Windows QPA: Add detection of dark mode

Read the dark mode setting and make it accessible
via native interface.
Add a command line option to set the support level.

Task-number: QTBUG-72028
Change-Id: I1e9fe296a6b1bda81512d003183038b866b67545
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 19 insertions, 1 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index c85d04b816..d322b0e92b 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -42,6 +42,7 @@
 #include "qwindowsintegration.h"
 #include "qwindowswindow.h"
 #include "qwindowskeymapper.h"
+#include "qwindowsnativeinterface.h"
 #include "qwindowsmousehandler.h"
 #include "qwindowspointerhandler.h"
 #include "qtwindowsglobal.h"
@@ -277,8 +278,11 @@ struct QWindowsContextPrivate {
     bool m_asyncExpose = false;
     HPOWERNOTIFY m_powerNotification = nullptr;
     HWND m_powerDummyWindow = nullptr;
+    static bool m_darkMode;
 };
 
+bool QWindowsContextPrivate::m_darkMode = false;
+
 QWindowsContextPrivate::QWindowsContextPrivate()
     : m_oleInitializeResult(OleInitialize(nullptr))
 {
@@ -293,6 +297,7 @@ QWindowsContextPrivate::QWindowsContextPrivate()
         m_systemInfo |= QWindowsContext::SI_RTL_Extensions;
         m_keyMapper.setUseRTLExtensions(true);
     }
+    m_darkMode = QWindowsTheme::queryDarkMode();
     if (FAILED(m_oleInitializeResult)) {
        qWarning() << "QWindowsContext: OleInitialize() failed: "
            << QWindowsContext::comErrorString(m_oleInitializeResult);
@@ -485,6 +490,11 @@ void QWindowsContext::setProcessDpiAwareness(QtWindows::ProcessDpiAwareness dpiA
     }
 }
 
+bool QWindowsContext::isDarkMode()
+{
+    return QWindowsContextPrivate::m_darkMode;
+}
+
 QWindowsContext *QWindowsContext::instance()
 {
     return m_instance;
@@ -1203,9 +1213,17 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
             t->displayChanged();
         QWindowsWindow::displayChanged();
         return d->m_screenManager.handleDisplayChange(wParam, lParam);
-    case QtWindows::SettingChangedEvent:
+    case QtWindows::SettingChangedEvent: {
         QWindowsWindow::settingsChanged();
+        const bool darkMode = QWindowsTheme::queryDarkMode();
+        if (darkMode != QWindowsContextPrivate::m_darkMode) {
+            QWindowsContextPrivate::m_darkMode = darkMode;
+            auto nativeInterface =
+                static_cast<QWindowsNativeInterface *>(QWindowsIntegration::instance()->nativeInterface());
+            emit nativeInterface->darkModeChanged(darkMode);
+        }
         return d->m_screenManager.handleScreenChanges();
+    }
     default:
         break;
     }