Merge pull request #1964 from bungoboingo/feat/multi-window-support

[Feature] 🪟 Multi Window 🪟 .. redux!

15 files changed, 1825 insertions, 533 deletions

diff --git a/winit/Cargo.toml b/winit/Cargo.toml
index 674a66d3..87e600ae 100644
--- a/winit/Cargo.toml
+++ b/winit/Cargo.toml
@@ -19,6 +19,7 @@ x11 = ["winit/x11"]
 wayland = ["winit/wayland"]
 wayland-dlopen = ["winit/wayland-dlopen"]
 wayland-csd-adwaita = ["winit/wayland-csd-adwaita"]
+multi-window = ["iced_runtime/multi-window"]
 
 [dependencies]
 iced_graphics.workspace = true
@@ -26,7 +27,6 @@ iced_runtime.workspace = true
 iced_style.workspace = true
 
 log.workspace = true
-raw-window-handle.workspace = true
 thiserror.workspace = true
 tracing.workspace = true
 window_clipboard.workspace = true
diff --git a/winit/src/application.rs b/winit/src/application.rs
index 2c5c864a..d9700075 100644
--- a/winit/src/application.rs
+++ b/winit/src/application.rs
@@ -1,6 +1,4 @@
 //! Create interactive, native cross-platform applications.
-#[cfg(feature = "trace")]
-mod profiler;
 mod state;
 
 pub use state::State;
@@ -27,11 +25,6 @@ use futures::channel::mpsc;
 
 use std::mem::ManuallyDrop;
 
-#[cfg(feature = "trace")]
-pub use profiler::Profiler;
-#[cfg(feature = "trace")]
-use tracing::{info_span, instrument::Instrument};
-
 /// An interactive, native cross-platform application.
 ///
 /// This trait is the main entrypoint of Iced. Once implemented, you can run
@@ -119,15 +112,9 @@ where
     use futures::Future;
     use winit::event_loop::EventLoopBuilder;
 
-    #[cfg(feature = "trace")]
-    let _guard = Profiler::init();
-
     let mut debug = Debug::new();
     debug.startup_started();
 
-    #[cfg(feature = "trace")]
-    let _ = info_span!("Application", "RUN").entered();
-
     let event_loop = EventLoopBuilder::with_user_event().build();
     let proxy = event_loop.create_proxy();
 
@@ -148,14 +135,15 @@ where
     let target = settings.window.platform_specific.target.clone();
 
     let should_be_visible = settings.window.visible;
-    let builder = settings
-        .window
-        .into_builder(
-            &application.title(),
-            event_loop.primary_monitor(),
-            settings.id,
-        )
-        .with_visible(false);
+    let exit_on_close_request = settings.window.exit_on_close_request;
+
+    let builder = conversion::window_settings(
+        settings.window,
+        &application.title(),
+        event_loop.primary_monitor(),
+        settings.id,
+    )
+    .with_visible(false);
 
     log::debug!("Window builder: {builder:#?}");
 
@@ -193,8 +181,8 @@ where
         };
     }
 
-    let (compositor, mut renderer) =
-        C::new(compositor_settings, Some(&window))?;
+    let compositor = C::new(compositor_settings, Some(&window))?;
+    let mut renderer = compositor.create_renderer();
 
     for font in settings.fonts {
         use crate::core::text::Renderer;
@@ -205,28 +193,20 @@ where
     let (mut event_sender, event_receiver) = mpsc::unbounded();
     let (control_sender, mut control_receiver) = mpsc::unbounded();
 
-    let mut instance = Box::pin({
-        let run_instance = run_instance::<A, E, C>(
-            application,
-            compositor,
-            renderer,
-            runtime,
-            proxy,
-            debug,
-            event_receiver,
-            control_sender,
-            init_command,
-            window,
-            should_be_visible,
-            settings.exit_on_close_request,
-        );
-
-        #[cfg(feature = "trace")]
-        let run_instance =
-            run_instance.instrument(info_span!("Application", "LOOP"));
-
-        run_instance
-    });
+    let mut instance = Box::pin(run_instance::<A, E, C>(
+        application,
+        compositor,
+        renderer,
+        runtime,
+        proxy,
+        debug,
+        event_receiver,
+        control_sender,
+        init_command,
+        window,
+        should_be_visible,
+        exit_on_close_request,
+    ));
 
     let mut context = task::Context::from_waker(task::noop_waker_ref());
 
@@ -426,6 +406,7 @@ async fn run_instance<A, E, C>(
                 // Then, we can use the `interface_state` here to decide if a redraw
                 // is needed right away, or simply wait until a specific time.
                 let redraw_event = Event::Window(
+                    window::Id::MAIN,
                     window::Event::RedrawRequested(Instant::now()),
                 );
 
@@ -488,9 +469,6 @@ async fn run_instance<A, E, C>(
                 messages.push(message);
             }
             event::Event::RedrawRequested(_) => {
-                #[cfg(feature = "trace")]
-                let _ = info_span!("Application", "FRAME").entered();
-
                 let physical_size = state.physical_size();
 
                 if physical_size.width == 0 || physical_size.height == 0 {
@@ -578,6 +556,7 @@ async fn run_instance<A, E, C>(
                 state.update(&window, &window_event, &mut debug);
 
                 if let Some(event) = conversion::window_event(
+                    window::Id::MAIN,
                     &window_event,
                     state.scale_factor(),
                     state.modifiers(),
@@ -629,24 +608,12 @@ pub fn build_user_interface<'a, A: Application>(
 where
     <A::Renderer as core::Renderer>::Theme: StyleSheet,
 {
-    #[cfg(feature = "trace")]
-    let view_span = info_span!("Application", "VIEW").entered();
-
     debug.view_started();
     let view = application.view();
-
-    #[cfg(feature = "trace")]
-    let _ = view_span.exit();
     debug.view_finished();
 
-    #[cfg(feature = "trace")]
-    let layout_span = info_span!("Application", "LAYOUT").entered();
-
     debug.layout_started();
     let user_interface = UserInterface::build(view, size, cache, renderer);
-
-    #[cfg(feature = "trace")]
-    let _ = layout_span.exit();
     debug.layout_finished();
 
     user_interface
@@ -673,16 +640,10 @@ pub fn update<A: Application, C, E: Executor>(
     <A::Renderer as core::Renderer>::Theme: StyleSheet,
 {
     for message in messages.drain(..) {
-        #[cfg(feature = "trace")]
-        let update_span = info_span!("Application", "UPDATE").entered();
-
         debug.log_message(&message);
 
         debug.update_started();
         let command = runtime.enter(|| application.update(message));
-
-        #[cfg(feature = "trace")]
-        let _ = update_span.exit();
         debug.update_finished();
 
         run_command(
@@ -752,20 +713,27 @@ pub fn run_command<A, C, E>(
                 }
             },
             command::Action::Window(action) => match action {
-                window::Action::Close => {
+                window::Action::Close(_id) => {
                     *should_exit = true;
                 }
-                window::Action::Drag => {
+                window::Action::Drag(_id) => {
                     let _res = window.drag_window();
                 }
-                window::Action::Resize(size) => {
+                window::Action::Spawn { .. } => {
+                    log::warn!(
+                        "Spawning a window is only available with \
+                        multi-window applications."
+                    );
+                }
+                window::Action::Resize(_id, size) => {
                     window.set_inner_size(winit::dpi::LogicalSize {
                         width: size.width,
                         height: size.height,
                     });
                 }
-                window::Action::FetchSize(callback) => {
-                    let size = window.inner_size();
+                window::Action::FetchSize(_id, callback) => {
+                    let size =
+                        window.inner_size().to_logical(window.scale_factor());
 
