fix: remove 250ms movement lockout and refactor gesture handling

[Nakshatra480]

Closes #76

Overview

The trackpad previously felt laggy or "stuck" during rapid swipes and multi-touch transitions due to an artificial 250ms lockout period.

Changes

• Fixed Movement Lag: Removed the redundant lastEndTimeStamp check in handleTouchMove. This check was blocking all movement events for 250ms every time a finger was lifted, causing noticeable input delay.
• Refactored Gesture Logic: Abstracted the message-sending logic into a new processMovement helper function. This makes the code more readable and easier to maintain without changing the core behavior.
• Cleanup: Removed the now-obsolete lastEndTimeStamp reference and its associated logic to keep the hook clean and focused.

Technical Rationale

The moved.current flag already correctly handles the distinction between a "Tap" and a "Move" based on touch distance and initial duration. The additional timestamp check created a blackout period that interrupted the coordinate stream, especially during fluid gestures like two-finger scrolling. Removing this restores natural, real-time responsiveness.

Verification Results

• Tested rapid swiping: Cursor responds immediately without the previous "dead zone."
• Tested multi-touch transitions: Lifting one finger during a scroll no longer freezes the remaining input.
• Verified tap-to-click: Still works as expected since the distance-based logic remains intact.

Summary by CodeRabbit

• Refactor
  • Overhauled touch gesture handling to route movements through a unified processing flow, improving consistency for drag, pinch/zoom, and two-finger scroll interactions.
• Bug Fixes
  • Reduced missed or delayed movement recognition and removed time-based gating, yielding more responsive and reliable tap/click, drag, scroll, and pinch behaviors on touch devices.

[coderabbitai]

📝 Walkthrough

Walkthrough

Refactors touch gesture handling in useTrackpadGesture.ts by adding a centralized processMovement(sumX, sumY) helper, removing the lastEndTimeStamp timing gate, and routing movement/scroll/zoom/drag decisions by finger count and moved/drag state instead of timestamps.

Changes

Cohort / File(s)	Summary
Touch Gesture Handler Refactor src/hooks/useTrackpadGesture.ts	Introduces processMovement(sumX, sumY) to centralize movement handling; removes lastEndTimeStamp and all time-gated checks; touchMove now calls processMovement when movement detected; touchStart/touchEnd simplified (no timestamp side-effects); two-finger pinch/scroll/zoom and single-finger drag routing consolidated.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• Add pinch-to-zoom gesture support for trackpad #38: Edits the same touch handlers and adjusts two-finger/pinch behavior — likely overlaps with zoom/pinch logic here.
• optimized scroll performance #23: Modifies movement/scroll handling (axis-dominance/rounding) in the same file — may intersect with new centralized movement logic.

Poem

🐰 I nudged the timestamps out the door,
One helper now guides each hop and score,
Fingers dance, no pauses stay,
Smooth trails hop on, come what may—
✨🐇

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: removing the 250ms movement lockout and refactoring gesture handling logic in useTrackpadGesture.ts.
Linked Issues check	✅ Passed	The PR successfully implements all coding requirements from issue #76: removes the lastEndTimeStamp timestamp check blocking movement, refactors message logic into processMovement helper, and relies on existing moved.current flag for tap/move distinction.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to removing the 250ms lockout and refactoring gesture handling in useTrackpadGesture.ts; no unrelated modifications are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

No actionable comments were generated in the recent review. 🎉

🧹 Recent nitpick comments

src/hooks/useTrackpadGesture.ts (1)

58-65: Inconsistent rounding on scroll deltas in the non-scroll-mode two-finger path.

Lines 62–63 send raw floating-point values (-sumX * sensitivity * invertMult), while the scroll path at lines 80–81 and the move paths at lines 45–46 / 86–87 all round to one decimal place. This can cause subtle jitter differences between the two scroll paths.

Proposed fix

             } else {
                 lastPinchDist.current = dist;
                 send({ 
                     type: 'scroll', 
-                    dx: -sumX * sensitivity * invertMult, 
-                    dy: -sumY * sensitivity * invertMult 
+                    dx: Math.round(-sumX * sensitivity * 10 * invertMult) / 10, 
+                    dy: Math.round(-sumY * sensitivity * 10 * invertMult) / 10 
                 });
             }

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@src/hooks/useTrackpadGesture.ts`:
- Around line 39-56: The processMovement function currently prioritizes
scrollMode over dragging which causes drag gestures to be treated as scrolls;
update processMovement so that the dragging state is checked before the
scrollMode/ongoingTouches length branch: if dragging.current is true (or
ongoingTouches.current.length === 1 && dragging.current) send the 'move' event
via send({ type: 'move', dx: ..., dy: ... }) and return, otherwise proceed with
the existing two-finger/pinch and scrollMode logic (keep getTouchDistance,
lastPinchDist.current, pinching.current, sensitivity and ongoingTouches.current
checks intact) so drags always emit move events even when scrollMode is enabled.

🧹 Nitpick comments (2)

src/hooks/useTrackpadGesture.ts (2)

39-56: Unused parameter e in processMovement.

The e: React.TouchEvent parameter is accepted but never referenced inside the function body.

🧹 Remove unused parameter

-    const processMovement = (sumX: number, sumY: number, e: React.TouchEvent) => {
+    const processMovement = (sumX: number, sumY: number) => {

And at the call site (Line 151):

-            processMovement(sumX, sumY, e);
+            processMovement(sumX, sumY);

---

24-34: Consider cleaning up draggingTimeout on unmount to avoid firing send after the component is gone.

This is pre-existing, but since the hook is being refactored, it may be worth adding a cleanup effect. A stale timeout could call send after unmount.

Example: add cleanup via useEffect

Add at the end of the hook body (before the return):

import { useRef, useState, useEffect } from 'react';

// ... inside the hook, before return:
useEffect(() => {
    return () => {
        if (draggingTimeout.current) {
            clearTimeout(draggingTimeout.current);
        }
    };
}, []);

[Nakshatra480]

@imxade Please review this PR where I've implemented the following improvements:

• Removed the lastEndTimeStamp check to fix the 250ms lockout and ensure instant trackpad responsiveness.
• Consolidated the gesture handling into a single processMovement helper for a cleaner and more maintainable structure.
• Prioritized the dragging state so that drag-and-drop works correctly even when scroll mode is active.
• Unified coordinate rounding and sensitivity scaling to provide consistent and precise input handling.

Thanks for your time and effort.