Startup the project (aka just rip off smallvil)

.gitignore

+/target

Cargo.toml

+[package]
+name = "custom-wayland-compositor"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tracing-subscriber = { version = "0.3.16", features = ["env-filter"] }
+bitflags = "2.2.1"
+
+[dependencies.smithay]
+git = "https://github.com/Smithay/smithay.git"
+default-features = false
+features = ["backend_winit", "wayland_frontend", "desktop"]

src/grabs/mod.rs

+pub mod move_grab;
+pub use move_grab::MoveSurfaceGrab;
+
+pub mod resize_grab;
+pub use resize_grab::ResizeSurfaceGrab;

src/grabs/move_grab.rs

+use crate::Smallvil;
+use smithay::{
+    desktop::Window,
+    input::pointer::{
+        AxisFrame, ButtonEvent, GestureHoldBeginEvent, GestureHoldEndEvent, GesturePinchBeginEvent,
+        GesturePinchEndEvent, GesturePinchUpdateEvent, GestureSwipeBeginEvent, GestureSwipeEndEvent,
+        GestureSwipeUpdateEvent, GrabStartData as PointerGrabStartData, MotionEvent, PointerGrab,
+        PointerInnerHandle, RelativeMotionEvent,
+    },
+    reexports::wayland_server::protocol::wl_surface::WlSurface,
+    utils::{Logical, Point},
+};
+
+pub struct MoveSurfaceGrab {
+    pub start_data: PointerGrabStartData<Smallvil>,
+    pub window: Window,
+    pub initial_window_location: Point<i32, Logical>,
+}
+
+impl PointerGrab<Smallvil> for MoveSurfaceGrab {
+    fn motion(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        _focus: Option<(WlSurface, Point<i32, Logical>)>,
+        event: &MotionEvent,
+    ) {
+        // While the grab is active, no client has pointer focus
+        handle.motion(data, None, event);
+
+        let delta = event.location - self.start_data.location;
+        let new_location = self.initial_window_location.to_f64() + delta;
+        data.space
+            .map_element(self.window.clone(), new_location.to_i32_round(), true);
+    }
+
+    fn relative_motion(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        focus: Option<(WlSurface, Point<i32, Logical>)>,
+        event: &RelativeMotionEvent,
+    ) {
+        handle.relative_motion(data, focus, event);
+    }
+
+    fn button(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &ButtonEvent,
+    ) {
+        handle.button(data, event);
+
+        // The button is a button code as defined in the
+        // Linux kernel's linux/input-event-codes.h header file, e.g. BTN_LEFT.
+        const BTN_LEFT: u32 = 0x110;
+
+        if !handle.current_pressed().contains(&BTN_LEFT) {
+            // No more buttons are pressed, release the grab.
+            handle.unset_grab(data, event.serial, event.time, true);
+        }
+    }
+
+    fn axis(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        details: AxisFrame,
+    ) {
+        handle.axis(data, details)
+    }
+
+    fn frame(&mut self, data: &mut Smallvil, handle: &mut PointerInnerHandle<'_, Smallvil>) {
+        handle.frame(data);
+    }
+
+    fn gesture_swipe_begin(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureSwipeBeginEvent,
+    ) {
+        handle.gesture_swipe_begin(data, event)
+    }
+
+    fn gesture_swipe_update(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureSwipeUpdateEvent,
+    ) {
+        handle.gesture_swipe_update(data, event)
+    }
+
+    fn gesture_swipe_end(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureSwipeEndEvent,
+    ) {
+        handle.gesture_swipe_end(data, event)
+    }
+
+    fn gesture_pinch_begin(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GesturePinchBeginEvent,
+    ) {
+        handle.gesture_pinch_begin(data, event)
+    }
+
+    fn gesture_pinch_update(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GesturePinchUpdateEvent,
+    ) {
+        handle.gesture_pinch_update(data, event)
+    }
+
+    fn gesture_pinch_end(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GesturePinchEndEvent,
+    ) {
+        handle.gesture_pinch_end(data, event)
+    }
+
+    fn gesture_hold_begin(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureHoldBeginEvent,
+    ) {
+        handle.gesture_hold_begin(data, event)
+    }
+
+    fn gesture_hold_end(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureHoldEndEvent,
+    ) {
+        handle.gesture_hold_end(data, event)
+    }
+
+    fn start_data(&self) -> &PointerGrabStartData<Smallvil> {
+        &self.start_data
+    }
+}

