A script to set the stroke width in a Xournal++ document as a percentage of the current width

xoppwidth.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# xoppwidth.py is a simple Python script to set the stroke width in
# a Xournal++ .xopp document as a percentage of the current stroke
# width.  For instance, to double the stroke width, run
#
#   xoppwidth.py -w 200 -o output.xopp input.xopp
#
# For a detailed description of the options, run
#
#   xoppwidth.py --help
#
# This script was written because Xournal++ currently doesn't provide
# a way to set the stroke width [1, 2] as a floating point.
#
# [1]: https://github.com/xournalpp/xournalpp/issues/1361
# [2]: https://github.com/xournalpp/xournalpp/issues/1998
#

from __future__ import print_function

import argparse
import gzip
import os
import sys
import xml.etree.ElementTree as ET


def stroke_width(name, output=None, percent=100.0):
    """Set the stroke width to the given percentage."""
    with gzip.open(name, "rb") as fd:
        tree = ET.fromstring(fd.read())

    for stroke in tree.iter("stroke"):
        if stroke.attrib.get("tool", "") in ("pen", "highlighter"):
            width = list()
            for w in stroke.attrib["width"].split(" "):
                width.append("{:.8f}".format(float(w) * 0.01 * percent))

            stroke.set("width", " ".join(width))

    if output is None:
        output = os.path.splitext(name)[0] + "_w{:d}.xopp".format(int(percent))
    with gzip.open(output, "wb") as fd:
        fd.write(ET.tostring(tree, encoding="UTF-8"))

    print("output written to {}".format(output), file=sys.stderr)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        prog="xoppwidth", description="set the stroke width in a Xournal++ document"
    )
    parser.add_argument("name", help="input files", metavar="FILE")
    parser.add_argument(
        "-o", "--output", default=None, help="output file", metavar="FILE"
    )
    parser.add_argument(
        "-w",
        "--width",
        default=100.0,
        help="width as percentage of current width",
        metavar="PERCENT",
        type=float,
    )
    args = parser.parse_args()
    sys.exit(stroke_width(args.name, args.output, args.width))