                     proxy
                         .send_event(callback(Size::new(
@@ -774,29 +742,29 @@ pub fn run_command<A, C, E>(
                         )))
                         .expect("Send message to event loop");
                 }
-                window::Action::Maximize(maximized) => {
+                window::Action::Maximize(_id, maximized) => {
                     window.set_maximized(maximized);
                 }
-                window::Action::Minimize(minimized) => {
+                window::Action::Minimize(_id, minimized) => {
                     window.set_minimized(minimized);
                 }
-                window::Action::Move { x, y } => {
+                window::Action::Move(_id, position) => {
                     window.set_outer_position(winit::dpi::LogicalPosition {
-                        x,
-                        y,
+                        x: position.x,
+                        y: position.y,
                     });
                 }
-                window::Action::ChangeMode(mode) => {
+                window::Action::ChangeMode(_id, mode) => {
                     window.set_visible(conversion::visible(mode));
                     window.set_fullscreen(conversion::fullscreen(
                         window.current_monitor(),
                         mode,
                     ));
                 }
-                window::Action::ChangeIcon(icon) => {
+                window::Action::ChangeIcon(_id, icon) => {
                     window.set_window_icon(conversion::icon(icon));
                 }
-                window::Action::FetchMode(tag) => {
+                window::Action::FetchMode(_id, tag) => {
                     let mode = if window.is_visible().unwrap_or(true) {
                         conversion::mode(window.fullscreen())
                     } else {
@@ -807,29 +775,29 @@ pub fn run_command<A, C, E>(
                         .send_event(tag(mode))
                         .expect("Send message to event loop");
                 }
-                window::Action::ToggleMaximize => {
+                window::Action::ToggleMaximize(_id) => {
                     window.set_maximized(!window.is_maximized());
                 }
-                window::Action::ToggleDecorations => {
+                window::Action::ToggleDecorations(_id) => {
                     window.set_decorations(!window.is_decorated());
                 }
-                window::Action::RequestUserAttention(user_attention) => {
+                window::Action::RequestUserAttention(_id, user_attention) => {
                     window.request_user_attention(
                         user_attention.map(conversion::user_attention),
                     );
                 }
-                window::Action::GainFocus => {
+                window::Action::GainFocus(_id) => {
                     window.focus_window();
                 }
-                window::Action::ChangeLevel(level) => {
+                window::Action::ChangeLevel(_id, level) => {
                     window.set_window_level(conversion::window_level(level));
                 }
-                window::Action::FetchId(tag) => {
+                window::Action::FetchId(_id, tag) => {
                     proxy
                         .send_event(tag(window.id().into()))
                         .expect("Send message to event loop");
                 }
-                window::Action::Screenshot(tag) => {
+                window::Action::Screenshot(_id, tag) => {
                     let bytes = compositor.screenshot(
                         renderer,
                         surface,
diff --git a/winit/src/application/profiler.rs b/winit/src/application/profiler.rs
deleted file mode 100644
index 7031507a..00000000
--- a/winit/src/application/profiler.rs
+++ /dev/null
@@ -1,101 +0,0 @@
-//! A simple profiler for Iced.
-use std::ffi::OsStr;
-use std::path::Path;
-use std::time::Duration;
-use tracing_subscriber::prelude::*;
-use tracing_subscriber::Registry;
-#[cfg(feature = "chrome-trace")]
-use {
-    tracing_chrome::FlushGuard,
-    tracing_subscriber::fmt::{format::DefaultFields, FormattedFields},
-};
-
-/// Profiler state. This will likely need to be updated or reworked when adding new tracing backends.
-#[allow(missing_debug_implementations)]
-pub struct Profiler {
-    #[cfg(feature = "chrome-trace")]
-    /// [`FlushGuard`] must not be dropped until the application scope is dropped for accurate tracing.
-    _guard: FlushGuard,
-}
-
-impl Profiler {
-    /// Initializes the [`Profiler`].
-    pub fn init() -> Self {
-        // Registry stores the spans & generates unique span IDs
-        let subscriber = Registry::default();
-
-        let default_path = Path::new(env!("CARGO_MANIFEST_DIR"));
-        let curr_exe = std::env::current_exe()
-            .unwrap_or_else(|_| default_path.to_path_buf());
-        let out_dir = curr_exe.parent().unwrap_or(default_path).join("traces");
-
-        #[cfg(feature = "chrome-trace")]
-        let (chrome_layer, guard) = {
-            let mut layer = tracing_chrome::ChromeLayerBuilder::new();
-
-            // Optional configurable env var: CHROME_TRACE_FILE=/path/to/trace_file/file.json,
-            // for uploading to chrome://tracing (old) or ui.perfetto.dev (new).
-            if let Ok(path) = std::env::var("CHROME_TRACE_FILE") {
-                layer = layer.file(path);
-            } else if std::fs::create_dir_all(&out_dir).is_ok() {
-                let time = std::time::SystemTime::now()
-                    .duration_since(std::time::UNIX_EPOCH)
-                    .unwrap_or(Duration::from_millis(0))
-                    .as_millis();
-
-                let curr_exe_name = curr_exe
-                    .file_name()
-                    .unwrap_or_else(|| OsStr::new("trace"))
-                    .to_str()
-                    .unwrap_or("trace");
-
-                let path =
-                    out_dir.join(format!("{curr_exe_name}_trace_{time}.json"));
-
-                layer = layer.file(path);
-            } else {
-                layer = layer.file(env!("CARGO_MANIFEST_DIR"))
-            }
-
-            let (chrome_layer, guard) = layer
-                .name_fn(Box::new(|event_or_span| match event_or_span {
-                    tracing_chrome::EventOrSpan::Event(event) => {
-                        event.metadata().name().into()
-                    }
-                    tracing_chrome::EventOrSpan::Span(span) => {
-                        if let Some(fields) = span
-                            .extensions()
-                            .get::<FormattedFields<DefaultFields>>()
-                        {
-                            format!(
-                                "{}: {}",
-                                span.metadata().name(),
-                                fields.fields.as_str()
-                            )
-                        } else {
-                            span.metadata().name().into()
-                        }
-                    }
-                }))
-                .build();
-
-            (chrome_layer, guard)
-        };
-
-        let fmt_layer = tracing_subscriber::fmt::Layer::default();
-        let subscriber = subscriber.with(fmt_layer);
-
-        #[cfg(feature = "chrome-trace")]
-        let subscriber = subscriber.with(chrome_layer);
-
-        // create dispatcher which will forward span events to the subscriber
-        // this can only be set once or will panic
-        tracing::subscriber::set_global_default(subscriber)
-            .expect("Tracer could not set the global default subscriber.");
-
-        Profiler {
-            #[cfg(feature = "chrome-trace")]
-            _guard: guard,
-        }
-    }
-}
diff --git a/winit/src/conversion.rs b/winit/src/conversion.rs
index 3ecd044c..7e51a2d4 100644
--- a/winit/src/conversion.rs
+++ b/winit/src/conversion.rs
@@ -6,11 +6,128 @@ use crate::core::keyboard;
 use crate::core::mouse;
 use crate::core::touch;
 use crate::core::window;
-use crate::core::{Event, Point};
-use crate::Position;
+use crate::core::{Event, Point, Size};
+
+/// Converts some [`window::Settings`] into a `WindowBuilder` from `winit`.
+pub fn window_settings(
+    settings: window::Settings,
+    title: &str,
+    primary_monitor: Option<winit::monitor::MonitorHandle>,
+    _id: Option<String>,
+) -> winit::window::WindowBuilder {
+    let mut window_builder = winit::window::WindowBuilder::new();
+
+    window_builder = window_builder
+        .with_title(title)
+        .with_inner_size(winit::dpi::LogicalSize {
+            width: settings.size.width,
+            height: settings.size.height,
+        })
+        .with_resizable(settings.resizable)
+        .with_enabled_buttons(if settings.resizable {
+            winit::window::WindowButtons::all()
+        } else {
+            winit::window::WindowButtons::CLOSE
+                | winit::window::WindowButtons::MINIMIZE
+        })
+        .with_decorations(settings.decorations)
+        .with_transparent(settings.transparent)
+        .with_window_icon(settings.icon.and_then(icon))
+        .with_window_level(window_level(settings.level))
+        .with_visible(settings.visible);
+
+    if let Some(position) =
+        position(primary_monitor.as_ref(), settings.size, settings.position)
+    {
+        window_builder = window_builder.with_position(position);
+    }
+
+    if let Some(min_size) = settings.min_size {
+        window_builder =
+            window_builder.with_min_inner_size(winit::dpi::LogicalSize {
+                width: min_size.width,
+                height: min_size.height,
+            });
+    }
+
+    if let Some(max_size) = settings.max_size {
+        window_builder =
+            window_builder.with_max_inner_size(winit::dpi::LogicalSize {
+                width: max_size.width,
+                height: max_size.height,
+            });
+    }
+
+    #[cfg(any(
+        target_os = "dragonfly",
+        target_os = "freebsd",
+        target_os = "netbsd",
+        target_os = "openbsd"
+    ))]
+    {
+        // `with_name` is available on both `WindowBuilderExtWayland` and `WindowBuilderExtX11` and they do
+        // exactly the same thing. We arbitrarily choose `WindowBuilderExtWayland` here.
+        use ::winit::platform::wayland::WindowBuilderExtWayland;
+
+        if let Some(id) = _id {
+            window_builder = window_builder.with_name(id.clone(), id);
+        }
+    }
+
+    #[cfg(target_os = "windows")]
+    {
+        use winit::platform::windows::WindowBuilderExtWindows;
+        #[allow(unsafe_code)]
+        unsafe {
+            window_builder = window_builder
+                .with_parent_window(settings.platform_specific.parent);
+        }
+        window_builder = window_builder
+            .with_drag_and_drop(settings.platform_specific.drag_and_drop);
+    }
+
+    #[cfg(target_os = "macos")]
+    {
+        use winit::platform::macos::WindowBuilderExtMacOS;
+
+        window_builder = window_builder
+            .with_title_hidden(settings.platform_specific.title_hidden)
+            .with_titlebar_transparent(
+                settings.platform_specific.titlebar_transparent,
+            )
+            .with_fullsize_content_view(
+                settings.platform_specific.fullsize_content_view,
+            );
+    }
+
+    #[cfg(target_os = "linux")]
+    {
+        #[cfg(feature = "x11")]
+        {
+            use winit::platform::x11::WindowBuilderExtX11;
+
+            window_builder = window_builder.with_name(
+                &settings.platform_specific.application_id,
+                &settings.platform_specific.application_id,
+            );
+        }
+        #[cfg(feature = "wayland")]
+        {
+            use winit::platform::wayland::WindowBuilderExtWayland;
+
+            window_builder = window_builder.with_name(
+                &settings.platform_specific.application_id,
+                &settings.platform_specific.application_id,
+            );
+        }
+    }
+
+    window_builder
+}
 
 /// Converts a winit window event into an iced event.
 pub fn window_event(
+    id: window::Id,
     event: &winit::event::WindowEvent<'_>,
     scale_factor: f64,
     modifiers: winit::event::ModifiersState,
@@ -21,21 +138,27 @@ pub fn window_event(
         WindowEvent::Resized(new_size) => {
             let logical_size = new_size.to_logical(scale_factor);
 
-            Some(Event::Window(window::Event::Resized {
-                width: logical_size.width,
-                height: logical_size.height,
-            }))
+            Some(Event::Window(
+                id,
+                window::Event::Resized {
+                    width: logical_size.width,
+                    height: logical_size.height,
+                },
+            ))
         }
         WindowEvent::ScaleFactorChanged { new_inner_size, .. } => {
             let logical_size = new_inner_size.to_logical(scale_factor);
 
-            Some(Event::Window(window::Event::Resized {
-                width: logical_size.width,
-                height: logical_size.height,
-            }))
+            Some(Event::Window(
+                id,
+                window::Event::Resized {
+                    width: logical_size.width,
+                    height: logical_size.height,
+                },
+            ))
         }
         WindowEvent::CloseRequested => {
-            Some(Event::Window(window::Event::CloseRequested))
+            Some(Event::Window(id, window::Event::CloseRequested))
         }
         WindowEvent::CursorMoved { position, .. } => {
             let position = position.to_logical::<f64>(scale_factor);
@@ -113,19 +236,22 @@ pub fn window_event(
         WindowEvent::ModifiersChanged(new_modifiers) => Some(Event::Keyboard(
             keyboard::Event::ModifiersChanged(self::modifiers(*new_modifiers)),
         )),
-        WindowEvent::Focused(focused) => Some(Event::Window(if *focused {
-            window::Event::Focused
-        } else {
-            window::Event::Unfocused
-        })),
+        WindowEvent::Focused(focused) => Some(Event::Window(
+            id,
+            if *focused {
+                window::Event::Focused
+            } else {
+                window::Event::Unfocused
+            },
+        )),
         WindowEvent::HoveredFile(path) => {
-            Some(Event::Window(window::Event::FileHovered(path.clone())))
+            Some(Event::Window(id, window::Event::FileHovered(path.clone())))
         }
         WindowEvent::DroppedFile(path) => {
-            Some(Event::Window(window::Event::FileDropped(path.clone())))
+            Some(Event::Window(id, window::Event::FileDropped(path.clone())))
         }
         WindowEvent::HoveredFileCancelled => {
-            Some(Event::Window(window::Event::FilesHoveredLeft))
+            Some(Event::Window(id, window::Event::FilesHoveredLeft))
         }
         WindowEvent::Touch(touch) => {
             Some(Event::Touch(touch_event(*touch, scale_factor)))
@@ -134,7 +260,7 @@ pub fn window_event(
             let winit::dpi::LogicalPosition { x, y } =
                 position.to_logical(scale_factor);
 
