Follow a Vector2 in Camera and add onPositionUpdate (#716)

* No setter for position and size

* Use setter for position and size

* Add onPositionUpdate and snapTo to Camera

* Fix formatting

* Fix size in test

* Update packages/flame/CHANGELOG.md

Co-authored-by: Jochum van der Ploeg <jochum@vdploeg.net>

* Update packages/flame/CHANGELOG.md

Co-authored-by: Jochum van der Ploeg <jochum@vdploeg.net>

* Better naming for internal position state

* Anchor and angle defaults on effect test utils

* No setter for position and size

* Fix scale effect

* Fix formatting

Co-authored-by: Jochum van der Ploeg <jochum@vdploeg.net>
Co-authored-by: Erick Zanardo <erickzanardoo@gmail.com>

examples/lib/commons/square_component.dart

@@ -6,9 +6,7 @@ import 'package:flame/palette.dart';
 class SquareComponent extends PositionComponent {
   Paint paint = BasicPalette.white.paint();
 
-  SquareComponent() {
-    size = Vector2.all(100.0);
-  }
+  SquareComponent() : super(size: Vector2.all(100.0));
 
   @override
   void render(Canvas c) {

examples/lib/stories/animations/basic.dart

@@ -59,8 +59,7 @@ class BasicAnimations extends BaseGame with TapDetector {
       removeOnFinish: true,
     );
 
-    animationComponent.position = position;
-    animationComponent.position = animationComponent.position - size / 2;
+    animationComponent.position = position - size / 2;
     add(animationComponent);
   }
 

examples/lib/stories/controls/draggables.dart

@@ -42,7 +42,7 @@ class DraggableSquare extends PositionComponent
     final localCoords = gameRef!.convertGlobalToLocalCoordinate(
       details.globalPosition.toVector2(),
     );
-    position = localCoords - dragDeltaPosition;
+    position.setFrom(localCoords - dragDeltaPosition);
     return false;
   }
 

examples/lib/stories/effects/combined_effect.dart

@@ -16,11 +16,11 @@ class CombinedEffectGame extends BaseGame with TapDetector {
   Future<void> onLoad() async {
     greenSquare = SquareComponent()
       ..paint = green
-      ..position = Vector2.all(100);
+      ..position.setValues(100, 100);
 
     redSquare = SquareComponent()
       ..paint = red
-      ..position = Vector2.all(100);
+      ..position.setValues(100, 100);
 
     add(greenSquare);
     add(redSquare);

examples/lib/stories/effects/infinite_effect.dart

@@ -15,7 +15,7 @@ final orange = Paint()..color = const Color(0xAABB6633);
 SquareComponent makeSquare(Paint paint) {
   return SquareComponent()
     ..paint = paint
-    ..position = Vector2.all(100);
+    ..position.setValues(100, 100);
 }
 
 class InfiniteEffectGame extends BaseGame with TapDetector {

examples/lib/stories/effects/move_effect.dart

@@ -11,9 +11,8 @@ class MoveEffectGame extends BaseGame with TapDetector {
 
   @override
   Future<void> onLoad() async {
-    add(
-      square = SquareComponent()..position = Vector2.all(100),
-    );
+    square = SquareComponent()..position.setValues(100, 100);
+    add(square);
   }
 
   @override

examples/lib/stories/effects/rotate_effect.dart

@@ -2,7 +2,6 @@ import 'dart:math';
 
 import 'package:flame/components.dart';
 import 'package:flame/effects.dart';
-import 'package:flame/extensions.dart';
 import 'package:flame/game.dart';
 import 'package:flame/gestures.dart';
 import 'package:flutter/material.dart';
@@ -14,11 +13,10 @@ class RotateEffectGame extends BaseGame with TapDetector {
 
   @override
   Future<void> onLoad() async {
-    add(
     square = SquareComponent()
-        ..position = Vector2.all(200)
-        ..anchor = Anchor.center,
-    );
+      ..position.setValues(200, 200)
+      ..anchor = Anchor.center;
+    add(square);
   }
 
