audit switch

crates/core/src/switch.rs

@@ -96,16 +96,17 @@ impl RenderOnce for Switch {
         let ramps = theme.ramps;
         let metrics = theme.sizes.resolve(self.size);
 
-        let track_height = metrics.control_height;
+        let track_height = metrics.switch_height;
-        let track_width = metrics.control_height * 1.65;
+        let track_width = metrics.switch_width;
 
-        let knob = metrics.indicator_size;
+        let knob = metrics.switch_knob;
-        let inset = metrics.plate_inset;
+        let inset = (track_height - knob) / 2.;
         let travel = track_width - knob - inset * 2.;
 
         let next = !self.checked;
         let on_change = self.on_change;
         let a11y_label = self.a11y_label.or_else(|| self.label.clone());
+        let id = self.id.clone();
 
         let anim_config = SpringConfig::new(500., 35., 1.);
         let anim = SpringAnimation::new(anim_config).to(if self.checked { travel } else { px(0.) });
@@ -132,6 +133,10 @@ impl RenderOnce for Switch {
                 div()
                     .flex_none()
                     .relative()
+                    .debug_selector({
+                        let name = format!("{id}-track");
+                        move || name
+                    })
                     .w(track_width)
                     .h(track_height)
                     .rounded(theme.radius.full)
@@ -149,8 +154,6 @@ impl RenderOnce for Switch {
                             .size(knob)
                             .rounded(theme.radius.full)
                             .bg(colors.primary_foreground)
-                            .border_1()
-                            .border_color(colors.border)
                             .with_spring("switch-thumb", anim, move |thumb, offset| {
                                 thumb.left(inset + offset)
                             }),

crates/core/tests/switch.rs

@@ -83,6 +83,30 @@ fn disabled_switch_does_not_report_changes() {
     assert!(changes.borrow().is_empty());
 }
 
+/// The track renders at the platform's stated switch dims, not the generic
+/// control height — the stated metric is the whole chrome.
+#[test]
+fn track_renders_at_the_stated_switch_dims() {
+    let (mut cx, _window, _changes) = switch_window(false, false);
+    let (width, height) = cx.update(|_window, cx| {
+        let metrics = Theme::global(cx).sizes.medium;
+        (metrics.switch_width, metrics.switch_height)
+    });
+    let track = cx
+        .debug_bounds("test-switch-track")
+        .expect("the switch track should have been laid out");
+    assert!(
+        (track.size.width - width).abs() <= px(0.5),
+        "track is {:?} wide, stated switch width is {width:?}",
+        track.size.width
+    );
+    assert!(
+        (track.size.height - height).abs() <= px(0.5),
+        "track is {:?} tall, stated switch height is {height:?}",
+        track.size.height
+    );
+}
+
 #[test]
 fn enter_and_space_report_the_next_value_while_focused() {
     let (mut cx, window, changes) = switch_window(false, false);

docs/CHECKLIST.md

@@ -14,10 +14,6 @@ is the first downstream consumer; its screens drive the order.
 Platform metric adoption continues one component at a time; each stop goes
 through the review gate and a gallery pass.
 
-- [ ] **Switch platform chrome** — stated track and knob dims
-      (`switch_height` / `switch_width` / `switch_knob`, inset and travel
-      derived); borderless knob.
-
 Gaps surfaced by the signed comparison; ordered by signed's usage.
 
 - [ ] **Virtual list** — generic virtualized variable-height rows with a
@@ -143,6 +139,11 @@ Gaps surfaced by the signed comparison; ordered by signed's usage.
       `Theme::borders.overlays` (and dark mode), taking the surface color
       where the platform paints none; it rides the dialog elevation, so dark
       mode's no-shadow rule applies to it too
+- [x] Switch platform chrome — the track and knob take the stated
+      `switch_height` / `switch_width` / `switch_knob` (the knob's inset
+      derived to center it in the track, its travel from the remaining
+      width); the knob is borderless, and the track carries a debug selector
+      for headless geometry tests
 - [x] Button, Checkbox, Switch, Radio + RadioGroup, Toggle, Link, Slider,
       Progress, Avatar (image + seeded pixel-art fallback)
 - [x] Spinner — painted ring + rotating-icon variant, indeterminate and