Update SCTK to 0.11.0

* Update SCTK to 0.11.0

Updates smithay-client-toolkit to 0.11.0. The major highlight
of that updated, is update of wayland-rs to 0.27.0. Switching
to wayland-cursor, instead of using libwayland-cursor. It
also fixes the following bugs:

  - Disabled repeat rate not being handled.
  - Decoration buttons not working after tty switch.
  - Scaling not being applied on output reenable.
  - Crash when `XCURSOR_SIZE` is `0`.
  - Pointer getting created in some cases without pointer capability.
  - On kwin, fix space between window and decorations on startup.
  - Incorrect size event when entering fullscreen when using
    client side decorations.
  - Client side decorations not being hided properly in fullscreen.
  - Size tracking between fullscreen/tiled state changes.
  - Repeat rate triggering multiple times from slow callback handler.
  - Resizable attribute not being applied properly on startup.
  - Not working IME

Besides those fixes it also adds a bunch of missing virtual key codes,
implements proper cursor grabbing, adds right click on decorations
to open application menu, disabled maximize button for non-resizeable
window, and fall back for cursor icon to similar ones, if the requested
is missing.

It also adds new methods to a `Theme` trait, such as:
  - `title_font(&self) -> Option<(String, f32)>` - The font for a title.
  - `title_color(&self, window_active: bool) -> [u8; 4]` - The color of
  the text in the title.

Fixes #1680.
Fixes #1678.
Fixes #1676.
Fixes #1646.
Fixes #1614.
Fixes #1601.
Fixes #1533.
Fixes #1509.
Fixes #952.
Fixes #947.

src/platform_impl/linux/wayland/window/mod.rs

@@ -0,0 +1,656 @@
+use std::collections::VecDeque;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
+
+use sctk::reexports::client::protocol::wl_surface::WlSurface;
+use sctk::reexports::client::Display;
+
+use sctk::reexports::calloop;
+
+use sctk::window::{
+    ARGBColor, ButtonColorSpec, ColorSpec, ConceptConfig, ConceptFrame, Decorations,
+};
+
+use raw_window_handle::unix::WaylandHandle;
+
+use crate::dpi::{LogicalSize, PhysicalPosition, PhysicalSize, Position, Size};
+use crate::error::{ExternalError, NotSupportedError, OsError as RootOsError};
+use crate::monitor::MonitorHandle as RootMonitorHandle;
+use crate::platform::unix::{ARGBColor as LocalARGBColor, Button, ButtonState, Element, Theme};
+use crate::platform_impl::{
+    MonitorHandle as PlatformMonitorHandle, OsError,
+    PlatformSpecificWindowBuilderAttributes as PlatformAttributes,
+};
+use crate::window::{CursorIcon, Fullscreen, WindowAttributes};
+
+use super::env::WindowingFeatures;
+use super::event_loop::WinitState;
+use super::output::{MonitorHandle, OutputManagerHandle};
+use super::{EventLoopWindowTarget, WindowId};
+
+pub mod shim;
+
+use shim::{WindowHandle, WindowRequest, WindowUpdate};
+
+pub struct Window {
+    /// Window id.
+    window_id: WindowId,
+
+    /// The Wayland display.
+    display: Display,
+
+    /// The underlying wl_surface.
+    surface: WlSurface,
+
+    /// The current window size.
+    size: Arc<Mutex<LogicalSize<u32>>>,
+
+    /// A handle to output manager.
+    output_manager_handle: OutputManagerHandle,
+
+    /// Event loop proxy to wake it up.
+    event_loop_awakener: calloop::ping::Ping,
+
+    /// Fullscreen state.
+    fullscreen: Arc<AtomicBool>,
+
+    /// Available windowing features.
+    windowing_features: WindowingFeatures,
+
+    /// Requests that SCTK window should perform.
+    window_requests: Arc<Mutex<Vec<WindowRequest>>>,
+}
+
+impl Window {
+    pub fn new<T>(
+        event_loop_window_target: &EventLoopWindowTarget<T>,
+        attributes: WindowAttributes,
+        platform_attributes: PlatformAttributes,
+    ) -> Result<Self, RootOsError> {
+        let surface = event_loop_window_target
+            .env
+            .create_surface_with_scale_callback(move |scale, surface, mut dispatch_data| {
+                let winit_state = dispatch_data.get::<WinitState>().unwrap();
+
+                // Get the window that receiced the event.
