Lazily compute PointerEvent's transformed positions (#63813)

* PointerEvent.local* properties are calculated lazily; other properties are delegated to original.
* Transformed PointerEvent becomes a subclass of its original class.
* Unnamed constructors no longer accepts transform and origin.

packages/flutter/lib/src/services/platform_views.dart

@@ -568,27 +568,22 @@ class _AndroidMotionEventConverter {
     }
 
     int action;
-    switch (event.runtimeType) {
-      case PointerDownEvent:
-        action = numPointers == 1
-            ? AndroidViewController.kActionDown
-            : AndroidViewController.pointerAction(
-                pointerIdx, AndroidViewController.kActionPointerDown);
-        break;
-      case PointerUpEvent:
-        action = numPointers == 1
-            ? AndroidViewController.kActionUp
-            : AndroidViewController.pointerAction(
-                pointerIdx, AndroidViewController.kActionPointerUp);
-        break;
-      case PointerMoveEvent:
-        action = AndroidViewController.kActionMove;
-        break;
-      case PointerCancelEvent:
-        action = AndroidViewController.kActionCancel;
-        break;
-      default:
-        return null;
+    if (event is PointerDownEvent) {
+      action = numPointers == 1
+          ? AndroidViewController.kActionDown
+          : AndroidViewController.pointerAction(
+              pointerIdx, AndroidViewController.kActionPointerDown);
+    } else if (event is PointerUpEvent) {
+      action = numPointers == 1
+          ? AndroidViewController.kActionUp
+          : AndroidViewController.pointerAction(
+              pointerIdx, AndroidViewController.kActionPointerUp);
+    } else if (event is PointerMoveEvent) {
+      action = AndroidViewController.kActionMove;
+    } else if (event is PointerCancelEvent) {
+      action = AndroidViewController.kActionCancel;
+    } else {
+      return null;
     }
 
     return AndroidMotionEvent(

packages/flutter/test/gestures/gesture_binding_resample_event_on_widget_test.dart

@@ -83,7 +83,7 @@ void main() {
 
     await tester.pump(const Duration(milliseconds: 7));
     expect(events.length, 1);
-    expect(events[0].runtimeType, equals(PointerDownEvent));
+    expect(events[0], isA<PointerDownEvent>());
     expect(events[0].timeStamp, currentTestFrameTime() + kSamplingOffset);
     expect(events[0].position, Offset(5.0 / ui.window.devicePixelRatio, 0.0));
 
@@ -91,7 +91,7 @@ void main() {
     await tester.pump(const Duration(milliseconds: 2));
     expect(events.length, 2);
     expect(events[1].timeStamp, currentTestFrameTime() + kSamplingOffset);
-    expect(events[1].runtimeType, equals(PointerMoveEvent));
+    expect(events[1], isA<PointerMoveEvent>());
     expect(events[1].position, Offset(25.0 / ui.window.devicePixelRatio, 0.0));
     expect(events[1].delta, Offset(20.0 / ui.window.devicePixelRatio, 0.0));
 
@@ -99,11 +99,11 @@ void main() {
     await tester.pump(const Duration(milliseconds: 2));
     expect(events.length, 4);
     expect(events[2].timeStamp, currentTestFrameTime() + kSamplingOffset);
-    expect(events[2].runtimeType, equals(PointerMoveEvent));
+    expect(events[2], isA<PointerMoveEvent>());
     expect(events[2].position, Offset(40.0 / ui.window.devicePixelRatio, 0.0));
     expect(events[2].delta, Offset(15.0 / ui.window.devicePixelRatio, 0.0));
     expect(events[3].timeStamp, currentTestFrameTime() + kSamplingOffset);
-    expect(events[3].runtimeType, equals(PointerUpEvent));
+    expect(events[3], isA<PointerUpEvent>());
     expect(events[3].position, Offset(40.0 / ui.window.devicePixelRatio, 0.0));
   });
 }

packages/flutter/test/gestures/gesture_binding_test.dart

@@ -63,8 +63,8 @@ void main() {
 
     ui.window.onPointerDataPacket(packet);
     expect(events.length, 2);
-    expect(events[0].runtimeType, equals(PointerDownEvent));
-    expect(events[1].runtimeType, equals(PointerUpEvent));
+    expect(events[0], isA<PointerDownEvent>());
+    expect(events[1], isA<PointerUpEvent>());
   });
 
   test('Pointer move events', () {
@@ -81,9 +81,9 @@ void main() {
 
     ui.window.onPointerDataPacket(packet);
     expect(events.length, 3);
-    expect(events[0].runtimeType, equals(PointerDownEvent));
-    expect(events[1].runtimeType, equals(PointerMoveEvent));
-    expect(events[2].runtimeType, equals(PointerUpEvent));
+    expect(events[0], isA<PointerDownEvent>());
+    expect(events[1], isA<PointerMoveEvent>());
+    expect(events[2], isA<PointerUpEvent>());
   });
 
