main.py

import os
import sys
from pathlib import Path
import argparse
import pycpdflib

__version__ = '1.0.7'
__package_name__ = 'booklet'

INCHES_PER_POINT = 72
PAPER_SIZES = {
    'LTR': {'w': 11, 'h': 8.5},
    '11x17': {'w': 11, 'h': 17},
}

if sys.platform.startswith('win32') or sys.platform.startswith('cygwin'):
    lib_path = Path(getattr(sys, '_MEIPASS', Path.cwd()))
    os.add_dll_directory(str(lib_path / "libcpdf"))
    pycpdflib.loadDLL("libpycpdf.dll")
else:
    print("This platform is not supported.")
    sys.exit(1)


def get_basename_file(file_path):
    path = Path(file_path)
    return path.parent / path.stem


def booklet_pdf(data):
    pdf_file = data['input_pdf']
    output_file = data['output_pdf'] if data['output_pdf'] else str(get_basename_file(pdf_file)) + "_booklet.pdf"
    hp = data.get('hp', False)
    resize_only = data.get('resize_only', False)
    ltr = data.get('ltr', False)
    paper = data.get('paper', 'LTR')

    source_pdf = pycpdflib.fromFile(pdf_file, '')
    pdf_range = pycpdflib.all(source_pdf)

    total_pages = pycpdflib.pages(source_pdf)
    paper_size = PAPER_SIZES.get(paper, False)

    if not paper_size:
        print("Invalid paper size")
        sys.exit(1)

    desired_width_in_inch = paper_size.get('w')
    desired_height_in_inch = paper_size.get('h')

    #      rotate page size and split width in half
    if paper_size.get('h') > paper_size.get('w'):
        desired_width_in_inch = paper_size.get('h')
        desired_height_in_inch = paper_size.get('w')

    desired_width_in_inch = desired_width_in_inch / 2

    print("_______________")
    print('Desired width per page: ' + str(desired_width_in_inch))
    print('Desired height per page: ' + str(desired_height_in_inch))
    print("_______________")

    desired_width = desired_width_in_inch * INCHES_PER_POINT
    desired_height = desired_height_in_inch * INCHES_PER_POINT

    # iterate over each page and calculate the scale factor
    page_scales = []
    for page_num in range(1, total_pages + 1):
        pdf_size = pycpdflib.getMediaBox(source_pdf, page_num)
        pdf_width = pdf_size[1]
        pdf_height = pdf_size[3]

        page_scale = (desired_width / pdf_width, desired_height / pdf_height)
        page_scales.append(page_scale)

    page_scales = get_identical_ranges(page_scales)
    print(page_scales)

    # iterate over each page and apply the scale factor
    for page_rage, page_scale in page_scales:
        pycpdflib.scalePages(source_pdf, page_rage, page_scale[0], page_scale[1])

    remainder = total_pages % 4
    blank_pages = 0 if remainder == 0 else 4 - remainder

    # add blank pages
    for blankPage in range(total_pages, total_pages + blank_pages):
        pycpdflib.padAfter(source_pdf, [blankPage])

    # create page order
    pages = list(range(1, (total_pages + blank_pages + 1)))
    page_order = []

    while pages:
        page_order.append(pages.pop())
        page_order.append(pages.pop(0))
        page_order.append(pages.pop(0))
        page_order.append(pages.pop())

    if hp:
        print("hp mode is running")
        page_order = hp_sort(page_order)

    if not resize_only:
        source_pdf = pycpdflib.selectPages(source_pdf, page_order)
        pycpdflib.impose(source_pdf, 2, 1, False, False, (not ltr), False, False, False, False, False)

    pycpdflib.toFile(source_pdf, output_file, False, False)

    print("Resized PDF to", output_file)


def get_identical_ranges(data):
    results = []
    start_index = 0
    for i in range(1, len(data)):
        if data[i] != data[start_index]:
            if i - start_index >= 1:
                results.append((list(range(start_index + 1, i + 1)), data[start_index]))
            start_index = i
    if len(data) - start_index >= 1:  # check the last sequence
        results.append((list(range(start_index + 1, len(data) + 1)), data[start_index]))
    return results


def hp_sort(arr):
    # splitting list into sub-lists of 4 elements
    sub_lists = [arr[i:i + 4] for i in range(0, len(arr), 4)]

    # reversing order of sub-lists
    sub_lists = sub_lists[::-1]

    # flattening list of sub-lists into one list
    flipped_arr = [item for sublist in sub_lists for item in sublist]

    return flipped_arr


if __name__ == '__main__':
    parser = argparse.ArgumentParser(prog=__package_name__, description='Convert pdf to booklet')
    parser.add_argument('input_pdf', type=str, help='Path to the input pdf file')
    parser.add_argument('output_pdf', type=str, help='Path to the output pdf file', nargs='?')
    parser.add_argument('--hp', help='HP mode', action='store_true')
    parser.add_argument('--ltr', help='left to right', action='store_true')
    parser.add_argument('--resize_only', help='just resize, no booklet', action='store_true')
    parser.add_argument('--paper', type=str, help='Specify paper size. Available options: LTR, 11x17',
                        choices=['LTR', '11x17'], default='LTR')

    args = parser.parse_args()
    data = vars(args)

    booklet_pdf(data)