[Fabric] Implement snapToAlignment property for ScrollView #14841
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…ure (#14830) * Initial plan * Implement snapToAlignment support for Fabric ScrollView - interface and prop handling Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Add test support and UI for snapToAlignment in ScrollView Fabric implementation Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Remove unnecessary changes from vnext/codegen files Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Change files * Run yarn change prerelease, yarn lint:fix, and yarn format as requested Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Remove all changes from vnext/codegen files as requested Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Remove XAML dependency from IDL by defining local SnapAlignment enum Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Extract snap alignment conversion into separate function for better readability Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Revert changes to ScrollViewExample.js as requested Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> * Revert changes to ScrollViewComponentTest.test.ts as requested Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com>
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vnext/Microsoft.ReactNative/Fabric/Composition/ScrollViewComponentView.cpp
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Add this case to scrollview/samples |
anupriya13
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It's already added |
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Waiting on review since long time > assigned to @satkh for iteration 2507-02 |
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Description
Type of Change
Why
Implement snapToAlignment property for ScrollView in Fabric
Resolves #13148
What
Implement snapToAlignment property for ScrollView in Fabric
https://reactnative.dev/docs/scrollview#snaptoalignment
Refer IOS implementation https://github.com/facebook/react-native/blob/618279508159191f2b11c0b20446f91e82a27abf/packages/react-native/React/Views/ScrollView/RCTScrollView.m#L833
Background
The
snapToAlignmentproperty was available in RNW Paper via ScrollViewManager but missing from the Fabric implementation, causing a parity gap between the two architectures.We came up with this implementation to ensure that snap points align correctly within the viewport depending on the desired alignment. Since snap positions are relative to the start edge by default, we subtract half the viewport size for center alignment or the full viewport size for end alignment. This way, when scrolling settles on a snap point, it appears at the right position in the visible area.
More context:
What is a snap point?
When the user scrolls or flicks the content, instead of stopping anywhere, the scroller will settle on the closest snap point, making the scrolling feel natural and intentional.
This is what m_snapToAlignment controls:
Start: snap position aligns to start of viewport
Center: snap position aligns to center of viewport
End: snap position aligns to end of viewport
Screenshots
Recording.2025-07-09.122123.mp4
Testing
Tested in playground and e2etestappfabric already added
Changes
Core Implementation
CompositionSwitcher.idlto acceptsnapToAlignmentparameterScrollViewComponentView.cppwith proper enum conversion from React Native to Windows typesChangelog
Should this change be included in the release notes: YES
Add a brief summary of the change to use in the release notes for the next release.
Implement snapToAlignment property for ScrollView in Fabric
Microsoft Reviewers: Open in CodeFlow