   @override

examples/lib/stories/effects/scale_effect.dart

@@ -13,11 +13,10 @@ class ScaleEffectGame extends BaseGame with TapDetector {
 
   @override
   Future<void> onLoad() async {
-    add(
     square = SquareComponent()
-        ..position = Vector2.all(200)
-        ..anchor = Anchor.center,
-    );
+      ..position.setValues(200, 200)
+      ..anchor = Anchor.center;
+    add(square);
   }
 
   @override

examples/lib/stories/effects/sequence_effect.dart

@@ -13,11 +13,10 @@ class SequenceEffectGame extends BaseGame with TapDetector {
 
   @override
   Future<void> onLoad() async {
-    add(
     greenSquare = SquareComponent()
       ..paint = green
-        ..position = Vector2.all(100),
-    );
+      ..position.setValues(100, 100);
+    add(greenSquare);
   }
 
   @override

examples/lib/stories/rendering/text.dart

@@ -52,13 +52,13 @@ class TextGame extends BaseGame {
     add(
       TextComponent('center', config: _tiny)
         ..anchor = Anchor.center
-        ..position = size / 2,
+        ..position.setFrom(size / 2),
     );
 
     add(
       TextComponent('bottomRight', config: _tiny)
         ..anchor = Anchor.bottomRight
-        ..position = size,
+        ..position.setFrom(size),
     );
 
     add(

examples/lib/stories/tile_maps/isometric_tile_map.dart

@@ -76,6 +76,6 @@ class IsometricTileMapGame extends BaseGame with MouseMovementDetector {
     final screenPosition = event.localPosition.toVector2();
     final block = base.getBlock(screenPosition);
     selector.show = base.containsBlock(block);
-    selector.position = base.getBlockPosition(block) + topLeft;
+    selector.position.setFrom(base.getBlockPosition(block) + topLeft);
   }
 }

examples/lib/stories/utils/camera_and_viewport.dart

@@ -34,7 +34,7 @@ class MovableSquare extends SquareComponent
     timer.update(dt);
 
     final ds = velocity * (speed * dt);
-    position += ds;
+    position.add(ds);
   }
 
   @override
@@ -83,8 +83,8 @@ class Map extends Component {
 
 class Rock extends SquareComponent with Hitbox, Collidable {
   Rock(Vector2 position) {
-    this.position = position;
-    size = Vector2.all(50);
+    this.position.setFrom(position);
+    size.setValues(50, 50);
     paint = Paint()..color = const Color(0xFF2222FF);
     addShape(HitboxRectangle());
   }
@@ -104,7 +104,7 @@ class CameraAndViewportGame extends BaseGame
 
     add(square = MovableSquare());
     camera.cameraSpeed = 1;
-    camera.followObject(square, worldBounds: Map.bounds);
+    camera.followComponent(square, worldBounds: Map.bounds);
 
     for (var i = 0; i < 30; i++) {
       add(Rock(Vector2(Map.genCoord(), Map.genCoord())));

packages/flame/CHANGELOG.md

@@ -10,6 +10,8 @@
  - Adding some more basic colors entries to the `BasicPalette`
  - Fixing Flutter and Dart version constraints
  - Exporting Images and AssetsCache
+ - Make `size` and `position` in `PositionComponent` final
+ - Add a `snapTo` and `onPositionUpdate` method to the `Camera`
  - Remove the SpriteAnimationComponent when the animation is really done, not when it is on the last frame
  - Revamp all the docs to be up to date with v1.0.0
 

packages/flame/example/lib/main.dart

@@ -42,7 +42,7 @@ class Square extends PositionComponent {
   @override
   void onMount() {
     super.onMount();
-    size = Vector2.all(squareSize);
+    size.setValues(squareSize, squareSize);
     anchor = Anchor.center;
   }
 }

