gifchess.py

#!/usr/bin/env python3

# sudo apt-get install libcairo2
# pip install requests python-chess Pillow CairoSVG

import io
import sys
import time

import cairosvg
import chess.pgn
import chess.svg
import requests

from PIL import Image

def fetch_pgn(game_id):
    r = requests.get('https://lichess.org/game/export/' + game_id)
    assert r.ok, r.content
    return r.content.decode('utf8').strip()

def board_to_png(board, move=None):
    check = None
    if board.is_check():
        check = board.king(board.turn)
    b = chess.svg.board(board, lastmove=move, coordinates=False, check=check)
    return cairosvg.svg2png(b)

def export_gif(images, fname):
    duration = [450] * len(images)
    duration[-1] = 2000
    images[0].save(fname, format='GIF', append_images=images[1:], save_all=True, duration=duration, loop=0)

def main(args):
    pgn = fetch_pgn(args[0])
    game = chess.pgn.read_game(io.StringIO(pgn))
    assert game.headers['Variant'] == 'Standard'

    board = game.board()

    png = board_to_png(board)

    images = []
    im = Image.open(io.BytesIO(png))
    images.append(im)

    for i, move in enumerate(game.mainline_moves()):
        board.push(move)

        png = board_to_png(board, move)
        im = Image.open(io.BytesIO(png))
        images.append(im)

    export_gif(images, args[1])


if __name__ == '__main__':
    main(sys.argv[1:])