Remove one duplicate definition of track panel area subdivision

src/CellularPanel.cpp

@@ -1043,6 +1043,21 @@ wxRect CellularPanel::FindRect( const TrackPanelCell &cell )
    return result;
 }
 
+wxRect CellularPanel::FindRect(
+   const std::function< bool( TrackPanelNode& ) > &pred)
+{
+   wxRect result;
+
+   struct Stop{};
+   try { VisitPreorder( [&]( const wxRect &rect, TrackPanelNode &visited ) {
+      if ( pred( visited ) )
+         result = rect, throw Stop{};
+   } ); }
+   catch ( const Stop& ) {}
+
+   return result;
+}
+
 UIHandlePtr CellularPanel::Target()
 {
    auto &state = *mState;

src/CellularPanel.h

@@ -97,6 +97,12 @@ public:
    // is not specified which rectangle is returned.
    wxRect FindRect(const TrackPanelCell &cell);
 
+   // Search the tree of subdivisions of the panel area for a node (group or
+   // cell) satisfying the predicate. If more than one sub-area is associated
+   // with some node satisfying the predicate, it is not specified which
+   // rectangle is returned.
+   wxRect FindRect(const std::function< bool( TrackPanelNode& ) > &pred);
+
    UIHandlePtr Target();
    
    std::shared_ptr<TrackPanelCell> LastCell() const;

src/LabelTrack.cpp

@@ -3079,7 +3079,8 @@ int LabelTrack::DialogForLabelName(
    auto trackPanel = project.GetTrackPanel();
    auto &viewInfo = project.GetViewInfo();
 
-   wxPoint position = trackPanel->FindTrackRect(trackPanel->GetFocusedTrack(), false).GetBottomLeft();
+   wxPoint position =
+      trackPanel->FindTrackRect(trackPanel->GetFocusedTrack()).GetBottomLeft();
    // The start of the text in the text box will be roughly in line with the label's position
    // if it's a point label, or the start of its region if it's a region label.
    position.x += trackPanel->GetLabelWidth()

src/TrackPanel.cpp

@@ -275,7 +275,8 @@ TrackPanel::~TrackPanel()
 
 LWSlider *TrackPanel::GainSlider( const WaveTrack *wt )
 {
-   auto rect = FindTrackRect( wt, true );
+   auto pControls = wt->GetTrackControl();
+   auto rect = FindRect( *pControls );
    wxRect sliderRect;
    TrackInfo::GetGainRect( rect.GetTopLeft(), sliderRect );
    return TrackInfo::GainSlider(sliderRect, wt, false, this);
@@ -283,7 +284,8 @@ LWSlider *TrackPanel::GainSlider( const WaveTrack *wt )
 
 LWSlider *TrackPanel::PanSlider( const WaveTrack *wt )
 {
-   auto rect = FindTrackRect( wt, true );
+   auto pControls = wt->GetTrackControl();
+   auto rect = FindRect( *pControls );
    wxRect sliderRect;
    TrackInfo::GetPanRect( rect.GetTopLeft(), sliderRect );
    return TrackInfo::PanSlider(sliderRect, wt, false, this);
@@ -292,7 +294,8 @@ LWSlider *TrackPanel::PanSlider( const WaveTrack *wt )
 #ifdef EXPERIMENTAL_MIDI_OUT
 LWSlider *TrackPanel::VelocitySlider( const NoteTrack *nt )
 {
-   auto rect = FindTrackRect( nt, true );
+   auto pControls = nt->GetTrackControl();
+   auto rect = FindRect( *pControls );
    wxRect sliderRect;
    TrackInfo::GetVelocityRect( rect.GetTopLeft(), sliderRect );
    return TrackInfo::VelocitySlider(sliderRect, nt, false, this);
@@ -2166,46 +2169,18 @@ std::shared_ptr<TrackPanelNode> TrackPanel::Root()
 // This finds the rectangle of a given track (including all channels),
 // either that of the label 'adornment' or the track itself
 // The given track is assumed to be the first channel
-wxRect TrackPanel::FindTrackRect( const Track * target, bool label )
+wxRect TrackPanel::FindTrackRect( const Track * target )
 {
-   if (!target) {
+   auto leader = *GetTracks()->FindLeader( target );
+   if (!leader) {
       return { 0, 0, 0, 0 };
    }
 
-   // PRL:  I think the following very old comment misused the term "race
-   // condition" for a bug that happened with only a single thread.  I think the
-   // real problem referred to, was that this function could be reached, via
-   // TrackPanelAx callbacks, during low-level operations while the TrackList
-   // was not in a consistent state.
-   // Now the problem is fixed by delaying the handling of events generated
-   // by TrackList.  And besides that, we use Channels() instead of looking
-   // directly at the links.
-
-   // Old comment:
-   // The check for a null linked track is necessary because there's
-   // a possible race condition between the time the 2 linked tracks
-   // are added and when wxAccessible methods are called.  This is
-   // most evident when using Jaws.
-   auto height = TrackList::Channels( target ).sum( &Track::GetHeight );
-
-   wxRect rect{
-      0,
-      target->GetY() - mViewInfo->vpos,
-      GetSize().GetWidth(),
-      height
-   };
-
-
-   rect.x += kLeftMargin;
-   if (label)
-      rect.width = GetVRulerOffset() - kLeftMargin;
-   else
-      rect.width -= (kLeftMargin + kRightMargin);
-
-   rect.y += kTopMargin;
-   rect.height -= (kTopMargin + kBottomMargin);
-
-   return rect;
+   return CellularPanel::FindRect( [&] ( TrackPanelNode &node ) {
+      if (auto pGroup = dynamic_cast<const LabeledChannelGroup*>( &node ))
+         return pGroup->mpTrack.get() == leader;
+      return false;
+   } );
 }
 
 int TrackPanel::GetVRulerWidth() const

src/TrackPanel.h

@@ -341,10 +341,9 @@ public:
 
    void MakeParentRedrawScrollbars();
 
-   // If label, rectangle includes track control panel only.
-   // If !label, rectangle includes all of that, and the vertical ruler, and
-   // the proper track area.
-   wxRect FindTrackRect( const Track * target, bool label );
+   // Rectangle includes track control panel, and the vertical ruler, and
+   // the proper track area of all channels, and the separators between them.
+   wxRect FindTrackRect( const Track * target );
 
 protected:
    void MakeParentModifyState(bool bWantsAutoSave);    // if true, writes auto-save file. Should set only if you really want the state change restored after

src/TrackPanelAx.cpp

@@ -306,7 +306,7 @@ wxAccStatus TrackPanelAx::GetLocation( wxRect& rect, int elementId )
          return wxACC_FAIL;
       }
 
-      rect = mTrackPanel->FindTrackRect( t.get(), false );
+      rect = mTrackPanel->FindTrackRect( t.get() );
       // Inflate the screen reader's rectangle so it overpaints Audacity's own
       // yellow focus rectangle.
 #ifdef __WXMAC__

src/commands/ScreenshotCommand.cpp

@@ -746,7 +746,7 @@ wxRect ScreenshotCommand::GetTrackRect( AudacityProject * pProj, TrackPanel * pa
       // This rectangle omits the focus ring about the track, and
       // also within that, a narrow black border with a "shadow" below and
       // to the right
-      wxRect rect = panel.FindTrackRect( &t, false );
+      wxRect rect = panel.FindTrackRect( &t );
 
       // Enlarge horizontally.
       // PRL:  perhaps it's one pixel too much each side, including some gray