packages/flame/lib/src/components/parallax_component.dart

@@ -64,7 +64,7 @@ class ParallaxComponent extends PositionComponent {
   @override
   void onGameResize(Vector2 size) {
     super.onGameResize(size);
-    this.size = size;
+    this.size.setFrom(size);
     parallax?.resize(size);
   }
 

packages/flame/lib/src/components/position_component.dart

@@ -23,19 +23,23 @@ import 'mixins/hitbox.dart';
 /// within this component's (width, height).
 abstract class PositionComponent extends BaseComponent {
   /// The position of this component on the screen (relative to the anchor).
-  Vector2 position;
+  final Vector2 _position;
+  Vector2 get position => _position;
+  set position(Vector2 position) => _position.setFrom(position);
 
   /// X position of this component on the screen (relative to the anchor).
-  double get x => position.x;
-  set x(double x) => position.x = x;
+  double get x => _position.x;
+  set x(double x) => _position.x = x;
 
   /// Y position of this component on the screen (relative to the anchor).
-  double get y => position.y;
-  set y(double y) => position.y = y;
+  double get y => _position.y;
+  set y(double y) => _position.y = y;
 
   /// The size that this component is rendered with.
   /// This is not necessarily the source size of the asset.
-  Vector2 size;
+  final Vector2 _size;
+  Vector2 get size => _size;
+  set size(Vector2 size) => _size.setFrom(size);
 
   /// Width (size) that this component is rendered with.
   double get width => size.x;
@@ -132,8 +136,8 @@ abstract class PositionComponent extends BaseComponent {
     this.anchor = Anchor.topLeft,
     this.renderFlipX = false,
     this.renderFlipY = false,
-  })  : position = position ?? Vector2.zero(),
-        size = size ?? Vector2.zero();
+  })  : _position = position ?? Vector2.zero(),
+        _size = size ?? Vector2.zero();
 
   @override
   bool containsPoint(Vector2 point) {

packages/flame/lib/src/effects/move_effect.dart

@@ -126,7 +126,7 @@ class MoveEffect extends SimplePositionComponentEffect {
     final lastEndAt = _currentSubPath!.startAt;
     final localPercentage =
         (curveProgress - lastEndAt) / (_currentSubPath!.endAt - lastEndAt);
-    component?.position = _currentSubPath!.previous +
-        ((_currentSubPath!.v - _currentSubPath!.previous) * localPercentage);
+    component?.position.setFrom(_currentSubPath!.previous +
+        ((_currentSubPath!.v - _currentSubPath!.previous) * localPercentage));
   }
 }

packages/flame/lib/src/effects/scale_effect.dart

@@ -39,7 +39,7 @@ class ScaleEffect extends SimplePositionComponentEffect {
   @override
   void initialize(PositionComponent component) {
     super.initialize(component);
-    _startSize = component.size;
+    _startSize = component.size.clone();
     _delta = isRelative ? size : size - _startSize;
     if (!isAlternating) {
       endSize = _startSize + _delta;
@@ -52,6 +52,6 @@ class ScaleEffect extends SimplePositionComponentEffect {
   @override
   void update(double dt) {
     super.update(dt);
-    component?.size = _startSize + _delta * curveProgress;
+    component?.size.setFrom(_startSize + _delta * curveProgress);
   }
 }

packages/flame/lib/src/game/camera.dart

@@ -35,7 +35,7 @@ void _moveToTarget(
 /// There are three major factors that determine the camera position:
 ///
 /// * Follow
-/// If you want, you can call [followObject] at the beginning of your
+/// If you want, you can call [followComponent] at the beginning of your
 /// stage/world/level, and provided a [PositionComponent].
 /// The camera will follow this component making sure its position is fixed
 /// on the screen.
@@ -89,29 +89,36 @@ class Camera {
   double cameraSpeed = defaultCameraSpeed;
   double shakeIntensity = defaultShakeIntensity;
 
