Sphinx extension to render emojis in XeLaTeX using emojicdn

emoji.py

import requests
import pathlib
import os
import re
from sphinx.util import logging

logger = logging.getLogger(__name__)


def emoji_to_identifier(emoji):
    return ord(emoji)


def parse_emoji_whitelist(whitelist):
    emoji = []
    for entry in whitelist:
        from_, _, to = entry.partition(":")
        if not to:
            to = from_
        emoji.extend([
            chr(c) for c in range(ord(from_), ord(to)+1)
        ])
    return emoji


def ensure_emoji_cache(cache_path, emoji, style):
    for symbol in emoji:
        # Find name of emoji
        symbol_path = cache_path / f"{emoji_to_identifier(symbol)}.png"
        if symbol_path.exists():
            continue

        logger.info(f"Could not find emoji: {symbol}, downloading...")

        # Request from CDN
        symbol_quote = requests.utils.quote(symbol)
        response = requests.get(
            f"https://emojicdn.elk.sh/{symbol_quote}",
            params={"style": style}
        )
        with symbol_path.open("wb") as f:
            f.write(response.content)


def update_latex_preamble(cache_path, emoji, config):    
    include = r"""
\usepackage{newunicodechar}
"""
    cache_command = rf"""
\providecommand{{\emojicachepath}}[1]{{{cache_path}/#1}}
"""
    emoji_command = r"""    
\newcommand{\staticemoji}[1]{%
    \bgroup\raisebox{-0.15em}{%
      \includegraphics[height=1em]{\emojicachepath{#1}}%
    }\egroup%
}
"""
    # Translate unicode into \includegraphics commands
    declarations = [
        rf"\newunicodechar{{{x}}}{{\staticemoji{{{emoji_to_identifier(x)}}}}}"
        for x in emoji
    ]

    preamble = include + cache_command + emoji_command + "\n".join(declarations)
    config['latex_elements']['preamble'] = config['latex_elements'].get('preamble', '') + preamble


def setup_emoji_cache(app, config):
    cache_path = pathlib.Path(config.emoji_cache).absolute()
    cache_path.mkdir(exist_ok=True, parents=True)

    emoji = parse_emoji_whitelist(config.emoji_whitelist)
    ensure_emoji_cache(cache_path, emoji, config.emoji_style)
    update_latex_preamble(cache_path, emoji, config)


def setup(app):
    app.add_config_value("emoji_whitelist", [], "html", [list])
    app.add_config_value("emoji_cache", ".emoji", "html", [str, bytes, os.PathLike])
    app.add_config_value("emoji_style", "google", "html", [str])
    app.connect('config-inited', setup_emoji_cache)

Inspired by https://github.com/mreq/xelatex-emoji/

Only supports single-codepoint emoji