set_pdf_dir.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
set_pdf_dir.py

Set direction and/or page layout properties of PDF files.

Usage:
$ ./set_pdf_dir.py -l r2l -d book -o my_pdf_1.pdf my_pdf_2.pdf

"""
import argparse
from enum import Enum
from pathlib import Path

import pikepdf


class Direction(Enum):
    R2L = "/R2L"
    L2R = "/L2R"


class PageLayout(Enum):
    SinglePage = "/SinglePage"
    OneColumn = "/OneColumn"
    TwoPageLeft = "/TwoPageLeft"
    TwoPageRight = "/TwoPageRight"
    TwoColumnLeft = "/TwoColumnLeft"
    TwoColumnRight = "/TwoColumnRight"


def set_direction(doc, d):
    doc.root.ViewerPreferences = pikepdf.Dictionary(
        {
            "/Direction": pikepdf.Name(d.value),
        }
    )


def set_layout(doc, pl):
    doc.root.PageLayout = pikepdf.Name(pl.value)


cmd_arg_dir = {
    "r2l": Direction.R2L,
    "l2r": Direction.L2R,
}

cmd_arg_layout = {
    "single": PageLayout.SinglePage,
    "facing": PageLayout.TwoPageLeft,
    "book": PageLayout.TwoPageRight,
}


parser = argparse.ArgumentParser(
    description="Set direction / page layout for PDF files."
)
parser.add_argument(
    "--direction", "-d", choices=list(cmd_arg_dir.keys()), help="page direction"
)
parser.add_argument(
    "--layout", "-l", choices=list(cmd_arg_layout.keys()), help="page layout"
)
parser.add_argument(
    "--overwrite",
    "-o",
    action="store_true",
    default=False,
    help="overwrite existing file",
)
parser.add_argument("input_files", type=Path, nargs="+", help="input PDF files")

args = parser.parse_args()

for f in args.input_files:
    if f.suffix.lower() != ".pdf":
        continue
    print('processing "{}"'.format(f))
    doc = pikepdf.Pdf.open(f, allow_overwriting_input=args.overwrite)
    if args.direction:
        set_direction(doc, cmd_arg_dir[args.direction])
    if args.layout:
        set_layout(doc, cmd_arg_layout[args.layout])
    if args.overwrite:
        doc.save()
    else:
        doc.save(f.with_suffix(".modified.pdf"))