Remove VisibleTrackIterator

src/Track.cpp

@@ -607,29 +607,6 @@ bool SelectedTrackListOfKindIterator::Condition(Track *t)
    return TrackListOfKindIterator::Condition(t) && t->GetSelected();
 }
 
-// VisibleTrackIterator
-//
-// Based on TrackListIterator returns only the currently visible tracks.
-//
-VisibleTrackIterator::VisibleTrackIterator(AudacityProject *project)
-:  TrackListCondIterator(project->GetTracks())
-{
-   mProject = project;
-   mPanelRect.SetTop(mProject->mViewInfo.vpos);
-   mPanelRect.SetSize(mProject->GetTPTracksUsableArea());
-}
-
-bool VisibleTrackIterator::Condition(Track *t)
-{
-   wxRect r(0, t->GetY(), 1, t->GetHeight());
-   if( r.Intersects(mPanelRect) )
-      return true;
-   auto partner = t->GetLink();
-   if ( partner && t->GetLinked() )
-      return Condition( partner );
-   return false;
-}
-
 // SyncLockedTracksIterator
 //
 // Based on TrackListIterator returns only tracks belonging to the group

src/Track.h

@@ -1224,26 +1224,6 @@ class AUDACITY_DLL_API SelectedTrackListOfKindIterator final : public TrackListO
    bool Condition(Track *t) override;
 };
 
-//
-// VisibleTrackIterator
-//
-// Based on TrackListIterator returns only the currently visible tracks.
-//
-class AUDACITY_DLL_API VisibleTrackIterator final : public TrackListCondIterator
-{
- public:
-   VisibleTrackIterator(AudacityProject *project);
-   virtual ~VisibleTrackIterator() {}
-
- protected:
-   bool Condition(Track *t) override;
-
- private:
-   AudacityProject *mProject;
-   wxRect mPanelRect;
-};
-
-
 // SyncLockedTracksIterator returns only tracks belonging to the sync-locked tracks
 // in which the starting track is a member.
 class AUDACITY_DLL_API SyncLockedTracksIterator final : public TrackListIterator

src/TrackPanel.cpp

@@ -1200,8 +1200,8 @@ void TrackPanel::DrawEverythingElse(TrackPanelDrawingContext &context,
    wxRect trackRect = clip;
    trackRect.height = 0;   // for drawing background in no tracks case.
 
-   VisibleTrackIterator iter(GetProject());
-   for (const Track *t = iter.First(); t; t = iter.Next()) {
+   for ( auto t :
+         GetTracks()->Any< const Track >() + IsVisibleTrack{ GetProject() } ) {
       t = t->SubstitutePendingChangedTrack().get();
       trackRect.y = t->GetY() - mViewInfo->vpos;
       trackRect.height = t->GetHeight();
@@ -1220,8 +1220,8 @@ void TrackPanel::DrawEverythingElse(TrackPanelDrawingContext &context,
       }
 
       // If the previous track is linked to this one but isn't on the screen
-      // (and thus would have been skipped by VisibleTrackIterator) we need to
-      // draw that track's border instead.
+      // (and thus would have been skipped) we need to draw that track's border
+      // instead.
       const Track *borderTrack = t;
       wxRect borderRect = rect;
 
@@ -2686,10 +2686,13 @@ IteratorRange< TrackPanelCellIterator > TrackPanel::Cells()
 
 TrackPanelCellIterator::TrackPanelCellIterator(TrackPanel *trackPanel, bool begin)
    : mPanel{ trackPanel }
-   , mIter{ trackPanel->GetProject() }
+   , mIter{
+        trackPanel->GetTracks()->Any().begin()
+           .Filter( IsVisibleTrack( trackPanel->GetProject() ) )
+     }
 {
    if (begin) {
-      mpTrack = Track::Pointer( mIter.First() );
+      mpTrack = Track::Pointer( *mIter );
       if (mpTrack)
          mpCell = mpTrack;
       else
@@ -2707,7 +2710,7 @@ TrackPanelCellIterator &TrackPanelCellIterator::operator++ ()
 {
    if ( mpTrack ) {
       if ( ++ mType == CellType::Background )
-         mType = CellType::Track, mpTrack = Track::Pointer( mIter.Next() );
+         mType = CellType::Track, mpTrack = Track::Pointer( * ++ mIter );
    }
    if ( mpTrack ) {
       if ( mType == CellType::Label &&
@@ -2909,3 +2912,23 @@ unsigned TrackPanelCell::Char(wxKeyEvent &event, ViewInfo &, wxWindow *)
    event.Skip();
    return RefreshCode::RefreshNone;
 }
+
+IsVisibleTrack::IsVisibleTrack(AudacityProject *project)
+   : mPanelRect {
+        wxPoint{ 0, project->mViewInfo.vpos },
+        project->GetTPTracksUsableArea()
+     }
+{}
+
+bool IsVisibleTrack::operator () (const Track *pTrack) const
+{
+   // Need to return true if this track or a later channel intersects
+   // the view
+   return
+   TrackList::Channels(pTrack).StartingWith(pTrack).any_of(
+      [this]( const Track *pT ) {
+         wxRect r(0, pT->GetY(), 1, pT->GetHeight());
+         return r.Intersects(mPanelRect);
+      }
+   );
+}

src/TrackPanel.h

@@ -489,6 +489,16 @@ protected:
    friend class GetInfoCommand;
 };
 
+// A predicate class
+struct IsVisibleTrack
+{
+   IsVisibleTrack(AudacityProject *project);
+
+   bool operator () (const Track *pTrack) const;
+
+   wxRect mPanelRect;
+};
+
 // See big pictorial comment in TrackPanel for explanation of these numbers
 enum : int {
    kLeftInset = 4,

src/TrackPanelCellIterator.h

@@ -53,7 +53,7 @@ private:
    void UpdateRect();
 
    TrackPanel *mPanel;
-   VisibleTrackIterator mIter;
+   TrackIter<Track> mIter;
    std::shared_ptr<Track> mpTrack;
    std::shared_ptr<TrackPanelCell> mpCell;
    CellType mType{ CellType::Track };

src/commands/GetInfoCommand.cpp

@@ -484,8 +484,7 @@ void GetInfoCommand::ExploreTrackPanel( const CommandContext &context,
 
    wxRect trackRect = pWin->GetRect();
 
-   VisibleTrackIterator iter(pProj);
-   for (Track *t = iter.First(); t; t = iter.Next()) {
+   for (auto t : pProj->GetTracks()->Any() + IsVisibleTrack{ pProj }) {
       trackRect.y = t->GetY() - pTP->mViewInfo->vpos;
       trackRect.height = t->GetHeight();