fix(mac): the glass covers what the picker draws and the bear windows are sized before they are placed

crates/linkunbound-mac/src/glass.rs

@@ -1,6 +1,4 @@
-use std::cell::Cell;
 use std::ptr::NonNull;
-use std::rc::Rc;
 
 use block2::RcBlock;
 use objc2::Message;
@@ -9,11 +7,11 @@ use objc2::runtime::AnyClass;
 use objc2_app_kit::{
     NSAppearance, NSAppearanceCustomization, NSAppearanceNameAqua, NSAppearanceNameDarkAqua,
     NSBackingStoreType, NSColor, NSGlassEffectView, NSUserInterfaceItemIdentification, NSView,
-    NSVisualEffectBlendingMode, NSVisualEffectMaterial, NSVisualEffectState, NSVisualEffectView,
-    NSWindow, NSWindowDidMoveNotification, NSWindowDidResizeNotification, NSWindowOrderingMode,
-    NSWindowStyleMask, NSWorkspace,
+    NSViewFrameDidChangeNotification, NSVisualEffectBlendingMode, NSVisualEffectMaterial,
+    NSVisualEffectState, NSVisualEffectView, NSWindow, NSWindowDidMoveNotification,
+    NSWindowDidResizeNotification, NSWindowOrderingMode, NSWindowStyleMask, NSWorkspace,
 };
-use objc2_foundation::{MainThreadMarker, NSNotification, NSNotificationCenter, NSPoint, NSString};
+use objc2_foundation::{MainThreadMarker, NSNotification, NSNotificationCenter, NSString};
 
 use crate::native::window_of;
 
@@ -119,47 +117,44 @@ fn glass_window(mtm: MainThreadMarker, picker: &NSWindow) -> Retained<NSWindow>
     window
 }
 
-/// AppKit grows and shrinks a window from its bottom edge: the picker keeps its top instead, as it
-/// does on Windows and as the bear leaning on it expects, and the glass takes its frame again.
+/// The glass covers what the picker draws, not its frame: AppKit at times gives the frame room
+/// above the content the picker never paints.
+fn cover(picker: &NSWindow, glass: &NSWindow) {
+    if let Some(content) = picker.contentView() {
+        glass.setFrame_display(picker.convertRectToScreen(content.frame()), true);
+    }
+}
+
 #[allow(unsafe_code)]
 fn keep_with(picker: &NSWindow, glass: &NSWindow) {
-    let top = Rc::new(Cell::new(None::<f64>));
-    let moved = {
-        let (picker, glass, top) = (picker.retain(), glass.retain(), Rc::clone(&top));
-        RcBlock::new(move |_: NonNull<NSNotification>| {
-            let frame = picker.frame();
-            top.set(Some(frame.origin.y + frame.size.height));
-            glass.setFrame_display(frame, true);
-        })
-    };
-    let resized = {
+    let follow = {
         let (picker, glass) = (picker.retain(), glass.retain());
-        RcBlock::new(move |_: NonNull<NSNotification>| {
-            let frame = picker.frame();
-            if let Some(top) = top.get()
-                && (frame.origin.y + frame.size.height - top).abs() > 0.5
-            {
-                picker.setFrameTopLeftPoint(NSPoint::new(frame.origin.x, top));
-            }
-            glass.setFrame_display(picker.frame(), true);
-        })
+        RcBlock::new(move |_: NonNull<NSNotification>| cover(&picker, &glass))
     };
     let centre = NSNotificationCenter::defaultCenter();
-    // SAFETY: AppKit's own names, posted on the main thread where the blocks run; the centre keeps
-    // both observers for as long as the picker, which lives as long as the app.
+    let content = picker.contentView();
+    if let Some(content) = &content {
+        content.setPostsFrameChangedNotifications(true);
+    }
+    // SAFETY: AppKit's own names, posted on the main thread where the block runs; the centre keeps
+    // the observers for as long as the picker, which lives as long as the app.
     unsafe {
-        centre.addObserverForName_object_queue_usingBlock(
-            Some(NSWindowDidMoveNotification),
-            Some(picker),
-            None,
-            &moved,
-        );
-        centre.addObserverForName_object_queue_usingBlock(
-            Some(NSWindowDidResizeNotification),
-            Some(picker),
-            None,
-            &resized,
-        );
+        for name in [NSWindowDidMoveNotification, NSWindowDidResizeNotification] {
+            centre.addObserverForName_object_queue_usingBlock(
+                Some(name),
+                Some(picker),
+                None,
+                &follow,
+            );
+        }
+        if let Some(content) = &content {
+            centre.addObserverForName_object_queue_usingBlock(
+                Some(NSViewFrameDidChangeNotification),
+                Some(content),
+                None,
+                &follow,
+            );
+        }
     }
 }
 