+                let window_id = super::make_wid(&surface);
+                let mut window_update = winit_state.window_updates.get_mut(&window_id).unwrap();
+
+                // Set pending scale factor.
+                window_update.scale_factor = Some(scale);
+                window_update.redraw_requested = true;
+
+                surface.set_buffer_scale(scale);
+            })
+            .detach();
+
+        let scale_factor = sctk::get_surface_scale_factor(&surface);
+
+        let window_id = super::make_wid(&surface);
+        let fullscreen = Arc::new(AtomicBool::new(false));
+        let fullscreen_clone = fullscreen.clone();
+
+        let (width, height) = attributes
+            .inner_size
+            .map(|size| size.to_logical::<f64>(scale_factor as f64).into())
+            .unwrap_or((800, 600));
+
+        let theme_manager = event_loop_window_target.theme_manager.clone();
+        let mut window = event_loop_window_target
+            .env
+            .create_window::<ConceptFrame, _>(
+                surface.clone(),
+                Some(theme_manager),
+                (width, height),
+                move |event, mut dispatch_data| {
+                    use sctk::window::{Event, State};
+
+                    let winit_state = dispatch_data.get::<WinitState>().unwrap();
+                    let mut window_update = winit_state.window_updates.get_mut(&window_id).unwrap();
+
+                    match event {
+                        Event::Refresh => {
+                            window_update.refresh_frame = true;
+                        }
+                        Event::Configure { new_size, states } => {
+                            let is_fullscreen = states.contains(&State::Fullscreen);
+                            fullscreen_clone.store(is_fullscreen, Ordering::Relaxed);
+
+                            window_update.refresh_frame = true;
+                            window_update.redraw_requested = true;
+                            if let Some((w, h)) = new_size {
+                                window_update.size = Some(LogicalSize::new(w, h));
+                            }
+                        }
+                        Event::Close => {
+                            window_update.close_window = true;
+                        }
+                    }
+                },
+            )
+            .map_err(|_| os_error!(OsError::WaylandMisc("failed to create window.")))?;
+
+        // Set decorations.
+        if attributes.decorations {
+            window.set_decorate(Decorations::FollowServer);
+        } else {
+            window.set_decorate(Decorations::None);
+        }
+
+        // Min dimensions.
+        let min_size = attributes
+            .min_inner_size
+            .map(|size| size.to_logical::<f64>(scale_factor as f64).into());
+        window.set_min_size(min_size);
+
+        // Max dimensions.
+        let max_size = attributes
+            .min_inner_size
+            .map(|size| size.to_logical::<f64>(scale_factor as f64).into());
+        window.set_max_size(max_size);
+
+        // Set Wayland specific window attributes.
+        if let Some(app_id) = platform_attributes.app_id {
+            window.set_app_id(app_id);
+        }
+
+        // Set common window attributes.
+        //
+        // We set resizable after other attributes, since it touches min and max size under
+        // the hood.
+        window.set_resizable(attributes.resizable);
+        window.set_title(attributes.title);
+
+        // Set fullscreen/maximized if so was requested.
+        match attributes.fullscreen {
+            Some(Fullscreen::Exclusive(_)) => {
+                warn!("`Fullscreen::Exclusive` is ignored on Wayland")
+            }
+            Some(Fullscreen::Borderless(monitor)) => {
+                let monitor =
+                    monitor.and_then(|RootMonitorHandle { inner: monitor }| match monitor {
+                        PlatformMonitorHandle::Wayland(monitor) => Some(monitor.proxy),
+                        #[cfg(feature = "x11")]
+                        PlatformMonitorHandle::X(_) => None,
+                    });
+
+                window.set_fullscreen(monitor.as_ref());
+            }
+            None => {
+                if attributes.maximized {
+                    window.set_maximized();
+                }
+            }
+        }
+
+        let size = Arc::new(Mutex::new(LogicalSize::new(width, height)));
+
+        // We should trigger redraw and commit the surface for the newly created window.
+        let mut window_update = WindowUpdate::new();
+        window_update.refresh_frame = true;
+        window_update.redraw_requested = true;
+
+        let window_id = super::make_wid(&surface);
+        let window_requests = Arc::new(Mutex::new(Vec::with_capacity(64)));
+
+        // Create a handle that performs all the requests on underlying sctk a window.
