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import asyncio
import hashlib
import pathlib
import re
from concurrent.futures import ThreadPoolExecutor
from io import BytesIO
import discord
import matplotlib.pyplot as plt
from discord.ext import commands
# configure fonts and colors for matplotlib
plt.rcParams.update(
{
"font.size": 16,
"mathtext.fontset": "cm", # Computer Modern font set
"mathtext.rm": "serif",
"figure.facecolor": "36393F", # matches Discord's dark mode background color
"text.color": "white",
}
)
FORMATTED_CODE_REGEX = re.compile(
r"(?P<delim>(?P<block>```)|``?)" # code delimiter: 1-3 backticks; (?P=block) only matches if it's a block
r"(?(block)(?:(?P<lang>[a-z]+)\n)?)" # if we're in a block, match optional language (only letters plus newline)
r"(?:[ \t]*\n)*" # any blank (empty or tabs/spaces only) lines before the code
r"(?P<code>.*?)" # extract all code inside the markup
r"\s*" # any more whitespace before the end of the code markup
r"(?P=delim)", # match the exact same delimiter from the start again
re.DOTALL | re.IGNORECASE, # "." also matches newlines, case insensitive
)
CACHE_DIRECTORY = pathlib.Path("_latex_cache")
CACHE_DIRECTORY.mkdir(exist_ok=True)
class Latex(commands.Cog):
"""Renders latex."""
@staticmethod
def _render(text: str, filepath: pathlib.Path) -> BytesIO:
"""
Return the rendered image if latex compiles without errors, otherwise raise a BadArgument Exception.
Saves rendered image to cache.
"""
fig = plt.figure()
rendered_image = BytesIO()
fig.text(0, 1, text, horizontalalignment="left", verticalalignment="top")
try:
plt.savefig(rendered_image, bbox_inches="tight", dpi=600)
except ValueError as e:
raise commands.BadArgument(str(e))
rendered_image.seek(0)
with open(filepath, "wb") as f:
f.write(rendered_image.getbuffer())
return rendered_image
@staticmethod
def _prepare_input(text: str) -> str:
text = text.replace(r"\\", "$\n$") # matplotlib uses \n for newlines, not \\
if match := FORMATTED_CODE_REGEX.match(text):
return match.group("code")
else:
return text
@commands.command()
@commands.max_concurrency(1, commands.BucketType.guild, wait=True)
async def latex(self, ctx: commands.Context, *, text: str) -> None:
"""Renders the text in latex and sends the image."""
text = self._prepare_input(text)
query_hash = hashlib.md5(text.encode()).hexdigest()
image_path = CACHE_DIRECTORY.joinpath(f"{query_hash}.png")
async with ctx.typing():
if image_path.exists():
await ctx.send(file=discord.File(image_path))
return
with ThreadPoolExecutor() as pool:
image = await asyncio.get_running_loop().run_in_executor(
pool, self._render, text, image_path
)
await ctx.send(file=discord.File(image, "latex.png"))
def setup(bot: commands.Bot) -> None:
"""Load the Latex Cog."""
bot.add_cog(Latex(bot))
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