feat: add Window::is_decorated (#2172)

* feat: add `Window::is_decorated`

* move it right after `set_decorations`

src/platform_impl/android/mod.rs

@@ -561,6 +561,10 @@ impl Window {
 
     pub fn set_decorations(&self, _decorations: bool) {}
 
+    pub fn is_decorated(&self) -> bool {
+        true
+    }
+
     pub fn set_always_on_top(&self, _always_on_top: bool) {}
 
     pub fn set_window_icon(&self, _window_icon: Option<crate::icon::Icon>) {}

src/platform_impl/ios/window.rs

@@ -260,6 +260,11 @@ impl Inner {
         warn!("`Window::set_decorations` is ignored on iOS")
     }
 
+    pub fn is_decorated(&self) -> bool {
+        warn!("`Window::is_decorated` is ignored on iOS");
+        true
+    }
+
     pub fn set_always_on_top(&self, _always_on_top: bool) {
         warn!("`Window::set_always_on_top` is ignored on iOS")
     }

src/platform_impl/linux/mod.rs

@@ -426,6 +426,11 @@ impl Window {
         x11_or_wayland!(match self; Window(w) => w.set_decorations(decorations))
     }
 
+    #[inline]
+    pub fn is_decorated(&self) -> bool {
+        x11_or_wayland!(match self; Window(w) => w.is_decorated())
+    }
+
     #[inline]
     pub fn set_always_on_top(&self, _always_on_top: bool) {
         match self {

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

@@ -348,6 +348,11 @@ impl Window {
         self.send_request(WindowRequest::Decorate(decorate));
     }
 
+    #[inline]
+    pub fn is_decorated(&self) -> bool {
+        true
+    }
+
     #[inline]
     pub fn set_minimized(&self, minimized: bool) {
         // You can't unminimize the window on Wayland.

src/platform_impl/linux/x11/window.rs

@@ -895,6 +895,11 @@ impl UnownedWindow {
         self.invalidate_cached_frame_extents();
     }
 
+    #[inline]
+    pub fn is_decorated(&self) -> bool {
+        true
+    }
+
     fn set_maximizable_inner(&self, maximizable: bool) -> util::Flusher<'_> {
         let mut hints = self.xconn.get_motif_hints(self.xwindow);
 

src/platform_impl/macos/window.rs

@@ -1003,6 +1003,11 @@ impl UnownedWindow {
         }
     }
 
+    #[inline]
+    pub fn is_decorated(&self) -> bool {
+        self.decorations.load(Ordering::Acquire)
+    }
+
     #[inline]
     pub fn set_always_on_top(&self, always_on_top: bool) {
         let level = if always_on_top {

src/platform_impl/web/window.rs

@@ -269,6 +269,10 @@ impl Window {
         // Intentionally a no-op, no canvas decorations
     }
 
+    pub fn is_decorated(&self) -> bool {
+        true
+    }
+
     #[inline]
     pub fn set_always_on_top(&self, _always_on_top: bool) {
         // Intentionally a no-op, no window ordering

src/platform_impl/windows/window.rs

@@ -544,6 +544,12 @@ impl Window {
         });
     }
 
+    #[inline]
+    pub fn is_decorated(&self) -> bool {
+        let window_state = self.window_state.lock();
+        window_state.window_flags.contains(WindowFlags::DECORATIONS)
+    }
+
     #[inline]
     pub fn set_always_on_top(&self, always_on_top: bool) {
         let window = self.window.clone();