feat: Add traffic light inset

.changes/traffic-light-inset.md

@@ -0,0 +1,5 @@
+---
+wry: patch
+---
+
+Add functionality to set the traffic light inset on macOS. This is required to prevent flickers if the WebView is injected via `build()` instead of `build_as_child()`.

Cargo.toml

@@ -156,6 +156,8 @@ objc2-ui-kit = { version = "0.2.2", features = [
 [target."cfg(target_os = \"macos\")".dependencies]
 objc2-app-kit = { version = "0.2.0", features = [
   "NSApplication",
+  "NSButton",
+  "NSControl",
   "NSEvent",
   "NSWindow",
   "NSView",

src/lib.rs

@@ -1238,6 +1238,7 @@ impl<'a> WebViewBuilder<'a> {
 #[derive(Clone, Default)]
 pub(crate) struct PlatformSpecificWebViewAttributes {
   data_store_identifier: Option<[u8; 16]>,
+  traffic_light_inset: Option<dpi::Position>,
 }
 
 #[cfg(any(target_os = "macos", target_os = "ios",))]
@@ -1247,6 +1248,12 @@ pub trait WebViewBuilderExtDarwin {
   ///
   /// - **macOS / iOS**: Available on macOS >= 14 and iOS >= 17
   fn with_data_store_identifier(self, identifier: [u8; 16]) -> Self;
+  /// Move the window controls to the specified position.
+  /// Normally this is handled by the Window but because `WebViewBuilder::build()` overwrites the window's NSView the controls will flicker on resizing.
+  /// Note: This method has no effects if the WebView is injected via `WebViewBuilder::build_as_child();` and there should be no flickers.
+  /// Warning: Do not use this if your chosen window library does not support traffic light insets.
+  /// Warning: Only use this in **decorated** windows with a **hidden titlebar**!
+  fn with_traffic_light_inset<P: Into<dpi::Position>>(self, position: P) -> Self;
 }
 
 #[cfg(any(target_os = "macos", target_os = "ios",))]
@@ -1257,6 +1264,13 @@ impl WebViewBuilderExtDarwin for WebViewBuilder<'_> {
       Ok(b)
     })
   }
+
+  fn with_traffic_light_inset<P: Into<dpi::Position>>(self, position: P) -> Self {
+    self.and_then(|mut b| {
+      b.platform_specific.traffic_light_inset = Some(position.into());
+      Ok(b)
+    })
+  }
 }
 
 #[cfg(windows)]
@@ -1915,6 +1929,12 @@ pub trait WebViewExtMacOS {
   fn reparent(&self, window: *mut NSWindow) -> Result<()>;
   // Prints with extra options
   fn print_with_options(&self, options: &PrintOptions) -> Result<()>;
+  /// Move the window controls to the specified position.
+  /// Normally this is handled by the Window but because `WebViewBuilder::build()` overwrites the window's NSView the controls will flicker on resizing.
+  /// Note: This method has no effects if the WebView is injected via `WebViewBuilder::build_as_child();` and there should be no flickers.
+  /// Warning: Do not use this if your chosen window library does not support traffic light insets.
+  /// Warning: Only use this in **decorated** windows with a **hidden titlebar**!
+  fn set_traffic_light_inset<P: Into<dpi::Position>>(&self, position: P) -> Result<()>;
 }
 
 #[cfg(target_os = "macos")]
@@ -1938,6 +1958,10 @@ impl WebViewExtMacOS for WebView {
   fn print_with_options(&self, options: &PrintOptions) -> Result<()> {
     self.webview.print_with_options(options)
   }
+
+  fn set_traffic_light_inset<P: Into<dpi::Position>>(&self, position: P) -> Result<()> {
+    self.webview.set_traffic_light_inset(position.into())
+  }
 }
 
 /// Additional methods on `WebView` that are specific to iOS.

src/wkwebview/class/wry_web_view_parent.rs

@@ -2,16 +2,23 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
+use std::cell::Cell;
+
 use objc2::{
   declare_class, msg_send_id, mutability::MainThreadOnly, rc::Retained, ClassType, DeclaredClass,
 };
 #[cfg(target_os = "macos")]
-use objc2_app_kit::{NSApplication, NSEvent, NSView};
+use objc2_app_kit::{NSApplication, NSEvent, NSView, NSWindow, NSWindowButton};
 use objc2_foundation::MainThreadMarker;
+#[cfg(target_os = "macos")]
+use objc2_foundation::NSRect;
 #[cfg(target_os = "ios")]
 use objc2_ui_kit::UIView as NSView;
 
-pub struct WryWebViewParentIvars {}
+pub struct WryWebViewParentIvars {
+  #[cfg(target_os = "macos")]
+  traffic_light_inset: Cell<Option<(f64, f64)>>,
+}
 
 declare_class!(
   pub struct WryWebViewParent;
@@ -41,6 +48,14 @@ declare_class!(
         }
       }
     }
+
+    #[cfg(target_os = "macos")]
+    #[method(drawRect:)]
+    fn draw(&self, _dirty_rect: NSRect) {
+      if let Some((x, y)) = self.ivars().traffic_light_inset.get() {
+        unsafe {inset_traffic_lights(&self.window().unwrap(), x, y)};
+      }
+    }
   }
 );
 
