chore: SpriteAnimationWidget from pre release flame (#228)

packages/pinball_flame/lib/pinball_flame.dart

@@ -3,3 +3,4 @@ library pinball_flame;
 export 'src/blueprint.dart';
 export 'src/component_controller.dart';
 export 'src/keyboard_input_controller.dart';
+export 'src/sprite_animation.dart';

packages/pinball_flame/lib/src/sprite_animation.dart

@@ -0,0 +1,102 @@
+// ignore_for_file: public_member_api_docs
+
+import 'dart:math';
+
+import 'package:flame/components.dart';
+import 'package:flame/image_composition.dart';
+import 'package:flutter/material.dart' hide Animation;
+
+/// {@template flame.widgets.sprite_animation_widget}
+/// A [StatelessWidget] that renders a [SpriteAnimation].
+/// {@endtemplate}
+// TODO(arturplaczek): Remove when this PR will be merged.
+// https://github.com/flame-engine/flame/pull/1552
+class SpriteAnimationWidget extends StatelessWidget {
+  /// {@macro flame.widgets.sprite_animation_widget}
+  const SpriteAnimationWidget({
+    required this.controller,
+    this.anchor = Anchor.topLeft,
+    Key? key,
+  }) : super(key: key);
+
+  /// The positioning [Anchor].
+  final Anchor anchor;
+
+  final SpriteAnimationController controller;
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: controller,
+      builder: (_, __) {
+        return CustomPaint(
+          painter: SpritePainter(
+            controller.animation.getSprite(),
+            anchor,
+          ),
+        );
+      },
+    );
+  }
+}
+
+class SpriteAnimationController extends AnimationController {
+  SpriteAnimationController({
+    required TickerProvider vsync,
+    required this.animation,
+  }) : super(vsync: vsync) {
+    duration = Duration(seconds: animation.totalDuration().ceil());
+  }
+
+  final SpriteAnimation animation;
+
+  double? _lastUpdated;
+
+  @override
+  void notifyListeners() {
+    super.notifyListeners();
+
+    final now = DateTime.now().millisecond.toDouble();
+    final dt = max<double>(0, (now - (_lastUpdated ?? 0)) / 1000);
+    animation.update(dt);
+    _lastUpdated = now;
+  }
+}
+
+class SpritePainter extends CustomPainter {
+  SpritePainter(
+    this._sprite,
+    this._anchor, {
+    double angle = 0,
+  }) : _angle = angle;
+
+  final Sprite _sprite;
+  final Anchor _anchor;
+  final double _angle;
+
+  @override
+  bool shouldRepaint(SpritePainter oldDelegate) {
+    return oldDelegate._sprite != _sprite ||
+        oldDelegate._anchor != _anchor ||
+        oldDelegate._angle != _angle;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final boxSize = size.toVector2();
+    final rate = boxSize.clone()..divide(_sprite.srcSize);
+    final minRate = min(rate.x, rate.y);
+    final paintSize = _sprite.srcSize * minRate;
+    final anchorPosition = _anchor.toVector2();
+    final boxAnchorPosition = boxSize.clone()..multiply(anchorPosition);
+    final spriteAnchorPosition = anchorPosition..multiply(paintSize);
+
+    canvas
+      ..translateVector(boxAnchorPosition..sub(spriteAnchorPosition))
+      ..renderRotated(
+        _angle,
+        spriteAnchorPosition,
+        (canvas) => _sprite.render(canvas, size: paintSize),
+      );
+  }
+}

packages/pinball_flame/test/src/sprite_animation_test.dart

@@ -0,0 +1,74 @@
+import 'package:flame/components.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball_flame/pinball_flame.dart';
+
+class MockSpriteAnimationController extends Mock
+    implements SpriteAnimationController {}
+
+class MockSpriteAnimation extends Mock implements SpriteAnimation {}
+
+class MockSprite extends Mock implements Sprite {}
+
+// TODO(arturplaczek): Remove when this PR will be merged.
+// https://github.com/flame-engine/flame/pull/1552
+
+void main() {
+  group('PinballSpriteAnimationWidget', () {
+    late SpriteAnimationController controller;
+    late SpriteAnimation animation;
+    late Sprite sprite;
+
+    setUp(() {
+      controller = MockSpriteAnimationController();
+      animation = MockSpriteAnimation();
+      sprite = MockSprite();
+
+      when(() => controller.animation).thenAnswer((_) => animation);
+
+      when(() => animation.totalDuration()).thenAnswer((_) => 1);
+      when(() => animation.getSprite()).thenAnswer((_) => sprite);
+      when(() => sprite.srcSize).thenAnswer((_) => Vector2(1, 1));
+      when(() => sprite.srcSize).thenAnswer((_) => Vector2(1, 1));
+    });
+
+    testWidgets('renders correctly', (tester) async {
+      await tester.pumpWidget(
+        SpriteAnimationWidget(
+          controller: controller,
+        ),
+      );
+
+      await tester.pumpAndSettle();
+      await tester.pumpAndSettle();
+
+      expect(find.byType(SpriteAnimationWidget), findsOneWidget);
+    });
+
+    test('SpriteAnimationController is updating animations', () {
+      SpriteAnimationController(
+        vsync: const TestVSync(),
+        animation: animation,
+      ).notifyListeners();
+
+      verify(() => animation.update(any())).called(1);
+    });
+
+    testWidgets('SpritePainter shouldRepaint returns true when Sprite changed',
+        (tester) async {
+      final spritePainter = SpritePainter(
+        sprite,
+        Anchor.center,
+        angle: 45,
+      );
+
+      final anotherPainter = SpritePainter(
+        sprite,
+        Anchor.center,
+        angle: 30,
+      );
+
+      expect(spritePainter.shouldRepaint(anotherPainter), isTrue);
+    });
+  });
+}