() method is used to draw a line on any image.
Syntax:
cv2.line(image, start_point, end_point, color, thickness) 
Parameters: image: It is the image on which line is to be drawn. 
start_point: It is the starting coordinates of the line. The coordinates are represented as tuples of two values i.e. (X coordinate value, Y coordinate value). 
end_point: It is the ending coordinates of the line. The coordinates are represented as tuples of two values i.e. (X coordinate value, Y coordinate value). 
color: It is the color of the line to be drawn. For RGB, we pass a tuple. eg: (255, 0, 0) for blue color.
thickness: It is the thickness of the line in px. 
Return Value: It returns an image.
The image used for examples n1 and 2 is as follows:
  
Example #1: 
Python3
# Python program to explain cv2.line() method  # importing cv2import cv2  # pathpath = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'  # Reading an image in default modeimage = cv2.imread(path)  # Window name in which image is displayedwindow_name = 'Image' # Start coordinate, here (0, 0)# represents the top left corner of imagestart_point = (0, 0) # End coordinate, here (250, 250)# represents the bottom right corner of imageend_point = (250, 250) # Green color in BGRcolor = (0, 255, 0) # Line thickness of 9 pxthickness = 9 # Using cv2.line() method# Draw a diagonal green line with thickness of 9 pximage = cv2.line(image, start_point, end_point, color, thickness) # Displaying the imagecv2.imshow(window_name, image)
Output:
Example #2:
Python3
# Python program to explain cv2.line() method  # importing cv2import cv2  # pathpath = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'  # Reading an image in grayscale modeimage = cv2.imread(path, 0)  # Window name in which image is displayedwindow_name = 'Image' # Start coordinate, here (225, 0)# represents the top right corner of imagestart_point = (225, 0) # End coordinate, here (0, 225)# represents the bottom left corner of imageend_point = (0, 225) # Black color in BGRcolor = (0, 0, 0) # Line thickness of 5 pxthickness = 5 # Using cv2.line() method# Draw a diagonal black line with thickness of 5 pximage = cv2.line(image, start_point, end_point, color, thickness) # Displaying the imagecv2.imshow(window_name, image)
Output: 
 
Example 3: Drawing a line on black screen using numpy library:
Python3
import numpy as npimport cv2# Creating a black screen image using nupy.zeros functionImg = np.zeros((512, 512, 3), dtype='uint8')# Start coordinate, here (100, 100). It represents the top left corner of imagestart_point = (100, 100)# End coordinate, here (450, 450). It represents the bottom right corner of the image according to resolutionend_point = (450, 450)# White color in BGRcolor = (255, 250, 255)# Line thickness of 9 pxthickness = 9# Using cv2.line() method to draw a diagonal green line with thickness of 9 pximage = cv2.line(Img, start_point, end_point, color, thickness)# Display the imagecv2.imshow('Drawing_Line', image)cv2.waitKey(0)cv2.destroyAllWindows()
Output:
Black Screen created using numpy and drawing line using cv2.line() function
sheetal18june
shafinamin
OpenCV
Python
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