fix(0.76, macOS): reconcile coordinate systems for mouse events (#2403) #2405
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…2403) On iOS, [-hitTest:withEvent:](https://developer.apple.com/documentation/uikit/uiview/hittest(_:with:)?changes=la_3_2_7_2_8&language=objc) works with the coordinate system of the view that is being hit tested. On the other hand, on macOS, [-hitTest:](https://developer.apple.com/documentation/appkit/nsview/hittest(_:)?language=objc) works with the coordinate system of the *superview*. React Native macOS currently appears to mix these two coordinate systems, which can lead to unexpected behaviors, one of which that I have personally observed is `mouseDown:` events being delievered to a view that does not pass OS-level hit testing (e.g. the hit point is completely outside of the view that was allegedly hit, even if accounting for not clipping to bounds and any possible descendant view larger than the hit view). To enforce consistent behavior, we will use the macOS style coordinate system for APIs that follow the macOS signature, and the iOS style coordinate system for APIs that follow the iOS signature, or are obviously React Native APIs. Several APIs were scrubbed for calls and implementation. The following APIs shall work with superview's coordinate space: * `- hitTest:` The following APIs shall work with the view's (i.e. self) coordinate space: * `RCTUIViewHitTestWithEvent` * `- reactTagAtMouseLocationFromEvent:` * `- reactTagAtPoint:` * `- hitTest:withEvent:` * `- betterHitTest:withEvent:` * `- pointInside:withEvent:` With the proper coordinate system usage, we no longer need new RN components inheriting from NSView to behave in special manners. Updating documentation to reflect that. Manual Testing: * Downstream scenario around misrouted mouseDown: events was verified fixed * Sanity tested mouse clicks -- everything seems to work as expected
JunielKatarn
approved these changes
Mar 8, 2025
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On iOS, -hitTest:withEvent: works with the coordinate system of the view that is being hit tested. On the other hand, on macOS, -hitTest: works with the coordinate system of the superview. React Native macOS currently appears to mix these two coordinate systems, which can lead to unexpected behaviors, one of which that I have personally observed is
mouseDown:events being delievered to a view that does not pass OS-level hit testing (e.g. the hit point is completely outside of the view that was allegedly hit, even if accounting for not clipping to bounds and any possible descendant view larger than the hit view).To enforce consistent behavior, we will use the macOS style coordinate system for APIs that follow the macOS signature, and the iOS style coordinate system for APIs that follow the iOS signature, or are obviously React Native APIs. Several APIs were scrubbed for calls and implementation.
The following APIs shall work with superview's coordinate space:
- hitTest:The following APIs shall work with the view's (i.e. self) coordinate space:
RCTUIViewHitTestWithEvent- reactTagAtMouseLocationFromEvent:- reactTagAtPoint:- hitTest:withEvent:- betterHitTest:withEvent:- pointInside:withEvent:With the proper coordinate system usage, we no longer need new RN components inheriting from NSView to behave in special manners. Updating documentation to reflect that.
Manual Testing:
Summary:
Test Plan: