darkfi/openspec/changes/app-gesture/tasks.md

1. Gesture core

• 1.1 Delete the dead code up front: ui/gesture.rs (pinch node, with its create_gesture registration and Pimpl::Gesture variant — the new module takes over its path) and win/gesture.rs (GestureProcessor and the old GestureAction, with the dead gesture_proc dispatch in Window::handle_touch); then create bin/app/src/ui/gesture/ module with GestureConstants (slop 10px, tap 300ms, sys long-press timeout, 20ms move period, 40ms sample window), the GestureAction stream (Down/Up/Tap/LongPress/DragStart/DragMove/DragEnd { vel }), and the GestureSet/config types (Axes, Direction, min_travel); repoint the ui::GestureAction re-export and the dead UIObject::handle_gesture signature to the new types; verify make compile-dev in bin/app
• 1.2 Implement the recognizer library as pure state machines (tap, long-press, drag lifecycle with 40ms velocity sampling) taking GestureConstants; verify unit tests pass covering: tap within/beyond slop, tap duration bound, long-press firing during hold, long-press cancelled by movement, throttled delivery vs full sampling, and DragEnd velocity from the sample window
• 1.3 Implement gesture arbitration rules (first-resolved-wins, tap vs drag via slop, cascade cancellation); verify unit tests cover descendant-tap-wins-within-slop and ancestor-drag-wins-beyond-slop

2. Session and dispatch

• 2.1 Implement GestureSession: fed from the Stage thread at the gfx touch entry before any sync claiming; resolves the hit-test target chain at Down (priority order, sticky ownership until Up/cancel); runs version-guarded long-press timers on the executor; throttles DragMove delivery to 20ms; ignores secondary touch ids; verify unit tests pass for sticky ownership, priority ordering, and cancellation teardown
• 2.2 Add gesture_set()/gesture_hit_test() defaults to UIObject and implement Layer/ScrollLayer gesture forwarding with coordinate translation (mirroring handle_touch translation); verify make compile-dev and a unit test pinning local-coordinate delivery through a nested layer
• 2.3 Route EMULATE_TOUCH mouse-emulated touches through the session so desktop emulation produces real gestures; verify an emulated tap triggers the gesture path on a desktop build with emulate-android enabled

3. Widget migrations

• 3.1 Migrate Button: Tap fires the click signal; delete handle_touch/handle_touch_sync and the mouse_btn_held gate; mouse path unchanged; verify emulated tap clicks on desktop with no double activation
• 3.2 Migrate TokenTable: row click on Tap; delete the touch-to-mouse simulation; verify emulated row tap fires row_click
• 3.3 Migrate EmojiPicker: 1:1 clamped scroll on vertical drag, emoji activation on Tap; resolve the flick-inertia open question (adopt or preserve dead-stop) and record the choice; verify scroll clamps at bounds and tap selects under emulation
• 3.4 Migrate Menu: LongPress enters edit mode (single fire during hold), Tap selects/deletes, reorder drag armed at Down on the reorder handle; delete TouchInfo/DragInfo and the long-press task juggling; verify edit mode, reorder commit, and item selection under emulation
• 3.5 Migrate ChatView: 1:1 scroll on drag, inertia fed from DragEnd velocity, grab-stops-inertia on DragStart, LongPress for line select / URL toast, Tap forwarding to message content (URLs, file downloads) and line-toggle; delete TouchInfo, the touch_hold_version timer, and end_touch_phase; first coordinate with app-chatview whether this task or chatview2 performs the migration; verify scroll, flick, grab-stop, and URL tap under emulation
• 3.6 Migrate BaseEdit (hybrid): Down arms selection-handle grab and word-select/cursor state, min_travel: 0. drag drives handle movement and vertical scroll, LongPress selects word + shows action menu, Tap sets cursor + requests focus, Up finalizes; delete TouchStateAction and the sync/async phase split; verify word-select, handle drag, cursor tap, and focus under emulation

4. Cleanup and verification

• 4.1 Delete the old paths: handle_touch/handle_touch_sync from UIObject and all implementors, and the four widget TouchInfo state machines; verify make compile-dev with no remaining references to the removed APIs or the old GestureAction
• 4.2 Verify make compile-apk succeeds
• 4.3 On-device feel pass: chat scroll/flick/grab-stop, URL tap, line selection, edit word-select and selection handles (latency check — if handle drag feels laggy, implement the documented handle_gesture_sync fallback for Down/DragMove), menu edit-mode/reorder, emoji scroll, button taps
• 4.4 Cross-check every scenario in specs/gesture/spec.md against unit tests and the on-device pass; record any scenario lacking coverage