How to flip an image in Python pillow
Pillow is a fork for the Python Imaging Library, PIL, that provides various image-processing features to manipulate images and apply different filters. It is a powerful library that is easy to integrate with other Python libraries and frameworks. By using the pillow library, we can perform various operations on an image as follows:
Image manipulation, like rotating and flipping
Filter effects like blurring
Image enhancement, like adjusting brightness and contrast
Image overlay, like adding text on an image
In this Answer, we shall apply vertical and horizontal flips to an image and observe how the image changes.
Required imports
We will use the PIL library to manipulate the image and then use matplotlib to display the results once the code is executed successfully.
import matplotlib.pyplot as pltfrom PIL import Imageimport requestsfrom io import BytesIO
matplotlib: To create visualizations and plots in the Python library.PIL: Computer vision library to apply operations on images.Image: To manipulate the images.
requests: To send the requests over the HTTP server to the website.BytesIO: To handle the binary data as an in-memory system.
Apply verticle flip
A verticle flip refers to reversing the order of the image's row. The top-row pixels of the image are swapped with the bottom-row pixels of the images, and consequently, the image pixels are vertically swapped. We use the Image.FLIP_TOP_BOTTOM method to vertically flip the image.
Expected output
We flip the image vertically along the y-axis to get an image that is an upside-down mirror reflection of the original image.
Example code
In this example, we fetch an online image through its link address and flip it vertically using transpose().
import matplotlib.pyplot as plt
from PIL import Image
import requests
from io import BytesIO
image_url = "https://images.pexels.com/photos/7006256/pexels-photo-7006256.jpeg?auto=compress&cs=tinysrgb&w=300"
# Fetch image
response = requests.get(image_url)
image_data = BytesIO(response.content)
original_image = Image.open(image_data)
# Apply vertical flip
vertical_flip_image = original_image.transpose(Image.FLIP_TOP_BOTTOM)
plt.figure(figsize=(10, 5))
plt.subplots_adjust(wspace=0.4, hspace=0.1)
plt.subplot(1, 2, 1)
plt.imshow(original_image)
plt.axis('off')
plt.title('Original Image')
plt.subplot(1, 2, 2)
plt.imshow(vertical_flip_image)
plt.axis('off')
plt.title('Vertically Flipped Image')
plt.show()
Code explanation
Lines 1–4: Import the required libraries and modules.
Line 6: Store the link of the image that is to be used on
image_url. We can also use a local image file and give its exact name.Lines 9–11: Use
requestto fetch the image from the server and open it using theImage.open()method and pass the converted image to it.Line 14: Use the
transpose()method of theImageclass and applyFLIP_TOP_BOTTOMto swap image pixels vertically.Lines 16–17: Specify the figure size that is to appear in the plot and assign the grid size.
Lines 19–22: Display the image using
imshow()and pass the original image to it, turn off the x-axis labels, and specify the title in thetitle().Lines 24–27: Display the image using
imshow()and pass the flipped image to it, turn off the x-axis labels, and specify the title in thetitle().Line 29: Show the resultant plot.
Apply horizontal flip
A horizontal flip refers to reversing the order of the image's column order. The left-column pixels of the image are swapped with the right-column pixels of the image, and consequently, the image pixels are horizontally swapped. We use the Image.FLIP_LEFT_RIGHT method to horizontally flip the image.
Expected output
We flip the image horizontally along the x-axis to get an image that is a left-right mirror reflection of the original image.
Example code
In this example, we fetch an online image through its link address and flip it horizontally using transpose().
import matplotlib.pyplot as plt
from PIL import Image
import requests
from io import BytesIO
image_url = "https://images.pexels.com/photos/7006256/pexels-photo-7006256.jpeg?auto=compress&cs=tinysrgb&w=300"
# Fetch image
response = requests.get(image_url)
image_data = BytesIO(response.content)
original_image = Image.open(image_data)
# Apply horizontal flip
horizontal_flip_image = original_image.transpose(Image.FLIP_LEFT_RIGHT)
plt.figure(figsize=(10, 5))
plt.subplots_adjust(wspace=0.4, hspace=0.1)
plt.subplot(1, 2, 1)
plt.imshow(original_image)
plt.axis('off')
plt.title('Original Image')
plt.subplot(1, 2, 2)
plt.imshow(horizontal_flip_image)
plt.axis('off')
plt.title('Horizontally Flipped Image')
plt.show()
Code explanation
Lines 1–4: Import the required libraries and modules.
Line 6: Store the link of the image that is to be used on
image_url. We can also use a local image file and give its exact name.Lines 9–11: Use
requestto fetch the image from the server and open it using theImage.open()method and pass the converted image to it.Line 14: Use the
transpose()method ofImageclass and applyFLIP_LEFT_RIGHTto swap image pixels horizontally.Lines 16–17: Specify the figure size that is to appear in the plot and assign the grid size.
Lines 19–22: Display the image using
imshow()and pass the original image to it, turn off the x-axis labels, and specify the title in thetitle().Lines 24–27: Display the image using
imshow()and pass the flipped image to it, turn off the x-axis labels, and specify the title in thetitle().Line 29: Show the resultant plot.
Real-life application
There are a lot of real-life scenarios where there is a need to flip an image. Let's take a look at a few of the scenarios where image flipping is useful.
Common query
Why do we use transpose() to flip the images?
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