Draggables Overhaul (#660)

doc/examples/gestures/lib/main_multitap_advanced.dart

@@ -1,6 +1,7 @@
 import 'package:flame/game.dart';
 import 'package:flutter/material.dart';
 import 'package:flame/gestures.dart';
+import 'package:flame/extensions.dart';
 import 'package:flame/palette.dart';
 
 void main() {
@@ -20,8 +21,8 @@ class MyGame extends BaseGame
 
   final Map<int, Rect> _taps = {};
 
-  Offset _start;
-  Offset _end;
+  Vector2 _start;
+  Vector2 _end;
   Rect _panRect;
 
   MyGame() {
@@ -49,37 +50,31 @@ class MyGame extends BaseGame
   }
 
   @override
-  void onReceiveDrag(DragEvent event) {
-    onPanStart(event.initialPosition);
-
-    event
-      ..onUpdate = onPanUpdate
-      ..onEnd = onPanEnd
-      ..onCancel = onPanCancel;
-  }
-
-  void onPanCancel() {
+  void onDragCancel(int pointerId) {
     _end = null;
     _start = null;
     _panRect = null;
   }
 
-  void onPanStart(Offset position) {
+  @override
+  void onDragStart(int pointerId, Vector2 initialPosition) {
     _end = null;
-    _start = position;
+    _start = initialPosition;
   }
 
-  void onPanUpdate(DragUpdateDetails details) {
-    _end = details.localPosition;
+  @override
+  void onDragUpdate(int pointerId, DragUpdateDetails details) {
+    _end = details.localPosition.toVector2();
   }
 
-  void onPanEnd(DragEndDetails details) {
+  @override
+  void onDragEnd(int pointerId, DragEndDetails details) {
     if (_start != null && _end != null) {
       _panRect = Rect.fromLTRB(
-        _start.dx,
-        _start.dy,
-        _end.dx,
-        _end.dy,
+        _start.x,
+        _start.y,
+        _end.x,
+        _end.y,
       );
     }
   }