[Native] Use correct coordinate space when using native detector

packages/react-native-gesture-handler/android/src/main/java/com/swmansion/gesturehandler/core/GestureHandler.kt

@@ -9,7 +9,6 @@ import android.view.MotionEvent
 import android.view.MotionEvent.PointerCoords
 import android.view.MotionEvent.PointerProperties
 import android.view.View
-import androidx.core.view.isNotEmpty
 import com.facebook.react.bridge.Arguments
 import com.facebook.react.bridge.ReactContext
 import com.facebook.react.bridge.ReadableMap
@@ -48,6 +47,26 @@ open class GestureHandler {
       }
     }
 
+  /**
+   * The view whose coordinate space should be used when reporting event positions to JS.
+   *
+   * Handlers attached via the V3 NativeDetector are registered against the DetectorView wrapper,
+   * which never carries user-applied transforms — those live on its child. When the detector has
+   * exactly one child we descend into it so reported coordinates match the visible (transformed)
+   * view, the same coordinate space V2 and the V3 VirtualGestureDetector report in. With
+   * multiple children there is no JS-side way to disambiguate which child caught the pointer,
+   * so we keep the detector itself as the reference frame.
+   */
+  val coordinateView: View?
+    get() {
+      val v = view
+      return if (v is RNGestureHandlerDetectorView && v.childCount == 1) {
+        v.getChildAt(0)
+      } else {
+        v
+      }
+    }
+
   var state = STATE_UNDETERMINED
     private set
   var x = 0f
@@ -387,42 +406,13 @@ open class GestureHandler {
 
     numberOfPointers = adaptedTransformedEvent.pointerCount
 
-    // TODO: this is likely wrong, and the transformed event itself should be
-    // in the coordinate system of the child view, but I'm not sure of the
-    // consequences
-    val detectorView = hostDetectorView
-    if (detectorView != null && view == detectorView && detectorView.isNotEmpty()) {
-      val outPoint = PointF()
-      var foundChild = false
-
-      for (i in 0 until detectorView.childCount) {
-        val child = detectorView.getChildAt(i)
-        GestureHandlerOrchestrator.transformPointToChildViewCoords(
-          adaptedTransformedEvent.x,
-          adaptedTransformedEvent.y,
-          detectorView,
-          child,
-          outPoint,
-        )
-        if (isWithinBounds(child, outPoint.x, outPoint.y)) {
-          x = outPoint.x
-          y = outPoint.y
-          isWithinBounds = true
-          foundChild = true
-          break
-        }
-      }
-
-      if (!foundChild) {
-        x = adaptedTransformedEvent.x
-        y = adaptedTransformedEvent.y
-        isWithinBounds = false
-      }
-    } else {
-      x = adaptedTransformedEvent.x
-      y = adaptedTransformedEvent.y
-      isWithinBounds = isWithinBounds(view, x, y)
-    }
+    x = adaptedTransformedEvent.x
+    y = adaptedTransformedEvent.y
+    // The orchestrator transforms incoming events into the coordinate space of the detector's
+    // child (when the handler is attached to a NativeDetector wrapper), so bounds-checking must
+    // also use that child rather than the wrapper, otherwise hit-testing would ignore the user's
+    // transforms applied to the visible view.
+    isWithinBounds = isWithinBounds(coordinateView, x, y)
 
     if (shouldCancelWhenOutside) {
       if (!isWithinBounds && (state == STATE_ACTIVE || state == STATE_BEGAN)) {
@@ -872,7 +862,7 @@ open class GestureHandler {
    * This method modifies and transforms the received point.
    */
   protected fun transformPoint(point: PointF): PointF =
-    orchestrator?.transformPointToViewCoords(this.view, point) ?: run {
+    orchestrator?.transformPointToViewCoords(coordinateView, point) ?: run {
       point.x = Float.NaN
       point.y = Float.NaN
       point

packages/react-native-gesture-handler/android/src/main/java/com/swmansion/gesturehandler/core/GestureHandlerOrchestrator.kt

@@ -297,7 +297,7 @@ class GestureHandlerOrchestrator(
     }
 
     val action = sourceEvent.actionMasked
-    val event = transformEventToViewCoords(handler.view, MotionEvent.obtain(sourceEvent))
+    val event = transformEventToViewCoords(handler.coordinateView, MotionEvent.obtain(sourceEvent))
 
     if (handler.needsPointerData) {
       handler.updatePointerData(event, sourceEvent)

packages/react-native-gesture-handler/apple/Handlers/RNForceTouchHandler.m

@@ -170,7 +170,7 @@ - (void)updateConfig:(NSDictionary *)config
 - (RNGestureHandlerEventExtraData *)eventExtraData:(RNForceTouchGestureRecognizer *)recognizer
 {
   return [RNGestureHandlerEventExtraData forForce:recognizer.force
-                                      forPosition:[recognizer locationInView:recognizer.view]
+                                      forPosition:[recognizer locationInView:self.coordinateView]
                              withAbsolutePosition:[recognizer locationInView:recognizer.view.window]
                               withNumberOfTouches:recognizer.numberOfTouches
                                   withPointerType:_pointerType];

packages/react-native-gesture-handler/apple/Handlers/RNHoverHandler.m

@@ -177,7 +177,7 @@ - (void)setCurrentPointerType:(RNGestureHandlerPointerType)pointerType
 
