Gate display frame callbacks on shared presentation visibility

compositor/src/backends/direct.rs

@@ -1552,14 +1552,14 @@ fn send_frame_callbacks(state: &mut Ferese, output: &Output) {
                 .is_some_and(|id| state.window_belongs_to_output(*id, output))
         })
         .for_each(|window| {
-            window.send_frame(output, state.start_time.elapsed(), Some(Duration::ZERO), |_, _| {
-                Some(output.clone())
+            window.send_frame(output, state.start_time.elapsed(), None, |surface, _| {
+                state.display_presentation.callback_output(&surface.into())
             });
         });
     let layers = layer_map_for_output(output).layers().cloned().collect::<Vec<_>>();
     layers.iter().for_each(|layer| {
-        layer.send_frame(output, state.start_time.elapsed(), Some(Duration::ZERO), |_, _| {
-            Some(output.clone())
+        layer.send_frame(output, state.start_time.elapsed(), None, |surface, _| {
+            state.display_presentation.callback_output(&surface.into())
         });
     });
     state.send_cursor_frame(output);

compositor/src/display_presentation.rs

@@ -44,6 +44,17 @@ impl DisplayPresentation {
         self.outputs.values().any(|record| record.displayed.contains(surface))
     }
 
+    // Membership describes every output; callback ownership is a separate choice.
+    // A stable tie-break avoids alternating owners when refresh rates match.
+    pub fn callback_output(&self, surface: &Id) -> Option<Output> {
+        self.outputs
+            .iter()
+            .filter(|(_, record)| record.displayed.contains(surface))
+            .map(|(output, _)| output)
+            .max_by_key(|output| (output.current_mode().map_or(0, |mode| mode.refresh), output.name()))
+            .cloned()
+    }
+
     pub fn remove_surface(&mut self, surface: &Id) {
         for record in self.outputs.values_mut() {
             record.displayed.remove(surface);
@@ -139,4 +150,20 @@ mod tests {
         states.states.get_mut(&id).unwrap().presentation_state = RenderElementPresentationState::Skipped;
         assert!(visible(&states).is_empty());
     }
+    #[test]
+    fn callback_ownership_is_stable_and_moves_when_an_output_disappears() {
+        let mut record = DisplayPresentation::default();
+        let a = output("a");
+        let b = output("b");
+        let id = Id::new();
+        for output in [&a, &b] {
+            record.queued(output, &scene(&id));
+            record.presented(output);
+        }
+        assert_eq!(record.callback_output(&id), Some(b.clone()));
+        record.remove_output(&b);
+        assert_eq!(record.callback_output(&id), Some(a.clone()));
+        record.remove_surface(&id);
+        assert_eq!(record.callback_output(&id), None);
+    }
 }

compositor/src/session_lock.rs

@@ -218,8 +218,8 @@ impl Ferese {
                 surface.wl_surface(),
                 output,
                 self.start_time.elapsed(),
-                Some(std::time::Duration::ZERO),
-                |_, _| Some(output.clone()),
+                None,
+                |surface, _| self.display_presentation.callback_output(&surface.into()),
             );
         }
     }

compositor/src/state/hit_testing.rs

@@ -119,13 +119,9 @@ impl Ferese {
             return;
         }
 
-        send_frames_surface_tree(
-            surface,
-            output,
-            self.start_time.elapsed(),
-            Some(Duration::ZERO),
-            |_, _| Some(output.clone()),
-        );
+        send_frames_surface_tree(surface, output, self.start_time.elapsed(), None, |surface, _| {
+            self.display_presentation.callback_output(&surface.into())
+        });
     }
 
     pub fn window_under_visual(&self, position: Point<f64, Logical>) -> Option<Window> {

compositor/src/winit.rs

@@ -163,7 +163,7 @@ pub fn init(event_loop: &mut EventLoop<Ferese>, state: &mut Ferese) -> Result<()
                             // A callback means permission to draw the next client
                             // frame, not proof of a new compositor presentation.
                             // No-damage frames must still unblock layer clients.
-                            send_nested_frame_callbacks(state, &output, refresh.get());
+                            send_nested_frame_callbacks(state, &output);
                             state.space.refresh();
                             state.popups.cleanup();
                             layer_map_for_output(&output).cleanup();
@@ -209,7 +209,7 @@ pub fn init(event_loop: &mut EventLoop<Ferese>, state: &mut Ferese) -> Result<()
                         sequence,
                         PresentationKind::Vsync,
                     );
-                    send_nested_frame_callbacks(state, &output, refresh.get());
+                    send_nested_frame_callbacks(state, &output);
                     state.space.refresh();
                     state.popups.cleanup();
                     layer_map_for_output(&output).cleanup();
@@ -224,7 +224,7 @@ pub fn init(event_loop: &mut EventLoop<Ferese>, state: &mut Ferese) -> Result<()
     Ok(())
 }
 
-fn send_nested_frame_callbacks(state: &mut Ferese, output: &Output, refresh: Duration) {
+fn send_nested_frame_callbacks(state: &mut Ferese, output: &Output) {
     if state.session_lock.active {
         state.lock_frame_callbacks(output);
         return;
@@ -237,10 +237,14 @@ fn send_nested_frame_callbacks(state: &mut Ferese, output: &Output, refresh: Dur
             .get(*window)
             .is_some_and(|id| state.window_belongs_to_output(*id, output))
     }) {
-        window.send_frame(output, time, Some(refresh), |_, _| Some(output.clone()));
+        window.send_frame(output, time, None, |surface, _| {
+            state.display_presentation.callback_output(&surface.into())
+        });
     }
     for layer in layer_surfaces(output) {
-        layer.send_frame(output, time, Some(refresh), |_, _| Some(output.clone()));
+        layer.send_frame(output, time, None, |surface, _| {
+            state.display_presentation.callback_output(&surface.into())
+        });
     }
     state.send_cursor_frame(output);
 }