Support dark mode on Windows (feature 7985)

components/platform/application.cpp

@@ -0,0 +1,98 @@
+#include "application.hpp"
+
+#include <QFile>
+#include <QStyle>
+#include <QStyleHints>
+
+#include <components/debug/debuglog.hpp>
+#include <components/misc/scalableicon.hpp>
+
+namespace Platform
+{
+    Application::Application(int& argc, char* argv[])
+        : QApplication(argc, argv)
+    {
+#if defined(WIN32) && QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+        init();
+    }
+
+    void Application::init()
+    {
+        connect(this, &Application::darkModeChanged, this, &Application::updateStyle);
+
+        const auto* hints = QGuiApplication::styleHints();
+        const auto currentStyle = QApplication::style()->objectName();
+        mInitialStyle = currentStyle.toStdString();
+        mCurrentStyle = currentStyle.toStdString();
+        if (hints->colorScheme() == Qt::ColorScheme::Dark)
+        {
+            mDarkMode = true;
+            if (currentStyle == "windowsvista")
+            {
+                mCurrentStyle = "windows";
+                setStyle("windows");
+
+                QFile file(":/dark/dark.qss");
+                file.open(QIODevice::ReadOnly);
+                setStyleSheet(file.readAll());
+            }
+        }
+    }
+
+    void Application::updateStyle(bool isDark)
+    {
+        if (mInitialStyle != "windowsvista")
+            return;
+
+        if (isDark)
+        {
+            mCurrentStyle = "windows";
+            setStyle("windows");
+
+            QFile file(":/dark/dark.qss");
+            file.open(QIODevice::ReadOnly);
+            setStyleSheet(file.readAll());
+        }
+        else
+        {
+            mCurrentStyle = mInitialStyle;
+            setStyleSheet("");
+            setStyle(mInitialStyle.c_str());
+        }
+#endif
+    }
+
+    bool Application::notify(QObject* receiver, QEvent* event)
+    {
+        try
+        {
+            if (event->type() == QEvent::ThemeChange || event->type() == QEvent::PaletteChange)
+            {
+#if defined(WIN32) && QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+                const auto* hints = QGuiApplication::styleHints();
+                const auto currentStyle = QApplication::style()->objectName();
+                bool isDark = hints->colorScheme() == Qt::ColorScheme::Dark;
+                if (isDark != mDarkMode)
+                {
+                    mDarkMode = isDark;
+
+                    bool result = QApplication::notify(receiver, event);
+
+                    emit darkModeChanged(isDark);
+
+                    return result;
+                }
+#endif
+                Misc::ScalableIcon::updateAllIcons();
+            }
+
+            return QApplication::notify(receiver, event);
+        }
+        catch (const std::exception& exception)
+        {
+            Log(Debug::Error) << "An exception has been caught: " << exception.what();
+        }
+
+        return false;
+    }
+}