-            Some(Event::Window(window::Event::Moved { x, y }))
+            Some(Event::Window(id, window::Event::Moved { x, y }))
         }
         _ => None,
     }
@@ -153,23 +279,23 @@ pub fn window_level(level: window::Level) -> winit::window::WindowLevel {
     }
 }
 
-/// Converts a [`Position`] to a [`winit`] logical position for a given monitor.
+/// Converts a [`window::Position`] to a [`winit`] logical position for a given monitor.
 ///
 /// [`winit`]: https://github.com/rust-windowing/winit
 pub fn position(
     monitor: Option<&winit::monitor::MonitorHandle>,
-    (width, height): (u32, u32),
-    position: Position,
+    size: Size,
+    position: window::Position,
 ) -> Option<winit::dpi::Position> {
     match position {
-        Position::Default => None,
-        Position::Specific(x, y) => {
+        window::Position::Default => None,
+        window::Position::Specific(position) => {
             Some(winit::dpi::Position::Logical(winit::dpi::LogicalPosition {
-                x: f64::from(x),
-                y: f64::from(y),
+                x: f64::from(position.x),
+                y: f64::from(position.y),
             }))
         }
-        Position::Centered => {
+        window::Position::Centered => {
             if let Some(monitor) = monitor {
                 let start = monitor.position();
 
@@ -178,8 +304,8 @@ pub fn position(
 
                 let centered: winit::dpi::PhysicalPosition<i32> =
                     winit::dpi::LogicalPosition {
-                        x: (resolution.width - f64::from(width)) / 2.0,
-                        y: (resolution.height - f64::from(height)) / 2.0,
+                        x: (resolution.width - f64::from(size.width)) / 2.0,
+                        y: (resolution.height - f64::from(size.height)) / 2.0,
                     }
                     .to_physical(monitor.scale_factor());
 
diff --git a/winit/src/lib.rs b/winit/src/lib.rs
index 95b55bb9..948576a2 100644
--- a/winit/src/lib.rs
+++ b/winit/src/lib.rs
@@ -33,6 +33,9 @@ pub use iced_runtime::futures;
 pub use iced_style as style;
 pub use winit;
 
+#[cfg(feature = "multi-window")]
+pub mod multi_window;
+
 #[cfg(feature = "application")]
 pub mod application;
 pub mod clipboard;
@@ -43,17 +46,11 @@ pub mod settings;
 pub mod system;
 
 mod error;
-mod position;
 mod proxy;
 
