3f1a5e9c41
Wire horizontal swipe into the mobile tap-zone overlay (single mode only, so continuous mode keeps native vertical scroll). A leftward swipe past the threshold turns to the next page, rightward to the previous; a mostly- vertical drag is ignored so panning a tall page never turns it. The gesture suppresses the synthesized zone tap so it doesn't double-fire. Swipe classification is a pure, unit-tested helper; e2e drives real touch pointer events for horizontal (both directions) and vertical cases. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
24 lines
893 B
TypeScript
24 lines
893 B
TypeScript
// Pure gesture helper for the reader's single-page swipe navigation. Kept
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// UI-free so the "is this a page-turn swipe, and which way" decision is
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// unit-testable without dispatching pointer events.
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export const SWIPE_THRESHOLD_PX = 45;
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/**
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* Classifies a pointer displacement as a page-turn swipe. Returns `'next'`
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* for a leftward swipe, `'prev'` for a rightward one, or `null` when the
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* gesture is too short or too vertical to be a deliberate horizontal swipe
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* (so vertical panning never turns the page).
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*/
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export function swipeDirection(
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dx: number,
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dy: number,
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threshold: number = SWIPE_THRESHOLD_PX
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): 'next' | 'prev' | null {
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if (Math.abs(dx) < threshold) return null;
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// Must be predominantly horizontal — a diagonal or vertical drag is not
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// a page turn.
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if (Math.abs(dx) <= Math.abs(dy)) return null;
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return dx < 0 ? 'next' : 'prev';
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}
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