+        let window_handle = WindowHandle::new(window, size.clone(), window_requests.clone());
+
+        let mut winit_state = event_loop_window_target.state.borrow_mut();
+
+        winit_state.window_map.insert(window_id, window_handle);
+
+        winit_state
+            .window_updates
+            .insert(window_id, WindowUpdate::new());
+
+        let windowing_features = event_loop_window_target.windowing_features;
+
+        // Send all updates to the server.
+        let wayland_source = &event_loop_window_target.wayland_source;
+        let event_loop_handle = &event_loop_window_target.event_loop_handle;
+
+        // To make our window usable for drawing right away we must `ack` a `configure`
+        // from the server, the acking part here is done by SCTK window frame, so we just
+        // need to sync with server so it'll be done automatically for us.
+        event_loop_handle.with_source(&wayland_source, |event_queue| {
+            let event_queue = event_queue.queue();
+            let _ = event_queue.sync_roundtrip(&mut *winit_state, |_, _, _| unreachable!());
+        });
+
+        // We all praise GNOME for these 3 lines of pure magic. If we don't do that,
+        // GNOME will shrink our window a bit for the size of the decorations. I guess it
+        // happens because we haven't committed them with buffers to the server.
+        let window_handle = winit_state.window_map.get_mut(&window_id).unwrap();
+        window_handle.window.refresh();
+
+        let output_manager_handle = event_loop_window_target.output_manager.handle();
+
+        let window = Self {
+            window_id,
+            surface,
+            display: event_loop_window_target.display.clone(),
+            output_manager_handle,
+            size,
+            window_requests,
+            event_loop_awakener: event_loop_window_target.event_loop_awakener.clone(),
+            fullscreen,
+            windowing_features,
+        };
+
+        Ok(window)
+    }
+}
+
+impl Window {
+    #[inline]
+    pub fn id(&self) -> WindowId {
+        self.window_id
+    }
+
+    #[inline]
+    pub fn set_title(&self, title: &str) {
+        let title_request = WindowRequest::Title(title.to_owned());
+        self.window_requests.lock().unwrap().push(title_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_visible(&self, _visible: bool) {
+        // Not possible on Wayland.
+    }
+
+    #[inline]
+    pub fn outer_position(&self) -> Result<PhysicalPosition<i32>, NotSupportedError> {
+        Err(NotSupportedError::new())
+    }
+
+    #[inline]
+    pub fn inner_position(&self) -> Result<PhysicalPosition<i32>, NotSupportedError> {
+        Err(NotSupportedError::new())
+    }
+
+    #[inline]
+    pub fn set_outer_position(&self, _: Position) {
+        // Not possible on Wayland.
+    }
+
+    pub fn inner_size(&self) -> PhysicalSize<u32> {
+        self.size
+            .lock()
+            .unwrap()
+            .to_physical(self.scale_factor() as f64)
+    }
+
+    #[inline]
+    pub fn request_redraw(&self) {
+        let redraw_request = WindowRequest::Redraw;
+        self.window_requests.lock().unwrap().push(redraw_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn outer_size(&self) -> PhysicalSize<u32> {
+        self.size
+            .lock()
+            .unwrap()
+            .to_physical(self.scale_factor() as f64)
+    }
+
+    #[inline]
+    pub fn set_inner_size(&self, size: Size) {
+        let scale_factor = self.scale_factor() as f64;
+
+        let size = size.to_logical::<u32>(scale_factor);
+        *self.size.lock().unwrap() = size;
+
+        let frame_size_request = WindowRequest::FrameSize(size);
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(frame_size_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_min_inner_size(&self, dimensions: Option<Size>) {
+        let scale_factor = self.scale_factor() as f64;
+        let size = dimensions.map(|size| size.to_logical::<u32>(scale_factor));
+
+        let min_size_request = WindowRequest::MinSize(size);
+        self.window_requests.lock().unwrap().push(min_size_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_max_inner_size(&self, dimensions: Option<Size>) {
+        let scale_factor = self.scale_factor() as f64;
+        let size = dimensions.map(|size| size.to_logical::<u32>(scale_factor));
+
+        let max_size_request = WindowRequest::MaxSize(size);
+        self.window_requests.lock().unwrap().push(max_size_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_resizable(&self, resizable: bool) {
+        let resizeable_request = WindowRequest::Resizeable(resizable);
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(resizeable_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn scale_factor(&self) -> u32 {
+        // The scale factor from `get_surface_scale_factor` is always greater than zero, so
+        // u32 conversion is safe.
