On macOS, emit resize event on frame_did_change

When the window switches mode from normal to tabbed one, it doesn't
get resized, however the frame gets resized. This commit makes
winit to track resizes when frame changes instead of window.

Fixes #2191.

CHANGELOG.md

@@ -50,6 +50,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - **Breaking:** Added new `WindowEvent::Ime` supported on desktop platforms.
 - Added `Window::set_ime_allowed` supported on desktop platforms.
 - **Breaking:** IME input on desktop platforms won't be received unless it's explicitly allowed via `Window::set_ime_allowed` and new `WindowEvent::Ime` events are handled.
+- On macOS, `WindowEvent::Resized` is now emitted in `frameDidChange` instead of `windowDidResize`.
 
 # 0.26.1 (2022-01-05)
 

src/platform_impl/macos/view.rs

@@ -20,7 +20,7 @@ use objc::{
 };
 
 use crate::{
-    dpi::LogicalPosition,
+    dpi::{LogicalPosition, LogicalSize},
     event::{
         DeviceEvent, ElementState, Event, Ime, KeyboardInput, ModifiersState, MouseButton,
         MouseScrollDelta, TouchPhase, VirtualKeyCode, WindowEvent,
@@ -400,8 +400,17 @@ extern "C" fn frame_did_change(this: &Object, _sel: Sel, _event: id) {
             userData:ptr::null_mut::<c_void>()
             assumeInside:NO
         ];
-
         state.tracking_rect = Some(tracking_rect);
+
+        // Emit resize event here rather than from windowDidResize because:
+        // 1. When a new window is created as a tab, the frame size may change without a window resize occurring.
+        // 2. Even when a window resize does occur on a new tabbed window, it contains the wrong size (includes tab height).
+        let logical_size = LogicalSize::new(rect.size.width as f64, rect.size.height as f64);
+        let size = logical_size.to_physical::<u32>(state.get_scale_factor());
+        AppState::queue_event(EventWrapper::StaticEvent(Event::WindowEvent {
+            window_id: WindowId(get_window_id(state.ns_window)),
+            event: WindowEvent::Resized(size),
+        }));
     }
 }
 

src/platform_impl/macos/window_delegate.rs

@@ -98,14 +98,6 @@ impl WindowDelegateState {
         AppState::queue_event(wrapper);
     }
 
-    pub fn emit_resize_event(&mut self) {
-        let rect = unsafe { NSView::frame(*self.ns_view) };
-        let scale_factor = self.get_scale_factor();
-        let logical_size = LogicalSize::new(rect.size.width as f64, rect.size.height as f64);
-        let size = logical_size.to_physical(scale_factor);
-        self.emit_event(WindowEvent::Resized(size));
-    }
-
     fn emit_move_event(&mut self) {
         let rect = unsafe { NSWindow::frame(*self.ns_window) };
         let x = rect.origin.x as f64;
@@ -286,7 +278,7 @@ extern "C" fn window_will_close(this: &Object, _: Sel, _: id) {
 extern "C" fn window_did_resize(this: &Object, _: Sel, _: id) {
     trace_scope!("windowDidResize:");
     with_state(this, |state| {
-        state.emit_resize_event();
+        // NOTE: WindowEvent::Resized is reported in frameDidChange.
         state.emit_move_event();
     });
 }