@@ -185,7 +180,7 @@ pub fn wear_glass(view: isize, dark: bool, corner: f64) -> bool {
     };
     let glass = glass_behind(&picker).unwrap_or_else(|| glass_window(mtm, &picker));
     glass.setLevel(picker.level());
-    glass.setFrame_display(picker.frame(), true);
+    cover(&picker, &glass);
     let Some(material) = glass.contentView() else {
         return false;
     };

crates/linkunbound-mac/tests/main_thread.rs

@@ -132,16 +132,15 @@ fn main() {
     assert_eq!(corner(&material), 10.0);
     assert_eq!(tone(&material).as_deref(), Some("NSAppearanceNameAqua"));
 
-    window.setFrameTopLeftPoint(NSPoint::new(50.0, 500.0));
-    let grown = NSRect::new(NSPoint::new(50.0, 490.0), NSSize::new(10.0, 50.0));
+    let grown = NSRect::new(NSPoint::new(50.0, 450.0), NSSize::new(10.0, 50.0));
     window.setFrame_display(grown, false);
-    let frame = window.frame();
+    let drawn = window.convertRectToScreen(view.frame());
+    assert_eq!(drawn.size.height, 50.0);
     assert_eq!(
-        frame.origin.y + frame.size.height,
-        500.0,
-        "the picker grows downwards, keeping its top"
+        glass.frame(),
+        drawn,
+        "the glass follows what the picker draws"
     );
-    assert_eq!(glass.frame(), frame, "and the glass grows with it");
 
     take_off_glass(handle);
     assert_eq!(

crates/linkunbound-shell/src/mascot.rs

@@ -82,8 +82,16 @@
             picker.get_halo(),
             scale,
         );
-        put(self.head.window(), head.0, head.1);
-        put(self.paws.window(), paws.0, paws.1);
+        put(
+            self.head.window(),
+            head,
+            (self.head.get_wide(), self.head.get_tall()),
+        );
+        put(
+            self.paws.window(),
+            paws,
+            (self.paws.get_wide(), self.paws.get_tall()),
+        );
         self.mood(0.0, picker.get_private_on());
         let _ = self.head.show();
         let _ = self.paws.show();
@@ -141,11 +149,19 @@
     }
 }
 
-fn put(window: &slint::Window, x: i32, y: i32) {
+/// On macOS the size goes first: AppKit keeps a window's bottom edge when Slint resizes it later,
+/// which would sink the head of a smaller pose into the picker.
+fn put(window: &slint::Window, (x, y): (i32, i32), (wide, tall): (f32, f32)) {
     #[cfg(target_os = "macos")]
-    window.set_position(slint::LogicalPosition::new(x as f32, y as f32));
+    {
+        window.set_size(slint::LogicalSize::new(wide, tall));
+        window.set_position(slint::LogicalPosition::new(x as f32, y as f32));
+    }
     #[cfg(not(target_os = "macos"))]
-    window.set_position(slint::PhysicalPosition::new(x, y));
+    {
+        let _ = (wide, tall);
+        window.set_position(slint::PhysicalPosition::new(x, y));
+    }
 }
 
 /// The picker says where the bear should look and whether it wears the mask, and an empty slot

crates/linkunbound-shell/ui/bear.slint

@@ -111,12 +111,14 @@ export component BearHead inherits Window {
     in property <bool> masked;
     in property <float> look;
     in property <length> side: 92px;
+    out property <length> wide: root.side;
+    out property <length> tall: root.side * 256 / 312;
     title: "LinkUnbound";
     no-frame: true;
     always-on-top: true;
     background: transparent;
-    width: root.side;
-    height: root.side * 256 / 312;
+    width: root.wide;
+    height: root.tall;
 
     Head {
         masked: root.masked;
@@ -132,8 +134,10 @@ export component BearPaws inherits Window {
     no-frame: true;
     always-on-top: true;
     background: transparent;
-    width: root.gap + 2 * root.paw;
-    height: root.paw * 31 / 40;
+    out property <length> wide: root.gap + 2 * root.paw;
+    out property <length> tall: root.paw * 31 / 40;
+    width: root.wide;
+    height: root.tall;
 
     Paw {
         x: 0;