-  /// This is the current position of the camera, ie the world coordinate that is
-  /// rendered on the top left of the screen (origin of the screen space).
+  /// This is the current position of the camera, ie the world coordinate that
+  /// is rendered on the top left of the screen (origin of the screen space).
   ///
   /// Zero means no translation is applied.
   /// You can't change this directly; the camera will handle all ongoing
   /// movements so they smoothly transition.
   /// If you want to immediately snap the camera to a new place, you can do:
   /// ```
-  ///   camera.moveTo(newPosition);
-  ///   camera.snap();
+  ///   camera.snapTo(newPosition);
   /// ```
-  Vector2 get position => _position.clone();
+  Vector2 get position => _internalPosition.clone();
 
-  final Vector2 _position = Vector2.zero();
+  /// Do not change this directly since it bypasses [onPositionUpdate]
+  final Vector2 _internalPosition = Vector2.zero();
 
-  /// If set, the camera will "follow" this component, making sure that this
-  /// component is always rendered in a fixed position in the screen, by
-  /// immediately moving the camera to "focus" on the object.
+  Vector2 get _position => _internalPosition;
+  set _position(Vector2 position) {
+    _internalPosition.setFrom(position);
+    onPositionUpdate(_internalPosition);
+  }
+
+  /// If set, the camera will "follow" this vector, making sure that this
+  /// vector is always rendered in a fixed position in the screen, by
+  /// immediately moving the camera to "focus" on the where the vector is.
   ///
-  /// You probably want to set it to the player component.
-  /// Note that this is not smooth because the movement of the follow object
+  /// You might want to set it to the player component by using the
+  /// [followComponent] method.
+  /// Note that this is not smooth because the movement of the followed vector
   /// is assumed to be smooth.
-  PositionComponent? follow;
+  Vector2? follow;
 
   /// Where in the screen the follow object should be.
   ///
@@ -146,10 +153,10 @@ class Camera {
 
     if (_targetCameraDelta != null && _currentCameraDelta != null) {
       _moveToTarget(_currentCameraDelta!, _targetCameraDelta!, ds);
-      _position.setFrom(_currentCameraDelta! + shake);
+      _position = _currentCameraDelta! + shake;
     } else {
       _moveToTarget(_currentRelativeOffset, _targetRelativeOffset, ds);
-      _position.setFrom(_getTarget() + shake);
+      _position = _target() + shake;
     }
 
     if (shaking) {
@@ -182,23 +189,23 @@ class Camera {
 
   // Follow
 
-  /// Immediately snaps the camera to start following the object [follow].
+  /// Immediately snaps the camera to start following the [component].
   ///
-  /// This means that the camera will move so that the [follow] object is
-  /// in a fixed position on the screen.
+  /// This means that the camera will move so that the position vector of the
+  /// component is in a fixed position on the screen.
   /// That position is determined by a fraction of screen size defined by
   /// [relativeOffset] (default to the center).
   /// [worldBounds] can be optionally set to add boundaries to how far the
   /// camera is allowed to move.
-  /// The object is "grabbed" by its anchor (default top left). So for example
-  /// if you want the center of the object to be at the fixed position, set
-  /// its anchor to center.
-  void followObject(
-    PositionComponent follow, {
+  /// The component is "grabbed" by its anchor (default top left).
+  /// So for example if you want the center of the object to be at the fixed
+  /// position, set the components anchor to center.
+  void followComponent(
+    PositionComponent component, {
     Vector2? relativeOffset,
     Rect? worldBounds,
   }) {
-    this.follow = follow;
+    follow = component.position;
     this.worldBounds = worldBounds;
     _targetRelativeOffset.setFrom(relativeOffset ?? Anchor.center.toVector2());
     _currentRelativeOffset.setFrom(_targetRelativeOffset);
@@ -214,12 +221,12 @@ class Camera {
     _targetRelativeOffset.setFrom(newRelativeOffset);
   }
 