src/grabs/resize_grab.rs

+use crate::Smallvil;
+use smithay::{
+    desktop::{Space, Window},
+    input::pointer::{
+        AxisFrame, ButtonEvent, GestureHoldBeginEvent, GestureHoldEndEvent, GesturePinchBeginEvent,
+        GesturePinchEndEvent, GesturePinchUpdateEvent, GestureSwipeBeginEvent, GestureSwipeEndEvent,
+        GestureSwipeUpdateEvent, GrabStartData as PointerGrabStartData, MotionEvent, PointerGrab,
+        PointerInnerHandle, RelativeMotionEvent,
+    },
+    reexports::{
+        wayland_protocols::xdg::shell::server::xdg_toplevel, wayland_server::protocol::wl_surface::WlSurface,
+    },
+    utils::{Logical, Point, Rectangle, Size},
+    wayland::{compositor, shell::xdg::SurfaceCachedState},
+};
+use std::cell::RefCell;
+
+bitflags::bitflags! {
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+    pub struct ResizeEdge: u32 {
+        const TOP          = 0b0001;
+        const BOTTOM       = 0b0010;
+        const LEFT         = 0b0100;
+        const RIGHT        = 0b1000;
+
+        const TOP_LEFT     = Self::TOP.bits() | Self::LEFT.bits();
+        const BOTTOM_LEFT  = Self::BOTTOM.bits() | Self::LEFT.bits();
+
+        const TOP_RIGHT    = Self::TOP.bits() | Self::RIGHT.bits();
+        const BOTTOM_RIGHT = Self::BOTTOM.bits() | Self::RIGHT.bits();
+    }
+}
+
+impl From<xdg_toplevel::ResizeEdge> for ResizeEdge {
+    #[inline]
+    fn from(x: xdg_toplevel::ResizeEdge) -> Self {
+        Self::from_bits(x as u32).unwrap()
+    }
+}
+
+pub struct ResizeSurfaceGrab {
+    start_data: PointerGrabStartData<Smallvil>,
+    window: Window,
+
+    edges: ResizeEdge,
+
+    initial_rect: Rectangle<i32, Logical>,
+    last_window_size: Size<i32, Logical>,
+}
+
+impl ResizeSurfaceGrab {
+    pub fn start(
+        start_data: PointerGrabStartData<Smallvil>,
+        window: Window,
+        edges: ResizeEdge,
+        initial_window_rect: Rectangle<i32, Logical>,
+    ) -> Self {
+        let initial_rect = initial_window_rect;
+
+        ResizeSurfaceState::with(window.toplevel().wl_surface(), |state| {
+            *state = ResizeSurfaceState::Resizing { edges, initial_rect };
+        });
+
+        Self {
+            start_data,
+            window,
+            edges,
+            initial_rect,
+            last_window_size: initial_rect.size,
+        }
+    }
+}
+
+impl PointerGrab<Smallvil> for ResizeSurfaceGrab {
+    fn motion(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        _focus: Option<(WlSurface, Point<i32, Logical>)>,
+        event: &MotionEvent,
+    ) {
+        // While the grab is active, no client has pointer focus
+        handle.motion(data, None, event);
+
+        let mut delta = event.location - self.start_data.location;
+
+        let mut new_window_width = self.initial_rect.size.w;
+        let mut new_window_height = self.initial_rect.size.h;
+
+        if self.edges.intersects(ResizeEdge::LEFT | ResizeEdge::RIGHT) {
+            if self.edges.intersects(ResizeEdge::LEFT) {
+                delta.x = -delta.x;
+            }
+
+            new_window_width = (self.initial_rect.size.w as f64 + delta.x) as i32;
+        }
+
+        if self.edges.intersects(ResizeEdge::TOP | ResizeEdge::BOTTOM) {
+            if self.edges.intersects(ResizeEdge::TOP) {
+                delta.y = -delta.y;
+            }
+
+            new_window_height = (self.initial_rect.size.h as f64 + delta.y) as i32;
+        }
+
+        let (min_size, max_size) = compositor::with_states(self.window.toplevel().wl_surface(), |states| {
+            let data = states.cached_state.current::<SurfaceCachedState>();
+            (data.min_size, data.max_size)
+        });
+
+        let min_width = min_size.w.max(1);
+        let min_height = min_size.h.max(1);
+
+        let max_width = (max_size.w == 0).then(i32::max_value).unwrap_or(max_size.w);
+        let max_height = (max_size.h == 0).then(i32::max_value).unwrap_or(max_size.h);
+
+        self.last_window_size = Size::from((
+            new_window_width.max(min_width).min(max_width),
+            new_window_height.max(min_height).min(max_height),
+        ));
+
+        let xdg = self.window.toplevel();
+        xdg.with_pending_state(|state| {
+            state.states.set(xdg_toplevel::State::Resizing);
+            state.size = Some(self.last_window_size);
+        });
+
+        xdg.send_pending_configure();
+    }
+
+    fn relative_motion(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        focus: Option<(WlSurface, Point<i32, Logical>)>,
+        event: &RelativeMotionEvent,
+    ) {
+        handle.relative_motion(data, focus, event);
+    }
+
+    fn button(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &ButtonEvent,
+    ) {
+        handle.button(data, event);
+
+        // The button is a button code as defined in the
+        // Linux kernel's linux/input-event-codes.h header file, e.g. BTN_LEFT.
+        const BTN_LEFT: u32 = 0x110;
+
+        if !handle.current_pressed().contains(&BTN_LEFT) {
+            // No more buttons are pressed, release the grab.
+            handle.unset_grab(data, event.serial, event.time, true);
+
+            let xdg = self.window.toplevel();
+            xdg.with_pending_state(|state| {
+                state.states.unset(xdg_toplevel::State::Resizing);
