Add dark mode configuration setting in UI tab

- Allows to choose "Auto", "Always On" or "Always Off".
- If Auto is chosen, value is retrieved from OS
  - On Windows, the application needs a restart to apply the settings
  - On Windows, "Always On" is not available, the OS is responsible for
    selecting the dark palette

src/common/settings.cpp

@@ -67,6 +67,7 @@ SWITCHABLE(u8, true);
 // Used in UISettings
 // TODO see if we can move this to uisettings.cpp
 SWITCHABLE(ConfirmStop, true);
+SWITCHABLE(DarkModeState, true);
 
 #undef SETTING
 #undef SWITCHABLE

src/common/settings.h

@@ -88,6 +88,7 @@ SWITCHABLE(u8, true);
 // Used in UISettings
 // TODO see if we can move this to uisettings.h
 SWITCHABLE(ConfirmStop, true);
+SWITCHABLE(DarkModeState, true);
 
 #undef SETTING
 #undef SWITCHABLE

src/common/settings_enums.h

@@ -153,6 +153,8 @@ ENUM(ConsoleMode, Handheld, Docked);
 
 ENUM(AppletMode, HLE, LLE);
 
+ENUM(DarkModeState, Off, On, Auto);
+
 template <typename Type>
 inline std::string CanonicalizeEnum(Type id) {
     const auto group = EnumMetadata<Type>::Canonicalizations();

src/yuzu/configuration/configure_ui.cpp

@@ -18,6 +18,7 @@
 #include <QString>
 #include <QToolButton>
 #include <QVariant>
+#include <QtGlobal>
 
 #include "common/common_types.h"
 #include "common/fs/path_util.h"
@@ -29,6 +30,8 @@
 #include "ui_configure_ui.h"
 #include "yuzu/uisettings.h"
 
+using Settings::DarkModeState;
+
 namespace {
 constexpr std::array default_game_icon_sizes{
     std::make_pair(0, QT_TRANSLATE_NOOP("ConfigureUI", "None")),
@@ -131,6 +134,17 @@ ConfigureUi::ConfigureUi(Core::System& system_, QWidget* parent)
         ui->theme_combobox->addItem(theme_name, theme_dir);
     }
 
+    ui->dark_mode_combobox->addItem(tr("Auto"), QVariant::fromValue(DarkModeState::Auto));
+// Windows dark mode is based on palette swap made by OS, so the "Always On" option disabled.
+// We could check if the dark mode state is "On" and force a dark palette like on Linux to support
+// "Always On"
+#ifdef _WIN32
+    ui->dark_mode_label->setText(tr("Dark mode (needs restart)"));
+#else
+    ui->dark_mode_combobox->addItem(tr("Always On"), QVariant::fromValue(DarkModeState::On));
+#endif
+    ui->dark_mode_combobox->addItem(tr("Always Off"), QVariant::fromValue(DarkModeState::Off));
+
     InitializeIconSizeComboBox();
     InitializeRowComboBoxes();
 
@@ -185,6 +199,8 @@ ConfigureUi::~ConfigureUi() = default;
 void ConfigureUi::ApplyConfiguration() {
     UISettings::values.theme =
         ui->theme_combobox->itemData(ui->theme_combobox->currentIndex()).toString();
+    UISettings::values.dark_mode_state =
+        static_cast<DarkModeState>(ui->dark_mode_combobox->currentData().toUInt());
     UISettings::values.show_add_ons = ui->show_add_ons->isChecked();
     UISettings::values.show_compat = ui->show_compat->isChecked();
     UISettings::values.show_size = ui->show_size->isChecked();
@@ -212,6 +228,8 @@ void ConfigureUi::RequestGameListUpdate() {
 