-  Vector2 _getTarget() {
+  Vector2 _target() {
     if (follow == null) {
       return Vector2.zero();
     }
     final screenDelta = gameRef.size.clone()..multiply(_currentRelativeOffset);
-    final attemptedTarget = follow!.position - screenDelta;
+    final attemptedTarget = follow! - screenDelta;
 
     final bounds = worldBounds;
     if (bounds != null) {
@@ -259,9 +266,16 @@ class Camera {
   ///
   /// The camera will be smoothly transitioned to this position.
   /// This will replace any previous targets.
-  void moveTo(Vector2 p) {
+  void moveTo(Vector2 position) {
     _currentCameraDelta = _position;
-    _targetCameraDelta = p.clone();
+    _targetCameraDelta = position.clone();
+  }
+
+  /// Instantly moves the camera to the target, bypassing follow.
+  /// This will replace any previous targets.
+  void snapTo(Vector2 position) {
+    moveTo(position);
+    snap();
   }
 
   /// Smoothly resets any moveTo targets.
@@ -290,4 +304,8 @@ class Camera {
     }
     return 0.0;
   }
+
+  /// If you need updated on when the position of the camera is updated you
+  /// can override this.
+  void onPositionUpdate(Vector2 position) {}
 }

packages/flame/test/components/component_test.dart

@@ -7,30 +7,30 @@ void main() {
   group('component test', () {
     test('test get/set x/y or position', () {
       final PositionComponent c = SpriteComponent();
-      c.position = Vector2(2.2, 3.4);
+      c.position.setValues(2.2, 3.4);
       expect(c.x, 2.2);
       expect(c.y, 3.4);
 
-      c.position = Vector2(1.0, 0.0);
+      c.position.setValues(1.0, 0.0);
       expect(c.x, 1.0);
       expect(c.y, 0.0);
     });
 
     test('test get/set width/height or size', () {
       final PositionComponent c = SpriteComponent();
-      c.size = Vector2(2.2, 3.4);
+      c.size.setValues(2.2, 3.4);
       expect(c.size.x, 2.2);
       expect(c.size.y, 3.4);
 
-      c.size = Vector2(1.0, 0.0);
+      c.size.setValues(1.0, 0.0);
       expect(c.width, 1.0);
       expect(c.height, 0.0);
     });
 
     test('test get/set rect', () {
       final PositionComponent c = SpriteComponent();
-      c.position = Vector2(0.0, 1.0);
-      c.size = Vector2(2.0, 2.0);
+      c.position.setValues(0.0, 1.0);
+      c.size.setValues(2.0, 2.0);
       final rect = c.toRect();
       expect(rect.left, 0.0);
       expect(rect.top, 1.0);
@@ -46,8 +46,8 @@ void main() {
 
     test('test get/set rect with anchor', () {
       final PositionComponent c = SpriteComponent();
-      c.position = Vector2(0.0, 1.0);
-      c.size = Vector2(2.0, 2.0);
+      c.position.setValues(0.0, 1.0);
+      c.size.setValues(2.0, 2.0);
       c.anchor = Anchor.center;
       final rect = c.toRect();
       expect(rect.left, -1.0);
@@ -64,8 +64,8 @@ void main() {
 
     test('test get/set anchorPosition', () {
       final PositionComponent c = SpriteComponent();
-      c.position = Vector2(0.0, 1.0);
-      c.size = Vector2(2.0, 2.0);
+      c.position.setValues(0.0, 1.0);
+      c.size.setValues(2.0, 2.0);
       c.anchor = Anchor.center;
       final anchorPosition = c.topLeftPosition;
       expect(anchorPosition.x, -1.0);

packages/flame/test/components/composed_component_test.dart

@@ -88,7 +88,7 @@ void main() {
       final wrapper = MyComposed();
 
