Python OpenCV - cv2.rotate() method
OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.rotate() function is used to rotate images by multiples of 90 degrees. It is a simple and fast way to rotate an image in just one line of code. we use this image:
Example:
import cv2
path = r'C:\Users\user\Desktop\geeks14.png'
src = cv2.imread(path)
rotated = cv2.rotate(src, cv2.ROTATE_90_CLOCKWISE)
cv2.imshow("90° Clockwise", rotated)
cv2.waitKey(0)
cv2.destroyAllWindows()
Output
Explanation:
- cv2.imread() loads the image from the given file path and cv2.rotate() rotates it using a specified code like cv2.ROTATE_90_CLOCKWISE.
- cv2.imshow() displays the image in a window, cv2.waitKey(0) waits for a key press and cv2.destroyAllWindows() closes the window.
Syntax
cv2.rotate(src, rotateCode[, dst])
Parameter:
Parameter | Description |
---|---|
src | The input image (as a NumPy array). |
rotateCode | An enum value that defines the rotation direction. |
dst(Optional) | The output image (usually ignored, since the function returns the image). |
Returns: This function returns the rotated image.
Available rotateCode values
OpenCV offers constants to rotate images by 90°, 180° or 270° without manual pixel manipulation. Below are the common rotation codes and their meanings:
Constant | Description |
---|---|
cv2.ROTATE_90_CLOCKWISE | Rotates the image 90 degrees clockwise. |
cv2.ROTATE_180 | Rotates the image 180 degrees. |
cv2.ROTATE_90_COUNTERCLOCKWISE | Rotates the image 90 degrees counterclockwise (i.e., 270° clockwise). |
Examples
Example 1: In this example, we rotate the image upside down by rotating it 180 degrees.
import cv2
path = r'C:\Users\user\Desktop\geeks14.png'
src = cv2.imread(path)
rotated = cv2.rotate(src, cv2.ROTATE_180)
cv2.imshow("180° Rotation", rotated)
cv2.waitKey(0)
cv2.destroyAllWindows()
Output
Explanation:
- cv2.imread() loads the image from the given file path and cv2.rotate() rotates it using the cv2.ROTATE_180 code, which flips the image upside down.
- cv2.imshow() displays the image in a window, cv2.waitKey(0) waits for a key press and cv2.destroyAllWindows() closes the window afterward.
Example 2: In this example, we rotate the image 270 degrees clockwise (which is equivalent to 90 degrees counterclockwise)
import cv2
path = r'C:\Users\user\Desktop\geeks14.png'
src = cv2.imread(path)
rotated = cv2.rotate(src, cv2.ROTATE_90_COUNTERCLOCKWISE)
cv2.imshow("270° Clockwise", rotated)
cv2.waitKey(0)
cv2.destroyAllWindows()
Output
Explanation:
- cv2.imread() loads the image from the given file path and cv2.rotate() rotates it using the cv2.ROTATE_90_COUNTERCLOCKWISE code, which is equivalent to a 270-degree clockwise rotation (or 90 degrees to the left).
- cv2.imshow() displays the rotated image, cv2.waitKey(0) pauses for a key press and cv2.destroyAllWindows() closes the display window.