Generate inkscape / gimp palettes from seaborn and matplotlib color maps

colorblind.gpl

GIMP Palette
Name: colorblind (seaborn)
Columns: 0
#
1 115 178
35 176 253
145 215 254
222 143 5
250 185 70
252 220 162
2 158 115
24 252 189
139 253 222
213 94 0
255 144 57
255 199 156
204 120 188
221 164 210
238 210 232
202 145 97
219 181 149
237 218 202
251 175 228
252 201 237
253 228 246
148 148 148
183 183 183
219 219 219
236 225 51
242 235 119
248 244 187
86 180 233
142 205 240
198 230 247

seaborn_inkscape_palette.py

#!/usr/bin/env python

import argparse
import sys
from colorsys import hls_to_rgb, rgb_to_hls
from pathlib import Path

import numpy as np
import seaborn as sns
from matplotlib.colors import ListedColormap
from webcolors import hex_to_rgb


def to_hsl(rgb):
    rgb = [c / 255 for c in rgb]
    h, l, s = rgb_to_hls(*rgb)
    return h, s, l


def to_rgb(hsl):
    h, s, l = hsl
    return [int(c * 255) for c in hls_to_rgb(h, l, s)]


def write_rgb(f, rgb, name=None):
    f.write(" ".join(map(str, rgb)))
    if name is not None:
        f.write(" ")
        f.write(name)
    f.write("\n")


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-o", "--out", help="Palette file")
    parser.add_argument(
        "-p", "--palette", default="colorblind", help="Seaborn palette name"
    )
    parser.add_argument("-n", "--name", help="Inkscape palette name")
    args = parser.parse_args()

    out = args.out
    palette_name = args.palette
    out_name = args.name

    if out is None:
        out = f"~/.config/inkscape/palettes/{palette_name}.gpl"
    out = Path(out).expanduser()
    out.parent.mkdir(parents=True, exist_ok=True)

    if out_name is None:
        out_name = f"{palette_name} (seaborn)"

    cmap = sns.color_palette(palette_name, as_cmap=True)
    if isinstance(cmap, list):
        cmap = ListedColormap(cmap)

    if not isinstance(cmap, ListedColormap):
        sys.exit("Color map needs to be qualitative")

    with out.open("w") as f:
        f.write(f"GIMP Palette\nName: {out_name}\nColumns: 0\n#\n")

        for hexcolor in cmap.colors:
            rgb = hex_to_rgb(hexcolor)
            write_rgb(f, rgb)

            h, s, l = to_hsl(rgb)
            # Exclude the original luminance and full white
            for l_ in np.linspace(l, 1.0, num=4)[1:-1]:
                write_rgb(f, to_rgb((h, s, l_)))


if __name__ == "__main__":
    main()