readest/apps/readest-app/.claude/memory/cross-page-selection-autoturn-4741.md

name, description, metadata

name	description	metadata
cross-page-selection-autoturn-4741	Cross-page selection/highlight in paginated mode via extracted useAutoPageTurn; all four selection gestures drive the corner-dwell turn	node_type type originSessionId memory project 33b70e98-fb55-467a-b03f-e4065491bc7e

#4741: in paginated (non-scrolling) mode, extend a selection/highlight past the page edge by turning the page mid-gesture. Branch feat/cross-page-highlight-autoturn.

Extracted src/app/reader/hooks/useAutoPageTurn.ts from useTextSelector — the corner-dwell auto page-turn (#1354), now decoupled from the DOM selection so selection-less gestures can drive it. API: notePoint/noteAutoTurnPoint (window-coord engagement point), cancel, isAutoTurning, onAfterTurn(cb) (Set of subs), cornerAtPoint, readingAreaRect. Liveness at dwell fire-time is an injected predicate, not doc.getSelection(): noteCorner(corner, isInCorner). useTextSelector keeps the dual-signal native liveness (pointerCornerNow || caretCornerNow); point-only callers use noteAutoTurnPoint (last-point liveness). Pure exports getReadingAreaRect, turnForFocusBeyondPage, keyboardTurnDirection.

Key trap: the old armDwell required a valid DOM selection to turn. Instant Highlight (user-select:none + CFI overlay) and AnnotationRangeEditor (CFI overlay) have no DOM selection, so the machine refused to turn for them. The decoupling is what makes them work at all.

Four gestures, all feeding the one machine (useTextSelector re-exposes noteAutoTurnPoint/cancelAutoTurn/onAutoTurn to the editors via Annotator):

1. Instant Highlight drag — handlePointerMove/handleNativeTouchMove feed the finger corner. useInstantAnnotation now DOM-anchors the start (startPosRef = {node,offset} at pointer-down; buildRangeFromAnchor builds anchor->end each move) so it survives the scroll; relaxed the pointer-up distance<10 cancel with && !previewAnnotationRef.current. See instant-highlight-tap-paginate.
2. SelectionRangeEditor handle drag — already DOM-anchored the fixed end; just feed noteAutoTurnPoint(point) + cancel + re-emit.
3. AnnotationRangeEditor handle drag — useAnnotationEditor changed from handleAnnotationRangeChange(startPt,endPt) (buildRangeFromPoints resolved BOTH ends from window coords -> lost previous page) to applyAnnotationRange(range,...); component anchors the non-dragged end (fixedAnchorRef) + builds via rangeFromAnchorToPoint like SelectionRangeEditor.
4. Shift+Arrow keyboard adjust (#4728) — useBookShortcuts.adjustTextSelection, after extendSelectionFromContents, immediate turn-on-cross (no dwell): keyboardTurnDirection(contents, getReadingAreaRect(...)) -> view.next()/prev() when the extended focus leaves the page. Desktop-only; gated !scrolled.

After-turn re-emit: active gesture subscribes onAfterTurn to rebuild its range from the held point onto the new page immediately (instant: reapplyInstantAnnotation; editors: subscribeAutoTurnReemit -> updateFromDraggedPoint(lastPoint)). Native selection does NOT subscribe (browser extends its own). The Android #873 scroll-pin (selectionPosition) is re-anchored after every turn via onAfterTurn in useTextSelector.

focusCaretWindowPos promoted useTextSelector -> src/utils/sel.ts (keyboard reuse). Scope: within-section column turns only (a Range can't span two iframe docs). Tests: useAutoPageTurn.test.ts (21), useTextSelector-instantTurn.test.ts, useInstantAnnotation.test.ts, useAnnotationEditor.test.ts; existing autoTurn/ instantHold suites stay green (regression net for the extraction).