+                state.size = Some(self.last_window_size);
+            });
+
+            xdg.send_pending_configure();
+
+            ResizeSurfaceState::with(xdg.wl_surface(), |state| {
+                *state = ResizeSurfaceState::WaitingForLastCommit {
+                    edges: self.edges,
+                    initial_rect: self.initial_rect,
+                };
+            });
+        }
+    }
+
+    fn axis(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        details: AxisFrame,
+    ) {
+        handle.axis(data, details)
+    }
+
+    fn frame(&mut self, data: &mut Smallvil, handle: &mut PointerInnerHandle<'_, Smallvil>) {
+        handle.frame(data);
+    }
+
+    fn gesture_swipe_begin(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureSwipeBeginEvent,
+    ) {
+        handle.gesture_swipe_begin(data, event)
+    }
+
+    fn gesture_swipe_update(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureSwipeUpdateEvent,
+    ) {
+        handle.gesture_swipe_update(data, event)
+    }
+
+    fn gesture_swipe_end(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureSwipeEndEvent,
+    ) {
+        handle.gesture_swipe_end(data, event)
+    }
+
+    fn gesture_pinch_begin(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GesturePinchBeginEvent,
+    ) {
+        handle.gesture_pinch_begin(data, event)
+    }
+
+    fn gesture_pinch_update(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GesturePinchUpdateEvent,
+    ) {
+        handle.gesture_pinch_update(data, event)
+    }
+
+    fn gesture_pinch_end(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GesturePinchEndEvent,
+    ) {
+        handle.gesture_pinch_end(data, event)
+    }
+
+    fn gesture_hold_begin(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureHoldBeginEvent,
+    ) {
+        handle.gesture_hold_begin(data, event)
+    }
+
+    fn gesture_hold_end(
+        &mut self,
+        data: &mut Smallvil,
+        handle: &mut PointerInnerHandle<'_, Smallvil>,
+        event: &GestureHoldEndEvent,
+    ) {
+        handle.gesture_hold_end(data, event)
+    }
+
+    fn start_data(&self) -> &PointerGrabStartData<Smallvil> {
+        &self.start_data
+    }
+}
+
+/// State of the resize operation.
+///
+/// It is stored inside of WlSurface,
+/// and can be accessed using [`ResizeSurfaceState::with`]
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Default)]
+enum ResizeSurfaceState {
+    #[default]
+    Idle,
+    Resizing {
+        edges: ResizeEdge,
+        /// The initial window size and location.
+        initial_rect: Rectangle<i32, Logical>,
+    },
+    /// Resize is done, we are now waiting for last commit, to do the final move
+    WaitingForLastCommit {
+        edges: ResizeEdge,
+        /// The initial window size and location.
+        initial_rect: Rectangle<i32, Logical>,
+    },
+}
+
+impl ResizeSurfaceState {
+    fn with<F, T>(surface: &WlSurface, cb: F) -> T
+    where
+        F: FnOnce(&mut Self) -> T,
+    {
+        compositor::with_states(surface, |states| {
+            states.data_map.insert_if_missing(RefCell::<Self>::default);
+            let state = states.data_map.get::<RefCell<Self>>().unwrap();
+
+            cb(&mut state.borrow_mut())
+        })
+    }
+
+    fn commit(&mut self) -> Option<(ResizeEdge, Rectangle<i32, Logical>)> {
+        match *self {
+            Self::Resizing { edges, initial_rect } => Some((edges, initial_rect)),
+            Self::WaitingForLastCommit { edges, initial_rect } => {
+                // The resize is done, let's go back to idle
+                *self = Self::Idle;
+
+                Some((edges, initial_rect))
+            }
+            Self::Idle => None,
+        }
+    }
+}
+
+/// Should be called on `WlSurface::commit`
+pub fn handle_commit(space: &mut Space<Window>, surface: &WlSurface) -> Option<()> {
+    let window = space
+        .elements()
+        .find(|w| w.toplevel().wl_surface() == surface)
+        .cloned()?;
+
+    let mut window_loc = space.element_location(&window)?;
+    let geometry = window.geometry();
+
+    let new_loc: Point<Option<i32>, Logical> = ResizeSurfaceState::with(surface, |state| {
+        state
+            .commit()
+            .and_then(|(edges, initial_rect)| {
+                // If the window is being resized by top or left, its location must be adjusted
+                // accordingly.
+                edges.intersects(ResizeEdge::TOP_LEFT).then(|| {
+                    let new_x = edges
+                        .intersects(ResizeEdge::LEFT)
+                        .then_some(initial_rect.loc.x + (initial_rect.size.w - geometry.size.w));
+
+                    let new_y = edges
+                        .intersects(ResizeEdge::TOP)
+                        .then_some(initial_rect.loc.y + (initial_rect.size.h - geometry.size.h));
+
+                    (new_x, new_y).into()
+                })
+            })
+            .unwrap_or_default()
+    });
+
+    if let Some(new_x) = new_loc.x {
+        window_loc.x = new_x;
+    }
+    if let Some(new_y) = new_loc.y {
+        window_loc.y = new_y;
+    }
+
+    if new_loc.x.is_some() || new_loc.y.is_some() {
+        // If TOP or LEFT side of the window got resized, we have to move it
+        space.map_element(window, window_loc, false);
+    }
+
+    Some(())
+}

