Merge branch 'evl2' into eventloop-2.0

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,3 +2,4 @@
 - [ ] Added an entry to `CHANGELOG.md` if knowledge of this change could be valuable to users
 - [ ] Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
 - [ ] Created an example program if it would help users understand this functionality
+- [ ] Updated [feature matrix](https://github.com/tomaka/winit/blob/master/FEATURES.md), if new features were added or implemented

CONTRIBUTING.md

@@ -1,28 +1,10 @@
 # Winit Contributing Guidelines
 
 ## Scope
+[See `FEATURES.md`](./FEATURES.md). When requesting or implementing a new Winit feature, you should
+consider whether or not it's directly related to window creation or input handling. If it isn't, it
+may be worth creating a separate crate that extends Winit's API to add that functionality.
 
-Winit aims to provide a generic platform abstracting the main graphic platforms (Windows, macOS, X11,
-Wayland, Android, iOS and the web platform via Emscripten).
-
-Most platforms expose capabilities that cannot be meaningfully transposed to the others. Winit does not
-aim to support every single functionality of every platform, but rather to abstract the set of
-capabilities that is common to all platforms. In this context, APIs exposed in winit can be split into
-different "support levels":
-
-- Tier 1: features which are in the main scope of winit. They are part of the common API of winit, and
-  are taken care of by the maintainers. Any part of these features that is not working correctly is
-  considered a bug in winit.
-- Tier 2: some platform-specific features can be sufficiently fundamental to the platform that winit can
-  integrate support for them in the platform-specific part of the API. These features are not considered
-  directly handled by the maintainers of winit. If you have a strong incentive to have such a feature
-  integrated in winit, consider implementing it and proposing yourself to maintain it in the future.
-- Tier 3: these features are not directly exposed by winit, but rather can be implemented using the
-  raw handles to the underlying platform that winit exposes. If your feature of interest is rather
-  niche, this is probably where it belongs.
-
-The exact list of supported Tier 1 features is tracked in this issue:
-[#252](https://github.com/tomaka/winit/issues/252).
 
 ## Reporting an issue
 
@@ -44,6 +26,9 @@ When making a code contribution to winit, before opening your pull request, plea
 - you left comments in your code explaining any part that is not straightforward, so that the
   maintainers and future contributors don't have to try to guess what your code is supposed to do
 - your PR adds an entry to the changelog file if the introduced change is relevant to winit users
+- if your PR affects the platform compatibility of one or more features or adds another feature, the
+  relevant sections in [`FEATURES.md`](https://github.com/rust-windowing/winit/blob/master/FEATURES.md#features)
+  should be updated.
 
 Once your PR is open, you can ask for review by a maintainer of your platform. Winit's merging policy
 is that a PR must be approved by at least two maintainers of winit before being merged, including
@@ -56,14 +41,13 @@ backends of winit. As such, depending on your platform of interest, your contact
 
 This table summarizes who can be contacted in which case, with the following legend:
 
-- `M`: is a main maintainer for this platform
+- `M` - Maintainer: is a main maintainer for this platform
-- `R`: can review code for this platform
+- `C` - Collaborator: can review code and address issues on this platform
-- `T`: has the ability of testing the platform
+- `T` - Tester: has the ability of testing the platform
 - ` `: knows nothing of this platform
 
 | Platform            | Windows | macOS | X11   | Wayland | Android | iOS   | Emscripten |
 | :---                | :---:   | :---: | :---: | :---:   | :---:   | :---: | :---:      |
-| @francesca64 | R | M | M |  | M | R | |
 | @mitchmindtree      | T       |       | T     | T       |         |       |            |
 | @Osspial            | M       |       | T     | T       | T       |       | T          |
 | @vberger            |         |       | T     | M       |         |       |            |

