From 0c150b2289818267c940b6e726ec2f7725659817 Mon Sep 17 00:00:00 2001
From: Vincent Riemer <vincentriemer@meta.com>
Date: Wed, 18 Jan 2023 13:43:21 -0800
Subject: [PATCH] Add explicit support for Apple Pencil hovering

Summary:
Changelog: [IOS][ADDED] - Add explicit support for M2 iPad Apple Pencil hovering in the Pointer Events implementation

I personally am not a huge fan of how this has to be implemented but it's literally the way Apple suggests to differentiate between mouse and pen hover events.

Reviewed By: lunaleaps

Differential Revision: D40962916

fbshipit-source-id: a6fb5bcfe19bcf500021922baac3fa7c4375a874
---
 React/Fabric/RCTSurfaceTouchHandler.mm | 57 ++++++++++++++++++--------
 1 file changed, 41 insertions(+), 16 deletions(-)

diff --git a/React/Fabric/RCTSurfaceTouchHandler.mm b/React/Fabric/RCTSurfaceTouchHandler.mm
index c6b7fd9dcaf8ff..1fd0fda0fffed3 100644
--- a/React/Fabric/RCTSurfaceTouchHandler.mm
+++ b/React/Fabric/RCTSurfaceTouchHandler.mm
@@ -374,18 +374,17 @@ static PointerEvent CreatePointerEventFromActiveTouch(ActiveTouch activeTouch, R
 }
 
 static PointerEvent CreatePointerEventFromIncompleteHoverData(
+    int pointerId,
+    std::string pointerType,
     CGPoint clientLocation,
     CGPoint screenLocation,
     CGPoint offsetLocation,
     UIKeyModifierFlags modifierFlags)
 {
   PointerEvent event = {};
-  // "touch" events produced from a mouse cursor on iOS always have the ID 0 so
-  // we can just assume that here since these sort of hover events only ever come
-  // from the mouse
-  event.pointerId = kMousePointerId;
+  event.pointerId = pointerId;
   event.pressure = 0.0;
-  event.pointerType = "mouse";
+  event.pointerType = pointerType;
   event.clientPoint = RCTPointFromCGPoint(clientLocation);
   event.screenPoint = RCTPointFromCGPoint(screenLocation);
   event.offsetPoint = RCTPointFromCGPoint(offsetLocation);
@@ -473,7 +472,9 @@ @implementation RCTSurfaceTouchHandler {
   __weak UIView *_rootComponentView;
   IdentifierPool<11> _identifierPool;
 
-  UIHoverGestureRecognizer *_hoverRecognizer API_AVAILABLE(ios(13.0));
+  UIHoverGestureRecognizer *_mouseHoverRecognizer API_AVAILABLE(ios(13.0));
+  UIHoverGestureRecognizer *_penHoverRecognizer API_AVAILABLE(ios(13.0));
+
   NSMutableDictionary<NSNumber *, NSOrderedSet<RCTReactTaggedView *> *> *_currentlyHoveredViewsPerPointer;
 
   int _primaryTouchPointerId;
@@ -492,7 +493,9 @@ - (instancetype)init
 
     self.delegate = self;
 
-    _hoverRecognizer = nil;
+    _mouseHoverRecognizer = nil;
+    _penHoverRecognizer = nil;
+
     _currentlyHoveredViewsPerPointer = [[NSMutableDictionary alloc] init];
     _primaryTouchPointerId = -1;
   }
@@ -510,9 +513,14 @@ - (void)attachToView:(UIView *)view
   _rootComponentView = view;
 
   if (RCTGetDispatchW3CPointerEvents()) {
-    if (@available(iOS 13.0, *)) {
-      _hoverRecognizer = [[UIHoverGestureRecognizer alloc] initWithTarget:self action:@selector(hovering:)];
-      [view addGestureRecognizer:_hoverRecognizer];
+    if (@available(iOS 13.4, *)) {
+      _mouseHoverRecognizer = [[UIHoverGestureRecognizer alloc] initWithTarget:self action:@selector(mouseHovering:)];
+      _mouseHoverRecognizer.allowedTouchTypes = @[ @(UITouchTypeIndirectPointer) ];
+      [view addGestureRecognizer:_mouseHoverRecognizer];
+
+      _penHoverRecognizer = [[UIHoverGestureRecognizer alloc] initWithTarget:self action:@selector(penHovering:)];
+      _penHoverRecognizer.allowedTouchTypes = @[ @(UITouchTypePencil) ];
+      [view addGestureRecognizer:_penHoverRecognizer];
     }
   }
 }
@@ -525,9 +533,14 @@ - (void)detachFromView:(UIView *)view
   [view removeGestureRecognizer:self];
   _rootComponentView = nil;
 
-  if (_hoverRecognizer != nil) {
-    [view removeGestureRecognizer:_hoverRecognizer];
-    _hoverRecognizer = nil;
+  if (_mouseHoverRecognizer != nil) {
+    [view removeGestureRecognizer:_mouseHoverRecognizer];
+    _mouseHoverRecognizer = nil;
+  }
+
+  if (_penHoverRecognizer != nil) {
+    [view removeGestureRecognizer:_penHoverRecognizer];
+    _penHoverRecognizer = nil;
   }
 }
 
@@ -845,7 +858,19 @@ - (void)_cancelTouches
   [self setEnabled:YES];
 }
 
-- (void)hovering:(UIHoverGestureRecognizer *)recognizer API_AVAILABLE(ios(13.0))
+- (void)penHovering:(UIHoverGestureRecognizer *)recognizer API_AVAILABLE(ios(13.0))
+{
+  [self hovering:recognizer pointerId:kPencilPointerId pointerType:"pen"];
+}
+
+- (void)mouseHovering:(UIHoverGestureRecognizer *)recognizer API_AVAILABLE(ios(13.0))
+{
+  [self hovering:recognizer pointerId:kMousePointerId pointerType:"mouse"];
+}
+
+- (void)hovering:(UIHoverGestureRecognizer *)recognizer
+       pointerId:(int)pointerId
+     pointerType:(std::string)pointerType API_AVAILABLE(ios(13.0))
 {
   UIView *listenerView = recognizer.view;
   CGPoint clientLocation = [recognizer locationInView:listenerView];
@@ -864,8 +889,8 @@ - (void)hovering:(UIHoverGestureRecognizer *)recognizer API_AVAILABLE(ios(13.0))
     modifierFlags = 0;
   }
 
-  PointerEvent event =
-      CreatePointerEventFromIncompleteHoverData(clientLocation, screenLocation, offsetLocation, modifierFlags);
+  PointerEvent event = CreatePointerEventFromIncompleteHoverData(
+      pointerId, pointerType, clientLocation, screenLocation, offsetLocation, modifierFlags);
 
   NSOrderedSet<RCTReactTaggedView *> *eventPathViews = [self handleIncomingPointerEvent:event onView:targetView];
   SharedTouchEventEmitter eventEmitter = GetTouchEmitterFromView(targetView, offsetLocation);