Download and convert a lospec url to a Paint.NET palette.

lospec_to_paint.py

#! /usr/bin/env python

"""
Download and convert a lospec url to a Paint.NET palette.

CC0
"""

import argparse
import tempfile
import urllib.request
from pathlib import Path

MAX_COLORS = 96


def convert_palette(c):
    colours = c.strip().split()
    c_per_row = 16
    occupied_slots = c_per_row
    n_colours = len(colours)
    while occupied_slots < n_colours:
        occupied_slots += c_per_row
    # Add white to always start palette in first column.
    colours += ["FFFFFF"] * (occupied_slots - n_colours)

    # Choose variants based on how much space we have. Max 96 colours.
    alpha_variants = []
    n_variants = MAX_COLORS // len(colours)
    stride = 0x11 * (16 // n_variants)
    a = 0xFF
    while n_variants > 0:
        n_variants -= 1
        alpha_variants.append("{a:02X}".format(a=a))
        a -= stride

    return "\n".join([alpha + line for alpha in alpha_variants for line in colours])


def _parse_args():
    arg_parser = argparse.ArgumentParser(
        description="""Create a Paint.NET palette from lospec.""",
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )

    arg_parser.add_argument(
        "--url",
        help="The url of the palette.",
        type=str,
        required=True,
    )

    arg_parser.add_argument(
        "--output-folder",
        type=Path,
        help="Where to write the palette. <path to paint>/UserFiles/Palettes/. Defaults to path for paint installed with scoop.",
    )

    arg_parser.add_argument(
        "--output-name",
        type=str,
        help="Name of the output palette. Defaults to name from url.",
    )

    args = arg_parser.parse_args()
    if not args.url.endswith(".hex"):
        args.url += ".hex"

    i = args.url.rfind("/")
    name = args.url[i + 1 : -4] + ".txt"

    if not args.output_name:
        args.output_name = name

    if not args.output_folder:
        args.output_folder = (
            Path.home() / "scoop/apps/paint.net/current/UserFiles/Palettes/"
        )
        print(
            "Guessing scoop install. Selected output folder:",
            args.output_folder.as_posix(),
        )

    return args


def main(args):
    with tempfile.TemporaryDirectory() as tmpdir:
        tmp = Path(tmpdir) / "hex.txt"
        # Get the normal page first since it fails immediately if invalid.
        # Downloading the hex page may hang for a long time if you made a typo
        urllib.request.urlretrieve(args.url[:-4], tmp)
        urllib.request.urlretrieve(args.url, tmp)  # hex
        palette = convert_palette(tmp.read_text())
        output_file = args.output_folder / args.output_name
        print("Writing palette:", output_file.as_posix())
        output_file.write_text(palette)


if __name__ == "__main__":
    main(_parse_args())