FEATURES.md

@@ -0,0 +1,209 @@
+# Winit Scope
+
+Winit aims to expose an interface that abstracts over window creation and input handling, and can
+be used to create both games and applications. It supports the main graphical platforms:
+- Desktop
+  - Windows
+  - macOS
+  - Unix
+    - via X11
+    - via Wayland
+- Mobile
+  - iOS
+  - Android
+- Web
+  - via Emscripten
+  - via WASM
+
+Most platforms expose capabilities that cannot be meaningfully transposed onto others. Winit does not
+aim to support every single feature of every platform, but rather to abstract over the common features
+available everywhere. In this context, APIs exposed in winit can be split into different "support tiers":
+
+- **Core:** Features that are essential to providing a well-formed abstraction over each platform's
+  windowing and input APIs.
+- **Platform:** Platform-specific features that can't be meaningfully exposed through a common API and
+  cannot be implemented outside of Winit without exposing a significant amount of Winit's internals
+  or interfering with Winit's abstractions.
+- **Usability:** Features that are not strictly essential to Winit's functionality, but provide meaningful
+  usability improvements and cannot be reasonably implemented in an external crate. These are
+  generally optional and exposed through Cargo features.
+
+Core features are taken care of by the core Winit maintainers. Platform features are not.
+When a platform feature is submitted, the submitter is considered the expert in the
+feature and may be asked to support the feature should it break in the future.
+
+Winit ***does not*** directly expose functionality for drawing inside windows or creating native
+menus, but ***does*** commit to providing APIs that higher-level crates can use to implement that
+functionality.
+
+## `1.0` and stability
+
+When all core features are implemented to the satisfaction of the Winit maintainers, Winit 1.0 will
+be released and the library will enter maintenance mode. For the most part, new core features will not
+be added past this point. New platform features may be accepted and exposed through point releases.
+
+### Tier upgrades
+Some platform features could in theory be exposed across multiple platforms, but have not gone
+through the implementation work necessary to function on all platforms. When one of these features
+gets implemented across all platforms, a PR can be opened to upgrade the feature to a core feature.
+If that gets accepted, the platform-specific functions gets deprecated and become permanently
+exposed through the core, cross-platform API.
+
+# Features
+
+## Extending this section
+
+If your PR makes notable changes to Winit's features, please update this section as follows:
+
+- If your PR adds a new feature, add a brief description to the relevant section. If the feature is a core
+  feature, add a row to the feature matrix and describe what platforms the feature has been implemented on.
+
+- If your PR begins a new API rework, add a row to the `Pending API Reworks` table. If the PR implements the
+  API rework on all relevant platforms, please move it to the `Completed API Reworks` table.
+
+- If your PR implements an already-existing feature on a new platform, either mark the feature as *completed*,
+  or mark it as *mostly completed* and link to an issue describing the problems with the implementation.
+
+## Core
+
+### Windowing
+- **Window initialization**: Winit allows the creation of a window
+- **Providing pointer to init OpenGL**: Winit provides the necessary pointers to initialize a working opengl context
+- **Providing pointer to init Vulkan**: Same as OpenGL but for Vulkan
+- **Window decorations**: The windows created by winit are properly decorated, and the decorations can
+  be deactivated
+- **Window decorations toggle**: Decorations can be turned on or off after window creation
