fix(main-editor): ignore spurious scale-end on mid-gesture pointer change (#850) - #851
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…ange (#850) Flutter's ScaleGestureRecognizer fires a spurious onScaleEnd (followed by a fresh onScaleStart) whenever the active pointer count changes mid-gesture, e.g. when a third finger touches the screen while two fingers are rotating a layer. _onScaleEnd then ran its full interaction teardown (replacing the last screenshot, mutating the history stack, clearing the selection), which corrupted the history/screenshot stack and, on iOS, crashed the editor with a `_dependents.isEmpty` framework assertion. - _onScaleEnd now returns early when details.pointerCount > 0 (reconfiguration rather than a real end); the interactive viewer still receives the event so its start/end pairing stays balanced. - _onScaleStart no longer adds a second history entry when a transform is already in progress. Adds a deterministic multi-pointer widget test reproducing the crash.
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Problem
Fixes #850 — editor freezes / crashes after a three-finger gesture while rotating an emoji layer (reported on iOS).
Flutter's
ScaleGestureRecognizerfires a spuriousonScaleEnd(immediately followed by a freshonScaleStart) whenever the active pointer count changes mid-gesture — e.g. when a third finger touches the screen while two fingers are still rotating a layer (verified ingestures/scale.dart_reconfigure, line 717)._onScaleEndthen ran its full interaction teardown (replacing the last screenshot, mutating the history stack, clearing the selection) even though the gesture was only being reconfigured, not ended. Two symptoms of the same root cause:assert(_dependents.isEmpty)inInheritedElement.debugDeactivated()→ red screen + frozen editor on iOS.RangeErrorfromscreenshots.removeLast().Fix
_onScaleEndreturns early whendetails.pointerCount > 0(a reconfiguration rather than a real end). The interactive viewer still receives the event so its own start/end pairing stays balanced._onScaleStartno longer adds a second history entry when a transform is already in progress (!isLayerBeingTransformed).Test
Adds
test/features/main_editor/multitouch_third_finger_test.dart, a deterministic multi-pointer widget test that drives the exact sequence (two-finger rotate on a selected emoji layer, then a third pointer down). It reproduces the crash before the fix and passes after — no physical device needed.flutter analyze: clean