   test('Pointer hover events', () {
@@ -108,12 +108,12 @@ void main() {
     expect(events.length, 0);
     expect(pointerRouterEvents.length, 6,
         reason: 'pointerRouterEvents contains: $pointerRouterEvents');
-    expect(pointerRouterEvents[0].runtimeType, equals(PointerAddedEvent));
-    expect(pointerRouterEvents[1].runtimeType, equals(PointerHoverEvent));
-    expect(pointerRouterEvents[2].runtimeType, equals(PointerHoverEvent));
-    expect(pointerRouterEvents[3].runtimeType, equals(PointerRemovedEvent));
-    expect(pointerRouterEvents[4].runtimeType, equals(PointerAddedEvent));
-    expect(pointerRouterEvents[5].runtimeType, equals(PointerHoverEvent));
+    expect(pointerRouterEvents[0], isA<PointerAddedEvent>());
+    expect(pointerRouterEvents[1], isA<PointerHoverEvent>());
+    expect(pointerRouterEvents[2], isA<PointerHoverEvent>());
+    expect(pointerRouterEvents[3], isA<PointerRemovedEvent>());
+    expect(pointerRouterEvents[4], isA<PointerAddedEvent>());
+    expect(pointerRouterEvents[5], isA<PointerHoverEvent>());
   });
 
   test('Pointer cancel events', () {
@@ -129,8 +129,8 @@ void main() {
 
     ui.window.onPointerDataPacket(packet);
     expect(events.length, 2);
-    expect(events[0].runtimeType, equals(PointerDownEvent));
-    expect(events[1].runtimeType, equals(PointerCancelEvent));
+    expect(events[0], isA<PointerDownEvent>());
+    expect(events[1], isA<PointerCancelEvent>());
   });
 
   test('Can cancel pointers', () {
@@ -150,8 +150,8 @@ void main() {
 
     ui.window.onPointerDataPacket(packet);
     expect(events.length, 2);
-    expect(events[0].runtimeType, equals(PointerDownEvent));
-    expect(events[1].runtimeType, equals(PointerCancelEvent));
+    expect(events[0], isA<PointerDownEvent>());
+    expect(events[1], isA<PointerCancelEvent>());
   });
 
   test('Can expand add and hover pointers', () {
@@ -169,11 +169,11 @@ void main() {
       packet.data, ui.window.devicePixelRatio).toList();
 
     expect(events.length, 5);
-    expect(events[0].runtimeType, equals(PointerAddedEvent));
-    expect(events[1].runtimeType, equals(PointerHoverEvent));
-    expect(events[2].runtimeType, equals(PointerRemovedEvent));
-    expect(events[3].runtimeType, equals(PointerAddedEvent));
-    expect(events[4].runtimeType, equals(PointerHoverEvent));
+    expect(events[0], isA<PointerAddedEvent>());
+    expect(events[1], isA<PointerHoverEvent>());
+    expect(events[2], isA<PointerRemovedEvent>());
+    expect(events[3], isA<PointerAddedEvent>());
+    expect(events[4], isA<PointerHoverEvent>());
   });
 
   test('Can expand pointer scroll events', () {
@@ -188,8 +188,8 @@ void main() {
       packet.data, ui.window.devicePixelRatio).toList();
 
     expect(events.length, 2);
-    expect(events[0].runtimeType, equals(PointerAddedEvent));
-    expect(events[1].runtimeType, equals(PointerScrollEvent));
+    expect(events[0], isA<PointerAddedEvent>());
+    expect(events[1], isA<PointerScrollEvent>());
   });
 
   test('Should synthesize kPrimaryButton for touch', () {
@@ -209,15 +209,15 @@ void main() {
       packet.data, ui.window.devicePixelRatio).toList();
 
     expect(events.length, 5);
-    expect(events[0].runtimeType, equals(PointerAddedEvent));
+    expect(events[0], isA<PointerAddedEvent>());
     expect(events[0].buttons, equals(0));
-    expect(events[1].runtimeType, equals(PointerHoverEvent));
+    expect(events[1], isA<PointerHoverEvent>());
     expect(events[1].buttons, equals(0));
-    expect(events[2].runtimeType, equals(PointerDownEvent));
+    expect(events[2], isA<PointerDownEvent>());
     expect(events[2].buttons, equals(kPrimaryButton));
-    expect(events[3].runtimeType, equals(PointerMoveEvent));
+    expect(events[3], isA<PointerMoveEvent>());
     expect(events[3].buttons, equals(kPrimaryButton));
-    expect(events[4].runtimeType, equals(PointerUpEvent));
+    expect(events[4], isA<PointerUpEvent>());
     expect(events[4].buttons, equals(0));
   });
 
