feat: Window::is_focused (#533)

.changes/is-focused.md

@@ -0,0 +1,5 @@
+---
+"tao": "patch"
+---
+
+Add `Window::is_focused`.

examples/window_debug.rs

@@ -127,6 +127,12 @@ fn main() {
         window_id,
         ..
       } if window_id == window.id() => *control_flow = ControlFlow::Exit,
+      Event::WindowEvent {
+        event: WindowEvent::Focused(focused),
+        ..
+      } => {
+        dbg!(focused, window.is_focused());
+      }
       _ => (),
     }
   });

src/platform_impl/android/mod.rs

@@ -598,6 +598,11 @@ impl Window {
     warn!("set_focus not yet implemented on Android");
   }
 
+  pub fn is_focused(&self) -> bool {
+    log::warn!("`Window::is_focused` is ignored on Android");
+    false
+  }
+
   pub fn set_resizable(&self, _resizeable: bool) {}
 
   pub fn set_minimized(&self, _minimized: bool) {}

src/platform_impl/ios/window.rs

@@ -72,6 +72,11 @@ impl Inner {
     warn!("set_focus not yet implemented on iOS");
   }
 
+  pub fn is_focused(&self) -> bool {
+    warn!("`Window::is_focused` is ignored on iOS");
+    false
+  }
+
   pub fn request_redraw(&self) {
     unsafe {
       if self.gl_or_metal_backed {

src/platform_impl/linux/window.rs

@@ -467,6 +467,10 @@ impl Window {
     }
   }
 
+  pub fn is_focused(&self) -> bool {
+    self.window.is_active()
+  }
+
   pub fn set_resizable(&self, resizable: bool) {
     if let Err(e) = self
       .window_requests_tx

src/platform_impl/macos/window.rs

@@ -575,6 +575,14 @@ impl UnownedWindow {
     }
   }
 
+  #[inline]
+  pub fn is_focused(&self) -> bool {
+    unsafe {
+      let is_key_window: BOOL = msg_send![*self.ns_window, isKeyWindow];
+      is_key_window == YES
+    }
+  }
+
   pub fn request_redraw(&self) {
     AppState::queue_redraw(RootWindowId(self.id()));
   }

src/platform_impl/windows/window.rs

@@ -173,6 +173,12 @@ impl Window {
     }
   }
 
+  #[inline]
+  pub fn is_focused(&self) -> bool {
+    let window_state = self.window_state.lock();
+    window_state.has_active_focus()
+  }
+
   #[inline]
   pub fn request_redraw(&self) {
     unsafe {

src/window.rs

@@ -638,6 +638,16 @@ impl Window {
     self.window.set_focus()
   }
 
+  /// Is window active and focused?
+  ///
+  /// ## Platform-specific
+  ///
+  /// - **iOS / Android:** Unsupported.
+  #[inline]
+  pub fn is_focused(&self) -> bool {
+    self.window.is_focused()
+  }
+
   /// Sets whether the window is resizable or not.
   ///
   /// Note that making the window unresizable doesn't exempt you from handling `Resized`, as that event can still be
@@ -697,7 +707,7 @@ impl Window {
     self.window.is_minimized()
   }
 
-  /// Gets the window's current vibility state.
+  /// Gets the window's current visibility state.
   ///
   /// ## Platform-specific
   ///