src/handlers/compositor.rs

+use crate::{grabs::resize_grab, state::ClientState, Smallvil};
+use smithay::{
+    backend::renderer::utils::on_commit_buffer_handler,
+    delegate_compositor, delegate_shm,
+    reexports::wayland_server::{
+        protocol::{wl_buffer, wl_surface::WlSurface},
+        Client,
+    },
+    wayland::{
+        buffer::BufferHandler,
+        compositor::{
+            get_parent, is_sync_subsurface, CompositorClientState, CompositorHandler, CompositorState,
+        },
+        shm::{ShmHandler, ShmState},
+    },
+};
+
+use super::xdg_shell;
+
+impl CompositorHandler for Smallvil {
+    fn compositor_state(&mut self) -> &mut CompositorState {
+        &mut self.compositor_state
+    }
+
+    fn client_compositor_state<'a>(&self, client: &'a Client) -> &'a CompositorClientState {
+        &client.get_data::<ClientState>().unwrap().compositor_state
+    }
+
+    fn commit(&mut self, surface: &WlSurface) {
+        on_commit_buffer_handler::<Self>(surface);
+        if !is_sync_subsurface(surface) {
+            let mut root = surface.clone();
+            while let Some(parent) = get_parent(&root) {
+                root = parent;
+            }
+            if let Some(window) = self.space.elements().find(|w| w.toplevel().wl_surface() == &root) {
+                window.on_commit();
+            }
+        };
+
+        xdg_shell::handle_commit(&mut self.popups, &self.space, surface);
+        resize_grab::handle_commit(&mut self.space, surface);
+    }
+}
+
+impl BufferHandler for Smallvil {
+    fn buffer_destroyed(&mut self, _buffer: &wl_buffer::WlBuffer) {}
+}
+
+impl ShmHandler for Smallvil {
+    fn shm_state(&self) -> &ShmState {
+        &self.shm_state
+    }
+}
+
+delegate_compositor!(Smallvil);
+delegate_shm!(Smallvil);

src/handlers/mod.rs

+mod compositor;
+mod xdg_shell;
+
+use crate::Smallvil;
+
+//
+// Wl Seat
+//
+
+use smithay::input::{Seat, SeatHandler, SeatState};
+use smithay::reexports::wayland_server::protocol::wl_surface::WlSurface;
+use smithay::reexports::wayland_server::Resource;
+use smithay::wayland::selection::data_device::{
+    set_data_device_focus, ClientDndGrabHandler, DataDeviceHandler, DataDeviceState, ServerDndGrabHandler,
+};
+use smithay::wayland::selection::SelectionHandler;
+use smithay::{delegate_data_device, delegate_output, delegate_seat};
+
+impl SeatHandler for Smallvil {
+    type KeyboardFocus = WlSurface;
+    type PointerFocus = WlSurface;
+
+    fn seat_state(&mut self) -> &mut SeatState<Smallvil> {
+        &mut self.seat_state
+    }
+
+    fn cursor_image(&mut self, _seat: &Seat<Self>, _image: smithay::input::pointer::CursorImageStatus) {}
+
+    fn focus_changed(&mut self, seat: &Seat<Self>, focused: Option<&WlSurface>) {
+        let dh = &self.display_handle;
+        let client = focused.and_then(|s| dh.get_client(s.id()).ok());
+        set_data_device_focus(dh, seat, client);
+    }
+}
+
+delegate_seat!(Smallvil);
+
+//
+// Wl Data Device
+//
+
+impl SelectionHandler for Smallvil {
+    type SelectionUserData = ();
+}
+
+impl DataDeviceHandler for Smallvil {
+    fn data_device_state(&self) -> &DataDeviceState {
+        &self.data_device_state
+    }
+}
+
+impl ClientDndGrabHandler for Smallvil {}
+impl ServerDndGrabHandler for Smallvil {}
+
+delegate_data_device!(Smallvil);
+
+//
+// Wl Output & Xdg Output
+//
+
+delegate_output!(Smallvil);

