feat: Adding group to flame fire atlas (#3245)

packages/flame_fire_atlas/lib/flame_fire_atlas.dart

@@ -73,7 +73,7 @@ abstract class BaseSelection {
   final Selection _info;
 
   /// {@macro _base_selection}
-  BaseSelection(this._info);
+  BaseSelection(this._info, {this.group});
 
   /// The id of the selection.
   String get id => _info.id;
@@ -90,14 +90,21 @@ abstract class BaseSelection {
   /// The height of the selection.
   int get h => _info.h;
 
+  /// A group that this selection belongs to.
+  final String? group;
+
+  /// Copies this instance with a new group.
+  BaseSelection copyWithGroup(String? group);
+
   /// Returns this instance as a json.
   Map<String, dynamic> toJson() {
     final json = <String, dynamic>{}
       ..['id'] = id
       ..['x'] = x
       ..['y'] = y
       ..['w'] = w
-      ..['h'] = h;
+      ..['h'] = h
+      ..['group'] = group;
 
     return json;
   }
@@ -110,20 +117,28 @@ class SpriteSelection extends BaseSelection {
   /// {@macro _sprite_selection}
   SpriteSelection({
     required Selection info,
+    super.group,
   }) : super(info);
 
   /// Creates a [SpriteSelection] from [json].
   @override
   factory SpriteSelection.fromJson(Map<String, dynamic> json) {
     final info = Selection.fromJson(json);
-    return SpriteSelection(info: info);
+    final group = json['group'] as String?;
+    return SpriteSelection(info: info, group: group);
   }
 
   /// Returns this instance as a json.
   @override
   Map<String, dynamic> toJson() {
     return super.toJson()..['type'] = 'sprite';
   }
+
+  /// Copies this instance with a new group.
+  @override
+  SpriteSelection copyWithGroup(String? group) {
+    return SpriteSelection(info: _info, group: group);
+  }
 }
 
 /// {@template _animation_selection}
@@ -145,18 +160,21 @@ class AnimationSelection extends BaseSelection {
     required this.frameCount,
     required this.stepTime,
     required this.loop,
+    super.group,
   }) : super(info);
 
   /// Creates a [AnimationSelection] from [json].
   @override
   factory AnimationSelection.fromJson(Map<String, dynamic> json) {
     final info = Selection.fromJson(json);
+    final group = json['group'] as String?;
 
     return AnimationSelection(
       info: info,
       frameCount: json['frameCount'] as int,
       stepTime: json['stepTime'] as double,
       loop: json['loop'] as bool,
+      group: group,
     );
   }
 
@@ -169,6 +187,18 @@ class AnimationSelection extends BaseSelection {
       ..['loop'] = loop
       ..['type'] = 'animation';
   }
+
+  /// Copies this instance with a new group.
+  @override
+  AnimationSelection copyWithGroup(String? group) {
+    return AnimationSelection(
+      info: _info,
+      frameCount: frameCount,
+      stepTime: stepTime,
+      loop: loop,
+      group: group,
+    );
+  }
 }
 
 /// FireAtlas is a mapping file that can hold several [Sprite]s and

packages/flame_fire_atlas/test/flame_fire_atlas_test.dart

@@ -170,5 +170,148 @@ void main() {
         verify(() => game.images.fromBase64(any(), any())).called(1);
       },
     );
+
+    group('SpriteSelection', () {
+      test('can be created from a json', () async {
+        final sprite = SpriteSelection.fromJson({
+          'id': 'kinetic_bullet',
+          'x': 0,
+          'y': 0,
+          'w': 16,
+          'h': 16,
+          'group': 'bullets',
+        });
+        expect(sprite.id, 'kinetic_bullet');
+        expect(sprite.x, 0);
+        expect(sprite.y, 0);
+        expect(sprite.w, 16);
+        expect(sprite.h, 16);
+        expect(sprite.group, 'bullets');
+      });
+
+      test('serializes to json', () async {
+        final sprite = SpriteSelection(
+          info: Selection(
+            id: 'kinetic_bullet',
+            x: 0,
+            y: 0,
+            w: 16,
+            h: 16,
+          ),
+          group: 'bullets',
+        );
+        final json = sprite.toJson();
+        expect(json['id'], 'kinetic_bullet');
+        expect(json['x'], 0);
+        expect(json['y'], 0);
+        expect(json['w'], 16);
+        expect(json['h'], 16);
+        expect(json['group'], 'bullets');
+      });
+
+      group('copyWithGroup', () {
+        test('creates a copy with a new group', () async {
+          final sprite = SpriteSelection(
+            info: Selection(
+              id: 'kinetic_bullet',
+              x: 0,
+              y: 0,
+              w: 16,
+              h: 16,
+            ),
+            group: 'bullets',
+          );
+
+          final copy = sprite.copyWithGroup('new_group');
+          expect(copy.group, 'new_group');
+          expect(copy.id, 'kinetic_bullet');
+          expect(copy.x, 0);
+          expect(copy.y, 0);
+          expect(copy.w, 16);
+          expect(copy.h, 16);
+        });
+      });
+    });
+
+    group('AnimationSelection', () {
+      test('can be created from a json', () async {
+        final animation = AnimationSelection.fromJson({
+          'id': 'bomb_ptero',
+          'frameCount': 1,
+          'stepTime': .2,
+          'loop': true,
+          'x': 0,
+          'y': 0,
+          'w': 16,
+          'h': 16,
+          'group': 'enemies',
+        });
+
+        expect(animation.id, 'bomb_ptero');
+        expect(animation.frameCount, 1);
+        expect(animation.stepTime, .2);
+        expect(animation.loop, isTrue);
+        expect(animation.x, 0);
+        expect(animation.y, 0);
+        expect(animation.w, 16);
+        expect(animation.h, 16);
+        expect(animation.group, 'enemies');
+      });
+
+      test('serializes to json', () async {
+        final animation = AnimationSelection(
+          info: Selection(
+            id: 'bomb_ptero',
+            x: 0,
+            y: 0,
+            w: 16,
+            h: 16,
+          ),
+          frameCount: 1,
+          stepTime: .2,
+          loop: true,
+          group: 'enemies',
+        );
+        final json = animation.toJson();
+        expect(json['id'], 'bomb_ptero');
+        expect(json['frameCount'], 1);
+        expect(json['stepTime'], .2);
+        expect(json['loop'], isTrue);
+        expect(json['x'], 0);
+        expect(json['y'], 0);
+        expect(json['w'], 16);
+        expect(json['h'], 16);
+        expect(json['group'], 'enemies');
+      });
+
+      group('copyWithGroup', () {
+        test('creates a copy with a new group', () async {
+          final animation = AnimationSelection(
+            info: Selection(
+              id: 'bomb_ptero',
+              x: 0,
+              y: 0,
+              w: 16,
+              h: 16,
+            ),
+            frameCount: 1,
+            stepTime: .2,
+            loop: true,
+            group: 'enemies',
+          );
+
+          final copy = animation.copyWithGroup('new_group');
+          expect(copy.group, 'new_group');
+          expect(copy.id, 'bomb_ptero');
+          expect(copy.frameCount, 1);
+          expect(copy.stepTime, .2);
+          expect(copy.loop, isTrue);
+          expect(copy.x, 0);
+          expect(copy.y, 0);
+          expect(copy.w, 16);
+          expect(copy.h, 16);
+        });
+      });
+    });
   });
 }