Use an "always active" tracking area to detect `mouseMoved` events

Antonio Scandurra created 3 years ago

This ensures that we can still receive mouse moved events (e.g. for
setting the cursor style) for panels that float above other windows
even if the application isn't active.

Change summary

crates/gpui/src/platform/mac/window.rs | 30 +++++++++++++++++++--------
1 file changed, 21 insertions(+), 9 deletions(-)

Detailed changes

crates/gpui/src/platform/mac/window.rs

@@ -57,11 +57,21 @@ static mut WINDOW_CLASS: *const Class = ptr::null();
 static mut PANEL_CLASS: *const Class = ptr::null();
 static mut VIEW_CLASS: *const Class = ptr::null();
 
+#[allow(non_upper_case_globals)]
+const NSWindowStyleMaskNonactivatingPanel: NSWindowStyleMask =
+    unsafe { NSWindowStyleMask::from_bits_unchecked(1 << 7) };
 #[allow(non_upper_case_globals)]
 const NSNormalWindowLevel: NSInteger = 0;
-
 #[allow(non_upper_case_globals)]
 const NSPopUpWindowLevel: NSInteger = 101;
+#[allow(non_upper_case_globals)]
+const NSTrackingMouseMoved: NSUInteger = 0x02;
+#[allow(non_upper_case_globals)]
+const NSTrackingActiveAlways: NSUInteger = 0x80;
+#[allow(non_upper_case_globals)]
+const NSTrackingInVisibleRect: NSUInteger = 0x200;
+#[allow(non_upper_case_globals)]
+const NSWindowAnimationBehaviorUtilityWindow: NSInteger = 4;
 
 #[repr(C)]
 #[derive(Copy, Clone, Debug)]
@@ -362,10 +372,6 @@ impl Window {
             let native_window: id = match options.kind {
                 WindowKind::Normal => msg_send![WINDOW_CLASS, alloc],
                 WindowKind::PopUp => {
-                    #[allow(non_upper_case_globals)]
-                    const NSWindowStyleMaskNonactivatingPanel: NSWindowStyleMask =
-                        unsafe { NSWindowStyleMask::from_bits_unchecked(1 << 7) };
-
                     style_mask |= NSWindowStyleMaskNonactivatingPanel;
                     msg_send![PANEL_CLASS, alloc]
                 }
@@ -452,7 +458,16 @@ impl Window {
                 native_window.setTitlebarAppearsTransparent_(YES);
             }
 
-            native_window.setAcceptsMouseMovedEvents_(YES);
+            let tracking_area: id = msg_send![class!(NSTrackingArea), alloc];
+            let rect = NSRect::new(NSPoint::new(0., 0.), NSSize::new(0., 0.));
+            let _: () = msg_send![
+                tracking_area,
+                initWithRect: rect
+                options: NSTrackingMouseMoved | NSTrackingActiveAlways | NSTrackingInVisibleRect
+                owner: native_view
+                userInfo: nil
+            ];
+            let _: () = msg_send![native_view, addTrackingArea: tracking_area];
 
             native_view.setAutoresizingMask_(NSViewWidthSizable | NSViewHeightSizable);
             native_view.setWantsBestResolutionOpenGLSurface_(YES);
@@ -478,9 +493,6 @@ impl Window {
             match options.kind {
                 WindowKind::Normal => native_window.setLevel_(NSNormalWindowLevel),
                 WindowKind::PopUp => {
-                    #[allow(non_upper_case_globals)]
-                    const NSWindowAnimationBehaviorUtilityWindow: NSInteger = 4;
-
                     native_window.setLevel_(NSPopUpWindowLevel);
                     let _: () = msg_send![
                         native_window,