src/handlers/xdg_shell.rs

+use smithay::{
+    delegate_xdg_shell,
+    desktop::{find_popup_root_surface, get_popup_toplevel_coords, PopupKind, PopupManager, Space, Window},
+    input::{
+        pointer::{Focus, GrabStartData as PointerGrabStartData},
+        Seat,
+    },
+    reexports::{
+        wayland_protocols::xdg::shell::server::xdg_toplevel,
+        wayland_server::{
+            protocol::{wl_seat, wl_surface::WlSurface},
+            Resource,
+        },
+    },
+    utils::{Rectangle, Serial},
+    wayland::{
+        compositor::with_states,
+        shell::xdg::{
+            PopupSurface, PositionerState, ToplevelSurface, XdgPopupSurfaceData, XdgShellHandler,
+            XdgShellState, XdgToplevelSurfaceData,
+        },
+    },
+};
+
+use crate::{
+    grabs::{MoveSurfaceGrab, ResizeSurfaceGrab},
+    Smallvil,
+};
+
+impl XdgShellHandler for Smallvil {
+    fn xdg_shell_state(&mut self) -> &mut XdgShellState {
+        &mut self.xdg_shell_state
+    }
+
+    fn new_toplevel(&mut self, surface: ToplevelSurface) {
+        let window = Window::new(surface);
+        self.space.map_element(window, (0, 0), false);
+    }
+
+    fn new_popup(&mut self, surface: PopupSurface, _positioner: PositionerState) {
+        self.unconstrain_popup(&surface);
+        let _ = self.popups.track_popup(PopupKind::Xdg(surface));
+    }
+
+    fn reposition_request(&mut self, surface: PopupSurface, positioner: PositionerState, token: u32) {
+        surface.with_pending_state(|state| {
+            let geometry = positioner.get_geometry();
+            state.geometry = geometry;
+            state.positioner = positioner;
+        });
+        self.unconstrain_popup(&surface);
+        surface.send_repositioned(token);
+    }
+
+    fn move_request(&mut self, surface: ToplevelSurface, seat: wl_seat::WlSeat, serial: Serial) {
+        let seat = Seat::from_resource(&seat).unwrap();
+
+        let wl_surface = surface.wl_surface();
+
+        if let Some(start_data) = check_grab(&seat, wl_surface, serial) {
+            let pointer = seat.get_pointer().unwrap();
+
+            let window = self
+                .space
+                .elements()
+                .find(|w| w.toplevel().wl_surface() == wl_surface)
+                .unwrap()
+                .clone();
+            let initial_window_location = self.space.element_location(&window).unwrap();
+
+            let grab = MoveSurfaceGrab {
+                start_data,
+                window,
+                initial_window_location,
+            };
+
+            pointer.set_grab(self, grab, serial, Focus::Clear);
+        }
+    }
+
+    fn resize_request(
+        &mut self,
+        surface: ToplevelSurface,
+        seat: wl_seat::WlSeat,
+        serial: Serial,
+        edges: xdg_toplevel::ResizeEdge,
+    ) {
+        let seat = Seat::from_resource(&seat).unwrap();
+
+        let wl_surface = surface.wl_surface();
+
+        if let Some(start_data) = check_grab(&seat, wl_surface, serial) {
+            let pointer = seat.get_pointer().unwrap();
+
+            let window = self
+                .space
+                .elements()
+                .find(|w| w.toplevel().wl_surface() == wl_surface)
+                .unwrap()
+                .clone();
+            let initial_window_location = self.space.element_location(&window).unwrap();
+            let initial_window_size = window.geometry().size;
+
+            surface.with_pending_state(|state| {
+                state.states.set(xdg_toplevel::State::Resizing);
+            });
+
+            surface.send_pending_configure();
+
+            let grab = ResizeSurfaceGrab::start(
+                start_data,
+                window,
+                edges.into(),
+                Rectangle::from_loc_and_size(initial_window_location, initial_window_size),
+            );
+
+            pointer.set_grab(self, grab, serial, Focus::Clear);
+        }
+    }
+
+    fn grab(&mut self, _surface: PopupSurface, _seat: wl_seat::WlSeat, _serial: Serial) {
+        // TODO popup grabs
+    }
+}
+
+// Xdg Shell
+delegate_xdg_shell!(Smallvil);
+
+fn check_grab(
+    seat: &Seat<Smallvil>,
+    surface: &WlSurface,
+    serial: Serial,
+) -> Option<PointerGrabStartData<Smallvil>> {
+    let pointer = seat.get_pointer()?;
+
+    // Check that this surface has a click grab.
+    if !pointer.has_grab(serial) {
+        return None;
+    }
+
+    let start_data = pointer.grab_start_data()?;
+
+    let (focus, _) = start_data.focus.as_ref()?;
+    // If the focus was for a different surface, ignore the request.
+    if !focus.id().same_client_as(&surface.id()) {
+        return None;
+    }
+
+    Some(start_data)
+}
+
+/// Should be called on `WlSurface::commit`
+pub fn handle_commit(popups: &mut PopupManager, space: &Space<Window>, surface: &WlSurface) {
+    // Handle toplevel commits.
+    if let Some(window) = space
+        .elements()
+        .find(|w| w.toplevel().wl_surface() == surface)
+        .cloned()
+    {
+        let initial_configure_sent = with_states(surface, |states| {
+            states
+                .data_map
+                .get::<XdgToplevelSurfaceData>()
+                .unwrap()
+                .lock()
+                .unwrap()
+                .initial_configure_sent
+        });
+
+        if !initial_configure_sent {
+            window.toplevel().send_configure();
+        }
+    }
+
+    // Handle popup commits.
+    popups.commit(surface);
+    if let Some(popup) = popups.find_popup(surface) {
+        match popup {
+            PopupKind::Xdg(ref xdg) => {
+                let initial_configure_sent = with_states(surface, |states| {
+                    states
+                        .data_map
+                        .get::<XdgPopupSurfaceData>()
+                        .unwrap()
+                        .lock()
+                        .unwrap()
+                        .initial_configure_sent
+                });
+                if !initial_configure_sent {
+                    // NOTE: This should never fail as the initial configure is always
+                    // allowed.
+                    xdg.send_configure().expect("initial configure failed");
+                }
+            }
+            PopupKind::InputMethod(ref _input_method) => {}
+        }
+    }
+}
+
+impl Smallvil {
+    fn unconstrain_popup(&self, popup: &PopupSurface) {
+        let Ok(root) = find_popup_root_surface(&PopupKind::Xdg(popup.clone())) else {
+            return;
+        };
+        let Some(window) = self.space.elements().find(|w| w.toplevel().wl_surface() == &root) else {
+            return;
+        };
+
+        let output = self.space.outputs().next().unwrap();
+        let output_geo = self.space.output_geometry(output).unwrap();
+        let window_geo = self.space.element_geometry(window).unwrap();
+
+        // The target geometry for the positioner should be relative to its parent's geometry, so
+        // we will compute that here.
+        let mut target = output_geo;
+        target.loc -= get_popup_toplevel_coords(&PopupKind::Xdg(popup.clone()));
+        target.loc -= window_geo.loc;
+
+        popup.with_pending_state(|state| {
+            state.geometry = state.positioner.get_unconstrained_geometry(target);
+        });
+    }
+}