 void ConfigureUi::SetConfiguration() {
     ui->theme_combobox->setCurrentIndex(ui->theme_combobox->findData(UISettings::values.theme));
+    ui->dark_mode_combobox->setCurrentIndex(
+        ui->dark_mode_combobox->findData(QVariant::fromValue(UISettings::values.dark_mode_state)));
     ui->language_combobox->setCurrentIndex(ui->language_combobox->findData(
         QString::fromStdString(UISettings::values.language.GetValue())));
     ui->show_add_ons->setChecked(UISettings::values.show_add_ons.GetValue());

src/yuzu/configuration/configure_ui.ui

@@ -63,6 +63,20 @@
           </item>
          </layout>
         </item>
+        <item>
+         <layout class="QHBoxLayout" name="horizontalLayout_6">
+          <item>
+           <widget class="QLabel" name="dark_mode_label">
+            <property name="text">
+             <string>Dark Mode:</string>
+            </property>
+           </widget>
+          </item>
+          <item>
+           <widget class="QComboBox" name="dark_mode_combobox"/>
+          </item>
+         </layout>
+        </item>
        </layout>
       </item>
      </layout>

src/yuzu/configuration/qt_config.cpp

@@ -259,8 +259,10 @@ void QtConfig::ReadShortcutValues() {
 void QtConfig::ReadUIValues() {
     BeginGroup(Settings::TranslateCategory(Settings::Category::Ui));
 
-    UISettings::values.theme = QString::fromStdString(
+    UISettings::values.theme =
-        ReadStringSetting(std::string("theme"), std::string(UISettings::default_theme)));
+        QString::fromStdString(ReadStringSetting("theme", std::string(UISettings::default_theme)));
+    UISettings::values.dark_mode_state = static_cast<DarkModeState>(
+        ReadIntegerSetting("dark_mode_state", static_cast<int>(DarkModeState::Auto)));
 
     ReadUIGamelistValues();
     ReadUILayoutValues();
@@ -466,8 +468,10 @@ void QtConfig::SaveUIValues() {
     WriteCategory(Settings::Category::Ui);
     WriteCategory(Settings::Category::UiGeneral);
 
-    WriteStringSetting(std::string("theme"), UISettings::values.theme.toStdString(),
+    WriteStringSetting("theme", UISettings::values.theme.toStdString(),
                        std::make_optional(std::string(UISettings::default_theme)));
+    WriteIntegerSetting("dark_mode_state", static_cast<int>(UISettings::values.dark_mode_state),
+                        std::make_optional(static_cast<int>(DarkModeState::Auto)));
 
     SaveUIGamelistValues();
     SaveUILayoutValues();

src/yuzu/main.cpp

@@ -3721,6 +3721,7 @@ void GMainWindow::ResetWindowSize1080() {
 
 void GMainWindow::OnConfigure() {
     const QString old_theme = UISettings::values.theme;
+    DarkModeState old_dark_mode_state = UISettings::values.dark_mode_state;
     const bool old_discord_presence = UISettings::values.enable_discord_presence.GetValue();
     const auto old_language_index = Settings::values.language_index.GetValue();
 #ifdef __unix__
@@ -3781,7 +3782,8 @@ void GMainWindow::OnConfigure() {
     }
     InitializeHotkeys();
 
-    if (UISettings::values.theme != old_theme) {
+    if (UISettings::values.theme != old_theme ||
+        UISettings::values.dark_mode_state != old_dark_mode_state) {
         UpdateUITheme();
     }
     if (UISettings::values.enable_discord_presence.GetValue() != old_discord_presence) {
@@ -4795,13 +4797,11 @@ void GMainWindow::filterBarSetChecked(bool state) {
 }
 
 void GMainWindow::UpdateUITheme() {
-    LOG_DEBUG(Frontend, "Updating UI");
+    const QString default_theme = QString::fromStdString(UISettings::default_theme.data());
-    QString default_theme = QString::fromStdString(UISettings::default_theme.data());
     QString current_theme = UISettings::values.theme;
     if (current_theme.isEmpty()) {
         current_theme = default_theme;
     }
-    const bool current_dark_mode = CheckDarkMode();
 