+- **Window resizing**: The windows created by winit can be resized and generate the appropriate events
+  when they are. The application can precisely control its window size if desired.
+- **Window resize increments**: When the window gets resized, the application can choose to snap the window's
+  size to specific values.
+- **Window transparency**: Winit allows the creation of windows with a transparent background.
+- **Window maximization**: The windows created by winit can be maximized upon creation.
+- **Window maximization toggle**: The windows created by winit can be maximized and unmaximized after
+  creation.
+- **Fullscreen**: The windows created by winit can be put into fullscreen mode.
+- **Fullscreen toggle**: The windows created by winit can be switched to and from fullscreen after
+  creation.
+- **HiDPI support**: Winit assists developers in appropriately scaling HiDPI content.
+- **Popup / modal windows**: Windows can be created relative to the client area of other windows, and parent
+  windows can be disabled in favor of popup windows. This feature also guarantees that popup windows
+  get drawn above their owner.
+
+
+### System Information
+- **Monitor list**: Retrieve the list of monitors and their metadata, including which one is primary.
+
+### Input Handling
+- **Mouse events**: Generating mouse events associated with pointer motion, click, and scrolling events.
+- **Mouse set location**: Forcibly changing the location of the pointer.
+- **Cursor grab**: Locking the cursor so it cannot exit the client area of a window.
+- **Cursor icon**: Changing the cursor icon, or hiding the cursor.
+- **Touch events**: Single-touch events.
+- **Multitouch**: Multi-touch events, including cancellation of a gesture.
+- **Keyboard events**: Properly processing keyboard events using the user-specified keymap and
+  translating keypresses into UTF-8 characters, handling dead keys and IMEs.
+- **Drag & Drop**: Dragging content into winit, detecting when content enters, drops, or if the drop is cancelled.
+- **Raw Device Events**: Capturing input from input devices without any OS filtering.
+- **Gamepad/Joystick events**: Capturing input from gampads and joysticks.
+- **Device movement events:**: Capturing input from the device gyroscope and accelerometer.
+
+## Platform
+### Windows
+* Setting the taskbar icon
+* Setting the parent window
+* `WS_EX_NOREDIRECTIONBITMAP` support
+
+### macOS
+* Window activation policy
+* Window movable by background
+* Transparent titlebar
+* Hidden titlebar
+* Hidden titlebar buttons
+* Full-size content view
+
+### Unix
+* Window urgency
+* X11 Window Class
+* X11 Override Redirect Flag
+* GTK Theme Variant
+* Base window size
+
+## Usability
+* `serde`: Enables serialization/deserialization of certain types with Serde. (Maintainer: @Osspial)
+
+## Compatibility Matrix
+
+Legend:
+
+- ✔️: Works as intended
+- ▢: Mostly works but some bugs are known
+- ❌: Missing feature or large bugs making it unusable
+- **N/A**: Not applicable for this platform
+- ❓: Unknown status
+
+### Windowing
+|Feature                          |Windows|MacOS   |Linux x11   |Linux Wayland  |Android|iOS    |Emscripten|
+|-------------------------------- | ----- | ----   | -------    | -----------   | ----- | ----- | -------- |
+|Window initialization            |✔️     |✔️     |▢[#5]      |✔️             |▢[#33]|▢[#33] |❓        |
+|Providing pointer to init OpenGL |✔️     |✔️     |✔️         |✔️             |✔️     |✔️    |❓        |
+|Providing pointer to init Vulkan |✔️     |✔️     |✔️         |✔️             |✔️     |❓     |**N/A**   |
+|Window decorations               |✔️     |✔️     |✔️         |▢[#306]        |**N/A**|**N/A**|**N/A**   |
+|Window decorations toggle        |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**   |
+|Window resizing                  |✔️     |▢[#219]|✔️         |▢[#306]        |**N/A**|**N/A**|❓        |