src/input.rs

+use smithay::{
+    backend::input::{
+        AbsolutePositionEvent, Axis, AxisSource, ButtonState, Event, InputBackend, InputEvent,
+        KeyboardKeyEvent, PointerAxisEvent, PointerButtonEvent,
+    },
+    input::{
+        keyboard::FilterResult,
+        pointer::{AxisFrame, ButtonEvent, MotionEvent},
+    },
+    reexports::wayland_server::protocol::wl_surface::WlSurface,
+    utils::SERIAL_COUNTER,
+};
+
+use crate::state::Smallvil;
+
+impl Smallvil {
+    pub fn process_input_event<I: InputBackend>(&mut self, event: InputEvent<I>) {
+        match event {
+            InputEvent::Keyboard { event, .. } => {
+                let serial = SERIAL_COUNTER.next_serial();
+                let time = Event::time_msec(&event);
+
+                self.seat.get_keyboard().unwrap().input::<(), _>(
+                    self,
+                    event.key_code(),
+                    event.state(),
+                    serial,
+                    time,
+                    |_, _, _| FilterResult::Forward,
+                );
+            }
+            InputEvent::PointerMotion { .. } => {}
+            InputEvent::PointerMotionAbsolute { event, .. } => {
+                let output = self.space.outputs().next().unwrap();
+
+                let output_geo = self.space.output_geometry(output).unwrap();
+
+                let pos = event.position_transformed(output_geo.size) + output_geo.loc.to_f64();
+
+                let serial = SERIAL_COUNTER.next_serial();
+
+                let pointer = self.seat.get_pointer().unwrap();
+
+                let under = self.surface_under(pos);
+
+                pointer.motion(
+                    self,
+                    under,
+                    &MotionEvent {
+                        location: pos,
+                        serial,
+                        time: event.time_msec(),
+                    },
+                );
+                pointer.frame(self);
+            }
+            InputEvent::PointerButton { event, .. } => {
+                let pointer = self.seat.get_pointer().unwrap();
+                let keyboard = self.seat.get_keyboard().unwrap();
+
+                let serial = SERIAL_COUNTER.next_serial();
+
+                let button = event.button_code();
+
+                let button_state = event.state();
+
+                if ButtonState::Pressed == button_state && !pointer.is_grabbed() {
+                    if let Some((window, _loc)) = self
+                        .space
+                        .element_under(pointer.current_location())
+                        .map(|(w, l)| (w.clone(), l))
+                    {
+                        self.space.raise_element(&window, true);
+                        keyboard.set_focus(
+                            self,
+                            Some(window.toplevel().wl_surface().clone()),
+                            serial,
+                        );
+                        self.space.elements().for_each(|window| {
+                            window.toplevel().send_pending_configure();
+                        });
+                    } else {
+                        self.space.elements().for_each(|window| {
+                            window.set_activated(false);
+                            window.toplevel().send_pending_configure();
+                        });
+                        keyboard.set_focus(self, Option::<WlSurface>::None, serial);
+                    }
+                };
+
+                pointer.button(
+                    self,
+                    &ButtonEvent {
+                        button,
+                        state: button_state,
+                        serial,
+                        time: event.time_msec(),
+                    },
+                );
+                pointer.frame(self);
+            }
+            InputEvent::PointerAxis { event, .. } => {
+                let source = event.source();
+
+                let horizontal_amount = event.amount(Axis::Horizontal).unwrap_or_else(|| {
+                    event.amount_v120(Axis::Horizontal).unwrap_or(0.0) * 3.0 / 120.
+                });
+                let vertical_amount = event.amount(Axis::Vertical).unwrap_or_else(|| {
+                    event.amount_v120(Axis::Vertical).unwrap_or(0.0) * 3.0 / 120.
+                });
+                let horizontal_amount_discrete = event.amount_v120(Axis::Horizontal);
+                let vertical_amount_discrete = event.amount_v120(Axis::Vertical);
+
+                let mut frame = AxisFrame::new(event.time_msec()).source(source);
+                if horizontal_amount != 0.0 {
+                    frame = frame.value(Axis::Horizontal, horizontal_amount);
+                    if let Some(discrete) = horizontal_amount_discrete {
+                        frame = frame.v120(Axis::Horizontal, discrete as i32);
+                    }
+                }
+                if vertical_amount != 0.0 {
+                    frame = frame.value(Axis::Vertical, vertical_amount);
+                    if let Some(discrete) = vertical_amount_discrete {
+                        frame = frame.v120(Axis::Vertical, discrete as i32);
+                    }
+                }
+
+                if source == AxisSource::Finger {
+                    if event.amount(Axis::Horizontal) == Some(0.0) {
+                        frame = frame.stop(Axis::Horizontal);
+                    }
+                    if event.amount(Axis::Vertical) == Some(0.0) {
+                        frame = frame.stop(Axis::Vertical);
+                    }
+                }
+
+                let pointer = self.seat.get_pointer().unwrap();
+                pointer.axis(self, frame);
+                pointer.frame(self);
+            }
+            _ => {}
+        }
+    }
+}

