From 4d9302b33cba73557db8a50e443b18331437102a Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Thu, 4 Sep 2025 13:14:41 -0700
Subject: [PATCH] Add borderless fullscreen mode for orbital (#4343)

---
 winit-core/src/window.rs          |  7 ++++---
 winit-orbital/src/window.rs       | 30 +++++++++++++++++++++++++-----
 winit/src/changelog/unreleased.md |  1 +
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/winit-core/src/window.rs b/winit-core/src/window.rs
index 2618e2dc..d2d1d187 100644
--- a/winit-core/src/window.rs
+++ b/winit-core/src/window.rs
@@ -996,7 +996,8 @@ pub trait Window: AsAny + Send + Sync + fmt::Debug {
     ///   separate spaces are not preferred.
     ///
     ///   The dock and the menu bar are disabled in exclusive fullscreen mode.
-    /// - **Wayland:** Does not support exclusive fullscreen mode and will no-op a request.
+    /// - **Orbital / Wayland:** Does not support exclusive fullscreen mode and will no-op a
+    ///   request.
     /// - **Windows:** Screen saver is disabled in fullscreen mode.
     /// - **Web:** Passing a [`MonitorHandle`] or [`VideoMode`] that was not created with detailed
     ///   monitor permissions or calling without a [transient activation] does nothing.
@@ -1009,9 +1010,9 @@ pub trait Window: AsAny + Send + Sync + fmt::Debug {
     ///
     /// ## Platform-specific
     ///
-    /// - **Android / Orbital:** Will always return `None`.
+    /// - **Android:** Will always return `None`.
+    /// - **Orbital / Web:** Can only return `None` or `Borderless(None)`.
     /// - **Wayland:** Can return `Borderless(None)` when there are no monitors.
-    /// - **Web:** Can only return `None` or `Borderless(None)`.
     fn fullscreen(&self) -> Option<Fullscreen>;
 
     /// Turn window decorations on or off.
diff --git a/winit-orbital/src/window.rs b/winit-orbital/src/window.rs
index 7f3918f7..4858b29b 100644
--- a/winit-orbital/src/window.rs
+++ b/winit-orbital/src/window.rs
@@ -19,6 +19,7 @@ const ORBITAL_FLAG_FRONT: char = 'f';
 const ORBITAL_FLAG_HIDDEN: char = 'h';
 const ORBITAL_FLAG_BORDERLESS: char = 'l';
 const ORBITAL_FLAG_MAXIMIZED: char = 'm';
+const ORBITAL_FLAG_FULLSCREEN: char = 'M';
 const ORBITAL_FLAG_RESIZABLE: char = 'r';
 const ORBITAL_FLAG_TRANSPARENT: char = 't';
 
@@ -55,7 +56,10 @@ impl Window {
         // Async by default.
         let mut flag_str = ORBITAL_FLAG_ASYNC.to_string();
 
-        if attrs.maximized {
+        // Fullscreen takes precedence over maximize
+        if let Some(Fullscreen::Borderless(_)) = attrs.fullscreen {
+            flag_str.push(ORBITAL_FLAG_FULLSCREEN);
+        } else if attrs.maximized {
             flag_str.push(ORBITAL_FLAG_MAXIMIZED);
         }
 
@@ -63,8 +67,6 @@ impl Window {
             flag_str.push(ORBITAL_FLAG_RESIZABLE);
         }
 
-        // TODO: fullscreen
-
         if attrs.transparent {
             flag_str.push(ORBITAL_FLAG_TRANSPARENT);
         }
@@ -323,10 +325,28 @@ impl CoreWindow for Window {
         self.get_flag(ORBITAL_FLAG_MAXIMIZED).unwrap_or(false)
     }
 
-    fn set_fullscreen(&self, _monitor: Option<Fullscreen>) {}
+    fn set_fullscreen(&self, fullscreen: Option<Fullscreen>) {
+        match fullscreen {
+            Some(Fullscreen::Exclusive(..)) => {
+                // TODO: exclusive fullscreen not supported on orbital
+            },
+            Some(Fullscreen::Borderless(_monitor)) => {
+                // TODO: monitor selection not supported on orbital
+                let _ = self.set_flag(ORBITAL_FLAG_FULLSCREEN, true);
+            },
+            None => {
+                let _ = self.set_flag(ORBITAL_FLAG_FULLSCREEN, false);
+            },
+        }
+    }
 
     fn fullscreen(&self) -> Option<Fullscreen> {
-        None
+        if self.get_flag(ORBITAL_FLAG_FULLSCREEN).unwrap_or(false) {
+            // TODO: monitor selection not supported on orbital
+            Some(Fullscreen::Borderless(None))
+        } else {
+            None
+        }
     }
 
     #[inline]
diff --git a/winit/src/changelog/unreleased.md b/winit/src/changelog/unreleased.md
index 6c7cbbac..89ca902b 100644
--- a/winit/src/changelog/unreleased.md
+++ b/winit/src/changelog/unreleased.md
@@ -250,6 +250,7 @@ changelog entry.
 ### Fixed
 
 - On Orbital, `MonitorHandle::name()` now returns `None` instead of a dummy name.
+- On Orbital, implement `fullscreen`.
 - On iOS, fixed `SurfaceResized` and `Window::surface_size` not reporting the size of the actual surface.
 - On macOS, fixed the scancode conversion for audio volume keys.
 - On macOS, fixed the scancode conversion for `IntlBackslash`.