# Functions to cut up images (for tokenization) and to stitch them together again
from PIL import Image
import numpy as np
# Cut an image into square blocks of a specified size
# With padding where necessary.
# def cut_image(image, block_size):
# width, height = image.size
# blocks = []
# # Calculate the number of blocks in each dimension
# num_blocks_x = (width + block_size - 1) // block_size
# num_blocks_y = (height + block_size - 1) // block_size
# # Create blocks with padding if necessary
# for i in range(num_blocks_y):
# for j in range(num_blocks_x):
# left = j * block_size
# upper = i * block_size
# right = min(left + block_size, width)
# lower = min(upper + block_size, height)
# # Create a new image for the block
# cropped = image.crop((left, upper, right, lower))
# # If the block is smaller than the specified size, pad it
# if cropped.width < block_size or cropped.height < block_size:
# block = Image.new(
# image.mode, (block_size, block_size), color="white"
# ) # White padding
# block.paste(cropped, (0, 0))
# else:
# block = cropped
# blocks.append(block)
# return blocks
def cut_image(image, block_size, overlap=0.0):
"""
Cut an image into square blocks of a specified size with adjustable overlap.
Args:
image (PIL.Image): The input image.
block_size (int): The size of each block (in pixels).
overlap (float): Fraction of block size to overlap between blocks (0.0 to 1.0).
Returns:
list: List of image blocks.
"""
width, height = image.size
blocks = []
# Calculate the step size based on overlap
step_size = int(block_size * (1 - overlap))
# Create blocks with padding if necessary
for upper in range(0, height, step_size):
for left in range(0, width, step_size):
right = min(left + block_size, width)
lower = min(upper + block_size, height)
# Create a new image for the block
cropped = image.crop((left, upper, right, lower))
# If the block is smaller than the specified size, pad it
if cropped.width < block_size or cropped.height < block_size:
block = Image.new(
image.mode, (block_size, block_size), color="white"
) # White padding
block.paste(cropped, (0, 0))
else:
block = cropped
blocks.append(block)
return blocks
