saundersp-overlay/gui-apps/qt6ct-kde/files/qt6ct-kde-0.11-r5.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 475a47f..d4950b3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,15 +28,19 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_BUILD_RPATH_USE_ORIGIN ON)
 set(QT_NO_PRIVATE_MODULE_WARNING ON)
 
-add_definitions(-DQT_DISABLE_DEPRECATED_BEFORE=0x060200 -DUSE_WIDGETS -DQT_DEPRECATED_WARNINGS -DQT_MESSAGELOGCONTEXT)
+add_definitions(-DQT_DISABLE_DEPRECATED_BEFORE=0x060200 -DQT_DEPRECATED_WARNINGS -DQT_MESSAGELOGCONTEXT)
 add_compile_options(-Wall -Wextra)
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/src)
 
-find_package(Qt6 6.2 CONFIG REQUIRED COMPONENTS BuildInternals Core Widgets OPTIONAL_COMPONENTS LinguistTools)
+find_package(Qt6 6.2 CONFIG REQUIRED COMPONENTS BuildInternals Core OPTIONAL_COMPONENTS Widgets QuickControls2 LinguistTools)
 if(Qt6_VERSION VERSION_GREATER_EQUAL 6.10)
-    find_package(Qt6 6.10 CONFIG REQUIRED COMPONENTS WidgetsPrivate GuiPrivate)
+    find_package(Qt6 6.10 CONFIG REQUIRED COMPONENTS GuiPrivate OPTIONAL_COMPONENTS WidgetsPrivate)
 endif()
 
+find_package(KF6Config)
+find_package(KF6ColorScheme)
+find_package(KF6IconThemes)
+
 get_target_property(QT_QTPATHS_EXECUTABLE Qt6::qtpaths IMPORTED_LOCATION)
 
 if(Qt6LinguistTools_FOUND)
@@ -80,10 +84,12 @@ endif()
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/src/qt6ct-common)
 
 add_link_options(-Wl,--no-undefined)
-add_subdirectory(src/qt6ct)
 add_subdirectory(src/qt6ct-common)
 add_subdirectory(src/qt6ct-qtplugin)
-add_subdirectory(src/qt6ct-style)
+if(Qt6Widgets_FOUND)
+    add_subdirectory(src/qt6ct-style)
+    add_subdirectory(src/qt6ct)
+endif()
 
 install(DIRECTORY qss DESTINATION ${CMAKE_INSTALL_DATADIR}/qt6ct)
 install(DIRECTORY colors DESTINATION ${CMAKE_INSTALL_DATADIR}/qt6ct)
diff --git a/src/qt6ct-common/CMakeLists.txt b/src/qt6ct-common/CMakeLists.txt
index 3b9f0b9..2afce8d 100644
--- a/src/qt6ct-common/CMakeLists.txt
+++ b/src/qt6ct-common/CMakeLists.txt
@@ -24,5 +24,6 @@ set(app_SRCS
 
 add_library(qt6ct-common SHARED ${app_SRCS})
 set_target_properties(qt6ct-common PROPERTIES VERSION ${QT6CT_VERSION})
-target_link_libraries(qt6ct-common PRIVATE Qt6::Gui)
+target_link_libraries(qt6ct-common PRIVATE Qt6::Gui $<TARGET_NAME_IF_EXISTS:KF6::ConfigCore> $<TARGET_NAME_IF_EXISTS:KF6::ColorScheme>)
+target_compile_definitions(qt6ct-common PRIVATE $<$<TARGET_EXISTS:KF6::ConfigCore>:KF_CONFIGCORE_LIB> $<$<TARGET_EXISTS:KF6::ColorScheme>:KF_COLORSCHEME_LIB>)
 install(TARGETS qt6ct-common DESTINATION ${CMAKE_INSTALL_LIBDIR})
diff --git a/src/qt6ct-common/qt6ct.cpp b/src/qt6ct-common/qt6ct.cpp
index 616440b..250987d 100644
--- a/src/qt6ct-common/qt6ct.cpp
+++ b/src/qt6ct-common/qt6ct.cpp
@@ -34,6 +34,10 @@
 #include <QFile>
 #include <QSettings>
 #include <QtDebug>
+#if defined KF_CONFIGCORE_LIB && defined KF_COLORSCHEME_LIB
+#include <KSharedConfig>
+#include <KColorScheme>
+#endif
 #include "qt6ct.h"
 
 #ifndef QT6CT_DATADIR
@@ -121,6 +125,9 @@ QStringList Qt6CT::sharedColorSchemePaths()
     for(const QString &p : QStandardPaths::standardLocations(QStandardPaths::GenericDataLocation))
     {
         paths << (p + QStringLiteral("/qt6ct/colors"));
+#if defined KF_CONFIGCORE_LIB && defined KF_COLORSCHEME_LIB
+        paths << (p + QStringLiteral("/color-schemes"));
+#endif
     }
     paths << QStringLiteral(QT6CT_DATADIR"/qt6ct/colors");
     paths.removeDuplicates();
@@ -129,6 +136,9 @@ QStringList Qt6CT::sharedColorSchemePaths()
 
