lila-gif

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

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

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 piece set by Colin M.L. Burnett (GFDL or BSD or GPL).