WaveTrackView now delegates to the proper sub-view...

... by a redefined area subdivision policy in TrackPanel

So the SpectrumView, WaveformView, and associated ruler and handle classes
find real use, while WaveTrackView is really used only for its height and to
supply the delegate, and WaveTrackVRulerControls and WaveTrackVZoomHandle
are not used

There is also some anticipation of multiple track views

src/TrackPanel.cpp

@@ -916,15 +916,29 @@ void TrackPanel::UpdateTrackVRuler(Track *t)
       return;
 
    wxRect rect(mViewInfo->GetVRulerOffset(),
-            kTopMargin,
+            0,
             mViewInfo->GetVRulerWidth(),
             0);
 
 
    for (auto channel : TrackList::Channels(t)) {
       auto &view = TrackView::Get( *channel );
-      rect.height = view.GetHeight() - (kTopMargin + kBottomMargin);
-      TrackVRulerControls::Get( *channel ).UpdateRuler( rect );
+      const auto height = view.GetHeight() - (kTopMargin + kBottomMargin);
+      const auto subViews = view.GetSubViews( rect );
+      if (subViews.empty())
+         continue;
+   
+      auto iter = subViews.begin(), end = subViews.end(), next = iter;
+      auto yy = iter->first;
+      for ( ; iter != end; iter = next ) {
+         ++next;
+         auto nextY = ( next == end )
+            ? height
+            : next->first;
+         rect.SetHeight( nextY - yy );
+         TrackVRulerControls::Get( *iter->second ).UpdateRuler( rect );
+         yy = nextY;
+      }
    }
 }
 
@@ -1093,39 +1107,48 @@ struct EmptyCell final : CommonTrackPanelCell {
 // A vertical ruler left of a channel
 struct VRulerAndChannel final : TrackPanelGroup {
    VRulerAndChannel(
-      const std::shared_ptr< Track > &pChannel, wxCoord leftOffset )
-         : mpChannel{ pChannel }, mLeftOffset{ leftOffset } {}
+      const std::shared_ptr< TrackView > &pView, wxCoord leftOffset )
+         : mpView{ pView }, mLeftOffset{ leftOffset } {}
    Subdivision Children( const wxRect &rect ) override
    {
       return { Axis::X, Refinement{
          { rect.GetLeft(),
-           TrackVRulerControls::Get( *mpChannel ).shared_from_this() },
-         { mLeftOffset,
-           TrackView::Get( *mpChannel ).shared_from_this() }
+           TrackVRulerControls::Get( *mpView ).shared_from_this() },
+         { mLeftOffset, mpView }
       } };
    }
-   std::shared_ptr< Track > mpChannel;
+   std::shared_ptr< TrackView > mpView;
    wxCoord mLeftOffset;
 };
 
-// n channels with vertical rulers, alternating with n - 1 resizers
+// n channels with vertical rulers, alternating with n - 1 resizers;
+// each channel-ruler pair might be divided into multiple views
 struct ChannelGroup final : TrackPanelGroup {
    ChannelGroup( const std::shared_ptr< Track > &pTrack, wxCoord leftOffset )
       : mpTrack{ pTrack }, mLeftOffset{ leftOffset } {}
-   Subdivision Children( const wxRect &rect ) override
+   Subdivision Children( const wxRect &rect_ ) override
    {
+      auto rect = rect_;
       Refinement refinement;
 
       const auto channels = TrackList::Channels( mpTrack.get() );
       const auto pLast = *channels.rbegin();
       wxCoord yy = rect.GetTop();
       for ( auto channel : channels ) {
-         refinement.emplace_back( yy,
-            std::make_shared< VRulerAndChannel >(
-               channel->SharedPointer(), mLeftOffset ) );
-         if ( channel != pLast ) {
          auto &view = TrackView::Get( *channel );
-            yy += view.GetHeight();
+         auto height = view.GetHeight();
+         rect.SetTop( yy );
+         rect.SetHeight( height );
+         const auto subViews = TrackView::Get( *channel ).GetSubViews( rect );
+         auto y1 = yy;
+         for ( const auto &subView : subViews ) {
+            y1 = std::max( y1, subView.first );
+            refinement.emplace_back( y1,
+               std::make_shared< VRulerAndChannel >(
+                  subView.second, mLeftOffset ) );
+         }
+         if ( channel != pLast ) {
+            yy += height;
             refinement.emplace_back(
                yy - kSeparatorThickness,
                TrackView::Get( *channel ).GetResizer() );

src/tracks/playabletrack/wavetrack/ui/WaveTrackView.cpp

@@ -85,6 +85,19 @@ WaveTrackView::DoDetailedHitTest
    return { false, results };
 }
 
+auto WaveTrackView::GetSubViews( const wxRect &rect ) -> Refinement
+{
+   auto wt = static_cast<WaveTrack*>( FindTrack().get() );
+   return {
+      {
+         rect.GetTop(),
+         wt->GetDisplay() == WaveTrackViewConstants::Waveform
+            ? mWaveformView
+            : mSpectrumView
+      }
+   };
+}
+
 void WaveTrackView::DoSetMinimized( bool minimized )
 {
    auto wt = static_cast<WaveTrack*>( FindTrack().get() );

src/tracks/playabletrack/wavetrack/ui/WaveTrackView.h

@@ -50,6 +50,9 @@ private:
       const std::shared_ptr<WaveTrack> &wt,
       CommonTrackView &view);
 
+   // TrackView implementation
+   Refinement GetSubViews( const wxRect &rect ) override;
+
 protected:
    void DoSetMinimized( bool minimized ) override;
 

src/tracks/ui/TrackVRulerControls.cpp

@@ -33,16 +33,6 @@ TrackVRulerControls::~TrackVRulerControls()
 {
 }
 
-TrackVRulerControls &TrackVRulerControls::Get( Track &track )
-{
-   return *TrackView::Get( track ).GetVRulerControls();
-}
-
-const TrackVRulerControls &TrackVRulerControls::Get( const Track &track )
-{
-   return *TrackView::Get( track ).GetVRulerControls();
-}
-
 TrackVRulerControls &TrackVRulerControls::Get( TrackView &trackView )
 {
    return *trackView.GetVRulerControls();

src/tracks/ui/TrackVRulerControls.h

@@ -28,9 +28,6 @@ public:
 
    virtual ~TrackVRulerControls() = 0;
 
-   static TrackVRulerControls &Get( Track& );
-   static const TrackVRulerControls &Get( const Track& );
-
    static TrackVRulerControls &Get( TrackView& );
    static const TrackVRulerControls &Get( const TrackView& );
 

src/tracks/ui/TrackView.cpp

@@ -106,6 +106,11 @@ bool TrackView::HandleXMLAttribute( const wxChar *attr, const wxChar *value )
       return false;
 }
 
+auto TrackView::GetSubViews( const wxRect &rect ) -> Refinement
+{
+   return { { rect.GetTop(), shared_from_this() } };
+}
+
 void TrackView::DoSetMinimized(bool isMinimized)
 {
    mMinimized = isMinimized;

src/tracks/ui/TrackView.h

@@ -72,6 +72,13 @@ public:
    void WriteXMLAttributes( XMLWriter & ) const override;
    bool HandleXMLAttribute( const wxChar *attr, const wxChar *value ) override;
 
+   // New virtual function.  The default just returns a one-element array
+   // containing this.  Overrides might refine the Y axis.
+   using Refinement = std::vector< std::pair<
+      wxCoord, std::shared_ptr< TrackView >
+   > >;
+   virtual Refinement GetSubViews( const wxRect &rect );
+
 protected:
    virtual void DoSetMinimized( bool isMinimized );