 QString Qt6CT::resolvePath(const QString &path)
 {
+    if(path.isEmpty())
+        return path;
+
     QString tmp = path;
     tmp.replace(QLatin1Char('~'), QStandardPaths::writableLocation(QStandardPaths::HomeLocation));
     if(!tmp.contains(QLatin1Char('$')))
@@ -148,9 +158,21 @@ QString Qt6CT::resolvePath(const QString &path)
     return tmp;
 }
 
-QPalette Qt6CT::loadColorScheme(const QString &filePath, const QPalette &fallback)
+bool Qt6CT::isKColorScheme(const QString &filePath)
 {
-    QPalette customPalette;
+    return filePath.toLower().endsWith(".colors");
+}
+
+std::optional<QPalette> Qt6CT::loadColorScheme(const QString &filePath)
+{
+    if(filePath.isEmpty())
+        return std::nullopt;
+
+#if defined KF_CONFIGCORE_LIB && defined KF_COLORSCHEME_LIB
+    if(isKColorScheme(filePath))
+        return KColorScheme::createApplicationPalette(KSharedConfig::openConfig(filePath));
+#endif
+
     QSettings settings(filePath, QSettings::IniFormat);
     settings.beginGroup("ColorScheme"_L1);
     QStringList activeColors = settings.value("active_colors"_L1).toStringList();
@@ -158,7 +180,6 @@ QPalette Qt6CT::loadColorScheme(const QString &filePath, const QPalette &fallbac
     QStringList disabledColors = settings.value("disabled_colors"_L1).toStringList();
     settings.endGroup();
 
-
 #if (QT_VERSION >= QT_VERSION_CHECK(6,6,0))
     if(activeColors.count() == QPalette::Accent)
         activeColors << activeColors.at(QPalette::Highlight);
@@ -168,24 +189,19 @@ QPalette Qt6CT::loadColorScheme(const QString &filePath, const QPalette &fallbac
         disabledColors << disabledColors.at(QPalette::Highlight);
 #endif
 
+    if(activeColors.count() < QPalette::NColorRoles ||
+            inactiveColors.count() < QPalette::NColorRoles ||
+            disabledColors.count() < QPalette::NColorRoles)
+        return std::nullopt;
 
-    if(activeColors.count() >= QPalette::NColorRoles &&
-            inactiveColors.count() >= QPalette::NColorRoles &&
-            disabledColors.count() >= QPalette::NColorRoles)
-    {
-        for (int i = 0; i < QPalette::NColorRoles; i++)
-        {
-            QPalette::ColorRole role = QPalette::ColorRole(i);
-            customPalette.setColor(QPalette::Active, role, QColor(activeColors.at(i)));
-            customPalette.setColor(QPalette::Inactive, role, QColor(inactiveColors.at(i)));
-            customPalette.setColor(QPalette::Disabled, role, QColor(disabledColors.at(i)));
-        }
-    }
-    else
+    QPalette customPalette;
+    for (int i = 0; i < QPalette::NColorRoles; i++)
     {
-        customPalette = fallback; //load fallback palette
+        QPalette::ColorRole role = QPalette::ColorRole(i);
+        customPalette.setColor(QPalette::Active, role, QColor(activeColors.at(i)));
+        customPalette.setColor(QPalette::Inactive, role, QColor(inactiveColors.at(i)));
+        customPalette.setColor(QPalette::Disabled, role, QColor(disabledColors.at(i)));
     }
-
     return customPalette;
 }
 
diff --git a/src/qt6ct-common/qt6ct.h b/src/qt6ct-common/qt6ct.h
index f253987..06ea440 100644
--- a/src/qt6ct-common/qt6ct.h
+++ b/src/qt6ct-common/qt6ct.h
@@ -101,7 +101,8 @@ public:
     static QString styleColorSchemeFile();
     static QStringList sharedColorSchemePaths();
     static QString resolvePath(const QString &path);
-    static QPalette loadColorScheme(const QString &filePath, const QPalette &fallback);
+    static bool isKColorScheme(const QString &filePath);
+    static std::optional<QPalette> loadColorScheme(const QString &filePath);
 
     static void registerStyleInstance(StyleInstance *instance);
     static void unregisterStyleInstance(StyleInstance *instance);
diff --git a/src/qt6ct-qtplugin/CMakeLists.txt b/src/qt6ct-qtplugin/CMakeLists.txt
index 93a2b84..5e170c5 100644
--- a/src/qt6ct-qtplugin/CMakeLists.txt
+++ b/src/qt6ct-qtplugin/CMakeLists.txt
@@ -7,5 +7,6 @@ set(app_SRCS
 
 add_library(qt6ct-qtplugin MODULE ${app_SRCS})
 set_target_properties(qt6ct-qtplugin PROPERTIES OUTPUT_NAME qt6ct)
-target_link_libraries(qt6ct-qtplugin PRIVATE Qt6::Widgets Qt6::GuiPrivate qt6ct-common)
+target_link_libraries(qt6ct-qtplugin PRIVATE $<TARGET_NAME_IF_EXISTS:Qt6::WidgetsPrivate> Qt6::GuiPrivate $<TARGET_NAME_IF_EXISTS:Qt6::QuickControls2> $<TARGET_NAME_IF_EXISTS:KF6::IconThemes> qt6ct-common)
+target_compile_definitions(qt6ct-qtplugin PRIVATE $<$<TARGET_EXISTS:KF6::IconThemes>:KF_ICONTHEMES_LIB>)
 install(TARGETS qt6ct-qtplugin DESTINATION ${PLUGINDIR}/platformthemes)
diff --git a/src/qt6ct-qtplugin/qt6ct-qtplugin.pro b/src/qt6ct-qtplugin/qt6ct-qtplugin.pro
index f3e9ef6..a05a9b7 100644
--- a/src/qt6ct-qtplugin/qt6ct-qtplugin.pro
+++ b/src/qt6ct-qtplugin/qt6ct-qtplugin.pro
@@ -11,7 +11,7 @@ SOURCES += \
     qt6ctplatformtheme.cpp
 
