#!/usr/bin/env python3
'''
svgtool — tiny SVG recolor + preview helper for fast logo
tweaking. Rendering goes through headless firefox so CSS
(masks, `prefers-color-scheme`, webfonts) is honored exactly
like the real docs.
Subcommands
-----------
colors SVG
list the distinct fill/stroke/stop colors in an svg.
recolor SVG OUT old=new [old=new ...]
literal-replace color tokens, write OUT (great for
swapping `.stN{fill:#aaa}` style values or hex codes).
preview SVG OUT.png [--bg C] [--w N] [--scheme light|dark]
render an svg alone on a bg colour (default white, or
#1a1a1a under --scheme dark) to eyeball transparency +
shape. --scheme forces `prefers-color-scheme`.
page URL_or_path OUT.png [--w N --h N] [--scheme light|dark]
screenshot a *built* html page (e.g. docs/_build/html/
index.html). --scheme dark|light forces the page's
color-scheme so a pydata `data-theme=auto` site renders
its dark/light variant — the way to verify theme-adaptive
logos without clicking the toggle.
Examples
--------
svgtool.py colors docs/_static/tractor_logo_side.svg
svgtool.py recolor in.svg out.svg '#FCFCFB=none' '#0A0A0A=#fff'
svgtool.py preview out.svg /tmp/p.png --bg '#ff00ff' --w 600
svgtool.py page docs/_build/html/index.html /tmp/dark.png \
--w 1300 --h 900 --scheme dark
'''
from __future__ import annotations
import argparse
from pathlib import Path
import re
import subprocess as sp
import tempfile
FF: str = 'firefox'
_color_re = re.compile(
r'(?:fill|stroke|stop-color)\s*[:=]\s*"?'
r'(#[0-9a-fA-F]{3,8}|none|transparent|currentColor)'
)
def _colors(text: str) -> list[str]:
return sorted(set(_color_re.findall(text)))
def _profile(scheme: str|None) -> str:
'''
Spin up a throwaway firefox profile, optionally forcing
`prefers-color-scheme` via the content-override pref
(0 = dark, 1 = light).
'''
d: str = tempfile.mkdtemp(prefix='svgtool-ff-')
if scheme:
val: int = {'dark': 0, 'light': 1}[scheme]
Path(d, 'user.js').write_text(
f'user_pref('
f'"layout.css.prefers-color-scheme.content-override",'
f' {val});\n'
)
return d
def _shot(
url: str,
out: str,
w: int,
h: int,
scheme: str|None,
) -> None:
prof: str = _profile(scheme)
sp.run(
[
FF, '--headless', '--no-remote',
'-profile', prof,
'--screenshot', str(out),
f'--window-size={w},{h}',
url,
],
stdout=sp.DEVNULL,
stderr=sp.DEVNULL,
timeout=90,
)
print(out)
def cmd_colors(a: argparse.Namespace) -> None:
print('\n'.join(_colors(Path(a.svg).read_text())))
def cmd_recolor(a: argparse.Namespace) -> None:
text: str = Path(a.svg).read_text()
for pair in a.pairs:
old, new = pair.split('=', 1)
if old not in text:
print(f' ! {old!r} not found (skipped)')
continue
text = text.replace(old, new)
Path(a.out).write_text(text)
print(f'wrote {a.out}')
def cmd_preview(a: argparse.Namespace) -> None:
bg: str = a.bg or (
'#1a1a1a' if a.scheme == 'dark' else '#ffffff'
)
src: str = Path(a.svg).resolve().as_uri()
html = Path(tempfile.mktemp(suffix='.html'))
html.write_text(
f''
f'
'
)
_shot(
html.resolve().as_uri(),
a.out,
a.w + 40,
int(a.w * 0.9),
a.scheme,
)
# early script that pins a pydata-sphinx-theme page to a given
# mode/theme (beats the localStorage/auto default) so headless
# shots can verify theme-adaptive content without the toggle.
_force_theme = (
''
)
def cmd_page(a: argparse.Namespace) -> None:
src = Path(a.url)
if a.theme and src.exists():
# inject the force-theme script into a sibling temp copy
# (same dir → relative _static/ asset paths still resolve).
html: str = src.read_text()
inj: str = _force_theme.format(t=a.theme)
html = re.sub(
r'(]*>)',
r'\1' + inj,
html,
count=1,
)
tmp = src.with_name(f'._svgtool_{a.theme}.html')
tmp.write_text(html)
try:
_shot(tmp.resolve().as_uri(), a.out, a.w, a.h, None)
finally:
tmp.unlink(missing_ok=True)
return
url: str = (
a.url
if '://' in a.url
else src.resolve().as_uri()
)
_shot(url, a.out, a.w, a.h, a.scheme)
def main() -> None:
p = argparse.ArgumentParser(prog='svgtool.py')
sub = p.add_subparsers(required=True)
c = sub.add_parser('colors')
c.add_argument('svg')
c.set_defaults(fn=cmd_colors)
r = sub.add_parser('recolor')
r.add_argument('svg')
r.add_argument('out')
r.add_argument('pairs', nargs='+')
r.set_defaults(fn=cmd_recolor)
v = sub.add_parser('preview')
v.add_argument('svg')
v.add_argument('out')
v.add_argument('--bg', default=None)
v.add_argument('--w', type=int, default=600)
v.add_argument(
'--scheme',
choices=['light', 'dark'],
default=None,
)
v.set_defaults(fn=cmd_preview)
g = sub.add_parser('page')
g.add_argument('url')
g.add_argument('out')
g.add_argument('--w', type=int, default=1300)
g.add_argument('--h', type=int, default=900)
g.add_argument(
'--scheme',
choices=['light', 'dark'],
default=None,
)
g.add_argument(
'--theme',
choices=['light', 'dark'],
default=None,
help='force a pydata data-theme (toggle-accurate)',
)
g.set_defaults(fn=cmd_page)
a = p.parse_args()
a.fn(a)
if __name__ == '__main__':
main()