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Suspend overlapping view transitions (#56462)#56462

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zeyap:export-D99366975
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Suspend overlapping view transitions (#56462)#56462
zeyap wants to merge 6 commits intofacebook:mainfrom
zeyap:export-D99366975

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@zeyap zeyap commented Apr 15, 2026

Summary:

Changelog:

[Internal] [Added] - Suspend overlapping view transitions

When a new view transition starts while another is still active, queue it instead of running immediately. The queued transition runs after the current one finishes via startViewTransitionEnd (triggered when transition truly finishes).

  • Add suspendOnActiveViewTransition() to UIManagerViewTransitionDelegate, exposed as a method on nativeFabricUIManager so the reconciler can signal suspension
  • ViewTransitionModule queues pending transitions in a std::queue<PendingTransition> when suspendNextTransition_ is set
  • startViewTransitionEnd drains the queue sequentially, each transition triggering the next on completion

Reviewed By: sammy-SC

Differential Revision: D99366975

@meta-cla meta-cla bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Apr 15, 2026
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meta-codesync bot commented Apr 15, 2026

@zeyap has exported this pull request. If you are a Meta employee, you can view the originating Diff in D99366975.

@meta-codesync meta-codesync bot changed the title Suspend overlapping view transitions Suspend overlapping view transitions (#56462) Apr 15, 2026
zeyap added a commit to zeyap/react-native that referenced this pull request Apr 15, 2026
Summary:
Pull Request resolved: facebook#56462

## Changelog:

[Internal] [Added] - Suspend overlapping view transitions

When a new view transition starts while another is still active, queue it instead of running immediately. The queued transition runs after the current one finishes via `startViewTransitionEnd` (triggered when transition truly finishes).

- Add `suspendOnActiveViewTransition()` to `UIManagerViewTransitionDelegate`, exposed as a method on `nativeFabricUIManager` so the reconciler can signal suspension
- `ViewTransitionModule` queues pending transitions in a `std::queue<PendingTransition>` when `suspendNextTransition_` is set
- `startViewTransitionEnd` drains the queue sequentially, each transition triggering the next on completion

Reviewed By: sammy-SC

Differential Revision: D99366975
@zeyap zeyap force-pushed the export-D99366975 branch from 1e94858 to 9a77fa0 Compare April 15, 2026 18:23
Zeya Peng added 5 commits April 15, 2026 11:50
Summary:
Implement `createViewTransitionInstance`, which is invoked by the React reconciler to create pseudo-element shadow nodes that visually represent the old state of elements participating in a view transition.

Key changes:
- Add `createViewTransitionInstance` JSI binding in `UIManagerBinding`, accepting a transition name and pseudo-element tag
- Add virtual `createViewTransitionInstance` method to `UIManagerViewTransitionDelegate`
- Implement the method in `ViewTransitionModule`: creates an absolutely-positioned, non-interactive `View` shadow node matching the old element's layout metrics (position, size)
- Manage two pseudo-element node maps: `oldPseudoElementNodes_` for the current transition and `oldPseudoElementNodesForNextTransition_` for entering nodes that may exit in a future transition
- Update `getOldViewTransitionInstance` to return the pseudo-element's tag (instead of the original element's tag) when a pseudo-element exists
- Add `applySnapshotsOnPseudoElementShadowNodes` stub for future platform-level bitmap snapshot integration

`createViewTransitionInstance` is typically called after `applyViewTransitionName` in the React reconciler. See the diagram below for the full flow.

{F1987481080}

Differential Revision: D98981886
Summary:
Append view transition pseudo-element shadow nodes to the root's children at commit time (`shadowTreeWillCommit`), so they are committed into the shadow tree and rendered by the platform.

Key changes:
- Add `getPseudoElementNodes(surfaceId)` virtual method to `UIManagerViewTransitionDelegate`, returning pseudo-element shadow nodes filtered by surface ID
- Implement the method in `ViewTransitionModule`, iterating over `oldPseudoElementNodes_` and collecting nodes matching the given surface
- In `shadowTreeWillCommit`, when view transitions are enabled, query the delegate for pseudo-element nodes and insert them at the end of `rootChildren` before committing

This ensures pseudo-element nodes (created by `createViewTransitionInstance`) are included in the committed shadow tree and ultimately mounted as platform views that display old-element snapshots during transitions.

Differential Revision: D98982122
Summary:
Add `findPseudoElementShadowNodeByTag` to look up pseudo-element shadow nodes by tag from JS, and update the animation helper to connect animated nodes to pseudo-element shadow nodes for old-element animations.

