fix(ui): vertical swipes and drags scroll the list and text screens

The Forerunner 70 sends no page behaviour for a swipe on a custom view,
so the list and info screens only scrolled with the buttons. Swipes and
drags now scroll them directly; one gesture scrolls once even when the
device also sends the page behaviour, and a drag's release opens no row.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

6 files changed, 206 insertions, 9 deletions

diff --git a/source/ui/Gesture.mc b/source/ui/Gesture.mc
new file mode 100644
index 0000000..0824eb1
--- /dev/null
+++ b/source/ui/Gesture.mc
@@ -0,0 +1,88 @@
+// Author:  cirakg & claude ai
+// Summary: Vertical swipes and drags that scroll a custom view (the Forerunner 70 sends no next/previous-page behaviour for them), scrolling once per gesture.
+
+import Toybox.Lang;
+import Toybox.System;
+import Toybox.WatchUi;
+
+// A touch gesture can reach a delegate several ways at once: as drag events,
+// as a swipe, and as the next/previous-page behaviour. Some watches send only
+// the drag. The first one to scroll marks the time; the others arriving within
+// DEDUPE_MS are ignored, so one gesture scrolls once. The UP/DOWN buttons
+// never mark, so they are only held back right after a touch gesture.
+module Gesture {
+
+    const DEDUPE_MS = 300;
+    // A drag shorter than this part of the screen height does not scroll.
+    const MIN_DRAG_DIVISOR = 8;
+    // A drag longer than this part still counts as a drag, not a tap.
+    const SLOP_DIVISOR = 32;
+
+    var _scrolledMs as Number? = null;
+    var _draggedMs as Number? = null;
+    var _startY as Number? = null;
+
+    function _within(since as Number?) as Boolean {
+        if (since == null) {
+            return false;
+        }
+        var elapsed = System.getTimer() - since;
+        return elapsed >= 0 && elapsed < DEDUPE_MS;
+    }
+
+    // True right after a touch gesture scrolled: next/previous-page and
+    // swipe events in this window belong to that gesture.
+    function recent() as Boolean {
+        return _within(_scrolledMs);
+    }
+
+    // True right after a drag: a tap arriving now is its end, not a tap.
+    function tapIgnored() as Boolean {
+        return _within(_draggedMs);
+    }
+
+    function isVertical(event as WatchUi.SwipeEvent) as Boolean {
+        var direction = event.getDirection();
+        return direction == WatchUi.SWIPE_UP || direction == WatchUi.SWIPE_DOWN;
+    }
+
+    // The step for a vertical swipe: 1 (next, swipe up), -1 (previous), or 0
+    // when this gesture already scrolled.
+    function swipeStep(event as WatchUi.SwipeEvent) as Number {
+        if (recent()) {
+            return 0;
+        }
+        _scrolledMs = System.getTimer();
+        return event.getDirection() == WatchUi.SWIPE_UP ? 1 : -1;
+    }
+
+    // Feed a drag event. At the end of a long enough vertical drag returns
+    // the signed number of units to scroll (positive = next, finger moved
+    // up), at least 1 and distance / unit otherwise; 0 for anything else.
+    function dragStep(event as WatchUi.DragEvent, unit as Number) as Number {
+        var y = event.getCoordinates()[1];
+        var type = event.getType();
+        if (type == WatchUi.DRAG_TYPE_START) {
+            _startY = y;
+            return 0;
+        }
+        var start = _startY;
+        if (type != WatchUi.DRAG_TYPE_STOP || start == null) {
+            return 0;
+        }
+        _startY = null;
+        var height = System.getDeviceSettings().screenHeight;
+        var distance = start - y;
+        var length = distance < 0 ? -distance : distance;
+        if (length > height / SLOP_DIVISOR) {
+            _draggedMs = System.getTimer();
+        }
+        if (length < height / MIN_DRAG_DIVISOR || recent()) {
+            return 0;
+        }
+        _scrolledMs = System.getTimer();
+        var units = unit > 0 ? length / unit : 1;
+        units = units < 1 ? 1 : units;
+        return distance < 0 ? -units : units;
+    }
+}
diff --git a/source/ui/InfoView.mc b/source/ui/InfoView.mc
index cab4b52..a965713 100644
--- a/source/ui/InfoView.mc
+++ b/source/ui/InfoView.mc
@@ -16,6 +16,7 @@ class InfoView extends WatchUi.View {
     private var _first as Number = 0;
     private var _visible as Number = 1;
     private var _shownLogged as Boolean = false;
+    private var _lineH as Number = 1;
 
