[WIP] Fix issue where shadows may not appear on views

[Liron Yahdav (lyahdav)]

Credit goes to Scott Kyle (@appden). This isn't ready to commit because NSShadow.shadowBlurRadius is slightly different than CALayer.shadowRadius.

Fixes#824

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Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 71e8921
Branch: main

[Saad Najmi (Saadnajmi)]

Thanks! I didn't realize there was a shadowBlurRadius separate from shadowRadius :)

Mike Schreiber (@mischreiber)Liron Yahdav (@lyahdav)

[Saad Najmi (Saadnajmi)]

Liron Yahdav (@lyahdav) a quick update from our side. We have a bug on our plate to to fix shadows on macOS, but the engineer that's assigned to is on vacation, so we'll revisit once they are back. When I locally tested this, it almost felt like they were two shadows showing up, one from the original iOS layer.shadow* setters, and one from the NSShadow property you added. As for NSShadow.shadowBlurRadius vs shadowRadius, Apple documentation has me thinking they both control the same thing :)

[Saad Najmi (Saadnajmi)]

From local testing, it seems the shadow on the layer through the props in RCTViewManager is still showing up half the time, so it feels like we have 2 shadows:

• The one from the shadow override you introduced
• The one from layer, which only shows up half the time because of undefined behavior described here: Refactor to not modify view-backing layer properties which is documented as undefined behavior by Apple  #466

Could you instead change the RCTVIewManager macros to CUSTOM_VIEW_PROPERTY like we do here so we never set it directly on the layer? #1035

[Liron Yahdav (lyahdav)]

Saad Najmi (@Saadnajmi) I wasn't planning on trying to land this anytime soon, I just made this PR to share WIP. You can make a new PR with your suggested change.

[Christoph Purrer (christophpurrer)]

It seems that issue was fixed in #1352

[Saad Najmi (Saadnajmi)]

It seems that issue was fixed in #1352

Yep! We needed a little bit of extra code, so do give it a look.