Convert @jvns' strace zine into a standard PDF

requirements.txt

PyPDF2==1.24

zine2doc.py

#!/usr/bin/env python

import argparse
import sys
from itertools import chain, izip

from PyPDF2 import PdfFileReader, PdfFileWriter


def split_pages(zine):
    pages = []

    even_pdf = PdfFileReader(open(zine, 'rb'))
    odd_pdf = PdfFileReader(open(zine, 'rb'))

    for i in range(even_pdf.getNumPages()):
        even_page = even_pdf.getPage(i)
        odd_page = odd_pdf.getPage(i)

        midpoint_lower = list(even_page.cropBox.lowerRight)
        midpoint_upper = list(even_page.cropBox.upperRight)
        midpoint_lower[0] /= 2
        midpoint_upper[0] /= 2

        even_page.cropBox.lowerRight = midpoint_lower
        even_page.cropBox.upperRight = midpoint_upper

        odd_page.cropBox.lowerLeft = midpoint_lower
        odd_page.cropBox.upperLeft = midpoint_upper

        even_page.mediaBox = even_page.cropBox
        odd_page.mediaBox = odd_page.cropBox

        pages.append((i, 'left', even_page))
        pages.append((i, 'right', odd_page))

    unfolded_pages = pages[-2:]
    pages.pop()
    pages.pop()

    while len(pages) > 0:
        unfolded_pages.insert(0, pages.pop())
        unfolded_pages.append(pages.pop())
        unfolded_pages.reverse()

    unfolded_pages.reverse()
    return [x[2] for x in unfolded_pages]

def zine2doc(zine, output):
    output_pdf = PdfFileWriter()

    for i, page in enumerate(split_pages(zine)):
        output_pdf.addPage(page)

    with open(output, 'wb') as fp:
        output_pdf.write(fp)

def main():
    parser = argparse.ArgumentParser(
        description='convert a PDF in zine-style layout into one that reads '
        'like a regular document')

    parser.add_argument('zine', help='the zine to convert')
    parser.add_argument(
        '-o', '--output', default='converted.pdf',
        help='the file to output')
    args = parser.parse_args()

    zine2doc(**vars(args))


if __name__ == '__main__':
    main()