+|Window resize increments         |❌     |❌     |❌         |❌             |❌    |❌     |❌        |
+|Window transparency              |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**   |
+|Window maximization              |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**   |
+|Window maximization toggle       |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**   |
+|Fullscreen                       |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|❌        |
+|Fullscreen toggle                |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|❌        |
+|HiDPI support                    |✔️     |✔️     |✔️         |✔️             |▢[#721]|✔️    |✔️         |
+|Popup windows                    |❌     |❌     |❌         |❌             |❌    |❌     |❌        |
+
+### System information
+|Feature      |Windows|MacOS |Linux x11|Linux Wayland|Android|iOS    |Emscripten|
+|------------ | ----- | ---- | ------- | ----------- | ----- | ----- | -------- |
+|Monitor list |✔️    |✔️    |✔️       |✔️          |**N/A**|**N/A**|**N/A**   |
+
+### Input handling
+|Feature                 |Windows   |MacOS   |Linux x11|Linux Wayland|Android|iOS    |Emscripten|
+|----------------------- | -----    | ----   | ------- | ----------- | ----- | ----- | -------- |
+|Mouse events            |✔️       |▢[#63]  |✔️       |✔️          |**N/A**|**N/A**|✔️       |
+|Mouse set location      |✔️       |✔️      |✔️       |❓           |**N/A**|**N/A**|**N/A**  |
+|Cursor grab             |✔️       |▢[#165] |▢[#242]  |❌[#306]    |**N/A**|**N/A**|✔️       |
+|Cursor icon             |✔️       |✔️      |✔️       |❌[#306]    |**N/A**|**N/A**|❌       |
+|Touch events            |✔️       |❌      |✔️       |✔️          |✔️    |✔️     |✔️       |
+|Multitouch              |❓        |❌      |✔️       |✔️          |❓     |❌     |❌       |
+|Keyboard events         |✔️       |✔️      |✔️       |✔️          |❓     |❌     |✔️       |
+|Drag & Drop             |▢[#720]  |▢[#720] |▢[#720]  |❌[#306]    |**N/A**|**N/A**|❓        |
+|Raw Device Events       |▢[#750]  |▢[#750] |▢[#750]  |❌          |❌    |❌     |❌       |
+|Gamepad/Joystick events |❌[#804] |❌      |❌       |❌          |❌    |❌     |❌       |
+|Device movement events  |❓        |❓       |❓       |❓           |❌    |❌     |❌       |
+
+### Pending API Reworks
+Changes in the API that have been agreed upon but aren't implemented across all platforms.
+
+|Feature                             |Windows|MacOS |Linux x11|Linux Wayland|Android|iOS    |Emscripten|
+|------------------------------      | ----- | ---- | ------- | ----------- | ----- | ----- | -------- |
+|New API for HiDPI ([#315] [#319])   |✔️    |✔️    |✔️       |✔️          |▢[#721]|✔️    |✔️       |
+|Event Loop 2.0 ([#459])             |✔️    |❌    |❌       |✔️          |❌     |❌    |❌       |
+|Keyboard Input ([#812])             |❌    |❌    |❌       |❌          |❌     |❌     |❌      |
+
+### Completed API Reworks
+|Feature                             |Windows|MacOS |Linux x11|Linux Wayland|Android|iOS    |Emscripten|
+|------------------------------      | ----- | ---- | ------- | ----------- | ----- | ----- | -------- |
+
+[#165]: https://github.com/tomaka/winit/issues/165
+[#219]: https://github.com/tomaka/winit/issues/219
+[#242]: https://github.com/tomaka/winit/issues/242
+[#306]: https://github.com/tomaka/winit/issues/306
+[#315]: https://github.com/tomaka/winit/issues/315
+[#319]: https://github.com/tomaka/winit/issues/319
+[#33]: https://github.com/tomaka/winit/issues/33
+[#459]: https://github.com/tomaka/winit/issues/459
+[#5]: https://github.com/tomaka/winit/issues/5
+[#63]: https://github.com/tomaka/winit/issues/63
+[#720]: https://github.com/tomaka/winit/issues/720
+[#721]: https://github.com/tomaka/winit/issues/721
+[#750]: https://github.com/tomaka/winit/issues/750
+[#804]: https://github.com/tomaka/winit/issues/804
+[#812]: https://github.com/tomaka/winit/issues/812

