From acf9fd122f05f85ac04eea7df42ce3c5c92d6b1c Mon Sep 17 00:00:00 2001
From: Naman Agrawal <namana@mechasystems.com>
Date: Mon, 1 Sep 2025 10:57:24 +0530
Subject: [PATCH] feat: Add basic support for foreign top level management.

- Allow users to minimize other applications by sending a
`ForeignToplevelEvent`.
---
 Cargo.lock                      |   1 +
 Cargo.toml                      |   1 +
 examples/foreign_toplevel.rs    | 122 ++++++++++++++++++++++++++++++++
 src/foreign_toplevel_manager.rs |  96 +++++++++++++++++++++++++
 src/lib.rs                      |   3 +-
 5 files changed, 222 insertions(+), 1 deletion(-)
 create mode 100644 examples/foreign_toplevel.rs
 create mode 100644 src/foreign_toplevel_manager.rs

diff --git a/Cargo.lock b/Cargo.lock
index 1e6152c..90e5f08 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1101,6 +1101,7 @@ dependencies = [
  "raw-window-handle",
  "smithay-client-toolkit 0.20.0",
  "wayland-backend",
+ "wayland-protocols-wlr",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 514d734..c31619d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,3 +17,4 @@ lazy_static = "1.5.0"
 raw-window-handle = "0.6.2"
 smithay-client-toolkit = "0.20.0"
 wayland-backend = { version = "0.3.11", features = ["client_system"] }
+wayland-protocols-wlr = "0.3.9"
diff --git a/examples/foreign_toplevel.rs b/examples/foreign_toplevel.rs
new file mode 100644
index 0000000..a375225
--- /dev/null
+++ b/examples/foreign_toplevel.rs
@@ -0,0 +1,122 @@
+use bevy::{color::palettes::basic::*, prelude::*, window::WindowResolution, winit::WinitPlugin};
+use bevy_wayland::{foreign_toplevel_manager::ForeignToplevelEvent, prelude::*};
+
+const NORMAL_BUTTON: Color = Color::srgb(0.15, 0.15, 0.15);
+const HOVERED_BUTTON: Color = Color::srgb(0.25, 0.25, 0.25);
+const PRESSED_BUTTON: Color = Color::srgb(0.35, 0.75, 0.35);
+
+fn main() {
+    App::new()
+        .add_plugins((
+            DefaultPlugins
+                .build()
+                .disable::<WinitPlugin>()
+                .set(WindowPlugin {
+                    primary_window: Some(Window {
+                        resolution: WindowResolution::new(400.0, 400.0),
+                        present_mode: bevy::window::PresentMode::AutoVsync,
+                        ..Default::default()
+                    }),
+                    ..Default::default()
+                }),
+            WaylandPlugin,
+        ))
+        .add_systems(Startup, setup)
+        .add_systems(Update, (button_system, exit_on_esc))
+        .run();
+}
+
+#[allow(clippy::type_complexity)]
+fn button_system(
+    mut interaction_query: Query<
+        (
+            &Interaction,
+            &mut BackgroundColor,
+            &mut BorderColor,
+            &Children,
+        ),
+        (Changed<Interaction>, With<Button>),
+    >,
+    mut foreign_toplevel_event_writer: EventWriter<ForeignToplevelEvent>,
+    mut text_query: Query<&mut Text>,
+) {
+    //info!("Button system was called!!");
+    for (interaction, mut color, mut border_color, children) in &mut interaction_query {
+        let mut text = text_query.get_mut(children[0]).unwrap();
+        match *interaction {
+            Interaction::Pressed => {
+                **text = "Press".to_string();
+                *color = PRESSED_BUTTON.into();
+                border_color.0 = RED.into();
+                foreign_toplevel_event_writer.write(ForeignToplevelEvent::MinimizeOthers);
+            }
+            Interaction::Hovered => {
+                **text = "Hover".to_string();
+                *color = HOVERED_BUTTON.into();
+                border_color.0 = Color::WHITE;
+            }
+            Interaction::None => {
+                **text = "Button".to_string();
+                *color = NORMAL_BUTTON.into();
+                border_color.0 = Color::BLACK;
+            }
+        }
+    }
+}
+
+fn setup(mut commands: Commands, assets: Res<AssetServer>, windows: Query<Entity, With<Window>>) {
+    for entity in &windows {
+        commands.entity(entity).insert((LayerShellSettings {
+            anchor: Anchor::TOP | Anchor::LEFT,
+            layer: Layer::Top,
+            ..Default::default()
+        },));
+    }
+    // ui camera
+    commands.spawn(Camera2d);
+    commands.spawn(button(&assets));
+}
+
+fn exit_on_esc(keys: Res<ButtonInput<KeyCode>>) {
+    if keys.just_pressed(KeyCode::Escape) {
+        std::process::exit(0);
+    }
+}
+
+fn button(asset_server: &AssetServer) -> impl Bundle + use<> {
+    (
+        Node {
+            width: Val::Percent(100.0),
+            height: Val::Percent(100.0),
+            align_items: AlignItems::Center,
+            justify_content: JustifyContent::Center,
+            ..default()
+        },
+        children![(
+            Button,
+            Node {
+                width: Val::Px(150.0),
+                height: Val::Px(65.0),
+                border: UiRect::all(Val::Px(5.0)),
+                // horizontally center child text
+                justify_content: JustifyContent::Center,
+                // vertically center child text
+                align_items: AlignItems::Center,
+                ..default()
+            },
