macOS: Avoid redundant initial resize event

src/changelog/unreleased.md

@@ -154,3 +154,4 @@ changelog entry.
 ### Fixed
 
 - On Orbital, `MonitorHandle::name()` now returns `None` instead of a dummy name.
+- On macOS, fixed redundant `SurfaceResized` event at window creation.

src/platform_impl/apple/appkit/view.rs

@@ -4,17 +4,17 @@ use std::collections::{HashMap, VecDeque};
 use std::ptr;
 use std::rc::Rc;
 
-use objc2::rc::{Retained, WeakId};
+use objc2::rc::Retained;
 use objc2::runtime::{AnyObject, Sel};
-use objc2::{declare_class, msg_send_id, mutability, sel, ClassType, DeclaredClass};
+use objc2::{declare_class, msg_send_id, mutability, ClassType, DeclaredClass};
 use objc2_app_kit::{
     NSApplication, NSCursor, NSEvent, NSEventPhase, NSResponder, NSTextInputClient,
-    NSTrackingRectTag, NSView, NSViewFrameDidChangeNotification,
+    NSTrackingRectTag, NSView,
 };
 use objc2_foundation::{
     MainThreadMarker, NSArray, NSAttributedString, NSAttributedStringKey, NSCopying,
-    NSMutableAttributedString, NSNotFound, NSNotificationCenter, NSObject, NSObjectProtocol,
-    NSPoint, NSRange, NSRect, NSSize, NSString, NSUInteger,
+    NSMutableAttributedString, NSNotFound, NSObject, NSObjectProtocol, NSPoint, NSRange, NSRect,
+    NSSize, NSString, NSUInteger,
 };
 
 use super::app_state::AppState;
@@ -136,9 +136,6 @@ pub struct ViewState {
     marked_text: RefCell<Retained<NSMutableAttributedString>>,
     accepts_first_mouse: bool,
 
-    // Weak reference because the window keeps a strong reference to the view
-    _ns_window: WeakId<WinitWindow>,
-
     /// The state of the `Option` as `Alt`.
     option_as_alt: Cell<OptionAsAlt>,
 }
@@ -179,9 +176,10 @@ declare_class!(
             self.ivars().tracking_rect.set(Some(tracking_rect));
         }
 
-        #[method(frameDidChange:)]
-        fn frame_did_change(&self, _event: &NSEvent) {
-            trace_scope!("frameDidChange:");
+        // Not a normal method on `NSView`, it's triggered by `NSViewFrameDidChangeNotification`.
+        #[method(viewFrameDidChangeNotification:)]
+        fn frame_did_change(&self, _notification: Option<&AnyObject>) {
+            trace_scope!("NSViewFrameDidChangeNotification");
             if let Some(tracking_rect) = self.ivars().tracking_rect.take() {
                 self.removeTrackingRect(tracking_rect);
             }
@@ -205,10 +203,7 @@ declare_class!(
         fn draw_rect(&self, _rect: NSRect) {
             trace_scope!("drawRect:");
 
-            // It's a workaround for https://github.com/rust-windowing/winit/issues/2640, don't replace with `self.window_id()`.
-            if let Some(window) = self.ivars()._ns_window.load() {
-                self.ivars().app_state.handle_redraw(window.id());
-            }
+            self.ivars().app_state.handle_redraw(self.window().id());
 
             // This is a direct subclass of NSView, no need to call superclass' drawRect:
         }
@@ -784,11 +779,10 @@ declare_class!(
 impl WinitView {
     pub(super) fn new(
         app_state: &Rc<AppState>,
-        window: &WinitWindow,
         accepts_first_mouse: bool,
         option_as_alt: OptionAsAlt,
+        mtm: MainThreadMarker,
     ) -> Retained<Self> {
-        let mtm = MainThreadMarker::from(window);
         let this = mtm.alloc().set_ivars(ViewState {
             app_state: Rc::clone(app_state),
             cursor_state: Default::default(),
@@ -803,34 +797,24 @@ impl WinitView {
             forward_key_to_app: Default::default(),
             marked_text: Default::default(),
             accepts_first_mouse,
-            _ns_window: WeakId::new(&window.retain()),
             option_as_alt: Cell::new(option_as_alt),
         });
         let this: Retained<Self> = unsafe { msg_send_id![super(this), init] };
 