 !equals(DISABLE_WIDGETS,1) {
-   QT += widgets
+   QT += widgets widgets-private
 }
 
 OTHER_FILES += qt6ct.json
diff --git a/src/qt6ct-qtplugin/qt6ctplatformtheme.cpp b/src/qt6ct-qtplugin/qt6ctplatformtheme.cpp
index 569b13f..721e7c8 100644
--- a/src/qt6ct-qtplugin/qt6ctplatformtheme.cpp
+++ b/src/qt6ct-qtplugin/qt6ctplatformtheme.cpp
@@ -41,38 +41,74 @@
 #include <QStyleFactory>
 #include <QApplication>
 #include <QWidget>
+#if QT_CONFIG(graphicsview)
+#include <QGraphicsScene>
+#endif
+#include <private/qapplication_p.h>
 #endif
 #include <QFile>
 #include <QFileSystemWatcher>
-#include <private/qiconloader_p.h>
+#ifdef QT_QUICKCONTROLS2_LIB
+#include <QQuickStyle>
+#endif
 
 #include "qt6ct.h"
 #include "qt6ctplatformtheme.h"
 
 #include <QStringList>
 #include <qpa/qplatformthemefactory_p.h>
+#include <qpa/qwindowsysteminterface.h>
+
+#ifdef KF_ICONTHEMES_LIB
+#include <KIconEngine>
+#include <KIconLoader>
+#endif
 
 Q_LOGGING_CATEGORY(lqt6ct, "qt6ct", QtWarningMsg)
 
 //QT_QPA_PLATFORMTHEME=qt6ct
 
-Qt6CTPlatformTheme::Qt6CTPlatformTheme()
+Qt6CTPlatformTheme::Qt6CTPlatformTheme() :
+    m_generalFont(*QGenericUnixTheme::font(QPlatformTheme::SystemFont)),
+    m_fixedFont(*QGenericUnixTheme::font(QPlatformTheme::FixedFont))
 {
     Qt6CT::initConfig();
+#ifdef QT_WIDGETS_LIB
+    if(hasWidgets())
+    {
+        //styles such as Kvantum could use default QFont constructor
+        //which results in QGuiApplicationPrivate::app_font initializing
+        //into the wrong font as we haven't finished constructor yet
+        const bool hadFont = QGuiApplicationPrivate::app_font;
+        m_style.reset(QStyleFactory::create(u"qt6ct-style"_s));
+        if(!hadFont && QGuiApplicationPrivate::app_font)
+        {
+            delete QGuiApplicationPrivate::app_font;
+            QGuiApplicationPrivate::app_font = nullptr;
+        }
+    }
+#endif
     if(QGuiApplication::desktopSettingsAware())
     {
         readSettings();
         QMetaObject::invokeMethod(this, &Qt6CTPlatformTheme::applySettings, Qt::QueuedConnection);
-#ifdef QT_WIDGETS_LIB
         QMetaObject::invokeMethod(this, &Qt6CTPlatformTheme::createFSWatcher, Qt::QueuedConnection);
+        //must be applied before Q_COREAPP_STARTUP_FUNCTION execution
+        if(Qt6CT::isKColorScheme(m_schemePath))
+            qApp->setProperty("KDE_COLOR_SCHEME_PATH", m_schemePath);
+#if defined QT_WIDGETS_LIB && defined QT_QUICKCONTROLS2_LIB
+        if(hasWidgets())
+            //don't override the value explicitly set by the user
+            if(QQuickStyle::name().isEmpty() || QQuickStyle::name() == QLatin1String("Fusion"))
+                QQuickStyle::setStyle(QLatin1String("org.kde.desktop"));
 #endif
-        QGuiApplication::setFont(m_generalFont);
     }
     qCDebug(lqt6ct) << "using qt6ct plugin";
 #ifdef QT_WIDGETS_LIB
     if(!QStyleFactory::keys().contains(u"qt6ct-style"_s))
         qCCritical(lqt6ct) << "unable to find qt6ct proxy style";
 #endif
+    QCoreApplication::instance()->installEventFilter(this);
 }
 
