Split a PDF vertically, used for scanned double sided PDF pages

split-page.py

# Source http://stackoverflow.com/a/15741856/1301753
# Source https://gist.github.com/breedx2/60409d2179508dba28c4159b81f26fc2

import copy
import sys
import math
import pypdf

def split_pages(src, dst):
    src_f = open(src, 'r+b')
    dst_f = open(dst, 'w+b')

    input = pypdf.PdfReader(src_f)
    output = pypdf.PdfWriter()

    for i in range(len(input.pages)):
        p = input.pages[i]
        q = copy.copy(p)
        q.mediabox = copy.copy(p.mediabox)

        x1, x2 = p.mediabox.lower_left
        x3, x4 = p.mediabox.upper_right

        x1, x2 = math.floor(x1), math.floor(x2)
        x3, x4 = math.floor(x3), math.floor(x4)
        x5, x6 = math.floor(x3/2), math.floor(x4/2)

        if x3 > x4:
            # horizontal
            p.mediabox.upper_right = (x5, x4)
            p.mediabox.lower_left = (x1, x2)

            q.mediabox.upper_right = (x3, x4)
            q.mediabox.lower_left = (x5, x2)
        else:
            # vertical
            p.mediabox.upper_right = (x3, x4)
            p.mediabox.lower_left = (x1, x6)

            q.mediabox.upper_right = (x3, x6)
            q.mediabox.lower_left = (x1, x2)

        output.add_page(p)
        output.add_page(q)

    output.write(dst_f)
    src_f.close()
    dst_f.close()

input_file=input("Enter the original PDF file name :")
output_file=input("Enter the splitted PDF file name :")

split_pages(input_file,output_file)

This is a quick and dirty python3 update in 2024 for the original at https://gist.github.com/tshrinivasan/23d8e4986cbae49b8a8c

Thanks for improving .