add a dark_theme flag to the mupp_startup.xml. This is can help if mupp at runtime cannot decide on the used theme.

src/musredit_qt5/mupp/PmuppAdmin.cpp

@@ -109,6 +109,8 @@ bool PmuppAdminXMLParser::startElement( const QString&, const QString&,
 {
   if (qName == "path_file_name") {
     fKeyWord = eRecentFile;
+  } else if (qName == "dark_theme") {
+    fKeyWord = eDarkTheme;
   } else if (qName == "marker") {
     fKeyWord = eMarker;
   } else if (qName == "color") {
@@ -152,6 +154,12 @@ bool PmuppAdminXMLParser::characters(const QString& str)
     case eRecentFile:
       fAdmin->addRecentFile(QString(str.toLatin1()).trimmed());
       break;
+    case eDarkTheme:
+      if ((str == "yes") || (str == "1") || (str == "true"))
+        fAdmin->setTheme(true);
+      else
+        fAdmin->setTheme(false);
+      break;
     case eMarker:
       tok = str.split(",", QString::SkipEmptyParts);
 
@@ -277,7 +285,7 @@ bool PmuppAdminXMLParser::fatalError( const QXmlParseException & exception )
  * <p>Initializes that PmuppAdmin object, and calls the XML parser which feeds
  * the object variables.
  */
-PmuppAdmin::PmuppAdmin() : QObject()
+PmuppAdmin::PmuppAdmin() : QObject(), fDarkTheme(false)
 {
   // XML Parser part
   // 1st: check local directory

src/musredit_qt5/mupp/PmuppAdmin.h

@@ -98,7 +98,7 @@ class PmuppAdminXMLParser : public QXmlDefaultHandler
     virtual ~PmuppAdminXMLParser() {}
 
   private:
-    enum EAdminKeyWords {eEmpty, eRecentFile, eMarker, eColor};
+    enum EAdminKeyWords {eEmpty, eRecentFile, eDarkTheme, eMarker, eColor};
 
     bool startDocument();
     bool startElement( const QString&, const QString&, const QString& ,
@@ -133,6 +133,8 @@ class PmuppAdmin : public QObject
     int     getNumRecentFiles() { return fRecentFile.size(); }
     QString getRecentFile(int idx);
 
+
+
     int getNoOfMarkers() { return fMarker.size(); }
     QVector<PmuppMarker> getMarkers() { return fMarker; }
     PmuppMarker getMarker(int idx);
@@ -142,6 +144,9 @@ class PmuppAdmin : public QObject
     void getColor(QString name, int &r, int &g, int &b);
     void getColor(int idx, int &r, int &g, int &b);
 
+    bool isDarkTheme() { return fDarkTheme; }
+
+    void setTheme(bool theme) { fDarkTheme = theme; }
     void setMarker(int marker, double size);
     void setColor(int r, int g, int b, QString name="");
 
@@ -150,6 +155,7 @@ class PmuppAdmin : public QObject
 
     QVector<QString> fRecentFile; ///< keep vector of recent path-file names
 
+    bool fDarkTheme;
     QVector<PmuppMarker> fMarker;
     QVector<PmuppColor> fColor;
 

src/musredit_qt5/mupp/PmuppGui.cpp

@@ -827,6 +827,14 @@ void PmuppGui::getTheme()
 
   QString str = QIcon::themeName();
 
+  if (str.isEmpty()) {
+    if (fAdmin->isDarkTheme()) {
+      fDarkTheme = true;
+      fDarkToolBarIcon = true;
+    }
+    return;
+  }
+
   if (str.contains("dark", Qt::CaseInsensitive)) {
     fDarkTheme = true;
     if (str.contains("ubuntu", Qt::CaseInsensitive)) {
@@ -835,6 +843,8 @@ void PmuppGui::getTheme()
       fDarkToolBarIcon = true;
     }
   }
+
+  QMessageBox::information(0, "INFO", QString("str='%1', fDarkTheme=%2").arg(str).arg(fDarkTheme));
 }
 
 //----------------------------------------------------------------------------------------------------

src/musredit_qt5/mupp/mupp_startup.xml.in

@@ -5,6 +5,7 @@
     </comment>
     <recent_files>
     </recent_files>
+    <dark_theme>no</dark_theme>
     <root_settings>
         <marker_list>
             <!-- Root marker numbers -->