 Qt6CTPlatformTheme::~Qt6CTPlatformTheme()
@@ -90,10 +126,41 @@ QPlatformDialogHelper *Qt6CTPlatformTheme::createPlatformDialogHelper(DialogType
                      QGenericUnixTheme::createPlatformDialogHelper(type);
 }
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+Qt::ColorScheme Qt6CTPlatformTheme::colorScheme() const
+{
+    //m_inColorScheme prevents QPlatformTheme::palette -> QPlatformThemePrivate::initializeSystemPalette
+    //-> qt_fusionPalette -> Qt6CTPlatformTheme::colorScheme infinite recursion
+    if(m_isIgnored || m_inColorScheme)
+        return QGenericUnixTheme::colorScheme();
+
+    m_inColorScheme = true;
+#ifdef QT_WIDGETS_LIB
+    //follow QApplicationPrivate::basePalette() logic
+    QPalette palette = m_style ? m_style->standardPalette() : Qt::gray;
+    if(const QPalette *themePalette = this->palette())
+        palette = themePalette->resolve(palette);
+    palette.setResolveMask(0);
+    if (m_style)
+        m_style->polish(palette);
+#else
+    //follow QGuiApplicationPrivate::basePalette() logic
+    const QPalette palette = this->palette() ? *this->palette() : Qt::gray;
+#endif
+    m_inColorScheme = false;
+
+    return palette.windowText().color().lightness() > palette.window().color().lightness()
+        ? Qt::ColorScheme::Dark
+        : palette.windowText().color().lightness() < palette.window().color().lightness()
+        ? Qt::ColorScheme::Light
+        : QGenericUnixTheme::colorScheme();
+}
+#endif
+
 const QPalette *Qt6CTPlatformTheme::palette(QPlatformTheme::Palette type) const
 {
-    if (type == QPlatformTheme::SystemPalette && !m_isIgnored)
-        return &m_palette;
+    if (type == QPlatformTheme::SystemPalette && m_palette)
+        return &*m_palette;
     return QGenericUnixTheme::palette(type);
 }
 
@@ -148,6 +215,13 @@ QIcon Qt6CTPlatformTheme::fileIcon(const QFileInfo &fileInfo, QPlatformTheme::Ic
     return QIcon::fromTheme(type.iconName());
 }
 
+#ifdef KF_ICONTHEMES_LIB
+QIconEngine *Qt6CTPlatformTheme::createIconEngine(const QString &iconName) const
+{
+    return new KIconEngine(iconName, KIconLoader::global());
+}
+#endif
+
 void Qt6CTPlatformTheme::applySettings()
 {
     if(!QGuiApplication::desktopSettingsAware() || m_isIgnored)
@@ -156,18 +230,18 @@ void Qt6CTPlatformTheme::applySettings()
         return;
     }
 
-    QGuiApplication::setFont(m_generalFont); //apply font
+    if(Qt6CT::isKColorScheme(m_schemePath))
+        qApp->setProperty("KDE_COLOR_SCHEME_PATH", m_schemePath);
+    else if(m_update)
+        qApp->setProperty("KDE_COLOR_SCHEME_PATH", QVariant());
 
 #ifdef QT_WIDGETS_LIB
     if(hasWidgets())
     {
-        qApp->setFont(m_generalFont);
-
-        //Qt 5.6 or higher should be use themeHint function on application startup.
-        //So, there is no need to call this function first time.
         if(m_update)
         {
-            qApp->setWheelScrollLines(m_wheelScrollLines);
+            if(FontHash *hash = qt_app_fonts_hash(); hash && hash->size())
+                hash->clear();
             Qt6CT::reloadStyleInstanceSettings();
         }
 
@@ -193,25 +267,26 @@ void Qt6CTPlatformTheme::applySettings()
 
     if(m_update)
     {
-        QIconLoader::instance()->updateSystemTheme(); //apply icons
-        QGuiApplication::setPalette(QGuiApplication::palette()); //apply palette
+        QWindowSystemInterface::handleThemeChange();
+        QCoreApplication::postEvent(qGuiApp, new QEvent(QEvent::ApplicationFontChange));
     }
 
 #ifdef QT_WIDGETS_LIB
     if(hasWidgets() && m_update)
     {
-        for(QWidget *w : qApp->allWidgets())
-        {
-            QEvent e(QEvent::ThemeChange);
-            QApplication::sendEvent(w, &e);
-        }
+#if QT_CONFIG(graphicsview)
+        for(auto scene : std::as_const(QApplicationPrivate::instance()->scene_list))
+            QCoreApplication::postEvent(scene, new QEvent(QEvent::ApplicationFontChange));
+#endif
+
+        for(QWidget *w : QApplication::allWidgets())
+            QCoreApplication::postEvent(w, new QEvent(QEvent::ThemeChange));
     }
 #endif
 
     m_update = true;
 }
 
-#ifdef QT_WIDGETS_LIB
 void Qt6CTPlatformTheme::createFSWatcher()
 {
     QFileSystemWatcher *watcher = new QFileSystemWatcher(this);
@@ -230,21 +305,16 @@ void Qt6CTPlatformTheme::updateSettings()
     readSettings();
     applySettings();
 }
-#endif
 
 void Qt6CTPlatformTheme::readSettings()
 {
     QSettings settings(Qt6CT::configFile(), QSettings::IniFormat);
 
