Python OpenCV | cv2.circle() method

07 Jun, 2022
OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.circle() method is used to draw a circle on any image. The syntax of cv2.circle() method is:
Syntax: 
cv2.circle(image, center_coordinates, radius, color, thickness)
Parameters: 
image: It is the image on which the circle is to be drawn. 
center_coordinates: It is the center coordinates of the circle. The coordinates are represented as tuples of two values i.e. (X coordinate value, Y coordinate value). 
radius: It is the radius of the circle. 
color: It is the color of the borderline of a circle to be drawn. For BGR, we pass a tuple. eg: (255, 0, 0) for blue color. 
thickness: It is the thickness of the circle border line in px. Thickness of -1 px will fill the circle shape by the specified color.
Return Value: It returns an image. 
The steps to create a circle on an image are:
Read the image using imread() function.Pass this image to the cv2.circle() method along with other parameters such as center_coordinates, radius, color and thickness.Display the image using cv2.imshow() method.
Read the image using imread() function.
Pass this image to the cv2.circle() method along with other parameters such as center_coordinates, radius, color and thickness.
Display the image using cv2.imshow() method.
Implementation:
Image used for all the below examples:  
Example #1:
Python3
# Python program to explain cv2.circle() 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'  # Center coordinatescenter_coordinates = (120, 50) # Radius of circleradius = 20  # Blue color in BGRcolor = (255, 0, 0)  # Line thickness of 2 pxthickness = 2  # Using cv2.circle() method# Draw a circle with blue line borders of thickness of 2 pximage = cv2.circle(image, center_coordinates, radius, color, thickness)  # Displaying the imagecv2.imshow(window_name, image)
Output: 
 Example #2: Using thickness of -1 px to fill the circle with red color. 
Python3
# Python program to explain cv2.circle() 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'  # Center coordinatescenter_coordinates = (120, 100) # Radius of circleradius = 30  # Red color in BGRcolor = (0, 0, 255)  # Line thickness of -1 pxthickness = -1  # Using cv2.circle() method# Draw a circle of red color of thickness -1 pximage = cv2.circle(image, center_coordinates, radius, color, thickness)  # Displaying the imagecv2.imshow(window_name, image)
Output: 
 Example # 3: To display a circle on a black screen created using NumPy library.
Python3
import cv2import numpy as np     # Reading an image in default modeImg = np.zeros((512, 512, 3), np.uint8)    # Window name in which image is displayedwindow_name = 'Image'   # Center coordinatescenter_coordinates = (220, 150)  # Radius of circleradius = 100   # Red color in BGRcolor = (255, 133, 233)   # Line thickness of -1 pxthickness = -1   # Using cv2.circle() method# Draw a circle of red color of thickness -1 pximage = cv2.circle(Img, center_coordinates, radius, color, thickness)   # Displaying the imagecv2.imshow(window_name, image)cv2.waitKey(0)cv2.destroyAllWindows()
Output:
Circle on Black background 
iamaprogrammer0012
sheetal18june
OpenCV
Python
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