Allow to configure style and color scheme on all platforms

PR #23522.

src/base/preferences.cpp

@@ -494,10 +494,17 @@ void Preferences::setWinStartup(const bool b)
         settings.remove(profileID);
     }
 }
+#endif // Q_OS_WIN
 
 QString Preferences::getStyle() const
 {
-    return value<QString>(u"Appearance/Style"_s);
+#ifdef Q_OS_WIN
+    const QString defaultStyleName = u"Fusion"_s;
+#else
+    const QString defaultStyleName = u"system"_s;
+#endif
+    const auto styleName = value<QString>(u"Appearance/Style"_s);
+    return styleName.isEmpty() ? defaultStyleName : styleName;
 }
 
 void Preferences::setStyle(const QString &styleName)
@@ -507,7 +514,6 @@ void Preferences::setStyle(const QString &styleName)
 
     setValue(u"Appearance/Style"_s, styleName);
 }
-#endif // Q_OS_WIN
 
 // Downloads
 Path Preferences::getScanDirsLastPath() const

src/base/preferences.h

@@ -137,11 +137,11 @@ public:
     void setPreventFromSuspendWhenDownloading(bool b);
     bool preventFromSuspendWhenSeeding() const;
     void setPreventFromSuspendWhenSeeding(bool b);
+    QString getStyle() const;
+    void setStyle(const QString &styleName);
 #ifdef Q_OS_WIN
     bool WinStartup() const;
     void setWinStartup(bool b);
-    QString getStyle() const;
-    void setStyle(const QString &styleName);
 #endif
 
     // Downloads

src/gui/optionsdialog.cpp

@@ -43,13 +43,10 @@
 #include <QEvent>
 #include <QFileDialog>
 #include <QMessageBox>
+#include <QStyleFactory>
 #include <QSystemTrayIcon>
 #include <QTranslator>
 
-#ifdef Q_OS_WIN
-#include <QStyleFactory>
-#endif
-
 #include "base/bittorrent/session.h"
 #include "base/bittorrent/sharelimitaction.h"
 #include "base/exceptions.h"
@@ -376,11 +373,7 @@ void OptionsDialog::loadBehaviorTabOptions()
     m_ui->checkBoxPerformanceWarning->setChecked(session->isPerformanceWarningEnabled());
 
     connect(m_ui->comboLanguage, qComboBoxCurrentIndexChanged, this, &ThisType::enableApplyButton);
-
-#ifdef Q_OS_WIN
     connect(m_ui->comboStyle, qComboBoxCurrentIndexChanged, this, &ThisType::enableApplyButton);
-#endif
-
 #ifdef QBT_HAS_COLORSCHEME_OPTION
     connect(m_ui->comboColorScheme, qComboBoxCurrentIndexChanged, this, &ThisType::enableApplyButton);
 #endif
@@ -488,9 +481,7 @@ void OptionsDialog::saveBehaviorTabOptions() const
     }
     pref->setLocale(locale);
 
-#ifdef Q_OS_WIN
     pref->setStyle(m_ui->comboStyle->currentData().toString());
-#endif
 
 #ifdef QBT_HAS_COLORSCHEME_OPTION
     UIThemeManager::instance()->setColorScheme(m_ui->comboColorScheme->currentData().value<ColorScheme>());
@@ -1846,6 +1837,11 @@ void OptionsDialog::initializeStyleCombo()
 #ifdef Q_OS_WIN
     m_ui->labelStyleHint->setText(tr("%1 is recommended for best compatibility with Windows dark mode"
             , "Fusion is recommended for best compatibility with Windows dark mode").arg(u"Fusion"_s));
+#else
+    m_ui->labelStyleHint->hide();
+    m_ui->layoutStyle->removeWidget(m_ui->labelStyleHint);
+#endif
+
     m_ui->comboStyle->addItem(tr("System", "System default Qt style"), u"system"_s);
     m_ui->comboStyle->setItemData(0, tr("Let Qt decide the style for this system"), Qt::ToolTipRole);
     m_ui->comboStyle->insertSeparator(1);
@@ -1859,14 +1855,6 @@ void OptionsDialog::initializeStyleCombo()
     const QString selectedStyleName = prefStyleName.isEmpty() ? QApplication::style()->name() : prefStyleName;
     const int styleIndex = m_ui->comboStyle->findData(selectedStyleName, Qt::UserRole, Qt::MatchFixedString);
     m_ui->comboStyle->setCurrentIndex(std::max(0, styleIndex));
-#else
-    m_ui->labelStyle->hide();
-    m_ui->comboStyle->hide();
-    m_ui->labelStyleHint->hide();
-    m_ui->layoutStyle->removeWidget(m_ui->labelStyle);
-    m_ui->layoutStyle->removeWidget(m_ui->comboStyle);
-    m_ui->layoutStyle->removeWidget(m_ui->labelStyleHint);
-#endif
 }
 
 void OptionsDialog::initializeColorSchemeOptions()

src/gui/uithememanager.cpp

@@ -76,13 +76,11 @@ UIThemeManager::UIThemeManager()
     , m_useSystemIcons {Preferences::instance()->useSystemIcons()}
 #endif
 {
-#ifdef Q_OS_WIN
     if (const QString styleName = Preferences::instance()->getStyle(); styleName.compare(u"system", Qt::CaseInsensitive) != 0)
     {
-        if (!QApplication::setStyle(styleName.isEmpty() ? u"Fusion"_s : styleName))
+        if (!QApplication::setStyle(styleName))
             LogMsg(tr("Set app style failed. Unknown style: \"%1\"").arg(styleName), Log::WARNING);
     }
-#endif
 
 #ifdef QBT_HAS_COLORSCHEME_OPTION
     applyColorScheme();

src/gui/uithememanager.h

@@ -41,7 +41,7 @@
 
 #include "uithemesource.h"
 
-#if (QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)) && defined(Q_OS_WIN)
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 8, 0))
 #define QBT_HAS_COLORSCHEME_OPTION
 #endif