     settings.beginGroup("Appearance"_L1);
-    m_style = settings.value("style"_L1, u"Fusion"_s).toString();
-    m_palette = *QGenericUnixTheme::palette(SystemPalette);
-    QString schemePath = settings.value("color_scheme_path"_L1).toString();
-    if(!schemePath.isEmpty() && settings.value("custom_palette"_L1, false).toBool())
-    {
-        schemePath = Qt6CT::resolvePath(schemePath); //replace environment variables
-        m_palette = Qt6CT::loadColorScheme(schemePath, m_palette);
-    }
+    m_schemePath = !m_isIgnored && settings.value("custom_palette"_L1, false).toBool()
+        ? Qt6CT::resolvePath(settings.value("color_scheme_path"_L1).toString()) //replace environment variables
+        : QString();
+    m_palette = Qt6CT::loadColorScheme(m_schemePath);
     m_iconTheme = settings.value("icon_theme"_L1).toString();
     //load dialogs
     if(!m_update)
@@ -252,8 +322,9 @@ void Qt6CTPlatformTheme::readSettings()
         //do not mix gtk2 style and gtk3 dialogs
         QStringList keys = QPlatformThemeFactory::keys();
         QString dialogs = settings.value("standard_dialogs"_L1, u"default"_s).toString();
+        QString style = settings.value("style"_L1, u"Fusion"_s).toString();
 
-        if(m_style.endsWith(u"gtk2"_s) && dialogs == QLatin1String("gtk3"))
+        if(style.endsWith(u"gtk2"_s) && dialogs == QLatin1String("gtk3"))
             dialogs = u"gtk2"_s;
         if(keys.contains(dialogs))
             m_theme.reset(QPlatformThemeFactory::create(dialogs));
@@ -262,10 +333,10 @@ void Qt6CTPlatformTheme::readSettings()
     settings.endGroup();
 
     settings.beginGroup("Fonts"_L1);
-    m_generalFont = QGuiApplication::font();
-    m_generalFont.fromString(settings.value("general"_L1, QGuiApplication::font()).toString());
-    m_fixedFont = QGuiApplication::font();
-    m_fixedFont.fromString(settings.value("fixed"_L1, QGuiApplication::font()).toString());
+    m_generalFont = *QGenericUnixTheme::font(QPlatformTheme::SystemFont);
+    m_generalFont.fromString(settings.value("general"_L1).toString());
+    m_fixedFont = *QGenericUnixTheme::font(QPlatformTheme::FixedFont);
+    m_fixedFont.fromString(settings.value("fixed_L1").toString());
     settings.endGroup();
 
     settings.beginGroup("Interface"_L1);
@@ -354,3 +425,17 @@ QString Qt6CTPlatformTheme::loadStyleSheets(const QStringList &paths)
     content.replace(regExp, u"\n"_s);
     return content;
 }
+
+//There's such a thing as KColorSchemeManager that lets the user to change the color scheme
+//application-wide and we should re-apply the color scheme if KCSM resets it to the default
+//which leads KColorScheme to get the color scheme from kdeglobals which won't help us.
+bool Qt6CTPlatformTheme::eventFilter(QObject *obj, QEvent *e)
+{
+    if(obj == qApp &&
+            e->type() == QEvent::DynamicPropertyChange &&
+            static_cast<QDynamicPropertyChangeEvent*>(e)->propertyName() == "KDE_COLOR_SCHEME_PATH" &&
+            qApp->property("KDE_COLOR_SCHEME_PATH").toString().isEmpty() &&
+            Qt6CT::isKColorScheme(m_schemePath))
+        applySettings();
+    return QObject::eventFilter(obj, e);
+}
diff --git a/src/qt6ct-qtplugin/qt6ctplatformtheme.h b/src/qt6ct-qtplugin/qt6ctplatformtheme.h
index b2a7bcf..9327ef0 100644
--- a/src/qt6ct-qtplugin/qt6ctplatformtheme.h
+++ b/src/qt6ct-qtplugin/qt6ctplatformtheme.h
@@ -43,6 +43,8 @@
 #include <QFileInfo>
 #include <memory>
 
+class QStyle;
+
 Q_DECLARE_LOGGING_CATEGORY(lqt6ct)
 
 class Qt6CTPlatformTheme : public QObject, public QGenericUnixTheme
@@ -58,6 +60,9 @@ public:
     //virtual void showPlatformMenuBar() {}
     virtual bool usePlatformNativeDialog(DialogType type) const override;
     virtual QPlatformDialogHelper *createPlatformDialogHelper(DialogType type) const override;
+#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+    virtual Qt::ColorScheme colorScheme() const override;
+#endif
     virtual const QPalette *palette(Palette type = SystemPalette) const override;
     virtual const QFont *font(Font type = SystemFont) const override;
     virtual QVariant themeHint(ThemeHint hint) const override;
@@ -66,16 +71,19 @@ public:
     //virtual QPixmap fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
     //                               QPlatformTheme::IconOptions iconOptions = 0) const;
 
-    //virtual QIconEngine *createIconEngine(const QString &iconName) const;
+#ifdef KF_ICONTHEMES_LIB
+    virtual QIconEngine *createIconEngine(const QString &iconName) const override;
+#endif
     //virtual QList<QKeySequence> keyBindings(QKeySequence::StandardKey key) const;
     //virtual QString standardButtonText(int button) const;
 