     // screen names the view in "DIAG shown" lines for UI scripts.
     function initialize(title as String, text as Array<String>, screen as String) {
@@ -38,6 +39,7 @@ class InfoView extends WatchUi.View {
         var max = lines.size() - _visible > 0 ? lines.size() - _visible : 0;
         var next = _first + delta;
         next = next < 0 ? 0 : (next > max ? max : next);
+        Diag.data("info_scroll", "first=" + next);
         if (next == _first) {
             return false;
         }
@@ -46,12 +48,18 @@ class InfoView extends WatchUi.View {
         return true;
     }
 
+    // The height of a text line, as last drawn (for drags).
+    function lineHeight() as Number {
+        return _lineH;
+    }
+
     function onUpdate(dc as Graphics.Dc) as Void {
         Ui.clear(dc);
         var w = dc.getWidth();
         var h = dc.getHeight();
         var font = Graphics.FONT_XTINY;
         var lineH = dc.getFontHeight(font);
+        _lineH = lineH;
         var y = Ui.isRound() ? h / 8 : 6;
         dc.setColor(Ui.accent(), Graphics.COLOR_TRANSPARENT);
         dc.drawText(w / 2, y, Graphics.FONT_SMALL, Ui.fit(dc, _title, Graphics.FONT_SMALL, 2 * Ui.halfWidthAt(dc, y)),
@@ -114,20 +122,47 @@ class InfoDelegate extends WatchUi.BehaviorDelegate {
     }
 
     function onNextPage() as Boolean {
-        AppState.activity();
-        var v = view();
-        if (v != null) {
-            v.scroll(3);
+        if (!Gesture.recent()) {
+            scrollBy(3);
         }
         return true;
     }
 
     function onPreviousPage() as Boolean {
+        if (!Gesture.recent()) {
+            scrollBy(-3);
+        }
+        return true;
+    }
+
+    private function scrollBy(lines as Number) as Void {
         AppState.activity();
         var v = view();
         if (v != null) {
-            v.scroll(-3);
+            v.scroll(lines);
+        }
+    }
+
+    // A vertical swipe or drag scrolls too (the Forerunner 70 sends no page
+    // behaviour for them); Gesture makes a gesture count once.
+    function onSwipe(event as WatchUi.SwipeEvent) as Boolean {
+        if (!Gesture.isVertical(event)) {
+            return BehaviorDelegate.onSwipe(event);
+        }
+        var step = Gesture.swipeStep(event);
+        if (step != 0) {
+            scrollBy(3 * step);
+        }
+        return true;
+    }
+
+    function onDrag(event as WatchUi.DragEvent) as Boolean {
+        var v = view();
+        var step = Gesture.dragStep(event, v != null ? v.lineHeight() : 1);
+        if (step == 0) {
+            return false;
         }
+        scrollBy(step);
         return true;
     }
 
diff --git a/source/ui/ListDelegate.mc b/source/ui/ListDelegate.mc
index a7c8bf0..ca7cee9 100644
--- a/source/ui/ListDelegate.mc
+++ b/source/ui/ListDelegate.mc
@@ -14,14 +14,43 @@ class ListDelegate extends WatchUi.BehaviorDelegate {
     }
 
     function onNextPage() as Boolean {
-        AppState.activity();
-        _view.move(1);
+        if (!Gesture.recent()) {
+            AppState.activity();
+            _view.move(1);
+        }
         return true;
     }
 
     function onPreviousPage() as Boolean {
+        if (!Gesture.recent()) {
+            AppState.activity();
+            _view.move(-1);
+        }
+        return true;
+    }
+
+    // The Forerunner 70 sends no page behaviour for a vertical swipe, so the
+    // swipe and the drag scroll here; Gesture makes a gesture count once.
+    function onSwipe(event as WatchUi.SwipeEvent) as Boolean {
+        if (!Gesture.isVertical(event)) {
+            return BehaviorDelegate.onSwipe(event);
+        }
+        var step = Gesture.swipeStep(event);
+        if (step != 0) {
+            AppState.activity();
+            _view.move(step);
+        }
+        return true;
+    }
+
+    // A drag scrolls by the rows it covered, at least one.
+    function onDrag(event as WatchUi.DragEvent) as Boolean {
+        var step = Gesture.dragStep(event, _view.rowHeight());
+        if (step == 0) {
+            return false;
+        }
         AppState.activity();
-        _view.move(-1);
+        _view.move(step);
         return true;
     }
 