       game.onResize(size);
-      child.size = Vector2.all(1);
+      child.size.setValues(1.0, 1.0);
       game.add(wrapper);
       wrapper.addChild(child);
       game.update(0.0);
@@ -101,11 +101,11 @@ void main() {
     test('tap on offset children', () {
       final game = MyGame();
       final child = MyTap()
-        ..position = Vector2.all(100)
-        ..size = Vector2.all(100);
+        ..position.setFrom(Vector2.all(100))
+        ..size.setFrom(Vector2.all(100));
       final wrapper = MyComposed()
-        ..position = Vector2.all(100)
-        ..size = Vector2.all(300);
+        ..position.setFrom(Vector2.all(100))
+        ..size.setFrom(Vector2.all(300));
 
       game.onResize(size);
       game.add(wrapper);

packages/flame/test/components/position_component_test.dart

@@ -12,8 +12,8 @@ void main() {
   group('PositionComponent overlap test', () {
     test('overlap', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(4.0, 4.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(4.0, 4.0);
       component.angle = 0.0;
       component.anchor = Anchor.center;
 
@@ -23,8 +23,8 @@ void main() {
 
     test('overlap on edge', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(2.0, 2.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(2.0, 2.0);
       component.angle = 0.0;
       component.anchor = Anchor.center;
 
@@ -34,8 +34,8 @@ void main() {
 
     test('not overlapping with x', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(2.0, 2.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(2.0, 2.0);
       component.angle = 0.0;
       component.anchor = Anchor.center;
 
@@ -45,8 +45,8 @@ void main() {
 
     test('not overlapping with y', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(2.0, 2.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(2.0, 2.0);
       component.angle = 0.0;
       component.anchor = Anchor.center;
 
@@ -56,8 +56,8 @@ void main() {
 
     test('overlapping with angle', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(2.0, 2.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(2.0, 2.0);
       component.angle = math.pi / 4;
       component.anchor = Anchor.center;
 
@@ -67,8 +67,8 @@ void main() {
 
     test('not overlapping with angle', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(2.0, 2.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(2.0, 2.0);
       component.angle = math.pi / 4;
       component.anchor = Anchor.center;
 
@@ -78,8 +78,8 @@ void main() {
 
     test('overlapping with angle and topLeft anchor', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(1.0, 1.0);
-      component.size = Vector2(2.0, 2.0);
+      component.position.setValues(1.0, 1.0);
+      component.size.setValues(2.0, 2.0);
       component.angle = math.pi / 4;
       component.anchor = Anchor.topLeft;
 
@@ -88,11 +88,10 @@ void main() {
     });
 
     test('component with hitbox contains point', () {
-      final size = Vector2(2.0, 2.0);
       final Hitbox component = MyHitboxComponent();
-      component.position = Vector2(1.0, 1.0);
+      component.position.setValues(1.0, 1.0);
       component.anchor = Anchor.topLeft;
-      component.size = size;
+      component.size.setValues(2.0, 2.0);
       final hitbox = HitboxPolygon([
         Vector2(1, 0),
         Vector2(0, -1),
@@ -106,11 +105,10 @@ void main() {
     });
 
     test('component with anchor topLeft contains point on edge', () {
-      final size = Vector2(2.0, 2.0);
       final Hitbox component = MyHitboxComponent();
-      component.position = Vector2(-1, -1);
+      component.position.setValues(-1, -1);
       component.anchor = Anchor.topLeft;
-      component.size = size;
+      component.size.setValues(2.0, 2.0);
       final hitbox = HitboxRectangle();
       component.addShape(hitbox);
 
@@ -121,11 +119,10 @@ void main() {
     });
 
     test('component with anchor bottomRight contains point on edge', () {
-      final size = Vector2(2.0, 2.0);
       final Hitbox component = MyHitboxComponent();
-      component.position = Vector2(1, 1);
+      component.position.setValues(1, 1);
       component.anchor = Anchor.bottomRight;
-      component.size = size;
+      component.size.setValues(2.0, 2.0);
       final hitbox = HitboxRectangle();
       component.addShape(hitbox);
 