Key changes:
- Add `findPseudoElementShadowNodeByTag(tag)` virtual method to `UIManagerViewTransitionDelegate` and implement in `ViewTransitionModule` (linear scan over `oldPseudoElementNodes_`)
- Expose the method via `NativeViewTransition` TurboModule so JS can resolve a pseudo-element's shadow node by its native tag
- Add `findPseudoElementShadowNodeByTag` to `NativeViewTransition.js` spec
- Update `ViewTransitionAnimationHelper.js`:
  - `animateInternal` accepts a new `pseudo` parameter (`'old'` | `'new'`)
  - When `pseudo === 'old'`, use `findPseudoElementShadowNodeByTag` instead of `findShadowNodeByTag_DEPRECATED` to connect animated nodes to the correct shadow node family
  - Pass `'new'` for enter animations and propagate `_pseudo` from pseudo-element objects for exit animations

Differential Revision: D98982251
Summary:
Wire view transition bitmap snapshot capture and display through the C++
delegate chain so platforms can implement snapshotting old-element views.

**ViewTransitionModule.cpp**: Call `uiManagerDidCaptureViewSnapshot(tag,
surfaceId)` in `applyViewTransitionName` to capture a bitmap of the old view
while it is still mounted, and `uiManagerDidSetViewSnapshot(sourceTag,
targetTag, surfaceId)` in `applySnapshotsOnPseudoElementShadowNodes` to map
captured bitmaps onto pseudo-element views.

**UIManagerDelegate / SchedulerDelegate**: Add pure virtual
`captureViewSnapshot` and `setViewSnapshot` methods.

**Scheduler**: Forward `UIManagerDelegate` calls to `SchedulerDelegate`.

**Platform stubs**: Empty implementations for iOS (`RCTScheduler.mm`),
CxxPlatform (`SchedulerDelegateImpl`), and Android JNI
(`FabricUIManagerBinding`) — Android implementation follows in D99173446.

Differential Revision: D98354659
Summary:
Implement the Android side of view transition bitmap snapshots.

**`ViewTransitionSnapshotManager`** (new Kotlin class):
Manages the full snapshot lifecycle as a `UIManagerListener`. Captures bitmaps
on the UI thread, maps them from source to target pseudo-element tags,
re-applies after mount cycles (since views may be recreated), and self-cleans
when views are deleted.

**JNI bridge:**
`FabricUIManagerBinding` → `FabricMountingManager` → `FabricUIManager` JNI
delegates to the snapshot manager.

**`SurfaceMountingManager.applyViewSnapshot`:** sets bitmap as view background
using the KTX `Bitmap.toDrawable` extension.

Differential Revision: D99173446
zeyap added a commit to zeyap/react-native that referenced this pull request Apr 15, 2026
Summary:
Pull Request resolved: facebook#56462

## Changelog:

[Internal] [Added] - Suspend overlapping view transitions

When a new view transition starts while another is still active, queue it instead of running immediately. The queued transition runs after the current one finishes via `startViewTransitionEnd` (triggered when transition truly finishes).

- Add `suspendOnActiveViewTransition()` to `UIManagerViewTransitionDelegate`, exposed as a method on `nativeFabricUIManager` so the reconciler can signal suspension
- `ViewTransitionModule` queues pending transitions in a `std::queue<PendingTransition>` when `suspendNextTransition_` is set
- `startViewTransitionEnd` drains the queue sequentially, each transition triggering the next on completion

Reviewed By: sammy-SC

Differential Revision: D99366975
@zeyap zeyap force-pushed the export-D99366975 branch from 9a77fa0 to 8b31c55 Compare April 15, 2026 19:12
Summary:
Pull Request resolved: facebook#56462

## Changelog:

[Internal] [Added] - Suspend overlapping view transitions

When a new view transition starts while another is still active, queue it instead of running immediately. The queued transition runs after the current one finishes via `startViewTransitionEnd` (triggered when transition truly finishes).

- Add `suspendOnActiveViewTransition()` to `UIManagerViewTransitionDelegate`, exposed as a method on `nativeFabricUIManager` so the reconciler can signal suspension
- `ViewTransitionModule` queues pending transitions in a `std::queue<PendingTransition>` when `suspendNextTransition_` is set
- `startViewTransitionEnd` drains the queue sequentially, each transition triggering the next on completion

Reviewed By: sammy-SC

Differential Revision: D99366975
@zeyap zeyap force-pushed the export-D99366975 branch from 8b31c55 to 2d34a6c Compare April 15, 2026 20:32
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