Refactor to not modify view-backing layer properties which is documented as undefined behavior by Apple #466
Description
react-native for iOS implements several features (z-order, rotation, shadows, and clipping) by modifying view-backing layer properties directly which is permitted on iOS. When react-native for iOS was ported to react-native-macos it uses the same code as iOS. However, Apple has documented that modifing certain layer props on a layer owned by an NSView is "undefined behavior" since macOS 10.13 (https://developer.apple.com/library/archive/releasenotes/AppKit/RN-AppKit/#10_13Layer-backed%20Views).
Although modifying these layer props work up to macOS 10.15, a future release could break these features. This issue tracks the work to refactor react-native-macos to not modify these layer props. The following table lists the props that should not be modified on a view.layer and annotates where we are currently making modifications:
| Layer prop | view.layer change |
|---|---|
| bounds | |
| position | |
| zPosition | modified by setReactZIndex: in UIView+React.m |
| anchorPoint | |
| anchorPointZ | |
| transform | modified in RCTUIManager and RCTViewManager |
| affineTransform | modified in RCTUIKit by RCTUIView setTransform: |
| frame | |
| hidden | |
| geometryFlipped | |
| masksToBounds | modified by RCTView displayLayer: |
| opaque | |
| compositingFilter | |
| filters | |
| shadowColor | modified by RCTViewManager |
| shadowOpacity | modified by RCTViewManager |
| shadowOffset | modified by RCTViewManager |
| shadowRadius | modified by RCTViewManager |
| shadowPath | modified by RCTUpdateShadowPathForView in RCTView.m |
| layoutManager |