 - (RNGestureHandlerEventExtraData *)eventExtraData:(UIGestureRecognizer *)recognizer
 {
-  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:recognizer.view]
+  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:self.coordinateView]
                                 withAbsolutePosition:[recognizer locationInView:recognizer.view.window]
                                      withPointerType:_pointerType];
 }

packages/react-native-gesture-handler/apple/Handlers/RNLongPressHandler.m

@@ -287,7 +287,7 @@ - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
 
 - (RNGestureHandlerEventExtraData *)eventExtraData:(UIGestureRecognizer *)recognizer
 {
-  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:recognizer.view]
+  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:self.coordinateView]
                                 withAbsolutePosition:[recognizer locationInView:recognizer.view.window]
                                  withNumberOfTouches:recognizer.numberOfTouches
                                         withDuration:[(RNBetterLongPressGestureRecognizer *)recognizer getDuration]
@@ -298,7 +298,7 @@ - (RNGestureHandlerEventExtraData *)eventExtraData:(UIGestureRecognizer *)recogn
 
 - (RNGestureHandlerEventExtraData *)eventExtraData:(NSGestureRecognizer *)recognizer
 {
-  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:recognizer.view]
+  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:self.coordinateView]
                                 withAbsolutePosition:[recognizer locationInView:recognizer.view.window.contentView]
                                  withNumberOfTouches:1
                                         withDuration:[(RNBetterLongPressGestureRecognizer *)recognizer getDuration]

packages/react-native-gesture-handler/apple/Handlers/RNPanHandler.m

@@ -452,7 +452,7 @@ - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
 #if TARGET_OS_OSX
 - (RNGestureHandlerEventExtraData *)eventExtraData:(NSPanGestureRecognizer *)recognizer
 {
-  return [RNGestureHandlerEventExtraData forPan:[recognizer locationInView:recognizer.view]
+  return [RNGestureHandlerEventExtraData forPan:[recognizer locationInView:self.coordinateView]
                            withAbsolutePosition:[recognizer locationInView:recognizer.view.window.contentView]
                                 withTranslation:[recognizer translationInView:recognizer.view.window.contentView]
                                    withVelocity:[recognizer velocityInView:recognizer.view.window.contentView]
@@ -466,7 +466,7 @@ - (RNGestureHandlerEventExtraData *)eventExtraData:(UIPanGestureRecognizer *)rec
   RNBetterPanGestureRecognizer *panRecognizer = (RNBetterPanGestureRecognizer *)recognizer;
 
   return [RNGestureHandlerEventExtraData
-                    forPan:[recognizer locationInView:recognizer.view]
+                    forPan:[recognizer locationInView:self.coordinateView]
       withAbsolutePosition:[recognizer locationInView:recognizer.view.window]
            withTranslation:[recognizer translationInView:recognizer.view.window]
               withVelocity:[recognizer velocityInView:recognizer.view.window]

packages/react-native-gesture-handler/apple/Handlers/RNPinchHandler.m

@@ -167,7 +167,7 @@ - (instancetype)initWithTag:(NSNumber *)tag
 - (RNGestureHandlerEventExtraData *)eventExtraData:(NSMagnificationGestureRecognizer *)recognizer
 {
   return [RNGestureHandlerEventExtraData forPinch:recognizer.magnification
-                                   withFocalPoint:[recognizer locationInView:recognizer.view]
+                                   withFocalPoint:[recognizer locationInView:self.coordinateView]
                                      withVelocity:((RNBetterPinchRecognizer *)recognizer).velocity
                               withNumberOfTouches:2
                                   withPointerType:RNGestureHandlerMouse];
@@ -177,20 +177,21 @@ - (RNGestureHandlerEventExtraData *)eventExtraData:(UIPinchGestureRecognizer *)r
 {
   CGPoint focalPoint;
   NSUInteger numberOfTouches = recognizer.numberOfTouches;
+  RNGHUIView *coordinateView = self.coordinateView;
 
   if (numberOfTouches > 0) {
     CGPoint accumulatedPoint = CGPointZero;
 
     for (int i = 0; i < numberOfTouches; i++) {
-      CGPoint location = [recognizer locationOfTouch:i inView:recognizer.view];
+      CGPoint location = [recognizer locationOfTouch:i inView:coordinateView];
       accumulatedPoint.x += location.x;
       accumulatedPoint.y += location.y;
     }
 
