Avoid recreating windows when only duration changes (#1236)

This avoids possible flicker with windows such as OSDs.
The logic to do this was added in #263 but broke when durations were added.

Fixes #260.

crates/eww/src/app.rs

@@ -390,14 +390,24 @@ impl<B: DisplayBackend> App<B> {
         self.failed_windows.remove(instance_id);
         log::info!("Opening window {} as '{}'", window_args.window_name, instance_id);
 
-        // if an instance of this is already running, close it
-        if self.open_windows.contains_key(instance_id) {
+        // if an instance of this is already running and arguments haven't change, only update duration
+        let reuse_window = if self.open_windows.contains_key(instance_id) {
+            if self.instance_id_to_args.get(instance_id).is_some_and(|args| window_args.can_reuse_window_with_args(args)) {
+                true
+            } else {
                 self.close_window(instance_id)?;
+                false
             }
-
+        } else {
+            false
+        };
         self.instance_id_to_args.insert(instance_id.to_string(), window_args.clone());
 
         let open_result: Result<_> = (|| {
+            if reuse_window {
+                return Ok(());
+            }
+
             let window_name: &str = &window_args.window_name;
 
             let window_def = self.eww_config.get_window(window_name)?.clone();
@@ -454,7 +464,21 @@ impl<B: DisplayBackend> App<B> {
                 }
             }));
 
-            let duration = window_args.duration;
+            self.open_windows.insert(instance_id.to_string(), eww_window);
+            Ok(())
+        })();
+
+        self.update_window_duration(instance_id, window_args.duration);
+
+        if let Err(err) = open_result {
+            self.failed_windows.insert(instance_id.to_string());
+            Err(err).with_context(|| format!("failed to open window `{}`", instance_id))
+        } else {
+            Ok(())
+        }
+    }
+
+    fn update_window_duration(&mut self, instance_id: &str, duration: Option<std::time::Duration>) {
         if let Some(duration) = duration {
             let app_evt_sender = self.app_evt_send.clone();
 
@@ -480,17 +504,10 @@ impl<B: DisplayBackend> App<B> {
             if let Some(old_abort_send) = self.window_close_timer_abort_senders.insert(instance_id.to_string(), abort_send) {
                 _ = old_abort_send.send(());
             }
-            }
-
-            self.open_windows.insert(instance_id.to_string(), eww_window);
-            Ok(())
-        })();
-
-        if let Err(err) = open_result {
-            self.failed_windows.insert(instance_id.to_string());
-            Err(err).with_context(|| format!("failed to open window `{}`", instance_id))
         } else {
-            Ok(())
+            if let Some(old_abort_send) = self.window_close_timer_abort_senders.remove(instance_id) {
+                _ = old_abort_send.send(());
+            }
         }
     }
 

crates/eww/src/window_arguments.rs

@@ -87,4 +87,15 @@ impl WindowArguments {
 
         Ok(local_variables)
     }
+
+    // Compares all values except `duration`, since it's not used by the window itself
+    pub fn can_reuse_window_with_args(&self, other: &Self) -> bool {
+        self.window_name == other.window_name
+            && self.instance_id == other.instance_id
+            && self.anchor == other.anchor
+            && self.args == other.args
+            && self.monitor == other.monitor
+            && self.pos == other.pos
+            && self.size == other.size
+    }
 }