HALL_OF_CHAMPIONS.md

@@ -0,0 +1,11 @@
+# Hall of Champions
+
+The Winit maintainers would like to recognize the following former Winit
+contributors, without whom Winit would not exist in its current form. We thank
+them deeply for their time and efforts, and wish them best of luck in their
+future endeavors:
+
+* @tomaka: For creating the Winit project and guiding it through its early
+  years of existence.
+* @francesca64: For taking over the responsibility of maintaining almost every
+  Winit backend, and standardizing HiDPI support across all of them

README.md

@@ -2,8 +2,8 @@
 
 [![](http://meritbadge.herokuapp.com/winit)](https://crates.io/crates/winit)
 [![Docs.rs](https://docs.rs/winit/badge.svg)](https://docs.rs/winit)
-[![Build Status](https://travis-ci.org/tomaka/winit.svg?branch=master)](https://travis-ci.org/tomaka/winit)
+[![Build Status](https://travis-ci.org/rust-windowing/winit.svg?branch=master)](https://travis-ci.org/rust-windowing/winit)
-[![Build status](https://ci.appveyor.com/api/projects/status/5h87hj0g4q2xe3j9/branch/master?svg=true)](https://ci.appveyor.com/project/tomaka/winit/branch/master)
+[![Build status](https://ci.appveyor.com/api/projects/status/hr89but4x1n3dphq/branch/master?svg=true)](https://ci.appveyor.com/project/Osspial/winit/branch/master)
 
 ```toml
 [dependencies]

examples/fullscreen.rs

@@ -85,6 +85,15 @@ fn main() {
                             window.set_fullscreen(Some(window.get_current_monitor()));
                         }
                     }
+                    (VirtualKeyCode::S, ElementState::Pressed) => {
+                        println!("window.get_fullscreen {:?}", window.get_fullscreen());
+
+                        #[cfg(target_os = "macos")]
+                        {
+                            use winit::os::macos::WindowExt;
+                            println!("window.get_simple_fullscreen {:?}", WindowExt::get_simple_fullscreen(&window));
+                        }
+                    }
                     (VirtualKeyCode::M, ElementState::Pressed) => {
                         is_maximized = !is_maximized;
                         window.set_maximized(is_maximized);

src/platform/macos.rs

@@ -26,6 +26,9 @@ pub trait WindowExtMacOS {
     /// - `true`: the dock icon will bounce until the application is focused.
     fn request_user_attention(&self, is_critical: bool);
 
+    /// Returns whether or not the window is in simple fullscreen mode.
+    fn get_simple_fullscreen(&self) -> bool;
+
     /// Toggles a fullscreen mode that doesn't require a new macOS space.
     /// Returns a boolean indicating whether the transition was successful (this
     /// won't work if the window was already in the native fullscreen).
@@ -52,6 +55,11 @@ impl WindowExtMacOS for Window {
         self.window.request_user_attention(is_critical)
     }
 
+    #[inline]
+    fn get_simple_fullscreen(&self) -> bool {
+        self.window.get_simple_fullscreen()
+    }
+
     #[inline]
     fn set_simple_fullscreen(&self, fullscreen: bool) -> bool {
         self.window.set_simple_fullscreen(fullscreen)

src/platform_impl/android/mod.rs

@@ -368,6 +368,13 @@ impl Window {
         // Android has single screen maximized apps so nothing to do
     }
 
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<RootMonitorHandle> {
+        // N/A
+        // Android has single screen maximized apps so nothing to do
+        None
+    }
+
     #[inline]
     pub fn set_fullscreen(&self, _monitor: Option<RootMonitorHandle>) {
         // N/A

src/platform_impl/emscripten/mod.rs

@@ -580,6 +580,11 @@ impl Window {
         // iOS has single screen maximized apps so nothing to do
     }
 
