timeline: improved subtitle import behavior

app/widget/timelinewidget/timelinewidget.cpp

@@ -157,11 +157,6 @@ TimelineWidget::TimelineWidget(QWidget *parent) :
     connect(view, &TimelineView::DragLeft, this, &TimelineWidget::ViewDragLeft);
     connect(view, &TimelineView::DragDropped, this, &TimelineWidget::ViewDragDropped);
 
-    TrackView *tv = tview->track_view();
-    connect(tv, &TrackView::DragEntered, this, &TimelineWidget::ViewDragEntered);
-    connect(tv, &TrackView::DragLeft, this, &TimelineWidget::ViewDragLeft);
-    connect(tv, &TrackView::DragDropped, this, &TimelineWidget::ViewDragDropped);
-
     connect(tview->splitter(), &QSplitter::splitterMoved, this, &TimelineWidget::UpdateHorizontalSplitters);
 
     // Connect each view's scroll to each other

app/widget/timelinewidget/timelinewidget.h

@@ -109,8 +109,6 @@ public:
 
   void AddTentativeSubtitleTrack();
 
-  void ClearTentativeSubtitleTrack();
-
   /**
    * @brief Timelines should always be connected to sequences
    */
@@ -271,6 +269,9 @@ public:
 
   };
 
+public slots:
+  void ClearTentativeSubtitleTrack();
+
 signals:
   void BlockSelectionChanged(const QVector<Block*>& selected_blocks);
 

app/widget/timelinewidget/tool/import.cpp

@@ -97,6 +97,11 @@ void ImportTool::DragEnter(TimelineViewMouseEvent *event)
     PrepGhosts(ghost_offset_, drag_start_.GetTrack().index());
 
     if (parent()->HasGhosts() || !parent()->GetConnectedNode()) {
+      // We only clear the tentative track if the mimedata is about to be destroyed (i.e. the drag
+      // is cancelled). If we do this in DragLeave, it leads to undesirable behavior if the cursor
+      // is going between views (subtitle track rapidly appearing and disappearing)
+      QObject::connect(event->GetMimeData(), &QObject::destroyed, parent(), &TimelineWidget::ClearTentativeSubtitleTrack);
+
       event->accept();
     } else {
       event->ignore();
@@ -167,7 +172,6 @@ void ImportTool::DragLeave(QDragLeaveEvent* event)
 {
   if (!dragged_footage_.isEmpty()) {
     parent()->ClearGhosts();
-    parent()->ClearTentativeSubtitleTrack();
     dragged_footage_.clear();
 
     event->accept();

app/widget/timelinewidget/trackview/trackview.cpp

@@ -124,9 +124,6 @@ void TrackView::InsertTrack(Track *track)
   TrackViewItem *tvi = new TrackViewItem(track);
 
   connect(tvi, &TrackViewItem::AboutToDeleteTrack, this, &TrackView::AboutToDeleteTrack);
-  connect(tvi, &TrackViewItem::DragEntered, this, &TrackView::DragEntered);
-  connect(tvi, &TrackViewItem::DragLeft, this, &TrackView::DragLeft);
-  connect(tvi, &TrackViewItem::DragDropped, this, &TrackView::DragDropped);
 
   splitter_->Insert(track->Index(),
                     track->GetTrackHeightInPixels(),

app/widget/timelinewidget/trackview/trackview.h

@@ -43,10 +43,6 @@ public:
 signals:
   void AboutToDeleteTrack(Track *track);
 
-  void DragEntered(TimelineViewMouseEvent* event);
-  void DragLeft(QDragLeaveEvent* event);
-  void DragDropped(TimelineViewMouseEvent* event);
-
 protected:
   virtual void resizeEvent(QResizeEvent *e) override;
 

app/widget/timelinewidget/trackview/trackviewitem.cpp

@@ -76,34 +76,11 @@ TrackViewItem::TrackViewItem(Track* track, QWidget *parent) :
 
   setMinimumHeight(mute_button_->height());
   setContextMenuPolicy(Qt::CustomContextMenu);
-  setAcceptDrops(true);
 
   connect(track, &Track::MutedChanged, mute_button_, &QPushButton::setChecked);
   connect(this, &QWidget::customContextMenuRequested, this, &TrackViewItem::ShowContextMenu);
 }
 
-void TrackViewItem::dragEnterEvent(QDragEnterEvent *event)
-{
-  TimelineViewMouseEvent e(0, 1, 1, track_->ToReference(), Qt::NoButton, event->keyboardModifiers());
-  e.SetMimeData(event->mimeData());
-  e.SetEvent(event);
-  e.SetBypassImportBuffer(true);
-  emit DragEntered(&e);
-}
-
-void TrackViewItem::dragLeaveEvent(QDragLeaveEvent *event)
-{
-  emit DragLeft(event);
-}
-
-void TrackViewItem::dropEvent(QDropEvent *event)
-{
-  TimelineViewMouseEvent e(0, 1, 1, track_->ToReference(), Qt::NoButton, event->keyboardModifiers());
-  e.SetMimeData(event->mimeData());
-  e.SetEvent(event);
-  emit DragDropped(&e);
-}
-
 QPushButton *TrackViewItem::CreateMSLButton(const QColor& checked_color) const
 {
   QPushButton* button = new QPushButton();

app/widget/timelinewidget/trackview/trackviewitem.h

@@ -42,15 +42,6 @@ public:
 signals:
   void AboutToDeleteTrack(Track *track);
 
-  void DragEntered(TimelineViewMouseEvent* event);
-  void DragLeft(QDragLeaveEvent* event);
-  void DragDropped(TimelineViewMouseEvent* event);
-
-protected:
-  virtual void dragEnterEvent(QDragEnterEvent *event) override;
-  virtual void dragLeaveEvent(QDragLeaveEvent *event) override;
-  virtual void dropEvent(QDropEvent *event) override;
-
 private:
   QPushButton* CreateMSLButton(const QColor &checked_color) const;