FEAT(client): Automatically sync theme with OS color scheme- Fix

This update introduces an automatic theme switch that changes based on the OS color scheme at startup and during runtime. This feature is implemented for Qt 6.2 and includes compatibility for Qt 6.5 once Mumble upgrades.

Implements mumble-voip#6515

src/mumble/MainWindow.cpp

@@ -209,77 +209,6 @@ MainWindow::MainWindow(QWidget *p)
 
 	QAccessible::installFactory(AccessibleSlider::semanticSliderFactory);
 
-	applyTheme();
-}
-
-void MainWindow::applyTheme() {
-	boost::optional< ThemeInfo::StyleInfo > configuredStyle = Themes::getConfiguredStyle(Global::get().s);
-
-	QString lightThemePath = ":/themes/Default/Lite.qss"; // Default light theme path
-	QString darkThemePath  = ":/themes/Default/Dark.qss"; // Default dark theme path
-
-	if (configuredStyle) {
-		if (configuredStyle->name == "Auto") {
-#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
-			auto colorScheme = QGuiApplication::styleHints()->colorScheme();
-
-			if (colorScheme == Qt::ColorScheme::Dark) {
-				setStyleSheet(loadStyleSheet(darkThemePath)); // Apply dark theme
-			} else {
-				setStyleSheet(loadStyleSheet(lightThemePath)); // Apply light theme
-			}
-#else
-			bool isDarkTheme = detectSystemTheme();
-			if (isDarkTheme) {
-				setStyleSheet(loadStyleSheet(darkThemePath)); // Apply dark theme
-			} else {
-				setStyleSheet(loadStyleSheet(lightThemePath)); // Apply light theme
-			}
-#endif
-		} else if (configuredStyle->themeName == "none") {
-			setStyleSheet(""); // Clear the stylesheet if "None" is selected
-		} else {
-			QString themePath =
-				QString(":/themes/%1/%2.qss").arg(configuredStyle->themeName).arg(configuredStyle->name);
-			setStyleSheet(loadStyleSheet(themePath)); // Apply the selected theme and style
-		}
-	} else {
-		// Handle the case where no theme is configured (fallback to default behavior)
-		setStyleSheet(loadStyleSheet(lightThemePath)); // Default to light theme
-	}
-}
-
-bool MainWindow::detectSystemTheme() {
-#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
-	return false; // This should not be called for Qt 6.5 and above
-#else
-// Custom method to detect dark theme for Qt 6.2 and below
-#	ifdef Q_OS_WIN
-	QSettings settings("HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
-					   QSettings::NativeFormat);
-	return settings.value("AppsUseLightTheme", 1).toInt() == 0; // 0 means dark mode
-#	else
-	// Fallback for other OSes
-	QByteArray platform = qgetenv("QT_QPA_PLATFORM");
-	if (platform.contains("darkmode=2")) {
-		return true;
-	} else if (platform.contains("darkmode=1")) {
-		QPalette defaultPalette;
-		return defaultPalette.color(QPalette::WindowText).lightness()
-			   > defaultPalette.color(QPalette::Window).lightness();
-	}
-	return false;
-#	endif
-#endif
-}
-
-QString MainWindow::loadStyleSheet(const QString &path) {
-	QFile file(path);
-	if (file.open(QFile::ReadOnly | QFile::Text)) {
-		QTextStream stream(&file);
-		return stream.readAll(); // Return the stylesheet content
-	}
-	return QString(); // Return empty if the file cannot be loaded
 }
 
 void MainWindow::createActions() {
@@ -839,7 +768,7 @@ void MainWindow::changeEvent(QEvent *e) {
 	}
 #endif
 	if (e->type() == QEvent::ThemeChange) {
-		applyTheme();
+		Themes::apply();
 	}
 }
 

src/mumble/MainWindow.h

@@ -220,9 +220,6 @@ class MainWindow : public QMainWindow, public Ui::MainWindow {
 	ContextMenuTarget getContextMenuTargets();
 
 	void autocompleteUsername();
-	void applyTheme();
-	bool detectSystemTheme();
-	QString loadStyleSheet(const QString &path);
 
 public slots:
 	void on_qmServer_aboutToShow();

src/mumble/Themes.cpp

@@ -8,6 +8,14 @@
 #include "MumbleApplication.h"
 #include "Global.h"
 