     focalPoint = CGPointMake(accumulatedPoint.x / numberOfTouches, accumulatedPoint.y / numberOfTouches);
   } else {
     // Trackpad pinch gestures may report 0 touches - use the recognizer's location instead
-    focalPoint = [recognizer locationInView:recognizer.view];
+    focalPoint = [recognizer locationInView:coordinateView];
   }
 
   return [RNGestureHandlerEventExtraData forPinch:recognizer.scale

packages/react-native-gesture-handler/apple/Handlers/RNRotationHandler.m

@@ -161,7 +161,7 @@ - (instancetype)initWithTag:(NSNumber *)tag
 - (RNGestureHandlerEventExtraData *)eventExtraData:(NSRotationGestureRecognizer *)recognizer
 {
   return [RNGestureHandlerEventExtraData forRotation:-recognizer.rotation
-                                     withAnchorPoint:[recognizer locationInView:recognizer.view]
+                                     withAnchorPoint:[recognizer locationInView:self.coordinateView]
                                         withVelocity:((RNBetterRotationRecognizer *)recognizer).velocity
                                  withNumberOfTouches:2
                                      withPointerType:RNGestureHandlerMouse];
@@ -170,7 +170,7 @@ - (RNGestureHandlerEventExtraData *)eventExtraData:(NSRotationGestureRecognizer
 - (RNGestureHandlerEventExtraData *)eventExtraData:(UIRotationGestureRecognizer *)recognizer
 {
   return [RNGestureHandlerEventExtraData forRotation:recognizer.rotation
-                                     withAnchorPoint:[recognizer locationInView:recognizer.view]
+                                     withAnchorPoint:[recognizer locationInView:self.coordinateView]
                                         withVelocity:recognizer.velocity
                                  withNumberOfTouches:recognizer.numberOfTouches
                                      withPointerType:_pointerType];

packages/react-native-gesture-handler/apple/RNGestureHandler.h

@@ -88,6 +88,17 @@
 @property (nonatomic, copy, nullable) NSNumber *viewTag;
 @property (nonatomic, readonly) RNGestureHandlerState lastState;
 
+/**
+ The view whose coordinate space should be used when reporting event positions to JS.
+ Handlers attached via the V3 NativeDetector are bound to the `RNGestureHandlerDetector` wrapper,
+ which never carries user-applied transforms — those live on its child. When the detector has
+ exactly one subview we descend into it so reported coordinates match the visible (transformed)
+ view, the same coordinate space V2 and the V3 VirtualGestureDetector report in. With multiple
+ subviews there is no JS-side way to disambiguate which child caught the pointer, so we keep
+ the detector itself as the reference frame.
+ */
+@property (nonatomic, readonly, nullable) RNGHUIView *coordinateView;
+
 - (BOOL)isViewParagraphComponent:(nullable RNGHUIView *)view;
 - (nonnull RNGHUIView *)chooseViewForInteraction:(nonnull UIGestureRecognizer *)recognizer;
 - (void)bindToView:(nonnull RNGHUIView *)view;

packages/react-native-gesture-handler/apple/RNGestureHandler.mm

@@ -286,12 +286,12 @@ - (void)unbindFromView
 - (RNGestureHandlerEventExtraData *)eventExtraData:(UIGestureRecognizer *)recognizer
 {
 #if TARGET_OS_OSX
-  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:recognizer.view]
+  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:self.coordinateView]
                                 withAbsolutePosition:[recognizer locationInView:recognizer.view.window.contentView]
                                  withNumberOfTouches:1
                                      withPointerType:RNGestureHandlerMouse];
 #else
-  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:recognizer.view]
+  return [RNGestureHandlerEventExtraData forPosition:[recognizer locationInView:self.coordinateView]
                                 withAbsolutePosition:[recognizer locationInView:recognizer.view.window]
                                  withNumberOfTouches:recognizer.numberOfTouches
                                      withPointerType:_pointerType];
@@ -307,6 +307,16 @@ - (RNGHUIView *)chooseViewForInteraction:(UIGestureRecognizer *)recognizer
   return [self isViewParagraphComponent:recognizer.view] ? recognizer.view.subviews[0] : recognizer.view;
 }
 
+- (RNGHUIView *)coordinateView
+{
+  RNGHUIView *recognizerView = _recognizer.view;
+  if ([self usesNativeOrVirtualDetector] && recognizerView == self.hostDetectorView &&
+      recognizerView.subviews.count == 1) {
+    return recognizerView.subviews[0];
+  }
+  return recognizerView;
+}
+
 - (BOOL)shouldSuppressActiveEvent:(RNGestureHandlerEventExtraData *)extraData
 {
   return NO;