 #[cfg(feature = "application")]
 pub use application::Application;
-#[cfg(feature = "trace")]
-pub use application::Profiler;
 pub use clipboard::Clipboard;
 pub use error::Error;
-pub use position::Position;
 pub use proxy::Proxy;
 pub use settings::Settings;
-
-pub use iced_graphics::Viewport;
diff --git a/winit/src/multi_window.rs b/winit/src/multi_window.rs
new file mode 100644
index 00000000..84651d40
--- /dev/null
+++ b/winit/src/multi_window.rs
@@ -0,0 +1,1212 @@
+//! Create interactive, native cross-platform applications for WGPU.
+mod state;
+mod window_manager;
+
+pub use state::State;
+
+use crate::conversion;
+use crate::core;
+use crate::core::renderer;
+use crate::core::widget::operation;
+use crate::core::window;
+use crate::core::Size;
+use crate::futures::futures::channel::mpsc;
+use crate::futures::futures::{task, Future, StreamExt};
+use crate::futures::{Executor, Runtime, Subscription};
+use crate::graphics::{compositor, Compositor};
+use crate::multi_window::window_manager::WindowManager;
+use crate::runtime::command::{self, Command};
+use crate::runtime::multi_window::Program;
+use crate::runtime::user_interface::{self, UserInterface};
+use crate::runtime::Debug;
+use crate::style::application::StyleSheet;
+use crate::{Clipboard, Error, Proxy, Settings};
+
+use std::collections::HashMap;
+use std::mem::ManuallyDrop;
+use std::time::Instant;
+
+/// An interactive, native, cross-platform, multi-windowed application.
+///
+/// This trait is the main entrypoint of multi-window Iced. Once implemented, you can run
+/// your GUI application by simply calling [`run`]. It will run in
+/// its own window.
+///
+/// An [`Application`] can execute asynchronous actions by returning a
+/// [`Command`] in some of its methods.
+///
+/// When using an [`Application`] with the `debug` feature enabled, a debug view
+/// can be toggled by pressing `F12`.
+pub trait Application: Program
+where
+    <Self::Renderer as core::Renderer>::Theme: StyleSheet,
+{
+    /// The data needed to initialize your [`Application`].
+    type Flags;
+
+    /// Initializes the [`Application`] with the flags provided to
+    /// [`run`] as part of the [`Settings`].
+    ///
+    /// Here is where you should return the initial state of your app.
+    ///
+    /// Additionally, you can return a [`Command`] if you need to perform some
+    /// async action in the background on startup. This is useful if you want to
+    /// load state from a file, perform an initial HTTP request, etc.
+    fn new(flags: Self::Flags) -> (Self, Command<Self::Message>);
+
+    /// Returns the current title of the [`Application`].
+    ///
+    /// This title can be dynamic! The runtime will automatically update the
+    /// title of your application when necessary.
+    fn title(&self, window: window::Id) -> String;
+
+    /// Returns the current `Theme` of the [`Application`].
+    fn theme(
+        &self,
+        window: window::Id,
+    ) -> <Self::Renderer as core::Renderer>::Theme;
+
+    /// Returns the `Style` variation of the `Theme`.
+    fn style(
+        &self,
+    ) -> <<Self::Renderer as core::Renderer>::Theme as StyleSheet>::Style {
+        Default::default()
+    }
+
+    /// Returns the event `Subscription` for the current state of the
+    /// application.
+    ///
+    /// The messages produced by the `Subscription` will be handled by
+    /// [`update`](#tymethod.update).
+    ///
+    /// A `Subscription` will be kept alive as long as you keep returning it!
+    ///
+    /// By default, it returns an empty subscription.
+    fn subscription(&self) -> Subscription<Self::Message> {
+        Subscription::none()
+    }
+
+    /// Returns the scale factor of the window of the [`Application`].
+    ///
+    /// It can be used to dynamically control the size of the UI at runtime
+    /// (i.e. zooming).
+    ///
+    /// For instance, a scale factor of `2.0` will make widgets twice as big,
+    /// while a scale factor of `0.5` will shrink them to half their size.
+    ///
+    /// By default, it returns `1.0`.
+    #[allow(unused_variables)]
+    fn scale_factor(&self, window: window::Id) -> f64 {
+        1.0
+    }
+}
+
+/// Runs an [`Application`] with an executor, compositor, and the provided
+/// settings.
+pub fn run<A, E, C>(
+    settings: Settings<A::Flags>,
+    compositor_settings: C::Settings,
+) -> Result<(), Error>
+where
+    A: Application + 'static,
+    E: Executor + 'static,
+    C: Compositor<Renderer = A::Renderer> + 'static,
+    <A::Renderer as core::Renderer>::Theme: StyleSheet,
+{
+    use winit::event_loop::EventLoopBuilder;
+
+    let mut debug = Debug::new();
+    debug.startup_started();
+
+    let event_loop = EventLoopBuilder::with_user_event().build();
+    let proxy = event_loop.create_proxy();
+
+    let runtime = {
+        let proxy = Proxy::new(event_loop.create_proxy());
+        let executor = E::new().map_err(Error::ExecutorCreationFailed)?;
+
+        Runtime::new(executor, proxy)
+    };
+
+    let (application, init_command) = {
+        let flags = settings.flags;
+
+        runtime.enter(|| A::new(flags))
+    };
+
+    let should_main_be_visible = settings.window.visible;
+    let exit_on_close_request = settings.window.exit_on_close_request;
+
+    let builder = conversion::window_settings(
+        settings.window,
+        &application.title(window::Id::MAIN),
+        event_loop.primary_monitor(),
+        settings.id,
+    )
+    .with_visible(false);
+
+    log::info!("Window builder: {:#?}", builder);
+
+    let main_window = builder
+        .build(&event_loop)
+        .map_err(Error::WindowCreationFailed)?;
+
+    #[cfg(target_arch = "wasm32")]
+    {
+        use winit::platform::web::WindowExtWebSys;
+
+        let canvas = main_window.canvas();
+
+        let window = web_sys::window().unwrap();
+        let document = window.document().unwrap();
+        let body = document.body().unwrap();
+
+        let target = target.and_then(|target| {
+            body.query_selector(&format!("#{}", target))
+                .ok()
+                .unwrap_or(None)
+        });
+
+        match target {
+            Some(node) => {
+                let _ = node
+                    .replace_with_with_node_1(&canvas)
+                    .expect(&format!("Could not replace #{}", node.id()));
+            }
+            None => {
+                let _ = body
+                    .append_child(&canvas)
+                    .expect("Append canvas to HTML body");
+            }
+        };
+    }
+
+    let mut compositor = C::new(compositor_settings, Some(&main_window))?;
+
+    let mut window_manager = WindowManager::new();
+    let _ = window_manager.insert(
+        window::Id::MAIN,
+        main_window,
+        &application,
+        &mut compositor,
+        exit_on_close_request,
+    );
+
+    let (mut event_sender, event_receiver) = mpsc::unbounded();
+    let (control_sender, mut control_receiver) = mpsc::unbounded();
+
+    let mut instance = Box::pin(run_instance::<A, E, C>(
+        application,
+        compositor,
+        runtime,
+        proxy,
+        debug,
+        event_receiver,
+        control_sender,
+        init_command,
+        window_manager,
+        should_main_be_visible,
+    ));
+
+    let mut context = task::Context::from_waker(task::noop_waker_ref());
+
+    platform::run(event_loop, move |event, window_target, control_flow| {
+        use winit::event_loop::ControlFlow;
+
+        if let ControlFlow::ExitWithCode(_) = control_flow {
+            return;
+        }
+
+        let event = match event {
+            winit::event::Event::WindowEvent {
+                event:
+                    winit::event::WindowEvent::ScaleFactorChanged {
+                        new_inner_size,
+                        ..
+                    },
+                window_id,
+            } => Some(winit::event::Event::WindowEvent {
+                event: winit::event::WindowEvent::Resized(*new_inner_size),
+                window_id,
+            }),
+            _ => event.to_static(),
+        };
+
+        if let Some(event) = event {
+            event_sender
+                .start_send(Event::EventLoopAwakened(event))
+                .expect("Send event");
+
+            loop {
+                let poll = instance.as_mut().poll(&mut context);
+
+                match poll {
+                    task::Poll::Pending => match control_receiver.try_next() {
+                        Ok(Some(control)) => match control {
+                            Control::ChangeFlow(flow) => {
+                                *control_flow = flow;
+                            }
+                            Control::CreateWindow {
+                                id,
+                                settings,
+                                title,
+                                monitor,
+                            } => {
+                                let exit_on_close_request =
+                                    settings.exit_on_close_request;
+
+                                let window = conversion::window_settings(
+                                    settings, &title, monitor, None,
+                                )
+                                .build(window_target)
+                                .expect("Failed to build window");
+
+                                event_sender
+                                    .start_send(Event::WindowCreated {
+                                        id,
+                                        window,
+                                        exit_on_close_request,
+                                    })
+                                    .expect("Send event");
+                            }
+                        },
+                        _ => {
+                            break;
+                        }
+                    },
+                    task::Poll::Ready(_) => {
+                        *control_flow = ControlFlow::Exit;
+                        break;
+                    }
+                };
+            }
+        }
+    })
+}
+
+enum Event<Message: 'static> {
+    WindowCreated {
+        id: window::Id,
+        window: winit::window::Window,
+        exit_on_close_request: bool,
+    },
+    EventLoopAwakened(winit::event::Event<'static, Message>),
+}
+
+enum Control {
+    ChangeFlow(winit::event_loop::ControlFlow),
+    CreateWindow {
+        id: window::Id,
+        settings: window::Settings,
+        title: String,
+        monitor: Option<winit::monitor::MonitorHandle>,
+    },
+}
+
+async fn run_instance<A, E, C>(
+    mut application: A,
+    mut compositor: C,
+    mut runtime: Runtime<E, Proxy<A::Message>, A::Message>,
+    mut proxy: winit::event_loop::EventLoopProxy<A::Message>,
+    mut debug: Debug,
+    mut event_receiver: mpsc::UnboundedReceiver<Event<A::Message>>,
+    mut control_sender: mpsc::UnboundedSender<Control>,
+    init_command: Command<A::Message>,
+    mut window_manager: WindowManager<A, C>,
+    should_main_window_be_visible: bool,
+) where
+    A: Application + 'static,
+    E: Executor + 'static,
+    C: Compositor<Renderer = A::Renderer> + 'static,
+    <A::Renderer as core::Renderer>::Theme: StyleSheet,
+{
+    use winit::event;
+    use winit::event_loop::ControlFlow;
+
+    let main_window = window_manager
+        .get_mut(window::Id::MAIN)
+        .expect("Get main window");
+
+    if should_main_window_be_visible {
+        main_window.raw.set_visible(true);
+    }
+
+    let mut clipboard = Clipboard::connect(&main_window.raw);
+    let mut events = {
+        vec![(
+            Some(window::Id::MAIN),
+            core::Event::Window(
+                window::Id::MAIN,
+                window::Event::Opened {
+                    position: main_window.position(),
+                    size: main_window.size(),
+                },
+            ),
+        )]
+    };
+
+    let mut ui_caches = HashMap::new();
+    let mut user_interfaces = ManuallyDrop::new(build_user_interfaces(
+        &application,
+        &mut debug,
+        &mut window_manager,
+        HashMap::from_iter([(
+            window::Id::MAIN,
+            user_interface::Cache::default(),
+        )]),
+    ));
+
+    run_command(
+        &application,
+        &mut compositor,
+        init_command,
+        &mut runtime,
+        &mut clipboard,
+        &mut control_sender,
+        &mut proxy,
+        &mut debug,
+        &mut window_manager,
+        &mut ui_caches,
+    );
+
+    runtime.track(application.subscription().into_recipes());
+
+    let mut messages = Vec::new();
+    let mut redraw_pending = false;
+
+    debug.startup_finished();
+
+    'main: while let Some(event) = event_receiver.next().await {
+        match event {
+            Event::WindowCreated {
+                id,
+                window,
+                exit_on_close_request,
+            } => {
+                let window = window_manager.insert(
+                    id,
+                    window,
+                    &application,
+                    &mut compositor,
+                    exit_on_close_request,
+                );
+
+                let logical_size = window.state.logical_size();
+
+                let _ = user_interfaces.insert(
+                    id,
+                    build_user_interface(
+                        &application,
+                        user_interface::Cache::default(),
+                        &mut window.renderer,
+                        logical_size,
+                        &mut debug,
+                        id,
+                    ),
+                );
+                let _ = ui_caches.insert(id, user_interface::Cache::default());
+
+                events.push((
+                    Some(id),
+                    core::Event::Window(
+                        id,
+                        window::Event::Opened {
+                            position: window.position(),
+                            size: window.size(),
+                        },
+                    ),
+                ));
+            }
+            Event::EventLoopAwakened(event) => {
+                match event {
+                    event::Event::NewEvents(start_cause) => {
+                        redraw_pending = matches!(
+                            start_cause,
+                            event::StartCause::Init
+                                | event::StartCause::Poll
+                                | event::StartCause::ResumeTimeReached { .. }
+                        );
+                    }
+                    event::Event::MainEventsCleared => {
+                        debug.event_processing_started();
+                        let mut uis_stale = false;
+
+                        for (id, window) in window_manager.iter_mut() {
+                            let mut window_events = vec![];
+
+                            events.retain(|(window_id, event)| {
+                                if *window_id == Some(id) || window_id.is_none()
+                                {
