fix(reader): defer zoom state writes out of gesture callbacks - #960
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Publishing isZoomed synchronously from scrollViewDidZoom runs while the pinch gesture is still active, which can crash SwiftUI AttributeGraph on iOS 18 (issue #958). Defer the observable write to the next runloop in NativePagedPageContentView and NativeImagePageViewController, matching the existing pattern in PageScrollView, and skip zoom-scale resets while a pinch gesture is in flight.
everpcpc
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August 22, 2026 13:32
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Summary
Fixes the DIVINA reader crashes on iPadOS 18 reported in #958, where the app crashed on the first pinch-to-zoom gesture and on subsequent tap/drag gestures.
Root Cause
scrollViewDidZoomin the paged DIVINA reader (NativePagedPageContentView) and the Page Curl reader (NativeImagePageViewController) publishedviewModel.isZoomedsynchronously from inside the scroll view's zoom gesture callback. This triggers a SwiftUI re-render chain (DivinaReaderViewre-renders → controls hide →updateUIView→ slot content reconfigure/layout) while the pinch gesture is still in flight — a state publication pattern that crashes AttributeGraph on iOS 18.PageScrollViewalready defers this write viaDispatchQueue.main.async; these two zoom hosts were missing that guard.Changes
isZoomedwrite to the next runloop in both remaining zoom hosts (with a stale-value recheck), matching the existingPageScrollViewpattern.NativePagedPageContentView.resetScrollViewportState()while a pinch gesture is.began/.changed, retrying on the next runloop until the gesture settles. Resetting the scale mid-gesture desyncsUIScrollView's internal gesture state. (iOS only;pinchGestureRecognizeris unavailable on tvOS, where zoom is not user-driven anyway.)Validation
make build-ios/make build-macos/make build-tvosall pass.