From b6b7bc8453a5deecae0f0f4cc0c5f8639df97964 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?bbb651=20=F0=9F=87=AE=F0=9F=87=B1?=
 <53972231+bbb651@users.noreply.github.com>
Date: Wed, 5 Feb 2025 21:17:57 +0200
Subject: [PATCH] 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              | 83 ++++++++++++++++++------------
 crates/eww/src/window_arguments.rs | 11 ++++
 2 files changed, 61 insertions(+), 33 deletions(-)

diff --git a/crates/eww/src/app.rs b/crates/eww/src/app.rs
index 38a3f846..9494a9d3 100644
--- a/crates/eww/src/app.rs
+++ b/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) {
-            self.close_window(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();
@@ -454,38 +464,12 @@ impl<B: DisplayBackend> App<B> {
                 }
             }));
 
-            let duration = window_args.duration;
-            if let Some(duration) = duration {
-                let app_evt_sender = self.app_evt_send.clone();
-
-                let (abort_send, abort_recv) = futures::channel::oneshot::channel();
-
-                glib::MainContext::default().spawn_local({
-                    let instance_id = instance_id.to_string();
-                    async move {
-                        tokio::select! {
-                            _ = glib::timeout_future(duration) => {
-                                let (response_sender, mut response_recv) = daemon_response::create_pair();
-                                let command = DaemonCommand::CloseWindows { windows: vec![instance_id.clone()], sender: response_sender };
-                                if let Err(err) = app_evt_sender.send(command) {
-                                    log::error!("Error sending close window command to daemon after gtk window destroy event: {}", err);
-                                }
-                                _ = response_recv.recv().await;
-                            }
-                            _ = abort_recv => {}
-                        }
-                    }
-                });
-
-                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(())
         })();
 
+        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))
@@ -494,6 +478,39 @@ impl<B: DisplayBackend> App<B> {
         }
     }
 
+    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();
+
+            let (abort_send, abort_recv) = futures::channel::oneshot::channel();
+
+            glib::MainContext::default().spawn_local({
+                let instance_id = instance_id.to_string();
+                async move {
+                    tokio::select! {
+                        _ = glib::timeout_future(duration) => {
+                            let (response_sender, mut response_recv) = daemon_response::create_pair();
+                            let command = DaemonCommand::CloseWindows { windows: vec![instance_id.clone()], sender: response_sender };
+                            if let Err(err) = app_evt_sender.send(command) {
+                                log::error!("Error sending close window command to daemon after gtk window destroy event: {}", err);
+                            }
+                            _ = response_recv.recv().await;
+                        }
+                        _ = abort_recv => {}
+                    }
+                }
+            });
+
+            if let Some(old_abort_send) = self.window_close_timer_abort_senders.insert(instance_id.to_string(), abort_send) {
+                _ = old_abort_send.send(());
+            }
+        } else {
+            if let Some(old_abort_send) = self.window_close_timer_abort_senders.remove(instance_id) {
+                _ = old_abort_send.send(());
+            }
+        }
+    }
+
     /// Load the given configuration, reloading all script-vars and attempting to reopen all windows that where opened.
     pub fn load_config(&mut self, config: config::EwwConfig) -> Result<()> {
         log::info!("Reloading windows");
diff --git a/crates/eww/src/window_arguments.rs b/crates/eww/src/window_arguments.rs
index 5a079795..b6e64756 100644
--- a/crates/eww/src/window_arguments.rs
+++ b/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
+    }
 }