+                                    window_events.push(event.clone());
+                                    false
+                                } else {
+                                    true
+                                }
+                            });
+
+                            if !redraw_pending
+                                && window_events.is_empty()
+                                && messages.is_empty()
+                            {
+                                continue;
+                            }
+
+                            let (ui_state, statuses) = user_interfaces
+                                .get_mut(&id)
+                                .expect("Get user interface")
+                                .update(
+                                    &window_events,
+                                    window.state.cursor(),
+                                    &mut window.renderer,
+                                    &mut clipboard,
+                                    &mut messages,
+                                );
+
+                            if !uis_stale {
+                                uis_stale = matches!(
+                                    ui_state,
+                                    user_interface::State::Outdated
+                                );
+                            }
+
+                            for (event, status) in window_events
+                                .into_iter()
+                                .zip(statuses.into_iter())
+                            {
+                                runtime.broadcast(event, status);
+                            }
+                        }
+
+                        debug.event_processing_finished();
+
+                        // TODO mw application update returns which window IDs to update
+                        if !messages.is_empty() || uis_stale {
+                            let mut cached_interfaces: HashMap<
+                                window::Id,
+                                user_interface::Cache,
+                            > = ManuallyDrop::into_inner(user_interfaces)
+                                .drain()
+                                .map(|(id, ui)| (id, ui.into_cache()))
+                                .collect();
+
+                            // Update application
+                            update(
+                                &mut application,
+                                &mut compositor,
+                                &mut runtime,
+                                &mut clipboard,
+                                &mut control_sender,
+                                &mut proxy,
+                                &mut debug,
+                                &mut messages,
+                                &mut window_manager,
+                                &mut cached_interfaces,
+                            );
+
+                            // we must synchronize all window states with application state after an
+                            // application update since we don't know what changed
+                            for (id, window) in window_manager.iter_mut() {
+                                window.state.synchronize(
+                                    &application,
+                                    id,
+                                    &window.raw,
+                                );
+                            }
+
+                            // rebuild UIs with the synchronized states
+                            user_interfaces =
+                                ManuallyDrop::new(build_user_interfaces(
+                                    &application,
+                                    &mut debug,
+                                    &mut window_manager,
+                                    cached_interfaces,
+                                ));
+                        }
+
+                        debug.draw_started();
+
+                        for (id, window) in window_manager.iter_mut() {
+                            // TODO: Avoid redrawing all the time by forcing widgets to
+                            //  request redraws on state changes
+                            //
+                            // Then, we can use the `interface_state` here to decide if a redraw
+                            // is needed right away, or simply wait until a specific time.
+                            let redraw_event = core::Event::Window(
+                                id,
+                                window::Event::RedrawRequested(Instant::now()),
+                            );
+
+                            let cursor = window.state.cursor();
+
+                            let ui = user_interfaces
+                                .get_mut(&id)
+                                .expect("Get user interface");
+
+                            let (ui_state, _) = ui.update(
+                                &[redraw_event.clone()],
+                                cursor,
+                                &mut window.renderer,
+                                &mut clipboard,
+                                &mut messages,
+                            );
+
+                            let new_mouse_interaction = {
+                                let state = &window.state;
+
+                                ui.draw(
+                                    &mut window.renderer,
+                                    state.theme(),
+                                    &renderer::Style {
+                                        text_color: state.text_color(),
+                                    },
+                                    cursor,
+                                )
+                            };
+
+                            if new_mouse_interaction != window.mouse_interaction
+                            {
+                                window.raw.set_cursor_icon(
+                                    conversion::mouse_interaction(
+                                        new_mouse_interaction,
+                                    ),
+                                );
+
+                                window.mouse_interaction =
+                                    new_mouse_interaction;
+                            }
+
+                            // TODO once widgets can request to be redrawn, we can avoid always requesting a
+                            // redraw
+                            window.raw.request_redraw();
+
+                            runtime.broadcast(
+                                redraw_event.clone(),
+                                core::event::Status::Ignored,
+                            );
+
+                            let _ = control_sender.start_send(
+                                Control::ChangeFlow(match ui_state {
+                                    user_interface::State::Updated {
+                                        redraw_request: Some(redraw_request),
+                                    } => match redraw_request {
+                                        window::RedrawRequest::NextFrame => {
+                                            ControlFlow::Poll
+                                        }
+                                        window::RedrawRequest::At(at) => {
+                                            ControlFlow::WaitUntil(at)
+                                        }
+                                    },
+                                    _ => ControlFlow::Wait,
+                                }),
+                            );
+                        }
+
+                        redraw_pending = false;
+
+                        debug.draw_finished();
+                    }
+                    event::Event::PlatformSpecific(
+                        event::PlatformSpecific::MacOS(
+                            event::MacOS::ReceivedUrl(url),
+                        ),
+                    ) => {
+                        use crate::core::event;
+
+                        events.push((
+                            None,
+                            event::Event::PlatformSpecific(
+                                event::PlatformSpecific::MacOS(
+                                    event::MacOS::ReceivedUrl(url),
+                                ),
+                            ),
+                        ));
+                    }
+                    event::Event::UserEvent(message) => {
+                        messages.push(message);
+                    }
+                    event::Event::RedrawRequested(id) => {
+                        let Some((id, window)) =
+                            window_manager.get_mut_alias(id)
+                        else {
+                            continue;
+                        };
+
+                        let physical_size = window.state.physical_size();
+
+                        if physical_size.width == 0 || physical_size.height == 0
+                        {
+                            continue;
+                        }
+
+                        debug.render_started();
+                        if window.viewport_version
+                            != window.state.viewport_version()
+                        {
+                            let logical_size = window.state.logical_size();
+
+                            debug.layout_started();
+
+                            let ui = user_interfaces
+                                .remove(&id)
+                                .expect("Remove user interface");
+
+                            let _ = user_interfaces.insert(
+                                id,
+                                ui.relayout(logical_size, &mut window.renderer),
+                            );
+
+                            debug.layout_finished();
+
+                            debug.draw_started();
+                            let new_mouse_interaction = user_interfaces
+                                .get_mut(&id)
+                                .expect("Get user interface")
+                                .draw(
+                                    &mut window.renderer,
+                                    window.state.theme(),
+                                    &renderer::Style {
+                                        text_color: window.state.text_color(),
+                                    },
+                                    window.state.cursor(),
+                                );
+
+                            if new_mouse_interaction != window.mouse_interaction
+                            {
+                                window.raw.set_cursor_icon(
+                                    conversion::mouse_interaction(
+                                        new_mouse_interaction,
+                                    ),
+                                );
+
+                                window.mouse_interaction =
+                                    new_mouse_interaction;
+                            }
+                            debug.draw_finished();
+
+                            compositor.configure_surface(
+                                &mut window.surface,
+                                physical_size.width,
+                                physical_size.height,
+                            );
+
+                            window.viewport_version =
+                                window.state.viewport_version();
+                        }
+
+                        match compositor.present(
+                            &mut window.renderer,
+                            &mut window.surface,
+                            window.state.viewport(),
+                            window.state.background_color(),
+                            &debug.overlay(),
+                        ) {
+                            Ok(()) => {
+                                debug.render_finished();
+
+                                // TODO: Handle animations!
+                                // Maybe we can use `ControlFlow::WaitUntil` for this.
+                            }
+                            Err(error) => match error {
+                                // This is an unrecoverable error.
+                                compositor::SurfaceError::OutOfMemory => {
+                                    panic!("{:?}", error);
+                                }
+                                _ => {
+                                    debug.render_finished();
+                                    log::error!(
+                                "Error {error:?} when presenting surface."
+                            );
+
+                                    // Try rendering all windows again next frame.
+                                    for (_id, window) in
+                                        window_manager.iter_mut()
+                                    {
+                                        window.raw.request_redraw();
+                                    }
+                                }
+                            },
+                        }
+                    }
+                    event::Event::WindowEvent {
+                        event: window_event,
+                        window_id,
+                    } => {
+                        let Some((id, window)) =
+                            window_manager.get_mut_alias(window_id)
+                        else {
+                            continue;
+                        };
+
+                        if matches!(
+                            window_event,
+                            winit::event::WindowEvent::CloseRequested
+                        ) && window.exit_on_close_request
+                        {
+                            let _ = window_manager.remove(id);
+                            let _ = user_interfaces.remove(&id);
+                            let _ = ui_caches.remove(&id);
+
+                            events.push((
+                                None,
+                                core::Event::Window(id, window::Event::Closed),
+                            ));
+
+                            if window_manager.is_empty() {
+                                break 'main;
+                            }
+                        } else {
+                            window.state.update(
+                                &window.raw,
+                                &window_event,
+                                &mut debug,
+                            );
+
+                            if let Some(event) = conversion::window_event(
+                                id,
+                                &window_event,
+                                window.state.scale_factor(),
+                                window.state.modifiers(),
+                            ) {
+                                events.push((Some(id), event));
+                            }
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+    }
+
+    let _ = ManuallyDrop::into_inner(user_interfaces);
+}
+