+protected:
+    bool eventFilter(QObject *obj, QEvent *e) override;
+
 private slots:
     void applySettings();
-#ifdef QT_WIDGETS_LIB
     void createFSWatcher();
     void updateSettings();
-#endif
 
 private:
     void readSettings();
@@ -83,8 +91,8 @@ private:
     bool hasWidgets();
 #endif
     QString loadStyleSheets(const QStringList &paths);
-    QString m_style, m_iconTheme, m_userStyleSheet, m_prevStyleSheet;
-    QPalette m_palette;
+    QString m_schemePath, m_iconTheme, m_userStyleSheet, m_prevStyleSheet;
+    std::optional<QPalette> m_palette;
     QFont m_generalFont, m_fixedFont;
     int m_doubleClickInterval;
     int m_cursorFlashTime;
@@ -96,7 +104,11 @@ private:
     int m_wheelScrollLines = 3;
     bool m_showShortcutsInContextMenus = false;
     bool m_isIgnored = false;
+    mutable bool m_inColorScheme = false;
     std::unique_ptr<QPlatformTheme> m_theme;
+#ifdef QT_WIDGETS_LIB
+    std::unique_ptr<QStyle> m_style;
+#endif
 };
 
 Q_DECLARE_LOGGING_CATEGORY(lqt6ct)
diff --git a/src/qt6ct-style/CMakeLists.txt b/src/qt6ct-style/CMakeLists.txt
index 5ab1c21..c8870b3 100644
--- a/src/qt6ct-style/CMakeLists.txt
+++ b/src/qt6ct-style/CMakeLists.txt
@@ -1,7 +1,5 @@
 project(qt6ct-style)
 
-add_definitions(-DUSE_WIDGETS)
-
 set(app_SRCS
   plugin.cpp
   qt6ctproxystyle.cpp
diff --git a/src/qt6ct/CMakeLists.txt b/src/qt6ct/CMakeLists.txt
index fb0e1f7..f11071f 100644
--- a/src/qt6ct/CMakeLists.txt
+++ b/src/qt6ct/CMakeLists.txt
@@ -31,6 +31,7 @@ if(Qt6LinguistTools_FOUND)
 endif()
 
 add_executable(qt6ct ${app_SRCS})
-target_link_libraries(qt6ct PRIVATE Qt6::Widgets Qt6::WidgetsPrivate qt6ct-common)
+target_link_libraries(qt6ct PRIVATE Qt6::Widgets Qt6::GuiPrivate $<TARGET_NAME_IF_EXISTS:KF6::ConfigCore> qt6ct-common)
+target_compile_definitions(qt6ct PRIVATE USE_WIDGETS $<$<TARGET_EXISTS:KF6::ConfigCore>:KF_CONFIGCORE_LIB> $<$<TARGET_EXISTS:KF6::ColorScheme>:KF_COLORSCHEME_LIB>)
 install(TARGETS qt6ct DESTINATION ${CMAKE_INSTALL_BINDIR})
 install(FILES qt6ct.desktop DESTINATION ${CMAKE_INSTALL_DATADIR}/applications)
diff --git a/src/qt6ct/appearancepage.cpp b/src/qt6ct/appearancepage.cpp
index 2f1faf8..0c01d4a 100644
--- a/src/qt6ct/appearancepage.cpp
+++ b/src/qt6ct/appearancepage.cpp
@@ -35,6 +35,9 @@
 #include <QMenu>
 #include <QIcon>
 #include <QStringList>
+#ifdef KF_CONFIGCORE_LIB
+#include <KConfigGroup>
+#endif
 #include <qpa/qplatformthemefactory_p.h>
 #include <qpa/qplatformtheme.h>
 #include "qt6ct.h"
@@ -70,7 +73,7 @@ AppearancePage::AppearancePage(QWidget *parent) :
     QMenu *menu = new QMenu(this);
     menu->addAction(QIcon::fromTheme(u"document-new"_s), tr("Create"), this, qOverload<>(&AppearancePage::createColorScheme));
     m_changeColorSchemeAction = menu->addAction(QIcon::fromTheme(u"accessories-text-editor"_s), tr("Edit"), this, &AppearancePage::changeColorScheme);
-    menu->addAction(QIcon::fromTheme(u"edit-copy"_s), tr("Create a Copy"), this, &AppearancePage::copyColorScheme);
+    m_copyColorSchemeAction = menu->addAction(QIcon::fromTheme(u"edit-copy"_s), tr("Create a Copy"), this, &AppearancePage::copyColorScheme);
     m_renameColorSchemeAction = menu->addAction(tr("Rename"), this, &AppearancePage::renameColorScheme);
     menu->addSeparator();
     m_removeColorSchemeAction = menu->addAction(QIcon::fromTheme(u"edit-delete"_s), tr("Remove"), this, &AppearancePage::removeColorScheme);
@@ -126,6 +129,15 @@ void AppearancePage::writeSettings(QSettings *settings)
     settings->endGroup();
 }
 