     UpdateIcons(current_theme);
 
@@ -4873,7 +4873,7 @@ bool GMainWindow::TryLoadStylesheet(const QString& theme_uri) {
         style_path = theme_uri + QStringLiteral("light.qss");
     }
     if (!QFile::exists(style_path)) {
-        LOG_INFO(Frontend, "Themed (light/dark) stylesheet could not be found, using default one");
+        LOG_DEBUG(Frontend, "No themed (light/dark) stylesheet, using default one");
         // Use common stylesheet if themed one does not exist
         style_path = theme_uri + QStringLiteral("style.qss");
     }
@@ -4884,7 +4884,7 @@ bool GMainWindow::TryLoadStylesheet(const QString& theme_uri) {
         // Update the color palette before applying the stylesheet
         UpdateThemePalette();
 
-        LOG_INFO(Frontend, "Loading stylesheet in: {}", theme_uri.toStdString());
+        LOG_DEBUG(Frontend, "Loading stylesheet in: {}", theme_uri.toStdString());
         QTextStream ts_theme(&style_file);
         qApp->setStyleSheet(ts_theme.readAll());
         setStyleSheet(ts_theme.readAll());
@@ -4947,7 +4947,6 @@ void GMainWindow::UpdateThemePalette() {
 #else
     if (CheckDarkMode()) {
         // Set Dark palette on non Windows platforms (that may not have a dark palette)
-        LOG_INFO(Frontend, "Using custom dark palette");
         themePalette.setColor(QPalette::Window, QColor(53, 53, 53));
         themePalette.setColor(QPalette::WindowText, Qt::white);
         themePalette.setColor(QPalette::Disabled, QPalette::WindowText, QColor(127, 127, 127));
@@ -4969,7 +4968,6 @@ void GMainWindow::UpdateThemePalette() {
         themePalette.setColor(QPalette::HighlightedText, Qt::white);
         themePalette.setColor(QPalette::Disabled, QPalette::HighlightedText, QColor(127, 127, 127));
     } else {
-        LOG_INFO(Frontend, "Using standard palette");
         // Reset light palette on non Windows platforms
         themePalette = this->style()->standardPalette();
     }
@@ -5031,13 +5029,23 @@ bool GMainWindow::ListenColorSchemeChange() {
 #endif
 
 bool GMainWindow::CheckDarkMode() {
+    bool is_dark_mode_auto;
+#ifdef _WIN32
+    // Dark mode cannot be changed after the app started on Windows
+    is_dark_mode_auto = qgetenv("QT_QPA_PLATFORM").contains("darkmode=2");
+#else
+    is_dark_mode_auto = UISettings::values.dark_mode_state == DarkModeState::Auto;
+#endif
+    if (!is_dark_mode_auto) {
+        return UISettings::values.dark_mode_state == DarkModeState::On;
+    } else {
         const QPalette current_palette(qApp->palette());
 #ifdef __unix__
         QProcess process;
-    QStringList gdbus_arguments;
 
         // Using the freedesktop specifications for checking dark mode
-    LOG_INFO(Frontend, "Retrieving theme from freedesktop color-scheme...");
+        LOG_DEBUG(Frontend, "Retrieving theme from freedesktop color-scheme...");
+        QStringList gdbus_arguments;
         gdbus_arguments << QStringLiteral("--dest=org.freedesktop.portal.Desktop")
                         << QStringLiteral("--object-path /org/freedesktop/portal/desktop")
                         << QStringLiteral("--method org.freedesktop.portal.Settings.Read")
@@ -5064,7 +5072,7 @@ bool GMainWindow::CheckDarkMode() {
 
         // Try older gtk-theme method if the previous one failed
         if (gsettings_output.isEmpty()) {
-        LOG_INFO(Frontend, "failed, retrieving theme from gtk-theme...");
+            LOG_DEBUG(Frontend, "failed, retrieving theme from gtk-theme...");
             gsettings_arguments.takeLast();
             gsettings_arguments << QStringLiteral("gtk-theme");
 
