Add dark mode checker depending on Qt version

Author: ann0see

src/clientdlg.cpp

@@ -1479,7 +1479,18 @@ void CClientDlg::SetMixerBoardDeco ( const ERecorderState newRecorderState, cons
         }
         else
         {
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 5, 0 )
+            // for Qt 6.5.0 or later, we use the inbuilt cross platform color scheme picker.
+            if ( QGuiApplication::styleHints()->colorScheme() == Qt::ColorScheme::Dark )
+#else
+    #if defined( Q_OS_WINDOWS )
+            // for windows only, check lightnes as proposed in https://www.qt.io/blog/dark-mode-on-windows-11-with-qt-6.5
+            const QPalette defaultPalette;
+            if ( defaultPalette.color(QPalette::WindowText).lightness() > defaultPalette.color(QPalette::Window).lightness() )
+    #endif
             if ( palette().color ( QPalette::Window ) == QColor::fromRgbF ( 0.196078, 0.196078, 0.196078, 1 ) )
+#endif
+
             {
                 // Dark mode on macOS/Linux needs a light color
 

src/clientdlg.h

@@ -42,6 +42,12 @@
 #if QT_VERSION >= QT_VERSION_CHECK( 5, 6, 0 )
 #    include <QVersionNumber>
 #endif
+#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0) 
+// for checking dark or light mode, we need to import more libraries
+#    include <QGuiApplication>
+#    include <QPalette>
+#    include <QStyleHints>
+#endif
 #include "global.h"
 #include "util.h"
 #include "client.h"