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>

1 files changed, 88 insertions, 0 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;
+    }
+}