+        sctk::get_surface_scale_factor(&self.surface) as u32
+    }
+
+    #[inline]
+    pub fn set_decorations(&self, decorate: bool) {
+        let decorate_request = WindowRequest::Decorate(decorate);
+        self.window_requests.lock().unwrap().push(decorate_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_minimized(&self, minimized: bool) {
+        // You can't unminimize the window on Wayland.
+        if !minimized {
+            return;
+        }
+
+        let minimize_request = WindowRequest::Minimize;
+        self.window_requests.lock().unwrap().push(minimize_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_maximized(&self, maximized: bool) {
+        let maximize_request = WindowRequest::Maximize(maximized);
+        self.window_requests.lock().unwrap().push(maximize_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn fullscreen(&self) -> Option<Fullscreen> {
+        if self.fullscreen.load(Ordering::Relaxed) {
+            let current_monitor = self.current_monitor().map(|monitor| RootMonitorHandle {
+                inner: PlatformMonitorHandle::Wayland(monitor),
+            });
+
+            Some(Fullscreen::Borderless(current_monitor))
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    pub fn set_fullscreen(&self, fullscreen: Option<Fullscreen>) {
+        let fullscreen_request = match fullscreen {
+            Some(Fullscreen::Exclusive(_)) => {
+                warn!("`Fullscreen::Exclusive` is ignored on Wayland");
+                return;
+            }
+            Some(Fullscreen::Borderless(monitor)) => {
+                let monitor =
+                    monitor.and_then(|RootMonitorHandle { inner: monitor }| match monitor {
+                        PlatformMonitorHandle::Wayland(monitor) => Some(monitor.proxy),
+                        #[cfg(feature = "x11")]
+                        PlatformMonitorHandle::X(_) => None,
+                    });
+
+                WindowRequest::Fullscreen(monitor)
+            }
+            None => WindowRequest::UnsetFullscreen,
+        };
+
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(fullscreen_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_theme<T: Theme>(&self, theme: T) {
+        // First buttons is minimize, then maximize, and then close.
+        let buttons: Vec<(ButtonColorSpec, ButtonColorSpec)> =
+            [Button::Minimize, Button::Maximize, Button::Close]
+                .iter()
+                .map(|button| {
+                    let button = *button;
+                    let idle_active_bg = theme
+                        .button_color(button, ButtonState::Idle, false, true)
+                        .into();
+                    let idle_inactive_bg = theme
+                        .button_color(button, ButtonState::Idle, false, false)
+                        .into();
+                    let idle_active_icon = theme
+                        .button_color(button, ButtonState::Idle, true, true)
+                        .into();
+                    let idle_inactive_icon = theme
+                        .button_color(button, ButtonState::Idle, true, false)
+                        .into();
+                    let idle_bg = ColorSpec {
+                        active: idle_active_bg,
+                        inactive: idle_inactive_bg,
+                    };
+                    let idle_icon = ColorSpec {
+                        active: idle_active_icon,
+                        inactive: idle_inactive_icon,
+                    };
+
+                    let hovered_active_bg = theme
+                        .button_color(button, ButtonState::Hovered, false, true)
+                        .into();
+                    let hovered_inactive_bg = theme
+                        .button_color(button, ButtonState::Hovered, false, false)
+                        .into();
+                    let hovered_active_icon = theme
+                        .button_color(button, ButtonState::Hovered, true, true)
+                        .into();
+                    let hovered_inactive_icon = theme
+                        .button_color(button, ButtonState::Hovered, true, false)
+                        .into();
+                    let hovered_bg = ColorSpec {
+                        active: hovered_active_bg,
+                        inactive: hovered_inactive_bg,
+                    };
