better attachment between labels and tracks

timeline/track.cpp

@@ -71,6 +71,7 @@ int Track::height()
 void Track::set_height(int h)
 {
   height_ = qMax(h, olive::timeline::kTrackMinHeight);
+  emit HeightChanged(h);
 }
 
 QString Track::name()

timeline/track.h

@@ -98,6 +98,9 @@ public slots:
   void SetSoloed(bool soloed);
   void SetLocked(bool locked);
 
+signals:
+  void HeightChanged(int height);
+
 private:
   void ResizeClipArray(int new_size);
 

timeline/tracklist.cpp

@@ -37,6 +37,8 @@ void TrackList::AddTrack()
 {
   Track* track = new Track(this, type_);
   tracks_.append(track);
+
+  emit TrackCountChanged();
 }
 
 void TrackList::RemoveTrack(int i)
@@ -45,6 +47,8 @@ void TrackList::RemoveTrack(int i)
     return;
   }
   tracks_.removeAt(i);
+
+  emit TrackCountChanged();
 }
 
 Track *TrackList::First()
@@ -52,6 +56,11 @@ Track *TrackList::First()
   return tracks_.first();
 }
 
+Track *TrackList::Last()
+{
+  return tracks_.last();
+}
+
 int TrackList::TrackCount()
 {
   return tracks_.size();

timeline/tracklist.h

@@ -15,6 +15,7 @@ public:
   void AddTrack();
   void RemoveTrack(int i);
   Track* First();
+  Track* Last();
   int TrackCount();
   int IndexOfTrack(Track* track);
   Track* TrackAt(int i);
@@ -24,6 +25,9 @@ public:
 
   Sequence* GetParent();
 
+signals:
+  void TrackCountChanged();
+
 private:
   void ResizeTrackArray(int i);