Fixed #1 such that resizing the window still keeps every item where it should be, and maintains collision on all platforms.

lib/bug_holder.dart

@@ -117,4 +117,14 @@ class BugHolder {
       }
     }
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    for (List<Bug> platformLevel in bugs) {
+      for (Bug p in platformLevel) {
+        p.resize(newSize, xRatio, yRatio);
+        p.sprite.y = (p.sprite.position.y / p.gameRef.blockSize).round() *
+            p.gameRef.blockSize;
+      }
+    }
+  }
 }

lib/circuit_background.dart

@@ -140,8 +140,6 @@ class CircuitBackground extends MovingObject {
   void setUp() {
     windowA.current = WindowState.first;
     windowB.current = WindowState.first;
-    // gameRef.add(windowA);
-    // gameRef.add(windowB);
     background1Position = Vector2(0, 0);
     background1Size = Vector2(
         gameRef.viewport.canvasSize.y * (background.width / background.height),
@@ -219,4 +217,19 @@ class CircuitBackground extends MovingObject {
     windowB.render(canvas);
     canvas.restore();
   }
+
+  @override
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    background1Size =
+        Vector2(newSize.y * (background.width / background.height), newSize.y);
+    windowA.position = background1Position;
+    windowA.size = background1Size;
+
+    background2Position =
+        Vector2(background1Position.x + background1Size.x - 1, 0);
+    background2Size =
+        Vector2(newSize.y * (background.width / background.height), newSize.y);
+    windowB.position = background2Position;
+    windowB.size = background2Size;
+  }
 }

lib/coin_holder.dart

@@ -70,26 +70,6 @@ class CoinHolder {
       gameRef.add(coin.sprite);
     }
     return false;
-
-    // double xCoordinate = gameRef.platformHolder.getFlushX();
-    // xCoordinate = xCoordinate +
-    //     gameRef.blockSize * random.nextInt(5) +
-    //     gameRef.blockSize * 20;
-    //
-    // if (xCoordinate < gameRef.size.x || random.nextInt(100) > 25) {
-    //   return true;
-    // } else {
-    //   Coin coin = Coin(gameRef);
-    //   coin.setPosition(xCoordinate, gameRef.blockSize * level);
-    //
-    //   if (gameRef.isTooNearOtherObstacles(coin.sprite.toRect())) {
-    //     return false;
-    //   }
-    //
-    //   coins[level].add(coin);
-    //   gameRef.add(coin.sprite);
-    //   return false;
-    // }
   }
 
   int totalCoins() {
@@ -125,4 +105,12 @@ class CoinHolder {
       }
     }
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    for (List<Coin> coinLevel in coins) {
+      for (Coin p in coinLevel) {
+        p.resize(newSize, xRatio, yRatio);
+      }
+    }
+  }
 }

lib/firework.dart

@@ -97,4 +97,16 @@ class Firework extends Component {
     sprite1.animation!.reset();
     sprite2.animation!.reset();
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    sprite1.x *= xRatio;
+    sprite1.y *= yRatio;
+    sprite1.width *= xRatio;
+    sprite1.height *= yRatio;
+
+    sprite2.x *= xRatio;
+    sprite2.y *= yRatio;
+    sprite2.width *= xRatio;
+    sprite2.height *= yRatio;
+  }
 }

lib/main.dart

@@ -243,8 +243,20 @@ class MyGame extends BaseGame with PanDetector, TapDetector, KeyboardEvents {
 
   @override
   void onResize(Vector2 canvasSize) {
+    Vector2 oldSize = viewport.canvasSize;
     super.onResize(canvasSize);
     blockSize = canvasSize.y / 9;
+    if (loaded) {
+      double xRatio = canvasSize.x / oldSize.x;
+      double yRatio = canvasSize.y / oldSize.y;
+      circuitBackground.resize(canvasSize, xRatio, yRatio);
+      runner.resize(canvasSize, xRatio, yRatio);
+      platformHolder.resize(canvasSize, xRatio, yRatio);
+      coinHolder.resize(canvasSize, xRatio, yRatio);
+      wireHolder.resize(canvasSize, xRatio, yRatio);
+      bugHolder.resize(canvasSize, xRatio, yRatio);
+      fireworks.resize(canvasSize, xRatio, yRatio);
+    }
   }
 
   // Mobile controls

lib/moving_object.dart

@@ -47,4 +47,11 @@ class MovingObject {
     }
     return "none";
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    sprite.x *= xRatio;
+    sprite.y *= yRatio;
+    sprite.width *= xRatio;
+    sprite.height *= yRatio;
+  }
 }

lib/platform_holder.dart

@@ -196,4 +196,14 @@ class PlatformHolder {
     }
     return null;
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    for (List<Platform> platformLevel in platforms) {
+      for (Platform p in platformLevel) {
+        p.resize(newSize, xRatio, yRatio);
+        p.sprite.y = (p.sprite.position.y / p.gameRef.blockSize).round() *
+            p.gameRef.blockSize;
+      }
+    }
+  }
 }

lib/runner.dart

@@ -28,6 +28,7 @@ class Runner extends Component with HasGameRef<MyGame> {
   String previousState = "run";
   var runnerPosition = Vector2(0, 0);
   late Vector2 runnerSize;
+  // late Rect runnerRect;
   bool dead = false;
 
   void setUp() {
@@ -104,7 +105,7 @@ class Runner extends Component with HasGameRef<MyGame> {
           path: [
             Vector2(sprite.x, (level - 2) * gameRef.blockSize),
           ],
-          speed: 150,
+          duration: 0.5,
           curve: Curves.ease,
           onComplete: () {
             updateLevel();
@@ -315,22 +316,7 @@ class Runner extends Component with HasGameRef<MyGame> {
       return;
     }
     Rect runnerRect = sprite.toRect();
-    bool onTopOfPlatform = false;
+    bool onTopOfPlatform = this.onTopOfPlatform();
-    for (List<Platform> platformLevel in gameRef.platformHolder.platforms) {
-      for (Platform p in platformLevel) {
-        String side = p.intersect(runnerRect);
-        if (side == "none") {
-          Rect belowRunner = Rect.fromLTRB(runnerRect.left, runnerRect.top,
-              runnerRect.right, runnerRect.bottom + 1);
-          if (p.intersect(belowRunner) != "none") {
-            onTopOfPlatform = true;
-          }
-        } else if (side == "bottom") {
-          // event("die");
-          return;
-        }
-      }
-    }
 
     for (List<Coin> coinLevel in gameRef.coinHolder.coins) {
       for (int i = 0; i < coinLevel.length;) {
@@ -493,4 +479,14 @@ class Runner extends Component with HasGameRef<MyGame> {
 
     changePriorityWithoutResorting(RUNNER_PRIORITY);
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    sprite.x = gameRef.blockSize * 2;
+    sprite.y = gameRef.blockSize * level;
+    sprite.size.x = gameRef.blockSize;
+    sprite.size.y = gameRef.blockSize;
+    if (sprite.effects.isNotEmpty) {
+      sprite.effects.first.onComplete!();
+    }
+  }
 }

lib/wire_holder.dart

@@ -118,4 +118,12 @@ class WireHolder {
       }
     }
   }
+
+  void resize(Vector2 newSize, double xRatio, double yRatio) {
+    for (List<Wire> platformLevel in wires) {
+      for (Wire p in platformLevel) {
+        p.resize(newSize, xRatio, yRatio);
+      }
+    }
+  }
 }