+                    let hovered_icon = ColorSpec {
+                        active: hovered_active_icon,
+                        inactive: hovered_inactive_icon,
+                    };
+
+                    let disabled_active_bg = theme
+                        .button_color(button, ButtonState::Disabled, false, true)
+                        .into();
+                    let disabled_inactive_bg = theme
+                        .button_color(button, ButtonState::Disabled, false, false)
+                        .into();
+                    let disabled_active_icon = theme
+                        .button_color(button, ButtonState::Disabled, true, true)
+                        .into();
+                    let disabled_inactive_icon = theme
+                        .button_color(button, ButtonState::Disabled, true, false)
+                        .into();
+                    let disabled_bg = ColorSpec {
+                        active: disabled_active_bg,
+                        inactive: disabled_inactive_bg,
+                    };
+                    let disabled_icon = ColorSpec {
+                        active: disabled_active_icon,
+                        inactive: disabled_inactive_icon,
+                    };
+
+                    let button_bg = ButtonColorSpec {
+                        idle: idle_bg,
+                        hovered: hovered_bg,
+                        disabled: disabled_bg,
+                    };
+                    let button_icon = ButtonColorSpec {
+                        idle: idle_icon,
+                        hovered: hovered_icon,
+                        disabled: disabled_icon,
+                    };
+
+                    (button_icon, button_bg)
+                })
+                .collect();
+
+        let minimize_button = Some(buttons[0]);
+        let maximize_button = Some(buttons[1]);
+        let close_button = Some(buttons[2]);
+
+        // The first color is bar, then separator, and then text color.
+        let titlebar_colors: Vec<ColorSpec> = [Element::Bar, Element::Separator, Element::Text]
+            .iter()
+            .map(|element| {
+                let element = *element;
+                let active = theme.element_color(element, true).into();
+                let inactive = theme.element_color(element, false).into();
+
+                ColorSpec { active, inactive }
+            })
+            .collect();
+
+        let primary_color = titlebar_colors[0];
+        let secondary_color = titlebar_colors[1];
+        let title_color = titlebar_colors[2];
+
+        let title_font = theme.font();
+
+        let concept_config = ConceptConfig {
+            primary_color,
+            secondary_color,
+            title_color,
+            title_font,
+            minimize_button,
+            maximize_button,
+            close_button,
+        };
+
+        let theme_request = WindowRequest::Theme(concept_config);
+        self.window_requests.lock().unwrap().push(theme_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_cursor_icon(&self, cursor: CursorIcon) {
+        let cursor_icon_request = WindowRequest::NewCursorIcon(cursor);
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(cursor_icon_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_cursor_visible(&self, visible: bool) {
+        let cursor_visible_request = WindowRequest::ShowCursor(visible);
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(cursor_visible_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn set_cursor_grab(&self, grab: bool) -> Result<(), ExternalError> {
+        if !self.windowing_features.cursor_grab() {
+            return Err(ExternalError::NotSupported(NotSupportedError::new()));
+        }
+
+        let cursor_grab_request = WindowRequest::GrabCursor(grab);
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(cursor_grab_request);
+        self.event_loop_awakener.ping();
+
+        Ok(())
+    }
+
+    #[inline]
+    pub fn set_cursor_position(&self, _: Position) -> Result<(), ExternalError> {
+        // XXX This is possible if the locked pointer is being used. We don't have any
+        // API for that right now, but it could be added in
+        // https://github.com/rust-windowing/winit/issues/1677.
+        //
+        // This function is essential for the locked pointer API.
+        //
+        // See pointer-constraints-unstable-v1.xml.
