Add piece shape from mono assets

lib/src/models.dart

@@ -13,7 +13,23 @@ enum Side {
 enum InteractableSide { both, none, white, black }
 
 /// Piece role, such as pawn, knight, etc.
-enum Role { king, queen, knight, bishop, rook, pawn }
+enum Role {
+  king,
+  queen,
+  knight,
+  bishop,
+  rook,
+  pawn;
+
+  String get letter => switch (this) {
+        Role.king => 'K',
+        Role.queen => 'Q',
+        Role.knight => 'N',
+        Role.bishop => 'B',
+        Role.rook => 'R',
+        Role.pawn => 'P',
+      };
+}
 
 /// Piece kind, such as white pawn, black knight, etc.
 enum PieceKind {
@@ -413,3 +429,34 @@ class Arrow implements Shape {
   @override
   int get hashCode => Object.hash(color, orig, dest);
 }
+
+@immutable
+class PieceShape implements Shape {
+  final Color color;
+  final Role role;
+  final SquareId orig;
+
+  const PieceShape({
+    required this.color,
+    required this.role,
+    required this.orig,
+  });
+
+  @override
+  Shape newDest(SquareId newDest) {
+    return this;
+  }
+
+  @override
+  bool operator ==(Object other) {
+    return identical(this, other) ||
+        other is PieceShape &&
+            other.runtimeType == runtimeType &&
+            other.color == color &&
+            other.role == role &&
+            other.orig == orig;
+  }
+
+  @override
+  int get hashCode => Object.hash(color, role, orig);
+}

lib/src/widgets/board.dart

@@ -244,13 +244,13 @@ class _BoardState extends State<Board> {
         for (final shape in shapes)
           ShapeWidget(
             shape: shape,
-            size: widget.size,
+            boardSize: widget.size,
             orientation: widget.data.orientation,
           ),
         if (_shapeAvatar != null)
           ShapeWidget(
             shape: _shapeAvatar!,
-            size: widget.size,
+            boardSize: widget.size,
             orientation: widget.data.orientation,
           ),
       ],

lib/src/widgets/shape.dart

@@ -2,41 +2,62 @@ import 'dart:math' as math;
 import 'package:flutter/widgets.dart';
 
 import '../models.dart';
+import 'positioned_square.dart';
 
 class ShapeWidget extends StatelessWidget {
   const ShapeWidget({
     super.key,
     required this.shape,
-    required this.size,
+    required this.boardSize,
     required this.orientation,
   });
 
   final Shape shape;
-  final double size;
+  final double boardSize;
   final Side orientation;
 
+  double get squareSize => boardSize / 8;
+
   @override
   Widget build(BuildContext context) {
-    return SizedBox.square(
-      dimension: size,
-      child: CustomPaint(
-        painter: switch (shape) {
-          Arrow(
-            color: final color,
-            orig: final orig,
-            dest: final dest,
-          ) =>
-            _ArrowPainter(
+    return switch (shape) {
+      Arrow(
+        color: final color,
+        orig: final orig,
+        dest: final dest,
+      ) =>
+        SizedBox.square(
+          dimension: boardSize,
+          child: CustomPaint(
+            painter: _ArrowPainter(
               color,
               orientation,
               Coord.fromSquareId(orig),
               Coord.fromSquareId(dest),
             ),
-          Circle(color: final color, orig: final orig) =>
-            _CirclePainter(color, orientation, Coord.fromSquareId(orig)),
-        },
-      ),
-    );
+          ),
+        ),
+      Circle(color: final color, orig: final orig) => SizedBox.square(
+          dimension: boardSize,
+          child: CustomPaint(
+            painter:
+                _CirclePainter(color, orientation, Coord.fromSquareId(orig)),
+          ),
+        ),
+      PieceShape(orig: final orig, role: final role, color: final color) =>
+        PositionedSquare(
+          size: squareSize,
+          orientation: orientation,
+          squareId: orig,
+          child: Image.asset(
+            'assets/piece_sets/mono/${role.letter}.png',
+            package: 'chessground',
+            color: color,
+            width: squareSize,
+            height: squareSize,
+          ),
+        ),
+    };
   }
 }
 

pubspec.yaml

@@ -47,6 +47,7 @@ flutter:
     - assets/piece_sets/libra/
     - assets/piece_sets/maestro/
     - assets/piece_sets/merida/
+    - assets/piece_sets/mono/
     - assets/piece_sets/mpchess/
     - assets/piece_sets/pirouetti/
     - assets/piece_sets/pixel/