T06b forms selection: checkbox, radio, cards, switch, select, combobox, multi select, cascader, transfer list, list box, chips, rating, sliders, knob, stepper

src/motion/changes.rs

@@ -0,0 +1,26 @@
+use gpui::{App, ElementId, Window};
+
+struct Changes<T> {
+    last: T,
+    count: usize,
+}
+
+/// How often `value` changed since `id` first rendered. Key an animation on it to replay per change.
+pub(crate) fn changes<T: Clone + PartialEq + 'static>(
+    id: impl Into<ElementId>,
+    value: T,
+    window: &mut Window,
+    cx: &mut App,
+) -> usize {
+    let state = window.use_keyed_state(id, cx, |_, _| Changes {
+        last: value.clone(),
+        count: 0,
+    });
+    if state.read(cx).last != value {
+        state.update(cx, |state, _| {
+            state.last = value;
+            state.count += 1;
+        });
+    }
+    state.read(cx).count
+}

src/motion/mod.rs

@@ -1,3 +1,5 @@
+mod changes;
 mod curve;
 
+pub(crate) use changes::changes;
 pub use curve::*;