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<::MonitorHandle> {
+        None
+    }
+
     #[inline]
     pub fn set_fullscreen(&self, _monitor: Option<::MonitorHandle>) {
         // iOS has single screen maximized apps so nothing to do

src/platform_impl/ios/mod.rs

@@ -473,6 +473,13 @@ impl Window {
         // iOS has single screen maximized apps so nothing to do
     }
 
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<RootMonitorHandle> {
+        // N/A
+        // iOS has single screen maximized apps so nothing to do
+        None
+    }
+
     #[inline]
     pub fn set_fullscreen(&self, _monitor: Option<RootMonitorHandle>) {
         // N/A

src/platform_impl/linux/mod.rs

@@ -297,6 +297,15 @@ impl Window {
         }
     }
 
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<RootMonitorHandle> {
+        match self {
+            &Window::X(ref w) => w.get_fullscreen(),
+            &Window::Wayland(ref w) => w.get_fullscreen()
+                .map(|monitor_id| RootMonitorHandle { inner: MonitorHandle::Wayland(monitor_id) })
+        }
+    }
+
     #[inline]
     pub fn set_fullscreen(&self, monitor: Option<RootMonitorHandle>) {
         match self {

src/platform_impl/linux/wayland/window.rs

@@ -7,7 +7,7 @@ use monitor::MonitorHandle as RootMonitorHandle;
 use window::{CreationError, WindowAttributes, MouseCursor};
 
 use sctk::surface::{get_dpi_factor, get_outputs};
-use sctk::window::{ConceptFrame, Event as WEvent, Window as SWindow, Theme};
+use sctk::window::{ConceptFrame, Event as WEvent, State as WState, Window as SWindow, Theme};
 use sctk::reexports::client::Display;
 use sctk::reexports::client::protocol::{wl_seat, wl_surface};
 use sctk::output::OutputMgr;
@@ -23,7 +23,8 @@ pub struct Window {
     kill_switch: (Arc<Mutex<bool>>, Arc<Mutex<bool>>),
     display: Arc<Display>,
     need_frame_refresh: Arc<Mutex<bool>>,
-    need_refresh: Arc<Mutex<bool>>
+    need_refresh: Arc<Mutex<bool>>,
+    fullscreen: Arc<Mutex<bool>>,
 }
 
 impl Window {
@@ -31,6 +32,7 @@ impl Window {
         let (width, height) = attributes.dimensions.map(Into::into).unwrap_or((800, 600));
         // Create the window
         let size = Arc::new(Mutex::new((width, height)));
+        let fullscreen = Arc::new(Mutex::new(false));
 
         let window_store = evlp.store.clone();
         let surface = evlp.env.create_surface(move |dpi, surface| {
@@ -45,12 +47,15 @@ impl Window {
             surface.clone(),
             (width, height),
             move |event| match event {
-                WEvent::Configure { new_size, .. } => {
+                WEvent::Configure { new_size, states } => {
                     let mut store = window_store.lock().unwrap();
+                    let is_fullscreen = states.contains(&WState::Fullscreen);
+
                     for window in &mut store.windows {
                         if window.surface.as_ref().equals(&my_surface.as_ref()) {
                             window.newsize = new_size;
                             *(window.need_refresh.lock().unwrap()) = true;
+                            *(window.fullscreen.lock().unwrap()) = is_fullscreen;
                             *(window.need_frame_refresh.lock().unwrap()) = true;
                             return;
                         }
@@ -117,6 +122,7 @@ impl Window {
             newsize: None,
             size: size.clone(),
             need_refresh: need_refresh.clone(),
+            fullscreen: fullscreen.clone(),
             need_frame_refresh: need_frame_refresh.clone(),
             surface: surface.clone(),
             kill_switch: kill_switch.clone(),
@@ -135,6 +141,7 @@ impl Window {
             kill_switch: (kill_switch, evlp.cleanup_needed.clone()),
