chessground

Description:

chessground

Chessground is a chessboard package developed for lichess.org. It doesn't handle
chess logic so you can use it with different chess variants.
Features #

pieces animations: moving and fading away
board highlights: last move, piece destinations
move piece by tap or drag and drop
premoves
displays a shadow under dragged piece to indicate the drop square target
board themes
piece sets from lichess
promotion selector
draw shapes on board while playing using 2 fingers
move annotations
opponent's pieces can be displayed upside down
create positions with a board editor

Getting started #
This package exports a Chessboard widget which can be interactable or not.
It is configurable with a ChessboardSettings object which defines the board
behavior and appearance.
To interact with the board in order to play a game, you must provide a GameData
object to the Chessboard widget. This object is immutable and contains the game
state (which side is to move, the current valid moves, etc.), along with the
callback functions to handle user interactions.
All chess logic must be handled outside of this package. Any change in the state
of the game needs to be transferred to the board by creating a new GameData object.
Usage #
This will display a non-interactable board from the starting position, using the
default theme:
import 'package:flutter/material.dart';
import 'package:chessground/chessground.dart';

class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);

@override
State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
String fen = 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR';

@override
Widget build(BuildContext context) {
final double screenWidth = MediaQuery.of(context).size.width;

return Scaffold(
appBar: AppBar(
title: const Text('Chessground demo'),
),
body: Center(
child: Chessboard.fixed(
size: screenWidth,
orientation: Side.white,
fen: fen,
),
),
);
}
}
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See the example app for:

Random Bot: an interactable board for one player playing against a random bot,
Free Play: an interactable board for two players sitting opposite to each other,
Board editor: a board editor to create positions,
Draw Shapes: activate the draw shapes feature and draw on the board using 2
Board Thumbnails: a demo screen showing over hundred different boards in a grid,
fingers.