+/// Builds a window's [`UserInterface`] for the [`Application`].
+fn build_user_interface<'a, A: Application>(
+    application: &'a A,
+    cache: user_interface::Cache,
+    renderer: &mut A::Renderer,
+    size: Size,
+    debug: &mut Debug,
+    id: window::Id,
+) -> UserInterface<'a, A::Message, A::Renderer>
+where
+    <A::Renderer as core::Renderer>::Theme: StyleSheet,
+{
+    debug.view_started();
+    let view = application.view(id);
+    debug.view_finished();
+
+    debug.layout_started();
+    let user_interface = UserInterface::build(view, size, cache, renderer);
+    debug.layout_finished();
+
+    user_interface
+}
+
+/// Updates a multi-window [`Application`] by feeding it messages, spawning any
+/// resulting [`Command`], and tracking its [`Subscription`].
+fn update<A: Application, C, E: Executor>(
+    application: &mut A,
+    compositor: &mut C,
+    runtime: &mut Runtime<E, Proxy<A::Message>, A::Message>,
+    clipboard: &mut Clipboard,
+    control_sender: &mut mpsc::UnboundedSender<Control>,
+    proxy: &mut winit::event_loop::EventLoopProxy<A::Message>,
+    debug: &mut Debug,
+    messages: &mut Vec<A::Message>,
+    window_manager: &mut WindowManager<A, C>,
+    ui_caches: &mut HashMap<window::Id, user_interface::Cache>,
+) where
+    C: Compositor<Renderer = A::Renderer> + 'static,
+    <A::Renderer as core::Renderer>::Theme: StyleSheet,
+{
+    for message in messages.drain(..) {
+        debug.log_message(&message);
+        debug.update_started();
+
+        let command = runtime.enter(|| application.update(message));
+        debug.update_finished();
+
+        run_command(
+            application,
+            compositor,
+            command,
+            runtime,
+            clipboard,
+            control_sender,
+            proxy,
+            debug,
+            window_manager,
+            ui_caches,
+        );
+    }
+
+    let subscription = application.subscription();
+    runtime.track(subscription.into_recipes());
+}
+
+/// Runs the actions of a [`Command`].
+fn run_command<A, C, E>(
+    application: &A,
+    compositor: &mut C,
+    command: Command<A::Message>,
+    runtime: &mut Runtime<E, Proxy<A::Message>, A::Message>,
+    clipboard: &mut Clipboard,
+    control_sender: &mut mpsc::UnboundedSender<Control>,
+    proxy: &mut winit::event_loop::EventLoopProxy<A::Message>,
+    debug: &mut Debug,
+    window_manager: &mut WindowManager<A, C>,
+    ui_caches: &mut HashMap<window::Id, user_interface::Cache>,
+) where
+    A: Application,
+    E: Executor,
+    C: Compositor<Renderer = A::Renderer> + 'static,
+    <A::Renderer as core::Renderer>::Theme: StyleSheet,
+{
+    use crate::runtime::clipboard;
+    use crate::runtime::system;
+    use crate::runtime::window;
+
+    for action in command.actions() {
+        match action {
+            command::Action::Future(future) => {
+                runtime.spawn(Box::pin(future));
+            }
+            command::Action::Stream(stream) => {
+                runtime.run(Box::pin(stream));
+            }
+            command::Action::Clipboard(action) => match action {
+                clipboard::Action::Read(tag) => {
+                    let message = tag(clipboard.read());
+
+                    proxy
+                        .send_event(message)
+                        .expect("Send message to event loop");
+                }
+                clipboard::Action::Write(contents) => {
+                    clipboard.write(contents);
+                }
+            },
+            command::Action::Window(action) => match action {
+                window::Action::Spawn(id, settings) => {
+                    let monitor = window_manager.last_monitor();
+
+                    control_sender
+                        .start_send(Control::CreateWindow {
+                            id,
+                            settings,
+                            title: application.title(id),
+                            monitor,
+                        })
+                        .expect("Send control action");
+                }
+                window::Action::Close(id) => {
+                    use winit::event_loop::ControlFlow;
+
+                    let _ = window_manager.remove(id);
+                    let _ = ui_caches.remove(&id);
+
+                    if window_manager.is_empty() {
+                        control_sender
+                            .start_send(Control::ChangeFlow(
+                                ControlFlow::ExitWithCode(0),
+                            ))
+                            .expect("Send control action");
+                    }
+                }
+                window::Action::Drag(id) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        let _ = window.raw.drag_window();
+                    }
+                }
+                window::Action::Resize(id, size) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_inner_size(winit::dpi::LogicalSize {
+                            width: size.width,
+                            height: size.height,
+                        });
+                    }
+                }
+                window::Action::FetchSize(id, callback) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        let size = window
+                            .raw
+                            .inner_size()
+                            .to_logical(window.raw.scale_factor());
+
+                        proxy
+                            .send_event(callback(Size::new(
+                                size.width,
+                                size.height,
+                            )))
+                            .expect("Send message to event loop");
+                    }
+                }
+                window::Action::Maximize(id, maximized) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_maximized(maximized);
+                    }
+                }
+                window::Action::Minimize(id, minimized) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_minimized(minimized);
+                    }
+                }
+                window::Action::Move(id, position) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_outer_position(
+                            winit::dpi::LogicalPosition {
+                                x: position.x,
+                                y: position.y,
+                            },
+                        );
+                    }
+                }
+                window::Action::ChangeMode(id, mode) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_visible(conversion::visible(mode));
+                        window.raw.set_fullscreen(conversion::fullscreen(
+                            window.raw.current_monitor(),
+                            mode,
+                        ));
+                    }
+                }
+                window::Action::ChangeIcon(id, icon) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_window_icon(conversion::icon(icon));
+                    }
+                }
+                window::Action::FetchMode(id, tag) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        let mode = if window.raw.is_visible().unwrap_or(true) {
+                            conversion::mode(window.raw.fullscreen())
+                        } else {
+                            core::window::Mode::Hidden
+                        };
+
+                        proxy
+                            .send_event(tag(mode))
+                            .expect("Event loop doesn't exist.");
+                    }
+                }
+                window::Action::ToggleMaximize(id) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_maximized(!window.raw.is_maximized());
+                    }
+                }
+                window::Action::ToggleDecorations(id) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.set_decorations(!window.raw.is_decorated());
+                    }
+                }
+                window::Action::RequestUserAttention(id, attention_type) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.request_user_attention(
+                            attention_type.map(conversion::user_attention),
+                        );
+                    }
+                }
+                window::Action::GainFocus(id) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window.raw.focus_window();
+                    }
+                }
+                window::Action::ChangeLevel(id, level) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        window
+                            .raw
+                            .set_window_level(conversion::window_level(level));
+                    }
+                }
+                window::Action::FetchId(id, tag) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        proxy
+                            .send_event(tag(window.raw.id().into()))
+                            .expect("Event loop doesn't exist.");
+                    }
+                }
+                window::Action::Screenshot(id, tag) => {
+                    if let Some(window) = window_manager.get_mut(id) {
+                        let bytes = compositor.screenshot(
+                            &mut window.renderer,
+                            &mut window.surface,
+                            window.state.viewport(),
+                            window.state.background_color(),
+                            &debug.overlay(),
+                        );
+
+                        proxy
+                            .send_event(tag(window::Screenshot::new(
+                                bytes,
+                                window.state.physical_size(),
+                            )))
+                            .expect("Event loop doesn't exist.");
+                    }
+                }
+            },
+            command::Action::System(action) => match action {
+                system::Action::QueryInformation(_tag) => {
+                    #[cfg(feature = "system")]
+                    {
+                        let graphics_info = compositor.fetch_information();
+                        let proxy = proxy.clone();
+
+                        let _ = std::thread::spawn(move || {
+                            let information =
+                                crate::system::information(graphics_info);
+
+                            let message = _tag(information);
+
+                            proxy
+                                .send_event(message)
+                                .expect("Event loop doesn't exist.");
+                        });
+                    }
+                }
+            },
+            command::Action::Widget(action) => {
+                let mut current_operation = Some(action);
+
+                let mut uis = build_user_interfaces(
+                    application,
+                    debug,
+                    window_manager,
+                    std::mem::take(ui_caches),
+                );
+
+                'operate: while let Some(mut operation) =
+                    current_operation.take()
+                {
+                    for (id, ui) in uis.iter_mut() {
+                        if let Some(window) = window_manager.get_mut(*id) {
+                            ui.operate(&window.renderer, operation.as_mut());
+
+                            match operation.finish() {
+                                operation::Outcome::None => {}
+                                operation::Outcome::Some(message) => {
+                                    proxy
+                                        .send_event(message)
+                                        .expect("Event loop doesn't exist.");
+
+                                    // operation completed, don't need to try to operate on rest of UIs
+                                    break 'operate;
+                                }
+                                operation::Outcome::Chain(next) => {
+                                    current_operation = Some(next);
+                                }
+                            }
+                        }
+                    }
+                }
+
+                *ui_caches =
+                    uis.drain().map(|(id, ui)| (id, ui.into_cache())).collect();
+            }
+            command::Action::LoadFont { bytes, tagger } => {
+                use crate::core::text::Renderer;
+
+                // TODO change this once we change each renderer to having a single backend reference.. :pain:
+                // TODO: Error handling (?)
+                for (_, window) in window_manager.iter_mut() {
+                    window.renderer.load_font(bytes.clone());
+                }
+
+                proxy
+                    .send_event(tagger(Ok(())))
+                    .expect("Send message to event loop");
+            }
+        }
+    }
+}
+
+/// Build the user interface for every window.
+pub fn build_user_interfaces<'a, A: Application, C: Compositor>(
+    application: &'a A,
+    debug: &mut Debug,
+    window_manager: &mut WindowManager<A, C>,
+    mut cached_user_interfaces: HashMap<window::Id, user_interface::Cache>,
+) -> HashMap<window::Id, UserInterface<'a, A::Message, A::Renderer>>
+where
+    <A::Renderer as core::Renderer>::Theme: StyleSheet,
+    C: Compositor<Renderer = A::Renderer>,
+{
+    cached_user_interfaces
+        .drain()
+        .filter_map(|(id, cache)| {
+            let window = window_manager.get_mut(id)?;
+
+            Some((
+                id,
+                build_user_interface(
+                    application,
+                    cache,
+                    &mut window.renderer,
+                    window.state.logical_size(),
+                    debug,
+                    id,
+                ),
+            ))
+        })
+        .collect()
+}
+
+/// Returns true if the provided event should cause an [`Application`] to
+/// exit.
+pub fn user_force_quit(
+    event: &winit::event::WindowEvent<'_>,
+    _modifiers: winit::event::ModifiersState,
+) -> bool {
+    match event {
+        #[cfg(target_os = "macos")]
+        winit::event::WindowEvent::KeyboardInput {
+            input:
+                winit::event::KeyboardInput {
+                    virtual_keycode: Some(winit::event::VirtualKeyCode::Q),
+                    state: winit::event::ElementState::Pressed,
+                    ..
+                },
+            ..
+        } if _modifiers.logo() => true,
+        _ => false,
+    }
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+mod platform {
+    pub fn run<T, F>(
+        mut event_loop: winit::event_loop::EventLoop<T>,
+        event_handler: F,
+    ) -> Result<(), super::Error>
+    where
+        F: 'static
+            + FnMut(
+                winit::event::Event<'_, T>,
+                &winit::event_loop::EventLoopWindowTarget<T>,
+                &mut winit::event_loop::ControlFlow,
+            ),
+    {
+        use winit::platform::run_return::EventLoopExtRunReturn;
+
+        let _ = event_loop.run_return(event_handler);