+        Err(ExternalError::NotSupported(NotSupportedError::new()))
+    }
+
+    #[inline]
+    pub fn set_ime_position(&self, position: Position) {
+        let scale_factor = self.scale_factor() as f64;
+        let position = position.to_logical(scale_factor);
+        let ime_position_request = WindowRequest::IMEPosition(position);
+        self.window_requests
+            .lock()
+            .unwrap()
+            .push(ime_position_request);
+        self.event_loop_awakener.ping();
+    }
+
+    #[inline]
+    pub fn display(&self) -> &Display {
+        &self.display
+    }
+
+    #[inline]
+    pub fn surface(&self) -> &WlSurface {
+        &self.surface
+    }
+
+    #[inline]
+    pub fn current_monitor(&self) -> Option<MonitorHandle> {
+        let output = sctk::get_surface_outputs(&self.surface).last()?.clone();
+        Some(MonitorHandle::new(output))
+    }
+
+    #[inline]
+    pub fn available_monitors(&self) -> VecDeque<MonitorHandle> {
+        self.output_manager_handle.available_outputs()
+    }
+
+    #[inline]
+    pub fn primary_monitor(&self) -> Option<RootMonitorHandle> {
+        None
+    }
+
+    #[inline]
+    pub fn raw_window_handle(&self) -> WaylandHandle {
+        let display = self.display.get_display_ptr() as *mut _;
+        let surface = self.surface.as_ref().c_ptr() as *mut _;
+
+        WaylandHandle {
+            display,
+            surface,
+            ..WaylandHandle::empty()
+        }
+    }
+}
+
+impl From<LocalARGBColor> for ARGBColor {
+    fn from(color: LocalARGBColor) -> Self {
+        let a = color.a;
+        let r = color.r;
+        let g = color.g;
+        let b = color.b;
+        Self { a, r, g, b }
+    }
+}
+
+impl Drop for Window {
+    fn drop(&mut self) {
+        let close_request = WindowRequest::Close;
+        self.window_requests.lock().unwrap().push(close_request);
+        self.event_loop_awakener.ping();
+    }
+}

src/platform_impl/linux/wayland/window/shim.rs

@@ -0,0 +1,388 @@
+use std::cell::Cell;
+use std::sync::{Arc, Mutex};
+
+use sctk::reexports::client::protocol::wl_output::WlOutput;
+
+use sctk::window::{ConceptConfig, ConceptFrame, Decorations, Window};
+
+use crate::dpi::{LogicalPosition, LogicalSize};
+
+use crate::event::WindowEvent;
+use crate::platform_impl::wayland::event_loop::WinitState;
+use crate::platform_impl::wayland::seat::pointer::WinitPointer;
+use crate::platform_impl::wayland::seat::text_input::TextInputHandler;
+use crate::platform_impl::wayland::WindowId;
+use crate::window::CursorIcon;
+
+/// A request to SCTK window from Winit window.
+#[derive(Debug, Clone)]
+pub enum WindowRequest {
+    /// Set fullscreen.
+    ///
+    /// Passing `None` will set it on the current monitor.
+    Fullscreen(Option<WlOutput>),
+
+    /// Unset fullscreen.
+    UnsetFullscreen,
+
+    /// Show cursor for the certain window or not.
+    ShowCursor(bool),
+
+    /// Change the cursor icon.
+    NewCursorIcon(CursorIcon),
+
+    /// Grab cursor.
+    GrabCursor(bool),
+
+    /// Maximize the window.
+    Maximize(bool),
+
+    /// Minimize the window.
+    Minimize,
+
+    /// Request decorations change.
+    Decorate(bool),
+
+    /// Make the window resizeable.
+    Resizeable(bool),
+
+    /// Set the title for window.
+    Title(String),
+
+    /// Min size.
+    MinSize(Option<LogicalSize<u32>>),
+
+    /// Max size.
+    MaxSize(Option<LogicalSize<u32>>),
+
+    /// New frame size.
+    FrameSize(LogicalSize<u32>),
+
+    /// Set IME window position.
+    IMEPosition(LogicalPosition<u32>),
+
+    /// Redraw was requested.
+    Redraw,
+
+    /// A new theme for a concept frame was requested.
+    Theme(ConceptConfig),
+
+    /// Window should be closed.
+    Close,
+}
+
+/// Pending update to a window from SCTK window.
+#[derive(Debug, Clone, Copy)]
+pub struct WindowUpdate {
+    /// New window size.
+    pub size: Option<LogicalSize<u32>>,
+
+    /// New scale factor.
+    pub scale_factor: Option<i32>,
+
+    /// Whether `redraw` was requested.
+    pub redraw_requested: bool,
+
+    /// Wether the frame should be refreshed.
+    pub refresh_frame: bool,
+
+    /// Close the window.
+    pub close_window: bool,
+}
+
+impl WindowUpdate {
+    pub fn new() -> Self {
+        Self {
+            size: None,
+            scale_factor: None,
+            redraw_requested: false,
+            refresh_frame: false,
+            close_window: false,
+        }
+    }
+
+    pub fn take(&mut self) -> Self {
+        let size = self.size.take();
+        let scale_factor = self.scale_factor.take();
+
+        let redraw_requested = self.redraw_requested;
+        self.redraw_requested = false;
+
+        let refresh_frame = self.refresh_frame;
+        self.refresh_frame = false;
+
+        let close_window = self.close_window;
+        self.close_window = false;
+
+        Self {
+            size,
+            scale_factor,
+            redraw_requested,
+            refresh_frame,
+            close_window,
+        }
+    }
+}
+
+/// A handle to perform operations on SCTK window
+/// and react to events.