             need_frame_refresh,
             need_refresh,
+            fullscreen,
         })
     }
 
@@ -230,6 +237,14 @@ impl Window {
         }
     }
 
+    pub fn get_fullscreen(&self) -> Option<MonitorHandle> {
+        if *(self.fullscreen.lock().unwrap()) {
+            Some(self.get_current_monitor())
+        } else {
+            None
+        }
+    }
+
     pub fn set_fullscreen(&self, monitor: Option<RootMonitorHandle>) {
         if let Some(RootMonitorHandle {
             inner: PlatformMonitorHandle::Wayland(ref monitor_id),
@@ -310,6 +325,7 @@ struct InternalWindow {
     newsize: Option<(u32, u32)>,
     size: Arc<Mutex<(u32, u32)>>,
     need_refresh: Arc<Mutex<bool>>,
+    fullscreen: Arc<Mutex<bool>>,
     need_frame_refresh: Arc<Mutex<bool>>,
     closed: bool,
     kill_switch: Arc<Mutex<bool>>,

src/platform_impl/linux/x11/window.rs

@@ -38,6 +38,7 @@ pub struct SharedState {
     pub guessed_dpi: Option<f64>,
     pub last_monitor: Option<X11MonitorHandle>,
     pub dpi_adjusted: Option<(f64, f64)>,
+    pub fullscreen: Option<RootMonitorHandle>,
     // Used to restore position after exiting fullscreen.
     pub restore_position: Option<(i32, i32)>,
     pub frame_extents: Option<util::FrameExtentsHeuristic>,
@@ -544,8 +545,14 @@ impl UnownedWindow {
         }
     }
 
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<RootMonitorHandle> {
+        self.shared_state.lock().fullscreen.clone()
+    }
+
     #[inline]
     pub fn set_fullscreen(&self, monitor: Option<RootMonitorHandle>) {
+        self.shared_state.lock().fullscreen = monitor.clone();
         self.set_fullscreen_inner(monitor)
             .flush()
             .expect("Failed to change window fullscreen state");

src/platform_impl/macos/window.rs

@@ -636,9 +636,15 @@ impl UnownedWindow {
         trace!("Unlocked shared state in `set_maximized`");
     }
 
-    // TODO: `set_fullscreen` is only usable if you fullscreen on the same
-    // monitor the window's currently on.
     #[inline]
+    pub fn get_fullscreen(&self) -> Option<RootMonitorHandle> {
+        let shared_state_lock = self.shared_state.lock().unwrap();
+        shared_state_lock.fullscreen.clone()
+    }
+
+    #[inline]
+    /// TODO: Right now set_fullscreen do not work on switching monitors
+    /// in fullscreen mode
     pub fn set_fullscreen(&self, monitor: Option<RootMonitorHandle>) {
         let shared_state_lock = self.shared_state.lock().unwrap();
         if shared_state_lock.is_simple_fullscreen {
@@ -785,6 +791,12 @@ impl WindowExtMacOS for UnownedWindow {
         }
     }
 
+    #[inline]
+    fn get_simple_fullscreen(&self) -> bool {
+        let shared_state_lock = self.shared_state.lock().unwrap();
+        shared_state_lock.is_simple_fullscreen
+    }
+
     #[inline]
     fn set_simple_fullscreen(&self, fullscreen: bool) -> bool {
         let mut shared_state_lock = self.shared_state.lock().unwrap();

src/platform_impl/windows/window.rs

@@ -399,6 +399,12 @@ impl Window {
         });
     }
 
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<RootMonitorHandle> {
+        let window_state = self.window_state.lock();
+        window_state.fullscreen.clone()
+    }
+
     #[inline]
     pub fn set_fullscreen(&self, monitor: Option<RootMonitorHandle>) {
         unsafe {

src/window.rs

@@ -536,6 +536,12 @@ impl Window {
         self.window.set_fullscreen(monitor)
     }
 
+    /// Gets the window's current fullscreen state.
+    #[inline]
+    pub fn get_fullscreen(&self) -> Option<MonitorHandle> {
+        self.window.get_fullscreen()
+    }
+
     /// Turn window decorations on or off.
     #[inline]
     pub fn set_decorations(&self, decorations: bool) {