2 files changed, 21 insertions, 1 deletions
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.h b/src/plugins/platforms/cocoa/qcocoatheme.h
index a7c37a685c..90dc45264e 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.h
+++ b/src/plugins/platforms/cocoa/qcocoatheme.h
@@ -54,6 +54,9 @@ private:
     QMacNotificationObserver m_systemColorObserver;
     mutable QHash<QPlatformTheme::Palette, QPalette*> m_palettes;
     QMacKeyValueObserver m_appearanceObserver;
+
+    Qt::ColorScheme m_colorScheme = Qt::ColorScheme::Unknown;
+    void updateColorScheme();
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.mm b/src/plugins/platforms/cocoa/qcocoatheme.mm
index ac5bdf0ceb..56171b6dc2 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.mm
+++ b/src/plugins/platforms/cocoa/qcocoatheme.mm
@@ -224,6 +224,8 @@ QCocoaTheme::QCocoaTheme()
         NSSystemColorsDidChangeNotification, [this] {
             handleSystemThemeChange();
     });
+
+    updateColorScheme();
 }
 
 QCocoaTheme::~QCocoaTheme()
@@ -242,6 +244,9 @@ void QCocoaTheme::reset()
 void QCocoaTheme::handleSystemThemeChange()
 {
     reset();
+
+    updateColorScheme();
+
     m_systemPalette = qt_mac_createSystemPalette();
     m_palettes = qt_mac_createRolePalettes();
 
@@ -475,7 +480,19 @@ QVariant QCocoaTheme::themeHint(ThemeHint hint) const
 
 Qt::ColorScheme QCocoaTheme::colorScheme() const
 {
-    return qt_mac_applicationIsInDarkMode() ? Qt::ColorScheme::Dark : Qt::ColorScheme::Light;
+    return m_colorScheme;
+}
+
+/*
+    Update the theme's color scheme based on the current appearance.
+
+    We can only reference the appearance on the main thread, but the
+    CoreText font engine needs to know the color scheme, and might be
+    used from secondary threads, so we cache the color scheme.
+*/
+void QCocoaTheme::updateColorScheme()
+{
+    m_colorScheme = qt_mac_applicationIsInDarkMode() ? Qt::ColorScheme::Dark : Qt::ColorScheme::Light;
 }
 
 QString QCocoaTheme::standardButtonText(int button) const