Redraw upon starting PW stream

Otherwise it may take a while for the first frame to arrive.

src/dbus/mutter_screen_cast.rs

@@ -64,6 +64,7 @@ pub enum ScreenCastToNiri {
     StopCast {
         session_id: usize,
     },
+    Redraw(Output),
 }
 
 #[dbus_interface(name = "org.gnome.Mutter.ScreenCast")]

src/niri.rs

@@ -705,6 +705,7 @@ impl State {
                 }
             }
             ScreenCastToNiri::StopCast { session_id } => self.niri.stop_cast(session_id),
+            ScreenCastToNiri::Redraw(output) => self.niri.queue_redraw(output),
         }
     }
 

src/pw_utils.rs

@@ -95,11 +95,20 @@ impl PipeWire {
     ) -> anyhow::Result<Cast> {
         let _span = tracy_client::span!("PipeWire::start_cast");
 
+        let to_niri_ = to_niri.clone();
         let stop_cast = move || {
-            if let Err(err) = to_niri.send(ScreenCastToNiri::StopCast { session_id }) {
+            if let Err(err) = to_niri_.send(ScreenCastToNiri::StopCast { session_id }) {
                 warn!("error sending StopCast to niri: {err:?}");
             }
         };
+        let weak = output.downgrade();
+        let redraw = move || {
+            if let Some(output) = weak.upgrade() {
+                if let Err(err) = to_niri.send(ScreenCastToNiri::Redraw(output)) {
+                    warn!("error sending Redraw to niri: {err:?}");
+                }
+            }
+        };
 
         let mode = output.current_mode().unwrap();
         let size = mode.size;
@@ -158,6 +167,7 @@ impl PipeWire {
                         StreamState::Connecting => (),
                         StreamState::Streaming => {
                             is_active.set(true);
+                            redraw();
                         }
                     }
                 }