@@ -136,11 +133,10 @@ void main() {
     });
 
     test('component with anchor topRight does not contain close points', () {
-      final size = Vector2(2.0, 2.0);
       final Hitbox component = MyHitboxComponent();
-      component.position = Vector2(1, 1);
+      component.position.setValues(1, 1);
       component.anchor = Anchor.topLeft;
-      component.size = size;
+      component.size.setValues(2.0, 2.0);
       final hitbox = HitboxRectangle();
       component.addShape(hitbox);
 
@@ -151,11 +147,10 @@ void main() {
     });
 
     test('component with hitbox does not contains point', () {
-      final size = Vector2(2.0, 2.0);
       final Hitbox component = MyHitboxComponent();
-      component.position = Vector2(1.0, 1.0);
+      component.position.setValues(1.0, 1.0);
       component.anchor = Anchor.topLeft;
-      component.size = size;
+      component.size.setValues(2.0, 2.0);
       component.addShape(HitboxPolygon([
         Vector2(1, 0),
         Vector2(0, -1),
@@ -169,8 +164,8 @@ void main() {
 
     test('component with zero size does not contain point', () {
       final PositionComponent component = MyComponent();
-      component.position = Vector2(2.0, 2.0);
-      component.size = Vector2(0.0, 0.0);
+      component.position.setValues(2.0, 2.0);
+      component.size.setValues(0.0, 0.0);
       component.angle = 0.0;
       component.anchor = Anchor.center;
 

packages/flame/test/components/resizable_test.dart

@@ -5,7 +5,7 @@ import 'package:test/test.dart';
 class MyComponent extends PositionComponent {
   String name;
   @override
-  Vector2 size = Vector2(2.0, 2.0);
+  final Vector2 size = Vector2(2.0, 2.0);
   late Vector2 gameSize;
 
   MyComponent(this.name);

packages/flame/test/effects/effect_test_utils.dart

@@ -100,12 +100,12 @@ class TestComponent extends PositionComponent {
   TestComponent({
     Vector2? position,
     Vector2? size,
-    double? angle,
-    Anchor? anchor,
-  }) {
-    this.position = position ?? Vector2.zero();
-    this.size = size ?? Vector2.all(100.0);
-    this.angle = angle ?? 0.0;
-    this.anchor = anchor ?? Anchor.center;
-  }
+    double angle = 0.0,
+    Anchor anchor = Anchor.center,
+  }) : super(
+          position: position,
+          size: size ?? Vector2.all(100.0),
+          angle: angle,
+          anchor: anchor,
+        );
 }

packages/flame/test/effects/sequence_effect_test.dart

@@ -14,6 +14,7 @@ void main() {
   final argumentSize = randomVector2();
   final argumentAngle = randomAngle();
   final path = List.generate(3, (i) => randomVector2());
+
   TestComponent component() {
     return TestComponent(
       position: randomVector2(),

packages/flame/test/game/camera_and_viewport_test.dart

@@ -11,10 +11,13 @@ import '../util/mock_canvas.dart';
 
 class TestComponent extends PositionComponent {
   static final Paint _paint = Paint();
-  TestComponent(Vector2 position) {
-    this.position = position;
-    size = Vector2.all(1.0);
-  }
+
+  TestComponent(Vector2 position)
+      : super(
+          position: position,
+          size: Vector2.all(1.0),
+        );
+
   @override
   void render(Canvas c) {
     super.render(c);
@@ -181,10 +184,10 @@ void main() {
       final p = TestComponent(Vector2.all(10.0))..anchor = Anchor.center;
       game.add(p);
       game.update(0);
-      game.camera.followObject(p);
+      game.camera.followComponent(p);
 
       expect(game.camera.position, Vector2.all(0.0));
-      p.position = Vector2(10.0, 20.0);
+      p.position.setValues(10.0, 20.0);
       // follow happens immediately because the object's movement is assumed to be smooth
       game.update(0);
       // (10,20) - half screen (50,50)
@@ -210,10 +213,10 @@ void main() {
       game.add(p);
       game.update(0);
       // this would be a typical vertical shoot-em-up
-      game.camera.followObject(p, relativeOffset: Vector2(0.5, 0.8));
+      game.camera.followComponent(p, relativeOffset: Vector2(0.5, 0.8));
 
