viewer: clean up some font related functions

app/widget/viewer/viewertexteditor.cpp

@@ -40,7 +40,6 @@ ViewerTextEditor::ViewerTextEditor(double scale, QWidget *parent) :
   super(parent),
   transparent_clone_(nullptr),
   block_update_toolbar_signal_(false),
-  listen_to_focus_events_(false),
   forced_default_(false)
 {
   // Ensure default text color is white
@@ -208,10 +207,7 @@ void ViewerTextEditor::SetFamily(const QString &s)
   ViewerTextEditorToolBar *toolbar = static_cast<ViewerTextEditorToolBar *>(sender());
 
   QTextCharFormat f;
-  f.setFontFamily(s);
-#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
   f.setFontFamilies({s});
-#endif
 
   ApplyStyle(&f, s, toolbar->GetFontStyleName());
 
@@ -271,9 +267,8 @@ void ViewerTextEditor::ApplyStyle(QTextCharFormat *format, const QString &family
 {
   // NOTE: Windows appears to require setting weight and italic manually, while macOS and Linux are
   //       perfectly fine with just the style name
-  QFontDatabase fd;
-  format->setFontWeight(fd.weight(family, style));
-  format->setFontItalic(fd.italic(family, style));
+  format->setFontWeight(QFontDatabase::weight(family, style));
+  format->setFontItalic(QFontDatabase::italic(family, style));
 
   format->setFontStyleName(style);
 }
@@ -541,7 +536,7 @@ void ViewerTextEditorToolBar::UpdateFontStyleList(const QString &family)
 
   style_combo_->blockSignals(true);
   style_combo_->clear();
-  QStringList l = QFontDatabase().styles(family);
+  QStringList l = QFontDatabase::styles(family);
   foreach (const QString &style, l) {
     style_combo_->addItem(style);
   }

app/widget/viewer/viewertexteditor.h

@@ -151,8 +151,6 @@ public:
 
   void ConnectToolBar(ViewerTextEditorToolBar *toolbar);
 
-  void SetListenToFocusEvents(bool e) { listen_to_focus_events_ = e; }
-
   void Paint(QPainter *p, Qt::Alignment valign);
 
   virtual void dragEnterEvent(QDragEnterEvent *e) override { return QTextEdit::dragEnterEvent(e); }
@@ -178,8 +176,6 @@ private:
 
   bool block_update_toolbar_signal_;
 
-  bool listen_to_focus_events_;
-
   bool forced_default_;
   QTextCharFormat default_fmt_;