fix: make rectangle_tracker subscription only return update if there is some

src/widget/rectangle_tracker/subscription.rs

@@ -14,7 +14,7 @@ pub fn rectangle_tracker_subscription<
     R: 'static + Hash + Copy + Send + Sync + Debug + Eq,
 >(
     id: I,
-) -> iced::Subscription<Option<(I, RectangleUpdate<R>)>> {
+) -> iced::Subscription<(I, RectangleUpdate<R>)> {
     subscription::unfold(id, State::Ready, move |state| start_listening(id, state))
 }
 
@@ -26,9 +26,10 @@ pub enum State<I> {
 
 async fn start_listening<I: Copy, R: 'static + Hash + Copy + Send + Sync + Debug + Eq>(
     id: I,
-    state: State<R>,
+    mut state: State<R>,
-) -> (Option<(I, RectangleUpdate<R>)>, State<R>) {
+) -> ((I, RectangleUpdate<R>), State<R>) {
-    match state {
+    loop {
+        let (update, new_state) = match state {
             State::Ready => {
                 let (tx, rx) = unbounded();
 
@@ -47,23 +48,29 @@ async fn start_listening<I: Copy, R: 'static + Hash + Copy + Send + Sync + Debug
                             || (prev.y - new.y).abs() > 0.1
                         {
                             map.insert(u.0, new);
-                        return (
+                            (
                                 Some((id, RectangleUpdate::Rectangle(u))),
                                 State::Waiting(rx, map),
-                        );
+                            )
+                        } else {
+                            (None, State::Waiting(rx, map))
                         }
                     } else {
                         map.insert(u.0, u.1);
-                    return (
+                        (
                             Some((id, RectangleUpdate::Rectangle(u))),
                             State::Waiting(rx, map),
-                    );
+                        )
                     }
-                (None, State::Waiting(rx, map))
                 }
                 None => (None, State::Finished),
             },
             State::Finished => iced::futures::future::pending().await,
+        };
+        state = new_state;
+        if let Some(u) = update {
+            return (u, state);
+        }
     }
 }