+pub struct WindowHandle {
+    /// An actual window.
+    pub window: Window<ConceptFrame>,
+
+    /// The current size of the window.
+    pub size: Arc<Mutex<LogicalSize<u32>>>,
+
+    /// A pending requests to SCTK window.
+    pub pending_window_requests: Arc<Mutex<Vec<WindowRequest>>>,
+
+    /// Current cursor icon.
+    pub cursor_icon: Cell<CursorIcon>,
+
+    /// Visible cursor or not.
+    cursor_visible: Cell<bool>,
+
+    /// Cursor confined to the surface.
+    confined: Cell<bool>,
+
+    /// Pointers over the current surface.
+    pointers: Vec<WinitPointer>,
+
+    /// Text inputs on the current surface.
+    text_inputs: Vec<TextInputHandler>,
+}
+
+impl WindowHandle {
+    pub fn new(
+        window: Window<ConceptFrame>,
+        size: Arc<Mutex<LogicalSize<u32>>>,
+        pending_window_requests: Arc<Mutex<Vec<WindowRequest>>>,
+    ) -> Self {
+        Self {
+            window,
+            size,
+            pending_window_requests,
+            cursor_icon: Cell::new(CursorIcon::Default),
+            confined: Cell::new(false),
+            cursor_visible: Cell::new(true),
+            pointers: Vec::new(),
+            text_inputs: Vec::new(),
+        }
+    }
+
+    pub fn set_cursor_grab(&self, grab: bool) {
+        // The new requested state matches the current confine status, return.
+        if self.confined.get() == grab {
+            return;
+        }
+
+        self.confined.replace(grab);
+
+        for pointer in self.pointers.iter() {
+            if self.confined.get() {
+                let surface = self.window.surface();
+                pointer.confine(&surface);
+            } else {
+                pointer.unconfine();
+            }
+        }
+    }
+
+    /// Pointer appeared over the window.
+    pub fn pointer_entered(&mut self, pointer: WinitPointer) {
+        let position = self.pointers.iter().position(|p| *p == pointer);
+
+        if position.is_none() {
+            if self.confined.get() {
+                let surface = self.window.surface();
+                pointer.confine(&surface);
+            }
+            self.pointers.push(pointer);
+        }
+
+        // Apply the current cursor style.
+        self.set_cursor_visible(self.cursor_visible.get());
+    }
+
+    /// Pointer left the window.
+    pub fn pointer_left(&mut self, pointer: WinitPointer) {
+        let position = self.pointers.iter().position(|p| *p == pointer);
+
+        if let Some(position) = position {
+            let pointer = self.pointers.remove(position);
+
+            // Drop the confined pointer.
+            if self.confined.get() {
+                pointer.unconfine();
+            }
+        }
+    }
+
+    pub fn text_input_entered(&mut self, text_input: TextInputHandler) {
+        if self
+            .text_inputs
+            .iter()
+            .find(|t| *t == &text_input)
+            .is_none()
+        {
+            self.text_inputs.push(text_input);
+        }
+    }
+
+    pub fn text_input_left(&mut self, text_input: TextInputHandler) {
+        if let Some(position) = self.text_inputs.iter().position(|t| *t == text_input) {
+            self.text_inputs.remove(position);
+        }
+    }
+
+    pub fn set_ime_position(&self, position: LogicalPosition<u32>) {
+        // XXX This won't fly unless user will have a way to request IME window per seat, since
+        // the ime windows will be overlapping, but winit doesn't expose API to specify for
+        // which seat we're setting IME position.