+#ifdef KF_CONFIGCORE_LIB
+void AppearancePage::writeSettings(KSharedConfigPtr config)
+{
+    KConfigGroup group(config, "KDE");
+    group.writeEntry("widgetStyle", "qt6ct-style");
+    group.sync();
+}
+#endif
+
 void AppearancePage::on_styleComboBox_textActivated(const QString &text)
 {
     QStyle *style = QStyleFactory::create(text);
@@ -157,7 +169,7 @@ void AppearancePage::on_colorSchemeComboBox_activated(int)
     }
     else
     {
-        m_customPalette = Qt6CT::loadColorScheme(data, palette());
+        m_customPalette = Qt6CT::loadColorScheme(data).value_or(palette());
     }
     updatePalette();
 }
@@ -333,6 +345,7 @@ void AppearancePage::setPreviewPalette(const QPalette &p)
 
 void AppearancePage::updateActions()
 {
+    m_copyColorSchemeAction->setVisible(!Qt6CT::isKColorScheme(m_ui->colorSchemeComboBox->currentData().toString()));
     if(m_ui->colorSchemeComboBox->count() == 0 ||
             !QFileInfo(m_ui->colorSchemeComboBox->currentData().toString()).isWritable())
     {
@@ -364,8 +377,7 @@ void AppearancePage::readSettings()
     QString style = settings.value("style"_L1, u"Fusion"_s).toString();
     m_ui->styleComboBox->setCurrentText(style);
 
-    QString colorSchemePath = settings.value("color_scheme_path"_L1).toString();
-    colorSchemePath = Qt6CT::resolvePath(colorSchemePath); //replace environment variables
+    QString colorSchemePath = Qt6CT::resolvePath(settings.value("color_scheme_path").toString()); //replace environment variables
 
     m_ui->colorSchemeComboBox->addItem(tr("Default"), u"system"_s);
     m_ui->colorSchemeComboBox->addItem(tr("Style's colors"), u"style"_s);
@@ -382,7 +394,7 @@ void AppearancePage::readSettings()
             index = m_ui->colorSchemeComboBox->findData(u"style"_s);
 
         m_ui->colorSchemeComboBox->setCurrentIndex(index);
-        m_customPalette = Qt6CT::loadColorScheme(colorSchemePath, palette());
+        m_customPalette = Qt6CT::loadColorScheme(colorSchemePath).value_or(palette());
     }
     else
     {        
@@ -428,11 +440,26 @@ void AppearancePage::findColorSchemes(const QString &path)
 {
     QDir dir(path);
     dir.setFilter(QDir::Files);
-    dir.setNameFilters({ u"*.conf"_s });
+    QStringList nameFilters;
+    nameFilters << u"*.conf"_s;
+#if defined KF_CONFIGCORE_LIB && defined KF_COLORSCHEME_LIB
+    nameFilters << u"*.colors"_s;
+#endif
+    dir.setNameFilters(nameFilters);
 
     for(const QFileInfo &info : dir.entryInfoList())
     {
-        m_ui->colorSchemeComboBox->addItem(info.baseName(), info.filePath());
+        QString name = info.baseName();
+        QString path = info.filePath();
+#if defined KF_CONFIGCORE_LIB && defined KF_COLORSCHEME_LIB
+        if(Qt6CT::isKColorScheme(path))
+        {
+            KSharedConfigPtr config = KSharedConfig::openConfig(path, KConfig::SimpleConfig);
+            KConfigGroup group(config, "General");
+            name = group.readEntry("Name", name) + " (KColorScheme)";
+        }
+#endif
+        m_ui->colorSchemeComboBox->addItem(name, path);
     }
 }
 
diff --git a/src/qt6ct/appearancepage.h b/src/qt6ct/appearancepage.h
index e196b62..8e4902e 100644
--- a/src/qt6ct/appearancepage.h
+++ b/src/qt6ct/appearancepage.h
@@ -49,6 +49,10 @@ public:
 
     void writeSettings(QSettings *settings) override;
 
+#ifdef KF_CONFIGCORE_LIB
+    void writeSettings(KSharedConfigPtr config) override;
+#endif
+
 private slots:
     void on_styleComboBox_textActivated(const QString &text);
     void on_colorSchemeComboBox_activated(int);
@@ -73,7 +77,7 @@ private:
     QStyle *m_selectedStyle = nullptr;
     QPalette m_customPalette;
     QWidget *m_previewWidget;
-    QAction *m_changeColorSchemeAction, *m_renameColorSchemeAction, *m_removeColorSchemeAction;
+    QAction *m_changeColorSchemeAction, *m_copyColorSchemeAction, *m_renameColorSchemeAction, *m_removeColorSchemeAction;
     Ui::PreviewForm *m_previewUi;
 };
 
diff --git a/src/qt6ct/fontspage.cpp b/src/qt6ct/fontspage.cpp
index 75de0fd..ae0f091 100644
--- a/src/qt6ct/fontspage.cpp
+++ b/src/qt6ct/fontspage.cpp
@@ -29,6 +29,7 @@
 #include <QMessageBox>
 #include <QSettings>
 #include <QApplication>
+#include <QFontDatabase>
 #include <QFontDialog>
 #include <QDir>
 #include <QFile>
@@ -70,12 +71,19 @@ void FontsPage::onFontChangeRequested(QWidget *widget)
 {
     bool ok = false;
     QFont font = QFontDialog::getFont (&ok, widget->font(), this);
-    if(ok)
-    {
-        widget->setProperty("value", font.toString());
-        widget->setFont(font);
-        qobject_cast<QLabel*>(widget)->setText(font.family () + QChar::Space + QString::number(font.pointSize ()));
-    }
+    if(!ok)
+        return;
+
+    if(font.weight() == QFont::Normal
+        && (font.styleName() == "Regular"_L1
+            || font.styleName() == "Normal"_L1
+            || font.styleName() == "Book"_L1
+            || font.styleName() == "Roman"_L1))
+        font.setStyleName(QString());
+
+    widget->setProperty("value", font.toString());
+    widget->setFont(font);
+    qobject_cast<QLabel*>(widget)->setText(font.family () + QChar::Space + QString::number(font.pointSize ()));
 }
 
