lila-gif

Webservice to render Gifs of chess positions and games, and stream them frame by frame.

size	render time	frames	colors	width	height
336 KiB	~60 ms	93	63	720 px	840 px

Usage

lila-gif

USAGE:
    lila-gif [OPTIONS]

OPTIONS:
        --bind <BIND>    Listen on this address [default: 127.0.0.1:6175]
    -h, --help           Print help information

HTTP API

GET /image.gif

curl "http://localhost:6175/image.gif?fen=4k3/6KP/8/8/8/8/7p/8" --output image.gif

name	type	default	description
fen	ascii	starting position	FEN of the position. Board part is sufficient.
white	utf-8	none	Name of the white player. Known chess titles are highlighted. Limited to 100 bytes.
black	utf-8	none	Name of the black player. Known chess titles are highlighted. Limited to 100 bytes.
comment	utf-8	https://github.com/lichess-org/lila-gif	Comment to be added to GIF meta data. Limited to 255 bytes.
lastMove	ascii	none	Last move in UCI notation (like e2e4).
check	ascii	none	Square of king in check (like e1).
orientation		white	Pass black to flip the board.
theme		brown	Board theme. blue, brown, green, ic, pink, or purple.
piece		cburnett	Piece set from this list.

POST /game.gif

{
  "white": "Molinari", // optional
  "black": "Bordais", // optional
  "comment": "https://www.chessgames.com/perl/chessgame?gid=1251038", // optional
  "orientation": "white", // default
  "theme": "brown", // default
  "piece": "cburnett", // default
  "delay": 50, // default frame delay in centiseconds
  "frames": [
    // [...]
    {
      "fen": "r1bqkb1r/pp1ppppp/5n2/2p5/2P1P3/2Nn2P1/PP1PNP1P/R1BQKB1R w KQkq - 1 6",
      "delay": 500, // optionally overwrite default delay
      "lastMove": "b4d3", // optionally highlight last move
      "check": "e1" // optionally highlight king
    }
  ]
}

GET /example.gif

curl http://localhost:6175/example.gif --output example.gif

Render an example game.

Technique

Instead of rendering vector graphics at runtime, all pieces are prerendered on every possible background. This allows preparing a minimal color palette ahead of time. (Pieces are not just black and white, but need other colors for anti-aliasing on the different background colors).

All thats left to do at runtime, is copying sprites and Gif encoding. More than 95% of the rendering time is spent in LZW compression.

For animated games, frames only contain the changed squares on transparent background. The example below is the last frame of the animation.

License

lila-gif is licensed under the GNU Affero General Public License, version 3 or any later version, at your option.

The generated images include text in Noto Sans (Apache License 2.0) and a pieces sets with various licenses.