@@ -49,7 +64,55 @@ impl WryWebViewParent {
   pub fn new(mtm: MainThreadMarker) -> Retained<Self> {
     let delegate = mtm
       .alloc::<WryWebViewParent>()
-      .set_ivars(WryWebViewParentIvars {});
+      .set_ivars(WryWebViewParentIvars {
+        #[cfg(target_os = "macos")]
+        traffic_light_inset: Default::default(),
+      });
     unsafe { msg_send_id![super(delegate), init] }
   }
+
+  #[cfg(target_os = "macos")]
+  pub fn set_traffic_light_inset(&self, ns_window: &NSWindow, position: dpi::Position) {
+    let scale_factor = NSWindow::backingScaleFactor(ns_window);
+    let position = position.to_logical(scale_factor);
+    self
+      .ivars()
+      .traffic_light_inset
+      .replace(Some((position.x, position.y)));
+
+    unsafe {
+      inset_traffic_lights(ns_window, position.x, position.y);
+    }
+  }
+}
+
+#[cfg(target_os = "macos")]
+pub unsafe fn inset_traffic_lights(window: &NSWindow, x: f64, y: f64) {
+  let close = window
+    .standardWindowButton(NSWindowButton::NSWindowCloseButton)
+    .unwrap();
+  let miniaturize = window
+    .standardWindowButton(NSWindowButton::NSWindowMiniaturizeButton)
+    .unwrap();
+  let zoom = window
+    .standardWindowButton(NSWindowButton::NSWindowZoomButton)
+    .unwrap();
+
+  let title_bar_container_view = close.superview().unwrap().superview().unwrap();
+
+  let close_rect = NSView::frame(&close);
+  let title_bar_frame_height = close_rect.size.height + y;
+  let mut title_bar_rect = NSView::frame(&title_bar_container_view);
+  title_bar_rect.size.height = title_bar_frame_height;
+  title_bar_rect.origin.y = window.frame().size.height - title_bar_frame_height;
+  title_bar_container_view.setFrame(title_bar_rect);
+
+  let space_between = NSView::frame(&miniaturize).origin.x - close_rect.origin.x;
+  let window_buttons = vec![close, miniaturize, zoom];
+
+  for (i, button) in window_buttons.into_iter().enumerate() {
+    let mut rect = NSView::frame(&button);
+    rect.origin.x = x + (i as f64 * space_between);
+    button.setFrameOrigin(rect.origin);
+  }
 }

src/wkwebview/mod.rs

@@ -135,6 +135,9 @@ pub(crate) struct InnerWebView {
   // We need this the keep the reference count
   ui_delegate: Retained<WryWebViewUIDelegate>,
   protocol_ptrs: Vec<*mut Box<dyn Fn(crate::WebViewId, Request<Vec<u8>>, RequestAsyncResponder)>>,
+  #[cfg(target_os = "macos")]
+  // We need this to update the traffic light inset
+  parent_view: Option<Retained<WryWebViewParent>>,
 }
 
 impl InnerWebView {
@@ -459,7 +462,7 @@ impl InnerWebView {
         }
       }
 
-      let w = Self {
+      let mut w = Self {
         id: webview_id,
         webview: webview.clone(),
         manager: manager.clone(),
@@ -473,6 +476,8 @@ impl InnerWebView {
         ui_delegate,
         protocol_ptrs,
         is_child,
+        #[cfg(target_os = "macos")]
+        parent_view: None,
       };
 
       // Initialize scripts
@@ -504,19 +509,27 @@ r#"Object.defineProperty(window, 'ipc', {
         if is_child {
           ns_view.addSubview(&webview);
         } else {
+          // inject the webview into the window
+          let ns_window = ns_view.window().unwrap();
+
           let parent_view = WryWebViewParent::new(mtm);
+
+          if let Some(position) = pl_attrs.traffic_light_inset {
+            parent_view.set_traffic_light_inset(&ns_window, position);
+          }
+
           parent_view.setAutoresizingMask(
             NSAutoresizingMaskOptions::NSViewHeightSizable
               | NSAutoresizingMaskOptions::NSViewWidthSizable,
           );
           parent_view.addSubview(&webview.clone());
 
-          // inject the webview into the window
-          let ns_window = ns_view.window().unwrap();
           // Tell the webview receive keyboard events in the window.
           // See https://github.com/tauri-apps/wry/issues/739
           ns_window.setContentView(Some(&parent_view));
           ns_window.makeFirstResponder(Some(&webview));
+
+          w.parent_view = Some(parent_view);
         }
 
         // make sure the window is always on top when we create a new webview
@@ -884,7 +897,7 @@ r#"Object.defineProperty(window, 'ipc', {
             (secure && url.scheme() == "https") ||
             // or cookie is secure and is localhost
             (
-              secure && url.scheme() == "http" && 
+              secure && url.scheme() == "http" &&
               (url.domain() == Some("localhost") || url.domain().and_then(|d| Ipv4Addr::from_str(d).ok()).map(|ip| ip.is_loopback()).unwrap_or(false))
             ) ||
             // or cookie is not secure
@@ -926,6 +939,15 @@ r#"Object.defineProperty(window, 'ipc', {
 
     Ok(())
   }
+
+  #[cfg(target_os = "macos")]
+  pub(crate) fn set_traffic_light_inset(&self, position: dpi::Position) -> crate::Result<()> {
+    if let Some(parent_view) = &self.parent_view {
+      parent_view.set_traffic_light_inset(&self.webview.window().unwrap(), position);
+    }
+
+    Ok(())
+  }
 }
 
 pub fn url_from_webview(webview: &WKWebView) -> Result<String> {