Python Pillow - Rolling an Image

Pillow (Python Imaging Library) allows us to roll or shift the image's pixel data within the image. This operation moves the pixel data either horizontally (left or right) or vertically (up or down) to create a rolling effect.

There is no direct method in pillow to roll or shift the image pixel data but it can be performed by using the copy and paste operations on the image. The below are the steps to be followed to perform rolling of the image.

• Import the necessary modules.

• Next load the image that we want to roll.

• Define the rolling offset −

  The rolling offset determines how much we want to shift the image. A positive value for the offset will shift the image right i.e. horizontal rolling or down i.e. vertical rolling and a negative value will shift the image left or up. We can choose the offset value based on our desired rolling effect.

• Create a new image with the same size as the original. This new image will serve as the canvas for the rolled result.

• Perform the rolling operations i.e. either horizontal rolling or vertical rolling.

• Save the rolled image to a file.

• Optionally display the rolled image. This step is useful for visualizing the result but it's not necessary.

Following is the input image used in all the examples of this chapter.

Example - Horizontally Rolling an Image

In this example we are performing the horizontal rolling on the input image by specifying the horizontal offset as 50.

main.py

from PIL import Image
image = Image.open("Images/flowers.jpg")
horizontal_offset = 50  
#Change this value as needed
rolled_image = Image.new("RGB", image.size)
for y in range(image.height):
   for x in range(image.width):
      new_x = (x + horizontal_offset) % image.width
      pixel = image.getpixel((x, y))
      rolled_image.putpixel((new_x, y), pixel)
rolled_image.save("Output_Images/horizontal_rolled_image.jpg")
rolled_image.show()

Output

Example - Vertically Rolling an Image

In this example we are rolling the image vertically by specifying the offset value as 50.

main.py

from PIL import Image
image = Image.open("Images/flowers.jpg")
vertical_offset = 50  
#Change this value as needed
rolled_image = Image.new("RGB", image.size)
for x in range(image.width):
   for y in range(image.height):
      new_y = (y + vertical_offset) % image.height
      pixel = image.getpixel((x, y))
      rolled_image.putpixel((x, new_y), pixel)
rolled_image.save("Output_Images/vertical_rolled_image.jpg")
rolled_image.show()

Output