 void FontsPage::readSettings()
@@ -89,8 +97,9 @@ void FontsPage::readSettings()
 
 void FontsPage::loadFont(QSettings *settings, QLabel *label, const QString &key)
 {
-    QFont font = QApplication::font();
-    font.fromString(settings->value(key, QApplication::font().toString()).toString());
+    QFont font = settings->value(key, key == "fixed"_L1
+        ? QFontDatabase::systemFont(QFontDatabase::FixedFont)
+        : QFontDatabase::systemFont(QFontDatabase::GeneralFont)).value<QFont>();
     label->setText(font.family() + QChar::Space + QString::number(font.pointSize()));
     label->setFont(font);
     label->setProperty("value", font.toString());
diff --git a/src/qt6ct/iconthemepage.cpp b/src/qt6ct/iconthemepage.cpp
index 37960f9..9156116 100644
--- a/src/qt6ct/iconthemepage.cpp
+++ b/src/qt6ct/iconthemepage.cpp
@@ -34,6 +34,9 @@
 #include <QProgressBar>
 #include <QMetaObject>
 #include <QThread>
+#ifdef KF_CONFIGCORE_LIB
+#include <KConfigGroup>
+#endif
 #include "qt6ct.h"
 #include "iconthemepage.h"
 #include "ui_iconthemepage.h"
@@ -71,6 +74,19 @@ void IconThemePage::writeSettings(QSettings *settings)
         settings->setValue("Appearance/icon_theme"_L1, item->data(3, Qt::UserRole));
 }
 
+#ifdef KF_CONFIGCORE_LIB
+void IconThemePage::writeSettings(KSharedConfigPtr config)
+{
+    QTreeWidgetItem *item = m_ui->treeWidget->currentItem();
+    if(!item)
+        return;
+
+    KConfigGroup group(config, "Icons");
+    group.writeEntry("Theme", item->data(3, Qt::UserRole));
+    group.sync();
+}
+#endif
+
 void IconThemePage::onFinished()
 {
     m_ui->treeWidget->addTopLevelItems(m_items);
diff --git a/src/qt6ct/iconthemepage.h b/src/qt6ct/iconthemepage.h
index 8938671..9ad3580 100644
--- a/src/qt6ct/iconthemepage.h
+++ b/src/qt6ct/iconthemepage.h
@@ -51,6 +51,10 @@ public:
 
     void writeSettings(QSettings *settings) override;
 
+#ifdef KF_CONFIGCORE_LIB
+    void writeSettings(KSharedConfigPtr config) override;
+#endif
+
 private slots:
     void onFinished();
 
diff --git a/src/qt6ct/mainwindow.cpp b/src/qt6ct/mainwindow.cpp
index 122dff2..10296a4 100644
--- a/src/qt6ct/mainwindow.cpp
+++ b/src/qt6ct/mainwindow.cpp
@@ -91,11 +91,19 @@ void MainWindow::on_buttonBox_clicked(QAbstractButton *button)
     if(id == QDialogButtonBox::Ok || id == QDialogButtonBox::Apply)
     {
         QSettings settings(Qt6CT::configFile(), QSettings::IniFormat);
+#ifdef KF_CONFIGCORE_LIB
+        KSharedConfigPtr config = KSharedConfig::openConfig("kdeglobals");
+#endif
         for(int i = 0; i < m_ui->tabWidget->count(); ++i)
         {
             TabPage *p = qobject_cast<TabPage*>(m_ui->tabWidget->widget(i));
             if(p)
+            {
                 p->writeSettings(&settings);
+#ifdef KF_CONFIGCORE_LIB
+                p->writeSettings(config);
+#endif
+            }
         }
     }
 
diff --git a/src/qt6ct/tabpage.h b/src/qt6ct/tabpage.h
index c77b5a7..4e46ddd 100644
--- a/src/qt6ct/tabpage.h
+++ b/src/qt6ct/tabpage.h
@@ -32,6 +32,10 @@
 #include <QWidget>
 #include <QSettings>
 
+#ifdef KF_CONFIGCORE_LIB
+#include <KSharedConfig>
+#endif
+
 class TabPage : public QWidget
 {
     Q_OBJECT
@@ -39,6 +43,10 @@ public:
     explicit TabPage(QWidget *parent = nullptr);
 
     virtual void writeSettings(QSettings *settings) = 0;
+
+#ifdef KF_CONFIGCORE_LIB
+    virtual void writeSettings(KSharedConfigPtr config) {}
+#endif
 };
 
 #endif // TABPAGE_H