+
+        Ok(())
+    }
+}
+
+#[cfg(target_arch = "wasm32")]
+mod platform {
+    pub fn run<T, F>(
+        event_loop: winit::event_loop::EventLoop<T>,
+        event_handler: F,
+    ) -> !
+    where
+        F: 'static
+            + FnMut(
+                winit::event::Event<'_, T>,
+                &winit::event_loop::EventLoopWindowTarget<T>,
+                &mut winit::event_loop::ControlFlow,
+            ),
+    {
+        event_loop.run(event_handler)
+    }
+}
diff --git a/winit/src/multi_window/state.rs b/winit/src/multi_window/state.rs
new file mode 100644
index 00000000..03da5ad7
--- /dev/null
+++ b/winit/src/multi_window/state.rs
@@ -0,0 +1,240 @@
+use crate::conversion;
+use crate::core;
+use crate::core::{mouse, window};
+use crate::core::{Color, Size};
+use crate::graphics::Viewport;
+use crate::multi_window::Application;
+use crate::style::application;
+use std::fmt::{Debug, Formatter};
+
+use iced_style::application::StyleSheet;
+use winit::event::{Touch, WindowEvent};
+use winit::window::Window;
+
+/// The state of a multi-windowed [`Application`].
+pub struct State<A: Application>
+where
+    <A::Renderer as core::Renderer>::Theme: application::StyleSheet,
+{
+    title: String,
+    scale_factor: f64,
+    viewport: Viewport,
+    viewport_version: u64,
+    cursor_position: Option<winit::dpi::PhysicalPosition<f64>>,
+    modifiers: winit::event::ModifiersState,
+    theme: <A::Renderer as core::Renderer>::Theme,
+    appearance: application::Appearance,
+}
+
+impl<A: Application> Debug for State<A>
+where
+    <A::Renderer as core::Renderer>::Theme: application::StyleSheet,
+{
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("multi_window::State")
+            .field("title", &self.title)
+            .field("scale_factor", &self.scale_factor)
+            .field("viewport", &self.viewport)
+            .field("viewport_version", &self.viewport_version)
+            .field("cursor_position", &self.cursor_position)
+            .field("appearance", &self.appearance)
+            .finish()
+    }
+}
+
+impl<A: Application> State<A>
+where
+    <A::Renderer as core::Renderer>::Theme: application::StyleSheet,
+{
+    /// Creates a new [`State`] for the provided [`Application`]'s `window`.
+    pub fn new(
+        application: &A,
+        window_id: window::Id,
+        window: &Window,
+    ) -> Self {
+        let title = application.title(window_id);
+        let scale_factor = application.scale_factor(window_id);
+        let theme = application.theme(window_id);
+        let appearance = theme.appearance(&application.style());
+
+        let viewport = {
+            let physical_size = window.inner_size();
+
+            Viewport::with_physical_size(
+                Size::new(physical_size.width, physical_size.height),
+                window.scale_factor() * scale_factor,
+            )
+        };
+
+        Self {
+            title,
+            scale_factor,
+            viewport,
+            viewport_version: 0,
+            cursor_position: None,
+            modifiers: winit::event::ModifiersState::default(),
+            theme,
+            appearance,
+        }
+    }
+
+    /// Returns the current [`Viewport`] of the [`State`].
+    pub fn viewport(&self) -> &Viewport {
+        &self.viewport
+    }
+
+    /// Returns the version of the [`Viewport`] of the [`State`].
+    ///
+    /// The version is incremented every time the [`Viewport`] changes.
+    pub fn viewport_version(&self) -> u64 {
+        self.viewport_version
+    }
+
+    /// Returns the physical [`Size`] of the [`Viewport`] of the [`State`].
+    pub fn physical_size(&self) -> Size<u32> {
+        self.viewport.physical_size()
+    }
+
+    /// Returns the logical [`Size`] of the [`Viewport`] of the [`State`].
+    pub fn logical_size(&self) -> Size<f32> {
+        self.viewport.logical_size()
+    }
+
+    /// Returns the current scale factor of the [`Viewport`] of the [`State`].
+    pub fn scale_factor(&self) -> f64 {
+        self.viewport.scale_factor()
+    }
+
+    /// Returns the current cursor position of the [`State`].
+    pub fn cursor(&self) -> mouse::Cursor {
+        self.cursor_position
+            .map(|cursor_position| {
+                conversion::cursor_position(
+                    cursor_position,
+                    self.viewport.scale_factor(),
+                )
+            })
+            .map(mouse::Cursor::Available)
+            .unwrap_or(mouse::Cursor::Unavailable)
+    }
+
+    /// Returns the current keyboard modifiers of the [`State`].
+    pub fn modifiers(&self) -> winit::event::ModifiersState {
+        self.modifiers
+    }
+
+    /// Returns the current theme of the [`State`].
+    pub fn theme(&self) -> &<A::Renderer as core::Renderer>::Theme {
+        &self.theme
+    }
+
+    /// Returns the current background [`Color`] of the [`State`].
+    pub fn background_color(&self) -> Color {
+        self.appearance.background_color
+    }
+
+    /// Returns the current text [`Color`] of the [`State`].
+    pub fn text_color(&self) -> Color {
+        self.appearance.text_color
+    }
+
+    /// Processes the provided window event and updates the [`State`] accordingly.
+    pub fn update(
+        &mut self,
+        window: &Window,
+        event: &WindowEvent<'_>,
+        _debug: &mut crate::runtime::Debug,
+    ) {
+        match event {
+            WindowEvent::Resized(new_size) => {
+                let size = Size::new(new_size.width, new_size.height);
+
+                self.viewport = Viewport::with_physical_size(
+                    size,
+                    window.scale_factor() * self.scale_factor,
+                );
+
+                self.viewport_version = self.viewport_version.wrapping_add(1);
+            }
+            WindowEvent::ScaleFactorChanged {
+                scale_factor: new_scale_factor,
+                new_inner_size,
+            } => {
+                let size =
+                    Size::new(new_inner_size.width, new_inner_size.height);
+
+                self.viewport = Viewport::with_physical_size(
+                    size,
+                    new_scale_factor * self.scale_factor,
+                );
+
+                self.viewport_version = self.viewport_version.wrapping_add(1);
+            }
+            WindowEvent::CursorMoved { position, .. }
+            | WindowEvent::Touch(Touch {
+                location: position, ..
+            }) => {
+                self.cursor_position = Some(*position);
+            }
+            WindowEvent::CursorLeft { .. } => {
+                self.cursor_position = None;
+            }
+            WindowEvent::ModifiersChanged(new_modifiers) => {
+                self.modifiers = *new_modifiers;
+            }
+            #[cfg(feature = "debug")]
+            WindowEvent::KeyboardInput {
+                input:
+                    winit::event::KeyboardInput {
+                        virtual_keycode: Some(winit::event::VirtualKeyCode::F12),
+                        state: winit::event::ElementState::Pressed,
+                        ..
+                    },
+                ..
+            } => _debug.toggle(),
+            _ => {}
+        }
+    }
+
+    /// Synchronizes the [`State`] with its [`Application`] and its respective
+    /// window.
+    ///
+    /// Normally, an [`Application`] should be synchronized with its [`State`]
+    /// and window after calling [`State::update`].
+    pub fn synchronize(
+        &mut self,
+        application: &A,
+        window_id: window::Id,
+        window: &Window,
+    ) {
+        // Update window title
+        let new_title = application.title(window_id);
+
+        if self.title != new_title {
+            window.set_title(&new_title);
+            self.title = new_title;
+        }
+
+        // Update scale factor and size
+        let new_scale_factor = application.scale_factor(window_id);
+        let new_size = window.inner_size();
+        let current_size = self.viewport.physical_size();
+
+        if self.scale_factor != new_scale_factor
+            || (current_size.width, current_size.height)
+                != (new_size.width, new_size.height)
+        {
+            self.viewport = Viewport::with_physical_size(
+                Size::new(new_size.width, new_size.height),
+                window.scale_factor() * new_scale_factor,
+            );
+            self.viewport_version = self.viewport_version.wrapping_add(1);
+
+            self.scale_factor = new_scale_factor;
+        }
+
+        // Update theme and appearance
+        self.theme = application.theme(window_id);
+        self.appearance = self.theme.appearance(&application.style());
+    }
+}
diff --git a/winit/src/multi_window/window_manager.rs b/winit/src/multi_window/window_manager.rs
new file mode 100644
index 00000000..d54156e7
--- /dev/null
+++ b/winit/src/multi_window/window_manager.rs
@@ -0,0 +1,156 @@
+use crate::core::mouse;
+use crate::core::window::Id;
+use crate::core::{Point, Size};
+use crate::graphics::Compositor;
+use crate::multi_window::{Application, State};
+use crate::style::application::StyleSheet;
+
+use std::collections::BTreeMap;
+use winit::monitor::MonitorHandle;
+
+#[allow(missing_debug_implementations)]
+pub struct WindowManager<A: Application, C: Compositor>
+where
+    <A::Renderer as crate::core::Renderer>::Theme: StyleSheet,
+    C: Compositor<Renderer = A::Renderer>,
+{
+    aliases: BTreeMap<winit::window::WindowId, Id>,
+    entries: BTreeMap<Id, Window<A, C>>,
+}
+
+impl<A, C> WindowManager<A, C>
+where
+    A: Application,
+    C: Compositor<Renderer = A::Renderer>,
+    <A::Renderer as crate::core::Renderer>::Theme: StyleSheet,
+{
+    pub fn new() -> Self {
+        Self {
+            aliases: BTreeMap::new(),
+            entries: BTreeMap::new(),
+        }
+    }
+
+    pub fn insert(
+        &mut self,
+        id: Id,
+        window: winit::window::Window,
+        application: &A,
+        compositor: &mut C,
+        exit_on_close_request: bool,
+    ) -> &mut Window<A, C> {
+        let state = State::new(application, id, &window);
+        let viewport_version = state.viewport_version();
+        let physical_size = state.physical_size();
+        let surface = compositor.create_surface(
+            &window,
+            physical_size.width,
+            physical_size.height,
+        );
+        let renderer = compositor.create_renderer();
+
+        let _ = self.aliases.insert(window.id(), id);
+
+        let _ = self.entries.insert(
+            id,
+            Window {
+                raw: window,
+                state,
+                viewport_version,
+                exit_on_close_request,
+                surface,
+                renderer,
+                mouse_interaction: mouse::Interaction::Idle,
+            },
+        );
+
+        self.entries
+            .get_mut(&id)
+            .expect("Get window that was just inserted")
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.entries.is_empty()
+    }
+
+    pub fn iter_mut(
+        &mut self,
+    ) -> impl Iterator<Item = (Id, &mut Window<A, C>)> {
+        self.entries.iter_mut().map(|(k, v)| (*k, v))
+    }
+
+    pub fn get_mut(&mut self, id: Id) -> Option<&mut Window<A, C>> {
+        self.entries.get_mut(&id)
+    }
+
+    pub fn get_mut_alias(
+        &mut self,
+        id: winit::window::WindowId,
+    ) -> Option<(Id, &mut Window<A, C>)> {
+        let id = self.aliases.get(&id).copied()?;
+
+        Some((id, self.get_mut(id)?))
+    }
+
+    pub fn last_monitor(&self) -> Option<MonitorHandle> {
+        self.entries.values().last()?.raw.current_monitor()
+    }
+
+    pub fn remove(&mut self, id: Id) -> Option<Window<A, C>> {
+        let window = self.entries.remove(&id)?;
+        let _ = self.aliases.remove(&window.raw.id());
+
+        Some(window)
+    }
+}
+
+impl<A, C> Default for WindowManager<A, C>
+where
+    A: Application,
+    C: Compositor<Renderer = A::Renderer>,
+    <A::Renderer as crate::core::Renderer>::Theme: StyleSheet,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[allow(missing_debug_implementations)]
+pub struct Window<A, C>
+where
+    A: Application,
+    C: Compositor<Renderer = A::Renderer>,
+    <A::Renderer as crate::core::Renderer>::Theme: StyleSheet,
+{
+    pub raw: winit::window::Window,
+    pub state: State<A>,
+    pub viewport_version: u64,
+    pub exit_on_close_request: bool,
+    pub mouse_interaction: mouse::Interaction,
+    pub surface: C::Surface,
+    pub renderer: A::Renderer,
+}
+
+impl<A, C> Window<A, C>
+where
+    A: Application,
+    C: Compositor<Renderer = A::Renderer>,
+    <A::Renderer as crate::core::Renderer>::Theme: StyleSheet,
+{
+    pub fn position(&self) -> Option<Point> {
+        self.raw
+            .inner_position()
+            .ok()
+            .map(|position| position.to_logical(self.raw.scale_factor()))
+            .map(|position| Point {
+                x: position.x,
+                y: position.y,
+            })
+    }
+
+    pub fn size(&self) -> Size {
+        let size = self.raw.inner_size().to_logical(self.raw.scale_factor());
+
+        Size::new(size.width, size.height)
+    }
+}
diff --git a/winit/src/position.rs b/winit/src/position.rs
deleted file mode 100644
index c260c29e..00000000
--- a/winit/src/position.rs
+++ /dev/null
@@ -1,22 +0,0 @@
-/// The position of a window in a given screen.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum Position {
-    /// The platform-specific default position for a new window.
-    Default,
-    /// The window is completely centered on the screen.
-    Centered,
-    /// The window is positioned with specific coordinates: `(X, Y)`.
-    ///
-    /// When the decorations of the window are enabled, Windows 10 will add some
-    /// invisible padding to the window. This padding gets included in the
-    /// position. So if you have decorations enabled and want the window to be
-    /// at (0, 0) you would have to set the position to
-    /// `(PADDING_X, PADDING_Y)`.
-    Specific(i32, i32),
-}
-
-impl Default for Position {
-    fn default() -> Self {
-        Self::Default
-    }
-}
diff --git a/winit/src/settings.rs b/winit/src/settings.rs
index 599f33f1..2e541128 100644
--- a/winit/src/settings.rs
+++ b/winit/src/settings.rs
@@ -1,40 +1,7 @@
 //! Configure your application.
-#[cfg(target_os = "windows")]
-#[path = "settings/windows.rs"]
-mod platform;
-
-#[cfg(target_os = "macos")]
-#[path = "settings/macos.rs"]
-mod platform;
-
-#[cfg(target_os = "linux")]
-#[path = "settings/linux.rs"]
-mod platform;
-
-#[cfg(target_arch = "wasm32")]
-#[path = "settings/wasm.rs"]
-mod platform;
-
-#[cfg(not(any(
-    target_os = "windows",
-    target_os = "macos",
-    target_os = "linux",
-    target_arch = "wasm32"
-)))]
-#[path = "settings/other.rs"]
-mod platform;
-
-pub use platform::PlatformSpecific;
-
-use crate::conversion;
-use crate::core::window::{Icon, Level};
-use crate::Position;
-
-use winit::monitor::MonitorHandle;
-use winit::window::WindowBuilder;
+use crate::core::window;
 