@@ -55,6 +84,9 @@ class ListDelegate extends WatchUi.BehaviorDelegate {
     // A tap opens the row under the finger.
     function onTap(event as WatchUi.ClickEvent) as Boolean {
         AppState.activity();
+        if (Gesture.tapIgnored()) {
+            return true;
+        }
         var index = _view.rowAt(event.getCoordinates()[1]);
         if (index < 0) {
             return true;
diff --git a/source/ui/ListView.mc b/source/ui/ListView.mc
index 94b8c99..de73cce 100644
--- a/source/ui/ListView.mc
+++ b/source/ui/ListView.mc
@@ -82,9 +82,15 @@ class ListView extends WatchUi.View {
             return;
         }
         focus = ((focus + delta) % n + n) % n;
+        Diag.data("list_move", "focus=" + focus);
         WatchUi.requestUpdate();
     }
 
+    // The height of a row as last drawn (for drags).
+    function rowHeight() as Number {
+        return _rowHeight;
+    }
+
     function focusedId() as String? {
         return focus < _ids.size() ? _ids[focus] : null;
     }
diff --git a/tools/lint_project.py b/tools/lint_project.py
index 04d525f..c1c225a 100644
--- a/tools/lint_project.py
+++ b/tools/lint_project.py
@@ -42,7 +42,17 @@ AUTHOR = "cirakg & claude ai"
 HEADER_LINES = 15
 DIAG_FILE = Path("source/util/Diag.mc")
 # Folders that hold local tool state or generated output, never project files.
-SKIP_DIRS = {".git", ".cache", ".claude", "build", "node_modules", "__pycache__", ".pytest_cache", ".mypy_cache", ".ruff_cache"}
+SKIP_DIRS = {
+    ".git",
+    ".cache",
+    ".claude",
+    "build",
+    "node_modules",
+    "__pycache__",
+    ".pytest_cache",
+    ".mypy_cache",
+    ".ruff_cache",
+}
 # Written by a tool that would drop a hand-added header on the next run.
 GENERATED = {Path("docker/docs/package-lock.json")}
 
diff --git a/tools/ui_flow.py b/tools/ui_flow.py
index 8c08caf..3c7afb2 100644
--- a/tools/ui_flow.py
+++ b/tools/ui_flow.py
@@ -437,8 +437,33 @@ def flow_locked_entry(f: Flow) -> None:
     f.expect("list", AUTO_LOCK_TIMEOUT_S)
 
 
+def flow_swipes(f: Flow, screen: str) -> None:
+    """On touch screens a vertical swipe scrolls `screen` once, whatever the
+    watch does with page behaviour; checked through the debug logs so no
+    image is involved. A swipe up must report one scroll; on the list the
+    focus must move and a swipe back must return it."""
+    if not f.touch:
+        return
+    pattern = r"DIAG list_move focus=(\d+)" if screen == "list" else r"DIAG info_scroll first=(\d+)"
+    regex = re.compile(pattern)
+    x, top, bottom = f._w() // 2, f._h() // 4, f._h() * 3 // 4
+    seen: list[str] = []
+    for start, end in ((bottom, top), (top, bottom)):  # swipe up: next; down: previous
+        f.act()
+        f.sim.swipe(x, start, x, end)
+        f.log.wait_for(pattern, SCREEN_TIMEOUT_S)
+        time.sleep(SETTLE_S)
+        found = [m.group(1) for line in f.log.lines()[f.log.mark :] if (m := regex.search(line))]
+        if len(found) != 1:
+            raise FlowError(f"one swipe on {screen} scrolled {len(found)} times, not once")
+        seen.append(found[0])
+    if screen == "list" and seen[0] == seen[1]:
+        raise FlowError("a swipe on the list didn't move the focus")
+
+
 def flow_menu(f: Flow) -> None:
     """The menu, and About on watches whose menu has a focus to move."""
+    flow_swipes(f, "list")
     f.menu()
     time.sleep(MENU_SETTLE_S)
     f.shot("menu")
@@ -454,6 +479,7 @@ def flow_menu(f: Flow) -> None:
         f.select()
         f.expect("about")
         f.shot("about")
+        flow_swipes(f, "about")
         f.act()
     # Touch-only watches show the menu as a freely scrolling list without
     # focus, so there is no reliable "select About"; just close it.