@@ -5081,19 +5089,20 @@ bool GMainWindow::CheckDarkMode() {
         }
         LOG_DEBUG(Frontend, "failed, retrieving theme from palette");
 #endif
-    // Use default method based on palette swap by OS.
+        // Use default method based on palette swap by OS. It is the only method on Windows with
-    // It is the only method on Windows with Qt 5.
+        // Qt 5. Windows needs QT_QPA_PLATFORM env variable set to windows:darkmode=2 to force
-    // Windows needs QT_QPA_PLATFORM env variable set to windows:darkmode=2 to force palette change
+        // palette change
         return (current_palette.color(QPalette::WindowText).lightness() >
                 current_palette.color(QPalette::Window).lightness());
     }
+}
 
 void GMainWindow::changeEvent(QEvent* event) {
     // PaletteChange event appears to only reach so far into the GUI, explicitly asking to
     // UpdateUITheme is a decent work around
     if (event->type() == QEvent::PaletteChange ||
         event->type() == QEvent::ApplicationPaletteChange) {
-        LOG_INFO(Frontend,
+        LOG_DEBUG(Frontend,
                   "Window color palette changed by event: {} (QEvent::PaletteChange is: {})",
                   event->type(), QEvent::PaletteChange);
         const QPalette test_palette(qApp->palette());
@@ -5285,6 +5294,13 @@ int main(int argc, char* argv[]) {
     QCoreApplication::setApplicationName(QStringLiteral("yuzu"));
 
 #ifdef _WIN32
+    QByteArray current_qt_qpa = qgetenv("QT_QPA_PLATFORM");
+    // Follow dark mode setting, if the "-platform" launch option is not set
+    if (UISettings::values.dark_mode_state == DarkModeState::Auto && current_qt_qpa.isEmpty()) {
+        // When setting is Auto, force adapting window decoration and stylesheet palette to use
+        // Windows theme. Default is darkmode:0, which always uses light palette
+        qputenv("QT_QPA_PLATFORM", QByteArray("windows:darkmode=2"));
+    }
     // Increases the maximum open file limit to 8192
     _setmaxstdio(8192);
 #endif

src/yuzu/startup_checks.cpp

@@ -6,7 +6,6 @@
 #ifdef _WIN32
 #include <cstring>
 #include <QByteArray>
-#include <QtGlobal>
 #include <processthreadsapi.h>
 #include <windows.h>
 #elif defined(YUZU_UNIX)
@@ -38,9 +37,6 @@ void CheckVulkan() {
 
 bool CheckEnvVars(bool* is_child) {
 #ifdef _WIN32
-    // Force adapting theme to follow Windows dark mode
-    qputenv("QT_QPA_PLATFORM", QByteArray("windows:darkmode=2"));
-
     // Check environment variable to see if we are the child
     char variable_contents[8];
     const DWORD startup_check_var =

src/yuzu/uisettings.h

@@ -18,6 +18,7 @@
 
 using Settings::Category;
 using Settings::ConfirmStop;
+using Settings::DarkModeState;
 using Settings::Setting;
 using Settings::SwitchableSetting;
 
@@ -144,6 +145,7 @@ struct Values {
     Setting<std::string> language{linkage, {}, "language", Category::Paths};
 
     QString theme;
+    DarkModeState dark_mode_state;
 
     // Shortcut name <Shortcut, context>
     std::vector<Shortcut> shortcuts;
@@ -260,3 +262,4 @@ Q_DECLARE_METATYPE(Settings::RendererBackend);
 Q_DECLARE_METATYPE(Settings::ShaderBackend);
 Q_DECLARE_METATYPE(Settings::AstcRecompression);
 Q_DECLARE_METATYPE(Settings::AstcDecodeMode);
+Q_DECLARE_METATYPE(Settings::DarkModeState);