src/main.rs

+#![allow(irrefutable_let_patterns)]
+
+mod handlers;
+
+mod grabs;
+mod input;
+mod state;
+mod winit;
+
+use smithay::reexports::{
+    calloop::EventLoop,
+    wayland_server::{Display, DisplayHandle},
+};
+pub use state::Smallvil;
+
+pub struct CalloopData {
+    state: Smallvil,
+    display_handle: DisplayHandle,
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    if let Ok(env_filter) = tracing_subscriber::EnvFilter::try_from_default_env() {
+        tracing_subscriber::fmt().with_env_filter(env_filter).init();
+    } else {
+        tracing_subscriber::fmt().init();
+    }
+
+    let mut event_loop: EventLoop<CalloopData> = EventLoop::try_new()?;
+
+    let display: Display<Smallvil> = Display::new()?;
+    let display_handle = display.handle();
+    let state = Smallvil::new(&mut event_loop, display);
+
+    let mut data = CalloopData {
+        state,
+        display_handle,
+    };
+
+    crate::winit::init_winit(&mut event_loop, &mut data)?;
+
+    let mut args = std::env::args().skip(1);
+    let flag = args.next();
+    let arg = args.next();
+
+    match (flag.as_deref(), arg) {
+        (Some("-c") | Some("--command"), Some(command)) => {
+            std::process::Command::new(command).spawn().ok();
+        }
+        _ => {
+            std::process::Command::new("weston-terminal").spawn().ok();
+        }
+    }
+
+    event_loop.run(None, &mut data, move |_| {
+        // Smallvil is running
+    })?;
+
+    Ok(())
+}

src/state.rs

+use std::{ffi::OsString, sync::Arc};
+
+use smithay::{
+    desktop::{PopupManager, Space, Window, WindowSurfaceType},
+    input::{Seat, SeatState},
+    reexports::{
+        calloop::{generic::Generic, EventLoop, Interest, LoopSignal, Mode, PostAction},
+        wayland_server::{
+            backend::{ClientData, ClientId, DisconnectReason},
+            protocol::wl_surface::WlSurface,
+            Display, DisplayHandle,
+        },
+    },
+    utils::{Logical, Point},
+    wayland::{
+        compositor::{CompositorClientState, CompositorState},
+        output::OutputManagerState,
+        selection::data_device::DataDeviceState,
+        shell::xdg::XdgShellState,
+        shm::ShmState,
+        socket::ListeningSocketSource,
+    },
+};
+
+use crate::CalloopData;
+
+pub struct Smallvil {
+    pub start_time: std::time::Instant,
+    pub socket_name: OsString,
+    pub display_handle: DisplayHandle,
+
+    pub space: Space<Window>,
+    pub loop_signal: LoopSignal,
+
+    // Smithay State
+    pub compositor_state: CompositorState,
+    pub xdg_shell_state: XdgShellState,
+    pub shm_state: ShmState,
+    pub output_manager_state: OutputManagerState,
+    pub seat_state: SeatState<Smallvil>,
+    pub data_device_state: DataDeviceState,
+    pub popups: PopupManager,
+
+    pub seat: Seat<Self>,
+}
+
+impl Smallvil {
+    pub fn new(event_loop: &mut EventLoop<CalloopData>, display: Display<Self>) -> Self {
+        let start_time = std::time::Instant::now();
+
+        let dh = display.handle();
+
+        let compositor_state = CompositorState::new::<Self>(&dh);
+        let xdg_shell_state = XdgShellState::new::<Self>(&dh);
+        let shm_state = ShmState::new::<Self>(&dh, vec![]);
+        let output_manager_state = OutputManagerState::new_with_xdg_output::<Self>(&dh);
+        let mut seat_state = SeatState::new();
+        let data_device_state = DataDeviceState::new::<Self>(&dh);
+        let popups = PopupManager::default();
+
+        // A seat is a group of keyboards, pointer and touch devices.
+        // A seat typically has a pointer and maintains a keyboard focus and a pointer focus.
+        let mut seat: Seat<Self> = seat_state.new_wl_seat(&dh, "winit");
+
+        // Notify clients that we have a keyboard, for the sake of the example we assume that keyboard is always present.
+        // You may want to track keyboard hot-plug in real compositor.
+        seat.add_keyboard(Default::default(), 200, 25).unwrap();
+
+        // Notify clients that we have a pointer (mouse)
+        // Here we assume that there is always pointer plugged in
+        seat.add_pointer();
+
+        // A space represents a two-dimensional plane. Windows and Outputs can be mapped onto it.
+        //
+        // Windows get a position and stacking order through mapping.
+        // Outputs become views of a part of the Space and can be rendered via Space::render_output.
+        let space = Space::default();
+
+        let socket_name = Self::init_wayland_listener(display, event_loop);
+
+        // Get the loop signal, used to stop the event loop
+        let loop_signal = event_loop.get_signal();
+
+        Self {
+            start_time,
+            display_handle: dh,
+
+            space,
+            loop_signal,
+            socket_name,
+
+            compositor_state,
+            xdg_shell_state,
+            shm_state,
+            output_manager_state,
+            seat_state,
+            data_device_state,
+            popups,
+            seat,
+        }
+    }
+
+    fn init_wayland_listener(
+        display: Display<Smallvil>,
+        event_loop: &mut EventLoop<CalloopData>,
+    ) -> OsString {
+        // Creates a new listening socket, automatically choosing the next available `wayland` socket name.
+        let listening_socket = ListeningSocketSource::new_auto().unwrap();
+
+        // Get the name of the listening socket.
+        // Clients will connect to this socket.
+        let socket_name = listening_socket.socket_name().to_os_string();
+
+        let handle = event_loop.handle();
+
+        event_loop
+            .handle()
+            .insert_source(listening_socket, move |client_stream, _, state| {
+                // Inside the callback, you should insert the client into the display.
+                //
+                // You may also associate some data with the client when inserting the client.
+                state
+                    .display_handle
+                    .insert_client(client_stream, Arc::new(ClientState::default()))
+                    .unwrap();
+            })
+            .expect("Failed to init the wayland event source.");
+
+        // You also need to add the display itself to the event loop, so that client events will be processed by wayland-server.
+        handle
+            .insert_source(
+                Generic::new(display, Interest::READ, Mode::Level),
+                |_, display, state| {
+                    // Safety: we don't drop the display
+                    unsafe {
+                        display.get_mut().dispatch_clients(&mut state.state).unwrap();
+                    }
+                    Ok(PostAction::Continue)
+                },
+            )
+            .unwrap();
+
+        socket_name
+    }
+
+    pub fn surface_under(&self, pos: Point<f64, Logical>) -> Option<(WlSurface, Point<i32, Logical>)> {
+        self.space.element_under(pos).and_then(|(window, location)| {
+            window
+                .surface_under(pos - location.to_f64(), WindowSurfaceType::ALL)
+                .map(|(s, p)| (s, p + location))
+        })
+    }
+}
+
+#[derive(Default)]
+pub struct ClientState {
+    pub compositor_state: CompositorClientState,
+}
+
+impl ClientData for ClientState {
+    fn initialized(&self, _client_id: ClientId) {}
+    fn disconnected(&self, _client_id: ClientId, _reason: DisconnectReason) {}
+}

