Using Pillow to roll images horizontally and vertically.

_Python Pillow image roll - README.md

Use the Pillow module for Python to "roll" images horizontally or vertically. When an image is rolled, it is shifted in some direction. The part of the image that would be lost as a result of that shift is added onto the opposite side of the image.

icon1024x1024.png

roll.py

"""
roll.py

Inspired by an example from Pillow documentation:

https://pillow.readthedocs.io/en/stable/handbook/tutorial.html#:~:text=Rolling%20an%20image,))%0A%0A%20%20%20%20return%20im
"""
from PIL import Image


def roll(im: Image.Image, vector: (int, int)) -> Image.Image:
    """Roll an image in a given direction."""
    if vector[0] != 0:
        im = roll_horizontal(im, vector[0])
    if vector[1] != 0:
        im = roll_vertical(im, vector[1])
    return im


def roll_horizontal(im: Image.Image, delta: int) -> Image.Image:
    """Roll an image horizontally."""
    xsize, ysize = im.size

    delta = delta % xsize
    if delta == 0:
        return im

    part1 = im.crop((0, 0, delta, ysize))
    part2 = im.crop((delta, 0, xsize, ysize))
    im.paste(part1, (xsize - delta, 0, xsize, ysize))
    im.paste(part2, (0, 0, xsize - delta, ysize))

    return im


def roll_vertical(im: Image.Image, delta: int) -> Image.Image:
    """Roll an image horizontally."""
    xsize, ysize = im.size

    delta = delta % ysize
    if delta == 0:
        return im

    nim = im.copy() # Important: copy to avoid modifying the original

    part1 = nim.crop((0, 0, xsize, delta))
    part2 = nim.crop((0, delta, xsize, ysize))
    nim.paste(part1, (0, ysize - delta, xsize, ysize))
    nim.paste(part2, (0, 0, xsize, ysize - delta))

    return nim


try:
    image = Image.open('icon1024x1024.png')

    # Roll 800 pixels to the right
    rolled_image_horizontal = roll(image, (800, 0))
    rolled_image_horizontal.save('rolled_image_horizontal.png')

    # Roll 500 pixels down
    rolled_image_vertical = roll(image, (0, 500))
    rolled_image_vertical.save('rolled_example_vertical.png')

    # Roll 800 pixels left and 625 up
    rolled_image_diagonal = roll(image, (-800, -625))
    rolled_image_diagonal.save('rolled_image_diagonal.png')

except FileNotFoundError:
    print('Error: Image file not found.')
except Exception as e:
    print(f'An error occurred: {e}')