+            BorderColor(Color::BLACK),
+            BorderRadius::MAX,
+            BackgroundColor(NORMAL_BUTTON),
+            children![(
+                Text::new("Button"),
+                TextFont {
+                    font: asset_server.load("fonts/FiraSans-Bold.ttf"),
+                    font_size: 33.0,
+                    ..default()
+                },
+                TextColor(Color::srgb(0.9, 0.9, 0.9)),
+                TextShadow::default(),
+            )]
+        )],
+    )
+}
diff --git a/src/foreign_toplevel_manager.rs b/src/foreign_toplevel_manager.rs
new file mode 100644
index 0000000..877195b
--- /dev/null
+++ b/src/foreign_toplevel_manager.rs
@@ -0,0 +1,96 @@
+use bevy::prelude::*;
+use smithay_client_toolkit::{
+    reexports::client::{event_created_child, Dispatch, QueueHandle},
+    registry::RegistryState,
+};
+use wayland_protocols_wlr::foreign_toplevel::v1::client::{
+    zwlr_foreign_toplevel_handle_v1::{self, ZwlrForeignToplevelHandleV1},
+    zwlr_foreign_toplevel_manager_v1::{self, ZwlrForeignToplevelManagerV1},
+};
+
+use crate::WaylandState;
+#[derive(Debug, Copy, Clone, Event)]
+pub enum ForeignToplevelEvent {
+    MinimizeOthers,
+}
+
+#[derive(Default, Deref, DerefMut)]
+struct ForeignToplevels(Vec<ZwlrForeignToplevelHandleV1>);
+
+pub struct ForeignToplevelManagerPlugin;
+impl Plugin for ForeignToplevelManagerPlugin {
+    fn build(&self, app: &mut App) {
+        let registry_state = app.world().non_send_resource::<RegistryState>();
+        let queue_handle = app.world().non_send_resource::<QueueHandle<WaylandState>>();
+        let foreign_top_level_manager =
+            registry_state.bind_one::<ZwlrForeignToplevelManagerV1, _, _>(queue_handle, 2..=3, ());
+        if let Ok(foreign_top_level_manager) = foreign_top_level_manager {
+            info!("Foreign toplevel manager was bound!");
+            app.insert_non_send_resource(foreign_top_level_manager);
+            app.insert_non_send_resource(ForeignToplevels::default());
+            app.add_event::<ForeignToplevelEvent>();
+            app.add_systems(Update, foreign_top_level_event_handler);
+        } else {
+            let bind_error = foreign_top_level_manager.err().unwrap();
+            error!("Couldn't bind foreign toplevel manager! {:?}", bind_error);
+        }
+    }
+}
+
+fn foreign_top_level_event_handler(
+    foreign_top_levels: NonSendMut<ForeignToplevels>,
+    mut events: EventReader<ForeignToplevelEvent>,
+) {
+    for event in events.read() {
+        match event {
+            ForeignToplevelEvent::MinimizeOthers => {
+                info!("Minimizing other windows");
+                for toplevel in foreign_top_levels.iter() {
+                    toplevel.set_minimized();
+                }
+            }
+        }
+    }
+}
+
+impl Dispatch<ZwlrForeignToplevelManagerV1, ()> for WaylandState {
+    fn event(
+        state: &mut Self,
+        _proxy: &ZwlrForeignToplevelManagerV1,
+        event: <ZwlrForeignToplevelManagerV1 as smithay_client_toolkit::reexports::client::Proxy>::Event,
+        _data: &(),
+        _conn: &smithay_client_toolkit::reexports::client::Connection,
+        _qhandle: &QueueHandle<Self>,
+    ) {
+        let mut foreign_toplevels = state
+            .world_mut()
+            .non_send_resource_mut::<ForeignToplevels>();
+        match event {
+            wayland_protocols_wlr::foreign_toplevel::v1::client::zwlr_foreign_toplevel_manager_v1::Event::Toplevel { toplevel } => {
+                foreign_toplevels.push(toplevel);
+            },
+            wayland_protocols_wlr::foreign_toplevel::v1::client::zwlr_foreign_toplevel_manager_v1::Event::Finished => {},
+            _ => {},
+        }
+    }
+
+    event_created_child!(WaylandState, ZwlrForeignToplevelManagerV1, [
+        // Opcode 0 is the `toplevel` event. It creates a new `zwlr_foreign_toplevel_handle_v1`.
+        zwlr_foreign_toplevel_manager_v1::EVT_TOPLEVEL_OPCODE => (
+            zwlr_foreign_toplevel_handle_v1::ZwlrForeignToplevelHandleV1,
+            ()
+        )
+    ]);
+}
+
+impl Dispatch<ZwlrForeignToplevelHandleV1, ()> for WaylandState {
+    fn event(
+        _state: &mut Self,
+        _proxy: &ZwlrForeignToplevelHandleV1,
+        _event: <ZwlrForeignToplevelHandleV1 as smithay_client_toolkit::reexports::client::Proxy>::Event,
+        _data: &(),
+        _conn: &smithay_client_toolkit::reexports::client::Connection,
+        _qhandle: &QueueHandle<Self>,
+    ) {
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index e09cb93..cda2368 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,4 @@
 use std::{
-    num::NonZero,
     sync::mpsc::SendError,
     time::{Duration, Instant},
 };
@@ -18,6 +17,7 @@ use smithay_client_toolkit::{
     seat::SeatState,
 };
 
+pub mod foreign_toplevel_manager;
 mod input_handler;
 pub mod input_region;
 pub mod layer_shell;
@@ -85,6 +85,7 @@ impl Plugin for WaylandPlugin {
             layer_shell::LayerShellPlugin,
             session_lock::SessionLockPlugin,
             input_region::InputRegionPlugin,
+            foreign_toplevel_manager::ForeignToplevelManagerPlugin,
         ));
         app.set_runner(|app| runner(app, event_loop));
     }