opencv 39 rotation

45 degree

-90 degree

rotate by arbitrary point

180 degree

rotate without cropping

#main.py

import argparse

import imutils

import cv2

# construct the argument parser and parse the arguments

ap = argparse.ArgumentParser()

ap.add_argument("-i", "--image", type=str, default="opencv_logo.png",

                help="path to the input image")

args = vars(ap.parse_args())

# load the image and show it

image = cv2.imread(args["image"])

cv2.imshow("Original", image)

# grab the dimensions of the image and calculate the center of the

# image

(h, w) = image.shape[:2]

(cX, cY) = (w // 2, h // 2)

# rotate our image by 45 degrees around the center of the image

M = cv2.getRotationMatrix2D((cX, cY), 45, 1.0)

rotated = cv2.warpAffine(image, M, (w, h))

cv2.imshow("Rotated by 45 Degrees", rotated)

# rotate our image by -90 degrees around the image

M = cv2.getRotationMatrix2D((cX, cY), -90, 1.0)

rotated = cv2.warpAffine(image, M, (w, h))

cv2.imshow("Rotated by -90 Degrees", rotated)

# rotate our image around an arbitrary point rather than the center

M = cv2.getRotationMatrix2D((10, 10), 45, 1.0)

rotated = cv2.warpAffine(image, M, (w, h))

cv2.imshow("Rotated by Arbitrary Point", rotated)

# use our imutils function to rotate an image 180 degrees

rotated = imutils.rotate(image, 180)

cv2.imshow("Rotated by 180 Degrees", rotated)

# rotate our image by 33 degrees counterclockwise, ensuring the

# entire rotated image still renders within the viewing area

rotated = imutils.rotate_bound(image, -33)

cv2.imshow("Rotated Without Cropping", rotated)

cv2.waitKey(0)

reference:

https://www.pyimagesearch.com/2021/01/20/opencv-rotate-image/