@@ -242,15 +242,15 @@ void main() {
         packet.data, ui.window.devicePixelRatio).toList();
 
       expect(events.length, 5);
-      expect(events[0].runtimeType, equals(PointerAddedEvent));
+      expect(events[0], isA<PointerAddedEvent>());
       expect(events[0].buttons, equals(0));
-      expect(events[1].runtimeType, equals(PointerHoverEvent));
+      expect(events[1], isA<PointerHoverEvent>());
       expect(events[1].buttons, equals(0));
-      expect(events[2].runtimeType, equals(PointerDownEvent));
+      expect(events[2], isA<PointerDownEvent>());
       expect(events[2].buttons, equals(kPrimaryButton));
-      expect(events[3].runtimeType, equals(PointerMoveEvent));
+      expect(events[3], isA<PointerMoveEvent>());
       expect(events[3].buttons, equals(kPrimaryButton | kSecondaryStylusButton));
-      expect(events[4].runtimeType, equals(PointerUpEvent));
+      expect(events[4], isA<PointerUpEvent>());
       expect(events[4].buttons, equals(0));
     }
   });
@@ -272,15 +272,15 @@ void main() {
       packet.data, ui.window.devicePixelRatio).toList();
 
     expect(events.length, 5);
-    expect(events[0].runtimeType, equals(PointerAddedEvent));
+    expect(events[0], isA<PointerAddedEvent>());
     expect(events[0].buttons, equals(0));
-    expect(events[1].runtimeType, equals(PointerHoverEvent));
+    expect(events[1], isA<PointerHoverEvent>());
     expect(events[1].buttons, equals(0));
-    expect(events[2].runtimeType, equals(PointerDownEvent));
+    expect(events[2], isA<PointerDownEvent>());
     expect(events[2].buttons, equals(kPrimaryButton));
-    expect(events[3].runtimeType, equals(PointerMoveEvent));
+    expect(events[3], isA<PointerMoveEvent>());
     expect(events[3].buttons, equals(kPrimaryButton));
-    expect(events[4].runtimeType, equals(PointerUpEvent));
+    expect(events[4], isA<PointerUpEvent>());
     expect(events[4].buttons, equals(0));
   });
 
@@ -303,15 +303,15 @@ void main() {
         packet.data, ui.window.devicePixelRatio).toList();
 
       expect(events.length, 5);
-      expect(events[0].runtimeType, equals(PointerAddedEvent));
+      expect(events[0], isA<PointerAddedEvent>());
       expect(events[0].buttons, equals(0));
-      expect(events[1].runtimeType, equals(PointerHoverEvent));
+      expect(events[1], isA<PointerHoverEvent>());
       expect(events[1].buttons, equals(0));
-      expect(events[2].runtimeType, equals(PointerDownEvent));
+      expect(events[2], isA<PointerDownEvent>());
       expect(events[2].buttons, equals(kMiddleMouseButton));
-      expect(events[3].runtimeType, equals(PointerMoveEvent));
+      expect(events[3], isA<PointerMoveEvent>());
       expect(events[3].buttons, equals(kMiddleMouseButton | kSecondaryMouseButton));
-      expect(events[4].runtimeType, equals(PointerUpEvent));
+      expect(events[4], isA<PointerUpEvent>());
       expect(events[4].buttons, equals(0));
     }
   });

packages/flutter/test/gestures/locking_test.dart

@@ -59,7 +59,7 @@ void main() {
     });
     expect(tested, isTrue);
     expect(events.length, 2);
-    expect(events[0].runtimeType, equals(PointerDownEvent));
-    expect(events[1].runtimeType, equals(PointerUpEvent));
+    expect(events[0], isA<PointerDownEvent>());
+    expect(events[1], isA<PointerUpEvent>());
   });
 }

packages/flutter/test/widgets/platform_view_test.dart

@@ -2552,7 +2552,7 @@ void main() {
     await gesture.moveTo(const Offset(400, 300));
     expect(logs, <String>['enter1']);
     expect(controller.dispatchedPointerEvents, hasLength(1));
-    expect(controller.dispatchedPointerEvents[0].runtimeType, PointerHoverEvent);
+    expect(controller.dispatchedPointerEvents[0], isA<PointerHoverEvent>());
     logs.clear();
     controller.dispatchedPointerEvents.clear();
 
@@ -2582,7 +2582,7 @@ void main() {
     await gesture.moveBy(const Offset(1, 1));
     expect(logs, isEmpty);
     expect(controller.dispatchedPointerEvents, hasLength(1));
-    expect(controller.dispatchedPointerEvents[0].runtimeType, PointerHoverEvent);
+    expect(controller.dispatchedPointerEvents[0], isA<PointerHoverEvent>());
     expect(controller.dispatchedPointerEvents[0].position, const Offset(401, 301));
     expect(controller.dispatchedPointerEvents[0].localPosition, const Offset(101, 101));
     controller.dispatchedPointerEvents.clear();
@@ -2617,6 +2617,6 @@ void main() {
     await gesture.moveBy(const Offset(1, 1));
     expect(logs, isEmpty);
     expect(controller.dispatchedPointerEvents, hasLength(1));
-    expect(controller.dispatchedPointerEvents[0].runtimeType, PointerHoverEvent);
+    expect(controller.dispatchedPointerEvents[0], isA<PointerHoverEvent>());
   });
 }