feat: Add custom long tap delay (#3110)

Currently `longTapDelay` is hardcoded to 300ms.
This is good for most of the games. But same games required custom long
press values.
This PR allows it.

---------

Co-authored-by: Lukas Klingsbo <lukas.klingsbo@gmail.com>

doc/flame/inputs/tap_events.md

@@ -62,6 +62,10 @@ in `MultiTapDispatcher`), "long tap" will be triggered. This event invokes the
 `void onLongTapDown(TapDownEvent)` handler on those components that previously received the
 `onTapDown` event.
 
+By default, the `.longTapDelay` is set to 300 milliseconds, what may be different of the system default.
+You can change this value by setting the `TapConfig.longTapDelay` value.
+It may also be useful for specific accessibility needs.
+
 
 ### onTapUp
 

packages/flame/lib/src/events/flame_game_mixins/multi_tap_dispatcher.dart

@@ -5,6 +5,7 @@ import 'package:flame/src/events/messages/tap_cancel_event.dart';
 import 'package:flame/src/events/messages/tap_down_event.dart';
 import 'package:flame/src/events/messages/tap_up_event.dart';
 import 'package:flame/src/events/tagged_component.dart';
+import 'package:flame/src/events/tap_config.dart';
 import 'package:flame/src/game/flame_game.dart';
 import 'package:flame/src/game/game_render_box.dart';
 import 'package:flutter/gestures.dart';
@@ -120,7 +121,7 @@ class MultiTapDispatcher extends Component implements MultiTapListener {
 
   /// The delay (in seconds) after which a tap is considered a long tap.
   @override
-  double get longTapDelay => 0.300;
+  double get longTapDelay => TapConfig.longTapDelay;
 
   @override
   void handleTap(int pointerId) {}

packages/flame/lib/src/events/game_mixins/multi_touch_tap_detector.dart

@@ -1,4 +1,5 @@
 import 'package:flame/events.dart';
+import 'package:flame/src/events/tap_config.dart';
 import 'package:flame/src/game/game.dart';
 import 'package:flutter/gestures.dart';
 
@@ -22,7 +23,7 @@ mixin MultiTouchTapDetector on Game implements MultiTapListener {
 
   //#region MultiTapListener API
   @override
-  double get longTapDelay => 0.300;
+  double get longTapDelay => TapConfig.longTapDelay;
 
   @override
   void handleTap(int pointerId) => onTap(pointerId);

packages/flame/lib/src/events/tap_config.dart

@@ -0,0 +1,27 @@
+import 'dart:math';
+
+/// [TapConfig] is used to expose specific configurations
+/// related to the tap dispatcher.
+final class TapConfig {
+  TapConfig._();
+
+  static double _longTapDelay = _defaultLongTapDelay;
+
+  /// The delay (in seconds) after which a tap is considered a long tap.
+  static double get longTapDelay => _longTapDelay;
+
+  /// Set the delay (in seconds) after which a tap is considered a long tap.
+  /// Same games may want to change the long tap delay to better
+  /// fit their needs or accessibility requirements.
+  static set longTapDelay(double value) {
+    _longTapDelay = max(_minLongTapDelay, value);
+  }
+
+  /// Min delay to long tap delay is defined below.
+  /// Values too low don't make sense because they
+  /// would be basically a regular tap.
+  static const double _minLongTapDelay = 0.150;
+
+  /// Default long tap delay is 0.3 seconds.
+  static const double _defaultLongTapDelay = 0.3;
+}

packages/flame/test/events/tap_config_test.dart

@@ -0,0 +1,20 @@
+import 'package:flame/src/events/tap_config.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('TapConfig', () {
+    test('default longTapDelay is 0.3', () {
+      expect(TapConfig.longTapDelay, 0.3);
+    });
+
+    test('longTapDelay can be set new values', () {
+      TapConfig.longTapDelay = 0.5;
+      expect(TapConfig.longTapDelay, 0.5);
+    });
+
+    test('longTapDelay cannot be set to a value lower than 0.150', () {
+      TapConfig.longTapDelay = 0.1;
+      expect(TapConfig.longTapDelay, 0.150);
+    });
+  });
+}