Save opacity in prefs

Author: leplatrem

src/mainwindow.cpp

@@ -332,6 +332,7 @@ void MainWindow::closeEvent(QCloseEvent *) {
 
   settings.beginGroup("PreviewPanel");
   QList<int> sizes = ui->tableAndPreview->sizes();
+  settings.setValue("opacity", m_previewpanel->opacity());
   settings.setValue("tableHeight", sizes[0]);
   settings.setValue("previewHeight", sizes[1]);
   settings.endGroup();

src/subtitlesform.h

@@ -36,6 +36,8 @@ class SubtitlesForm : public QWidget {
 public:
   explicit SubtitlesForm(QWidget *parent = nullptr);
   ~SubtitlesForm();
+  double opacity() { return m_opacity; }
+
 signals:
   void geometryChanged(QRect);
 public slots: