Stop screencasts on size changes

src/niri.rs

@@ -2434,6 +2434,7 @@ impl Niri {
         let scale = Scale::from(output.current_scale().fractional_scale());
 
         let mut elements = None;
+        let mut casts_to_stop = vec![];
 
         let mut casts = mem::take(&mut self.casts);
         for cast in &mut casts {
@@ -2445,6 +2446,12 @@ impl Niri {
                 continue;
             }
 
+            if cast.size != size {
+                debug!("stopping screencast due to output size change");
+                casts_to_stop.push(cast.session_id);
+                continue;
+            }
+
             let last = cast.last_frame_time;
             let min = cast.min_time_between_frames.get();
             if last.is_zero() {
@@ -2499,6 +2506,10 @@ impl Niri {
             cast.last_frame_time = target_presentation_time;
         }
         self.casts = casts;
+
+        for id in casts_to_stop {
+            self.stop_cast(id);
+        }
     }
 
     #[cfg(feature = "xdp-gnome-screencast")]

src/pw_utils.rs

@@ -27,6 +27,7 @@ use smithay::output::Output;
 use smithay::reexports::calloop::generic::Generic;
 use smithay::reexports::calloop::{self, Interest, LoopHandle, Mode, PostAction};
 use smithay::reexports::gbm::Modifier;
+use smithay::utils::{Physical, Size};
 use zbus::SignalContext;
 
 use crate::dbus::mutter_screen_cast::{self, CursorMode, ScreenCastToNiri};
@@ -43,6 +44,7 @@ pub struct Cast {
     _listener: StreamListener<()>,
     pub is_active: Rc<Cell<bool>>,
     pub output: Output,
+    pub size: Size<i32, Physical>,
     pub cursor_mode: CursorMode,
     pub last_frame_time: Duration,
     pub min_time_between_frames: Rc<Cell<Duration>>,
@@ -385,6 +387,7 @@ impl PipeWire {
             _listener: listener,
             is_active,
             output,
+            size,
             cursor_mode,
             last_frame_time: Duration::ZERO,
             min_time_between_frames,