       expect(game.camera.position, Vector2.all(0.0));
-      p.position = Vector2(600.0, 2000.0);
+      p.position.setValues(600.0, 2000.0);
       // follow happens immediately because the object's movement is assumed to be smooth
       game.update(0);
       // (600,2000) - fractional screen (50,80)
@@ -238,29 +241,29 @@ void main() {
       final p = TestComponent(Vector2.all(10.0))..anchor = Anchor.center;
       game.add(p);
       game.update(0);
-      game.camera.followObject(
+      game.camera.followComponent(
         p,
         worldBounds: const Rect.fromLTWH(-1000, -1000, 2000, 2000),
       );
 
-      p.position = Vector2(600.0, 700.0); // well within bounds
+      p.position.setValues(600.0, 700.0); // well within bounds
       game.update(0);
       expect(game.camera.position, Vector2(550, 650));
 
       // x ok, y starts to get to bounds
-      p.position = Vector2(600.0, 950.0); // right on the edge
+      p.position.setValues(600.0, 950.0); // right on the edge
       game.update(0);
       expect(game.camera.position, Vector2(550, 900));
 
-      p.position = Vector2(600.0, 950.0); // stop advancing
+      p.position.setValues(600.0, 950.0); // stop advancing
       game.update(0);
       expect(game.camera.position, Vector2(550, 900));
 
-      p.position = Vector2(-1100.0, 950.0);
+      p.position.setValues(-1100.0, 950.0);
       game.update(0);
       expect(game.camera.position, Vector2(-1000, 900));
 
-      p.position = Vector2(1000.0, 1000.0);
+      p.position.setValues(1000.0, 1000.0);
       game.update(0);
       expect(game.camera.position, Vector2(900, 900));
     });
@@ -271,7 +274,7 @@ void main() {
       final p = TestComponent(Vector2.all(10.0))..anchor = Anchor.center;
       game.add(p);
       game.update(0);
-      game.camera.followObject(
+      game.camera.followComponent(
         p,
         worldBounds: const Rect.fromLTWH(0, 0, 100, 100),
       );
@@ -280,11 +283,11 @@ void main() {
       game.update(0);
       expect(game.camera.position, Vector2(50, 50));
 
-      p.position = Vector2(60.0, 50.0);
+      p.position.setValues(60.0, 50.0);
       game.update(0);
       expect(game.camera.position, Vector2(50, 50));
 
-      p.position = Vector2(-10.0, -20.0);
+      p.position.setValues(-10.0, -20.0);
       game.update(0);
       expect(game.camera.position, Vector2(50, 50));
     });
@@ -299,7 +302,7 @@ void main() {
 
       final p = TestComponent(Vector2.all(10.0))..anchor = Anchor.center;
       game.add(p);
-      game.camera.followObject(
+      game.camera.followComponent(
         p,
         // this could be a typical mario-like platformer, where the player is more on the bottom left to allow the scenario to be seem
         relativeOffset: Vector2(0.25, 0.25),
@@ -309,19 +312,19 @@ void main() {
       game.update(0);
       expect(game.camera.position, Vector2(0, 0));
 
-      p.position = Vector2(30.0, 0.0);
+      p.position.setValues(30.0, 0.0);
       game.update(0);
       expect(game.camera.position, Vector2(5, 0));
 
-      p.position = Vector2(30.0, 100.0);
+      p.position.setValues(30.0, 100.0);
       game.update(0);
       expect(game.camera.position, Vector2(5, 75));
 
-      p.position = Vector2(30.0, 1000.0);
+      p.position.setValues(30.0, 1000.0);
       game.update(0);
       expect(game.camera.position, Vector2(5, 900));
 
-      p.position = Vector2(950.0, 20.0);
+      p.position.setValues(950.0, 20.0);
       game.update(0);
       expect(game.camera.position, Vector2(900, 0));
     });