opt image viewer gesture

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/gesture/horizontal_drag_gesture_recognizer.dart

@@ -1,26 +1,29 @@
 import 'package:PiliPlus/utils/storage_pref.dart';
 import 'package:flutter/gestures.dart';
 
-class CustomHorizontalDragGestureRecognizer
-    extends HorizontalDragGestureRecognizer {
-  CustomHorizontalDragGestureRecognizer({
-    super.debugOwner,
-    super.supportedDevices,
-    super.allowedButtonsFilter,
-  });
-
+mixin InitialPositionMixin on GestureRecognizer {
   Offset? _initialPosition;
   Offset? get initialPosition => _initialPosition;
 
-  @override
-  DeviceGestureSettings get gestureSettings => _gestureSettings;
-  final _gestureSettings = DeviceGestureSettings(touchSlop: touchSlopH);
-
   @override
   void addAllowedPointer(PointerDownEvent event) {
     super.addAllowedPointer(event);
     _initialPosition = event.position;
   }
+}
+
+class CustomHorizontalDragGestureRecognizer
+    extends HorizontalDragGestureRecognizer
+    with InitialPositionMixin {
+  CustomHorizontalDragGestureRecognizer({
+    super.debugOwner,
+    super.supportedDevices,
+    super.allowedButtonsFilter,
+  });
+
+  @override
+  DeviceGestureSettings get gestureSettings => _gestureSettings;
+  final _gestureSettings = DeviceGestureSettings(touchSlop: touchSlopH);
 
   @override
   bool hasSufficientGlobalDistanceToAccept(
@@ -41,7 +44,7 @@ double touchSlopH = Pref.touchSlopH;
 
 bool _computeHitSlop(
   double globalDistanceMoved,
-  DeviceGestureSettings? settings,
+  DeviceGestureSettings settings,
   PointerDeviceKind kind,
   Offset? initialPosition,
   Offset lastPosition,
@@ -53,10 +56,10 @@ bool _computeHitSlop(
     case PointerDeviceKind.invertedStylus:
     case PointerDeviceKind.unknown:
     case PointerDeviceKind.touch:
-      return globalDistanceMoved > touchSlopH &&
+      return globalDistanceMoved > settings.touchSlop! &&
           _calc(initialPosition!, lastPosition);
     case PointerDeviceKind.trackpad:
-      return globalDistanceMoved > (settings?.touchSlop ?? kTouchSlop);
+      return globalDistanceMoved > settings.touchSlop!;
   }
 }
 

lib/common/widgets/gesture/image_horizontal_drag_gesture_recognizer.dart

@@ -1,22 +1,22 @@
 import 'package:PiliPlus/common/widgets/gesture/horizontal_drag_gesture_recognizer.dart';
+import 'package:PiliPlus/utils/platform_utils.dart';
 import 'package:flutter/gestures.dart';
 
 mixin ImageGestureRecognizerMixin on GestureRecognizer {
   int? _pointer;
 
   @override
-  void addPointer(PointerDownEvent event) {
+  void addPointer(PointerDownEvent event, {bool isPointerAllowed = true}) {
     if (_pointer == event.pointer) {
       return;
     }
     _pointer = event.pointer;
-    super.addPointer(event);
+    if (isPointerAllowed) {
+      super.addPointer(event);
+    }
   }
 }
 
-typedef IsBoundaryAllowed =
-    bool Function(Offset? initialPosition, OffsetPair lastPosition);
-
 class ImageHorizontalDragGestureRecognizer
     extends CustomHorizontalDragGestureRecognizer
     with ImageGestureRecognizerMixin {
@@ -26,23 +26,62 @@ class ImageHorizontalDragGestureRecognizer
     super.allowedButtonsFilter,
   });
 
-  IsBoundaryAllowed? isBoundaryAllowed;
+  static final double _touchSlop = PlatformUtils.isDesktop
+      ? kPrecisePointerHitSlop
+      : 3.0;
 
   @override
-  bool hasSufficientGlobalDistanceToAccept(
-    PointerDeviceKind pointerDeviceKind,
-    double? deviceTouchSlop,
-  ) {
-    return super.hasSufficientGlobalDistanceToAccept(
-          pointerDeviceKind,
-          deviceTouchSlop,
-        ) &&
-        (isBoundaryAllowed?.call(initialPosition, lastPosition) ?? true);
+  DeviceGestureSettings get gestureSettings => _gestureSettings;
+  final _gestureSettings = DeviceGestureSettings(touchSlop: _touchSlop);
+
+  bool isAtLeftEdge = false;
+  bool isAtRightEdge = false;
+
+  void setAtBothEdges() {
+    isAtLeftEdge = isAtRightEdge = true;
+  }
+
+  bool _isEdgeAllowed(double dx) {
+    if ((initialPosition!.dx - dx).abs() < _touchSlop) return true;
+    if (isAtLeftEdge) {
+      if (isAtRightEdge) {
+        return _hasAcceptedOrChecked = true;
+      }
+      _hasAcceptedOrChecked = true;
+      return initialPosition!.dx < dx;
+    } else if (isAtRightEdge) {
+      _hasAcceptedOrChecked = true;
+      return initialPosition!.dx > dx;
+    }
+    return true;
   }
 
   @override
-  void dispose() {
-    isBoundaryAllowed = null;
-    super.dispose();
+  void handleEvent(PointerEvent event) {
+    if (!_hasAcceptedOrChecked &&
+        event is PointerMoveEvent &&
+        _pointer == event.pointer) {
+      if (!_isEdgeAllowed(event.position.dx)) {
+        rejectGesture(event.pointer);
+        return;
+      }
+    }
+    super.handleEvent(event);
+  }
+
+  bool _hasAcceptedOrChecked = false;
+
+  @override
+  void acceptGesture(int pointer) {
+    _hasAcceptedOrChecked = true;
+    super.acceptGesture(pointer);
+  }
+
+  @override
+  void stopTrackingPointer(int pointer) {
+    _hasAcceptedOrChecked = false;
+    isAtLeftEdge = false;
+    isAtRightEdge = false;
+    super.stopTrackingPointer(pointer);
   }
 }