+#include <QFile>
+#include <QGuiApplication>
+#include <QPalette>
+#include <QSettings>
+#include <QStyleHints>
+#include <QTextStream>
+
+
 boost::optional< ThemeInfo::StyleInfo > Themes::getConfiguredStyle(const Settings &settings) {
 	if (settings.themeName.isEmpty() && settings.themeStyleName.isEmpty()) {
 		return boost::none;
@@ -55,25 +63,59 @@ void Themes::applyFallback() {
 }
 
 bool Themes::applyConfigured() {
+	static QString currentThemePath;
+
+
 	boost::optional< ThemeInfo::StyleInfo > style = Themes::getConfiguredStyle(Global::get().s);
 	if (!style) {
 		return false;
 	}
 
-	const QFileInfo qssFile(style->getPlatformQss());
+	QString themePath;
+	if (style->themeName == "Auto" || style->name == "Auto") {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+		auto colorScheme = QGuiApplication::styleHints()->colorScheme();
+		if (colorScheme == Qt::ColorScheme::Dark) {
+			themePath = ":/themes/Default/Dark.qss";
+		} else {
+			themePath = ":/themes/Default/Lite.qss";
+		}
+#else
+		bool isDarkTheme = detectSystemTheme();
+		if (isDarkTheme) {
+			themePath = ":/themes/Default/Dark.qss";
+		} else {
+			themePath = ":/themes/Default/Lite.qss";
+		}
+#endif
+	} else {
+		if (style->name == "Dark") {
+			themePath = ":/themes/Default/Dark.qss";
+		} else {
+			themePath = ":/themes/Default/Lite.qss";
+		}
+	}
+
+	// Early exit if the theme path is the same as the current one
+	if (themePath == currentThemePath) {
+		qWarning() << "Themes::applyConfigured(): Skipping redundant theme application for path:" << themePath;
+		return true;
+	}
+
+	currentThemePath = themePath; // Update the current theme path
 
 	qWarning() << "Theme:" << style->themeName;
 	qWarning() << "Style:" << style->name;
-	qWarning() << "--> qss:" << qssFile.absoluteFilePath();
+	qWarning() << "--> qss:" << themePath;
 
-	QFile file(qssFile.absoluteFilePath());
+	QFile file(themePath);
 	if (!file.open(QFile::ReadOnly)) {
 		qWarning() << "Failed to open theme stylesheet:" << file.errorString();
 		return false;
 	}
 
 	QStringList skinPaths;
-	skinPaths << qssFile.path();
+	skinPaths << QFileInfo(themePath).path();
 	skinPaths << QLatin1String(":/themes/Default"); // Some skins might want to fall-back on our built-in resources
 
 	QString themeQss = QString::fromUtf8(file.readAll());
@@ -105,6 +147,30 @@ bool Themes::apply() {
 	return result;
 }
 
+bool Themes::detectSystemTheme() {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+	return false; // This should not be called for Qt 6.5 and above
+#else
+// Custom method to detect dark theme for Qt 6.2 and below
+#	ifdef Q_OS_WIN
+	QSettings settings("HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
+					   QSettings::NativeFormat);
+	return settings.value("AppsUseLightTheme", 1).toInt() == 0; // 0 means dark mode
+#	else
+	// Fallback for other OSes
+	QByteArray platform = qgetenv("QT_QPA_PLATFORM");
+	if (platform.contains("darkmode=2")) {
+		return true;
+	} else if (platform.contains("darkmode=1")) {
+		QPalette defaultPalette;
+		return defaultPalette.color(QPalette::WindowText).lightness()
+			   > defaultPalette.color(QPalette::Window).lightness();
+	}
+	return false;
+#	endif
+#endif
+}
+
 ThemeMap Themes::getThemes() {
 	return ThemeInfo::scanDirectories(getSearchDirectories());
 }

src/mumble/Themes.h

@@ -31,6 +31,9 @@ class Themes {
 	/// @note Can only apply a theme before MainWindow etc. is opened
 	static bool apply();
 
+	/// Detects current OS theme
+	static bool detectSystemTheme();
+
 	/// Return a theme name to theme map
 	static ThemeMap getThemes();