src/winit.rs

+use std::time::Duration;
+
+use smithay::{
+    backend::{
+        renderer::{
+            damage::OutputDamageTracker, element::surface::WaylandSurfaceRenderElement, gles::GlesRenderer,
+        },
+        winit::{self, WinitEvent},
+    },
+    output::{Mode, Output, PhysicalProperties, Subpixel},
+    reexports::calloop::EventLoop,
+    utils::{Rectangle, Transform},
+};
+
+use crate::{CalloopData, Smallvil};
+
+pub fn init_winit(
+    event_loop: &mut EventLoop<CalloopData>,
+    data: &mut CalloopData,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let display_handle = &mut data.display_handle;
+    let state = &mut data.state;
+
+    let (mut backend, winit) = winit::init()?;
+
+    let mode = Mode {
+        size: backend.window_size(),
+        refresh: 60_000,
+    };
+
+    let output = Output::new(
+        "winit".to_string(),
+        PhysicalProperties {
+            size: (0, 0).into(),
+            subpixel: Subpixel::Unknown,
+            make: "Smithay".into(),
+            model: "Winit".into(),
+        },
+    );
+    let _global = output.create_global::<Smallvil>(display_handle);
+    output.change_current_state(Some(mode), Some(Transform::Flipped180), None, Some((0, 0).into()));
+    output.set_preferred(mode);
+
+    state.space.map_output(&output, (0, 0));
+
+    let mut damage_tracker = OutputDamageTracker::from_output(&output);
+
+    std::env::set_var("WAYLAND_DISPLAY", &state.socket_name);
+
+    event_loop.handle().insert_source(winit, move |event, _, data| {
+        let display = &mut data.display_handle;
+        let state = &mut data.state;
+
+        match event {
+            WinitEvent::Resized { size, .. } => {
+                output.change_current_state(
+                    Some(Mode {
+                        size,
+                        refresh: 60_000,
+                    }),
+                    None,
+                    None,
+                    None,
+                );
+            }
+            WinitEvent::Input(event) => state.process_input_event(event),
+            WinitEvent::Redraw => {
+                let size = backend.window_size();
+                let damage = Rectangle::from_loc_and_size((0, 0), size);
+
+                backend.bind().unwrap();
+                smithay::desktop::space::render_output::<_, WaylandSurfaceRenderElement<GlesRenderer>, _, _>(
+                    &output,
+                    backend.renderer(),
+                    1.0,
+                    0,
+                    [&state.space],
+                    &[],
+                    &mut damage_tracker,
+                    [0.1, 0.1, 0.1, 1.0],
+                )
+                .unwrap();
+                backend.submit(Some(&[damage])).unwrap();
+
+                state.space.elements().for_each(|window| {
+                    window.send_frame(
+                        &output,
+                        state.start_time.elapsed(),
+                        Some(Duration::ZERO),
+                        |_, _| Some(output.clone()),
+                    )
+                });
+
+                state.space.refresh();
+                state.popups.cleanup();
+                let _ = display.flush_clients();
+
+                // Ask for redraw to schedule new frame.
+                backend.window().request_redraw();
+            }
+            WinitEvent::CloseRequested => {
+                state.loop_signal.stop();
+            }
+            _ => (),
+        };
+    })?;
+
+    Ok(())
+}