+        let (x, y) = (position.x as i32, position.y as i32);
+        for text_input in self.text_inputs.iter() {
+            text_input.set_ime_position(x, y);
+        }
+    }
+
+    pub fn set_cursor_visible(&self, visible: bool) {
+        self.cursor_visible.replace(visible);
+        let cursor_icon = match visible {
+            true => Some(self.cursor_icon.get()),
+            false => None,
+        };
+
+        for pointer in self.pointers.iter() {
+            pointer.set_cursor(cursor_icon)
+        }
+    }
+
+    pub fn set_cursor_icon(&self, cursor_icon: CursorIcon) {
+        self.cursor_icon.replace(cursor_icon);
+
+        if !self.cursor_visible.get() {
+            return;
+        }
+
+        for pointer in self.pointers.iter() {
+            pointer.set_cursor(Some(cursor_icon));
+        }
+    }
+}
+
+#[inline]
+pub fn handle_window_requests(winit_state: &mut WinitState) {
+    let window_map = &mut winit_state.window_map;
+    let window_updates = &mut winit_state.window_updates;
+    let mut windows_to_close: Vec<WindowId> = Vec::new();
+
+    // Process the rest of the events.
+    for (window_id, window_handle) in window_map.iter_mut() {
+        let mut requests = window_handle.pending_window_requests.lock().unwrap();
+        for request in requests.drain(..) {
+            match request {
+                WindowRequest::Fullscreen(fullscreen) => {
+                    window_handle.window.set_fullscreen(fullscreen.as_ref());
+                }
+                WindowRequest::UnsetFullscreen => {
+                    window_handle.window.unset_fullscreen();
+                }
+                WindowRequest::ShowCursor(show_cursor) => {
+                    window_handle.set_cursor_visible(show_cursor);
+                }
+                WindowRequest::NewCursorIcon(cursor_icon) => {
+                    window_handle.set_cursor_icon(cursor_icon);
+                }
+                WindowRequest::IMEPosition(position) => {
+                    window_handle.set_ime_position(position);
+                }
+                WindowRequest::GrabCursor(grab) => {
+                    window_handle.set_cursor_grab(grab);
+                }
+                WindowRequest::Maximize(maximize) => {
+                    if maximize {
+                        window_handle.window.set_maximized();
+                    } else {
+                        window_handle.window.unset_maximized();
+                    }
+                }
+                WindowRequest::Minimize => {
+                    window_handle.window.set_minimized();
+                }
+                WindowRequest::Decorate(decorate) => {
+                    let decorations = match decorate {
+                        true => Decorations::FollowServer,
+                        false => Decorations::None,
+                    };
+
+                    window_handle.window.set_decorate(decorations);
+
+                    // We should refresh the frame to apply decorations change.
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.refresh_frame = true;
+                }
+                WindowRequest::Resizeable(resizeable) => {
+                    window_handle.window.set_resizable(resizeable);
+
+                    // We should refresh the frame to update button state.
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.refresh_frame = true;
+                }
+                WindowRequest::Title(title) => {
+                    window_handle.window.set_title(title);
+
+                    // We should refresh the frame to draw new title.
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.refresh_frame = true;
+                }
+                WindowRequest::MinSize(size) => {
+                    let size = size.map(|size| (size.width, size.height));
+                    window_handle.window.set_min_size(size);
+
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.redraw_requested = true;
+                }
+                WindowRequest::MaxSize(size) => {
+                    let size = size.map(|size| (size.width, size.height));
+                    window_handle.window.set_max_size(size);
+
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.redraw_requested = true;
+                }
+                WindowRequest::FrameSize(size) => {
+                    // Set new size.
+                    window_handle.window.resize(size.width, size.height);
+
+                    // We should refresh the frame after resize.
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.refresh_frame = true;
+                }
+                WindowRequest::Redraw => {
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.redraw_requested = true;
+                }
+                WindowRequest::Theme(concept_config) => {
+                    window_handle.window.set_frame_config(concept_config);
+
+                    // We should refresh the frame to apply new theme.
+                    let window_update = window_updates.get_mut(&window_id).unwrap();
+                    window_update.refresh_frame = true;
+                }
+                WindowRequest::Close => {
+                    // The window was requested to be closed.
+                    windows_to_close.push(*window_id);
+
+                    // Send event that the window was destroyed.
+                    let event_sink = &mut winit_state.event_sink;
+                    event_sink.push_window_event(WindowEvent::Destroyed, *window_id);
+                }
+            };
+        }
+    }
+
+    // Close the windows.
+    for window in windows_to_close {
+        let _ = window_map.remove(&window);
+        let _ = window_updates.remove(&window);
+    }
+}