 use std::borrow::Cow;
-use std::fmt;
 
 /// The settings of an application.
 #[derive(Debug, Clone, Default)]
@@ -45,8 +12,8 @@ pub struct Settings<Flags> {
     /// communicate with it through the windowing system.
     pub id: Option<String>,
 
-    /// The [`Window`] settings.
-    pub window: Window,
+    /// The [`window::Settings`].
+    pub window: window::Settings,
 
     /// The data needed to initialize an [`Application`].
     ///
@@ -55,197 +22,4 @@ pub struct Settings<Flags> {
 
     /// The fonts to load on boot.
     pub fonts: Vec<Cow<'static, [u8]>>,
-
-    /// Whether the [`Application`] should exit when the user requests the
-    /// window to close (e.g. the user presses the close button).
-    ///
-    /// [`Application`]: crate::Application
-    pub exit_on_close_request: bool,
-}
-
-/// The window settings of an application.
-#[derive(Clone)]
-pub struct Window {
-    /// The size of the window.
-    pub size: (u32, u32),
-
-    /// The position of the window.
-    pub position: Position,
-
-    /// The minimum size of the window.
-    pub min_size: Option<(u32, u32)>,
-
-    /// The maximum size of the window.
-    pub max_size: Option<(u32, u32)>,
-
-    /// Whether the window should be visible or not.
-    pub visible: bool,
-
-    /// Whether the window should be resizable or not.
-    pub resizable: bool,
-
-    /// Whether the window should have a border, a title bar, etc.
-    pub decorations: bool,
-
-    /// Whether the window should be transparent.
-    pub transparent: bool,
-
-    /// The window [`Level`].
-    pub level: Level,
-
-    /// The window icon, which is also usually used in the taskbar
-    pub icon: Option<Icon>,
-
-    /// Platform specific settings.
-    pub platform_specific: platform::PlatformSpecific,
-}
-
-impl fmt::Debug for Window {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("Window")
-            .field("size", &self.size)
-            .field("position", &self.position)
-            .field("min_size", &self.min_size)
-            .field("max_size", &self.max_size)
-            .field("visible", &self.visible)
-            .field("resizable", &self.resizable)
-            .field("decorations", &self.decorations)
-            .field("transparent", &self.transparent)
-            .field("level", &self.level)
-            .field("icon", &self.icon.is_some())
-            .field("platform_specific", &self.platform_specific)
-            .finish()
-    }
-}
-
-impl Window {
-    /// Converts the window settings into a `WindowBuilder` from `winit`.
-    pub fn into_builder(
-        self,
-        title: &str,
-        primary_monitor: Option<MonitorHandle>,
-        _id: Option<String>,
-    ) -> WindowBuilder {
-        let mut window_builder = WindowBuilder::new();
-
-        let (width, height) = self.size;
-
-        window_builder = window_builder
-            .with_title(title)
-            .with_inner_size(winit::dpi::LogicalSize { width, height })
-            .with_resizable(self.resizable)
-            .with_enabled_buttons(if self.resizable {
-                winit::window::WindowButtons::all()
-            } else {
-                winit::window::WindowButtons::CLOSE
-                    | winit::window::WindowButtons::MINIMIZE
-            })
-            .with_decorations(self.decorations)
-            .with_transparent(self.transparent)
-            .with_window_icon(self.icon.and_then(conversion::icon))
-            .with_window_level(conversion::window_level(self.level))
-            .with_visible(self.visible);
-
-        if let Some(position) = conversion::position(
-            primary_monitor.as_ref(),
-            self.size,
-            self.position,
-        ) {
-            window_builder = window_builder.with_position(position);
-        }
-
-        if let Some((width, height)) = self.min_size {
-            window_builder = window_builder
-                .with_min_inner_size(winit::dpi::LogicalSize { width, height });
-        }
-
-        if let Some((width, height)) = self.max_size {
-            window_builder = window_builder
-                .with_max_inner_size(winit::dpi::LogicalSize { width, height });
-        }
-
-        #[cfg(any(
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "netbsd",
-            target_os = "openbsd"
-        ))]
-        {
-            // `with_name` is available on both `WindowBuilderExtWayland` and `WindowBuilderExtX11` and they do
-            // exactly the same thing. We arbitrarily choose `WindowBuilderExtWayland` here.
-            use ::winit::platform::wayland::WindowBuilderExtWayland;
-
-            if let Some(id) = _id {
-                window_builder = window_builder.with_name(id.clone(), id);
-            }
-        }
-
-        #[cfg(target_os = "windows")]
-        {
-            use winit::platform::windows::WindowBuilderExtWindows;
-            #[allow(unsafe_code)]
-            unsafe {
-                window_builder = window_builder
-                    .with_parent_window(self.platform_specific.parent);
-            }
-            window_builder = window_builder
-                .with_drag_and_drop(self.platform_specific.drag_and_drop);
-        }
-
-        #[cfg(target_os = "macos")]
-        {
-            use winit::platform::macos::WindowBuilderExtMacOS;
-
-            window_builder = window_builder
-                .with_title_hidden(self.platform_specific.title_hidden)
-                .with_titlebar_transparent(
-                    self.platform_specific.titlebar_transparent,
-                )
-                .with_fullsize_content_view(
-                    self.platform_specific.fullsize_content_view,
-                );
-        }
-
-        #[cfg(target_os = "linux")]
-        {
-            #[cfg(feature = "x11")]
-            {
-                use winit::platform::x11::WindowBuilderExtX11;
-
-                window_builder = window_builder.with_name(
-                    &self.platform_specific.application_id,
-                    &self.platform_specific.application_id,
-                );
-            }
-            #[cfg(feature = "wayland")]
-            {
-                use winit::platform::wayland::WindowBuilderExtWayland;
-
-                window_builder = window_builder.with_name(
-                    &self.platform_specific.application_id,
-                    &self.platform_specific.application_id,
-                );
-            }
-        }
-
-        window_builder
-    }
-}
-
-impl Default for Window {
-    fn default() -> Window {
-        Window {
-            size: (1024, 768),
-            position: Position::default(),
-            min_size: None,
-            max_size: None,
-            visible: true,
-            resizable: true,
-            decorations: true,
-            transparent: false,
-            level: Level::default(),
-            icon: None,
-            platform_specific: PlatformSpecific::default(),
-        }
-    }
 }
diff --git a/winit/src/settings/linux.rs b/winit/src/settings/linux.rs
deleted file mode 100644
index 009b9d9e..00000000
--- a/winit/src/settings/linux.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-//! Platform specific settings for Linux.
-
-/// The platform specific window settings of an application.
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
-pub struct PlatformSpecific {
-    /// Sets the application id of the window.
-    ///
-    /// As a best practice, it is suggested to select an application id that match
-    /// the basename of the application’s .desktop file.
-    pub application_id: String,
-}
diff --git a/winit/src/settings/macos.rs b/winit/src/settings/macos.rs
deleted file mode 100644
index f86e63ad..00000000
--- a/winit/src/settings/macos.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//! Platform specific settings for macOS.
-
-/// The platform specific window settings of an application.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub struct PlatformSpecific {
-    /// Hides the window title.
-    pub title_hidden: bool,
-    /// Makes the titlebar transparent and allows the content to appear behind it.
-    pub titlebar_transparent: bool,
-    /// Makes the window content appear behind the titlebar.
-    pub fullsize_content_view: bool,
-}
diff --git a/winit/src/settings/other.rs b/winit/src/settings/other.rs
deleted file mode 100644
index b1103f62..00000000
--- a/winit/src/settings/other.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-/// The platform specific window settings of an application.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub struct PlatformSpecific;
diff --git a/winit/src/settings/wasm.rs b/winit/src/settings/wasm.rs
deleted file mode 100644
index 8e0f1bbc..00000000
--- a/winit/src/settings/wasm.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-//! Platform specific settings for WebAssembly.
-
-/// The platform specific window settings of an application.
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
-pub struct PlatformSpecific {
-    /// The identifier of a DOM element that will be replaced with the
-    /// application.
-    ///
-    /// If set to `None`, the application will be appended to the HTML body.
-    pub target: Option<String>,
-}
diff --git a/winit/src/settings/windows.rs b/winit/src/settings/windows.rs
deleted file mode 100644
index 45d753bd..00000000
--- a/winit/src/settings/windows.rs
+++ /dev/null
@@ -1,21 +0,0 @@
-//! Platform specific settings for Windows.
-use raw_window_handle::RawWindowHandle;
-
-/// The platform specific window settings of an application.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct PlatformSpecific {
-    /// Parent window
-    pub parent: Option<RawWindowHandle>,
-
-    /// Drag and drop support
-    pub drag_and_drop: bool,
-}
-
-impl Default for PlatformSpecific {
-    fn default() -> Self {
-        Self {
-            parent: None,
-            drag_and_drop: true,
-        }
-    }
-}