Python script that accepts a pdf file as input and creates an output with all the pages split in half, by the x axis – the output file will have twice as many pages as the original file.

split_in_half.py

#!/usr/bin/python
"""
Python script that accepts a pdf file as input and creates an output with all
the pages split in half, by the x axis - the output file will have twice as
many pages as the original file.

e.g. `python split_in_half.py ~/Documents/my-double-paged-document.pdf`

An output file called `output.pdf` will be created.

Requirements:
- [pyPdf](https://pypi.python.org/pypi/pyPdf/)
"""
import sys
from copy import copy

from pyPdf import PdfFileWriter, PdfFileReader
from pyPdf.utils import PdfReadError


def get_file_input(file_path):
    """
    Given a file_path, create a PdfFileReader instance and return it.
    """
    try:
        return PdfFileReader(file(file_path, "rb"))
    except PdfReadError, e:
        sys.exit('Error opening the file `{}`: {}'.format(file_path, e))
    except Exception, e:
        sys.exit('{}: {}'.format(e.__class__, e))


def get_pages(page):
    """
    Given a pdf page, split it in half by the x axis and return both halves
    as new pdf pages.
    """
    page_left = page
    page_right = copy(page)

    # Get height and width of what the output pages should have.
    output_page_height = page_left.mediaBox.getUpperRight_y()
    output_page_width = page_left.mediaBox.getUpperRight_x() / 2

    # Crop the left page.
    page_left.trimBox.lowerLeft = (0, 0)
    page_left.trimBox.upperRight = (output_page_width, output_page_height)
    page_left.cropBox.lowerLeft = (0, 0)
    page_left.cropBox.upperRight = (output_page_width, output_page_height)

    # Crop the right page.
    page_right.trimBox.lowerLeft = (output_page_width, 0)
    page_right.trimBox.upperRight = (output_page_width * 2, output_page_height)
    page_right.cropBox.lowerLeft = (output_page_width, 0)
    page_right.cropBox.upperRight = (output_page_width * 2, output_page_height)

    return page_left, page_right


def main():
    if len(sys.argv) < 2:
        sys.exit('You must specify a file path for the pdf file.')

    file_input = get_file_input(sys.argv[1])
    output = PdfFileWriter()

    for i in range(file_input.getNumPages()):
        print 'Splitting page {} into {} and {}'.format(i, i * 2, i * 2 + 1)
        page_left, page_right = get_pages(file_input.getPage(i))
        output.addPage(page_left)
        output.addPage(page_right)

    print 'Saving new file as output.pdf'
    output_stream = file('output.pdf', 'wb')
    output.write(output_stream)
    output_stream.close()

if __name__ == "__main__":
    main()