-        this.setPostsFrameChangedNotifications(true);
-        let notification_center = unsafe { NSNotificationCenter::defaultCenter() };
-        unsafe {
-            notification_center.addObserver_selector_name_object(
-                &this,
-                sel!(frameDidChange:),
-                Some(NSViewFrameDidChangeNotification),
-                Some(&this),
-            )
-        }
-
         *this.ivars().input_source.borrow_mut() = this.current_input_source();
 
         this
     }
 
     fn window(&self) -> Retained<WinitWindow> {
-        // TODO: Simply use `window` property on `NSView`.
-        // That only returns a window _after_ the view has been attached though!
-        // (which is incompatible with `frameDidChange:`)
-        //
-        // unsafe { msg_send_id![self, window] }
-        self.ivars()._ns_window.load().expect("view to have a window")
+        let window = (**self).window().expect("view must be installed in a window");
+
+        if !window.isKindOfClass(WinitWindow::class()) {
+            unreachable!("view installed in non-WinitWindow");
+        }
+
+        // SAFETY: Just checked that the window is `WinitWindow`
+        unsafe { Retained::cast(window) }
     }
 
     fn queue_event(&self, event: WindowEvent) {

src/platform_impl/apple/appkit/window_delegate.rs

@@ -15,15 +15,16 @@ use objc2_app_kit::{
     NSAppKitVersionNumber, NSAppKitVersionNumber10_12, NSAppearance, NSAppearanceCustomization,
     NSAppearanceNameAqua, NSApplication, NSApplicationPresentationOptions, NSBackingStoreType,
     NSColor, NSDraggingDestination, NSFilenamesPboardType, NSPasteboard,
-    NSRequestUserAttentionType, NSScreen, NSView, NSWindowButton, NSWindowDelegate,
-    NSWindowFullScreenButton, NSWindowLevel, NSWindowOcclusionState, NSWindowOrderingMode,
-    NSWindowSharingType, NSWindowStyleMask, NSWindowTabbingMode, NSWindowTitleVisibility,
+    NSRequestUserAttentionType, NSScreen, NSView, NSViewFrameDidChangeNotification, NSWindowButton,
+    NSWindowDelegate, NSWindowFullScreenButton, NSWindowLevel, NSWindowOcclusionState,
+    NSWindowOrderingMode, NSWindowSharingType, NSWindowStyleMask, NSWindowTabbingMode,
+    NSWindowTitleVisibility,
 };
 use objc2_foundation::{
     ns_string, CGFloat, MainThreadMarker, NSArray, NSCopying, NSDictionary, NSKeyValueChangeKey,
-    NSKeyValueChangeNewKey, NSKeyValueChangeOldKey, NSKeyValueObservingOptions, NSObject,
-    NSObjectNSDelayedPerforming, NSObjectNSKeyValueObserverRegistration, NSObjectProtocol, NSPoint,
-    NSRect, NSSize, NSString,
+    NSKeyValueChangeNewKey, NSKeyValueChangeOldKey, NSKeyValueObservingOptions,
+    NSNotificationCenter, NSObject, NSObjectNSDelayedPerforming,
+    NSObjectNSKeyValueObserverRegistration, NSObjectProtocol, NSPoint, NSRect, NSSize, NSString,
 };
 use tracing::{trace, warn};
 
@@ -164,7 +165,7 @@ declare_class!(
         #[method(windowDidResize:)]
         fn window_did_resize(&self, _: Option<&AnyObject>) {
             trace_scope!("windowDidResize:");
-            // NOTE: WindowEvent::SurfaceResized is reported in frameDidChange.
+            // NOTE: WindowEvent::SurfaceResized is reported using NSViewFrameDidChangeNotification.
             self.emit_move_event();
         }
 
@@ -632,9 +633,9 @@ fn new_window(
 
         let view = WinitView::new(
             app_state,
-            &window,
             attrs.platform_specific.accepts_first_mouse,
             attrs.platform_specific.option_as_alt,
+            mtm,
         );
 
         // The default value of `setWantsBestResolutionOpenGLSurface:` was `false` until
@@ -656,6 +657,23 @@ fn new_window(
         window.setContentView(Some(&view));
         window.setInitialFirstResponder(Some(&view));
 
+        // Configure the view to send notifications whenever its frame rectangle changes.
+        //
+        // We explicitly do this _after_ setting the view as the content view of the window, to
+        // avoid a resize event when creating the window.
+        view.setPostsFrameChangedNotifications(true);
+        // `setPostsFrameChangedNotifications` posts the notification immediately, so register the
+        // observer _after_, again so that the event isn't triggered initially.
+        let notification_center = unsafe { NSNotificationCenter::defaultCenter() };
+        unsafe {
+            notification_center.addObserver_selector_name_object(
+                &view,
+                sel!(viewFrameDidChangeNotification:),
+                Some(NSViewFrameDidChangeNotification),
+                Some(&view),
+            )
+        }
+
         if attrs.transparent {
             window.setOpaque(false);
             // See `set_transparent` for details on why we do this.