TrackPanelResizerCell, also in 1-to-1 with TrackView, now owned by it

src/Track.h

@@ -38,7 +38,6 @@ class LabelTrack;
 class TimeTrack;
 class TrackControls;
 class TrackView;
-class TrackPanelResizerCell;
 class WaveTrack;
 class NoteTrack;
 class AudacityProject;
@@ -297,9 +296,6 @@ class AUDACITY_DLL_API Track /* not final */
 
    // Return another, associated TrackPanelCell object that implements the
 
-   // click and drag to resize
-   std::shared_ptr<TrackPanelCell> GetResizer();
-
    // This just returns a constant and can be overriden by subclasses
    // to specify a different height for the case that the track is minimized.
    virtual int GetMinimizedHeight() const;
@@ -759,7 +755,6 @@ protected:
    // These hold the controls:
    std::shared_ptr<TrackView> mpView;
    std::shared_ptr<TrackControls> mpControls;
-   std::shared_ptr<TrackPanelResizerCell> mpResizer;
 
    std::weak_ptr<SelectHandle> mSelectHandle;
    std::weak_ptr<TimeShiftHandle> mTimeShiftHandle;

src/TrackPanel.cpp

@@ -101,6 +101,7 @@ is time to refresh some aspect of the screen.
 #include "toolbars/ControlToolBar.h"
 
 #include "tracks/ui/TrackControls.h"
+#include "tracks/ui/TrackView.h"
 #include "tracks/ui/TrackVRulerControls.h"
 
 //This loads the appropriate set of cursors, depending on platform.
@@ -2224,7 +2225,8 @@ struct ChannelGroup final : TrackPanelGroup {
                channel->SubstitutePendingChangedTrack();
             yy += substitute->GetHeight();
             refinement.emplace_back(
-               yy - kSeparatorThickness, channel->GetResizer() );
+               yy - kSeparatorThickness,
+               TrackView::Get( *channel ).GetResizer() );
          }
       }
 
@@ -2262,7 +2264,8 @@ struct ResizingChannelGroup final : TrackPanelGroup {
       { rect.GetTop(),
          std::make_shared< LabeledChannelGroup >( mpTrack, mLeftOffset ) },
       { rect.GetTop() + rect.GetHeight() - kSeparatorThickness,
-         ( *TrackList::Channels( mpTrack.get() ).rbegin() )->GetResizer() }
+         TrackView::Get( **TrackList::Channels( mpTrack.get() ).rbegin() )
+            .GetResizer() }
    } }; }
    std::shared_ptr< Track > mpTrack;
    wxCoord mLeftOffset;

src/TrackPanelResizerCell.cpp

@@ -15,11 +15,13 @@ Paul Licameli split from TrackPanel.cpp
 #include "TrackPanelMouseEvent.h"
 #include "HitTestResult.h"
 
+#include "tracks/ui/TrackView.h"
+
 #include <wx/mousestate.h>
 
 TrackPanelResizerCell::TrackPanelResizerCell(
-   const std::shared_ptr<Track> &pTrack )
-   : CommonTrackCell{ pTrack }
+   const std::shared_ptr<TrackView> &pView )
+   : mwView{ pView }
 {}
 
 std::vector<UIHandlePtr> TrackPanelResizerCell::HitTest
@@ -27,7 +29,7 @@ std::vector<UIHandlePtr> TrackPanelResizerCell::HitTest
 {
    (void)pProject;// Compiler food
    std::vector<UIHandlePtr> results;
-   auto pTrack = mpTrack.lock();
+   auto pTrack = FindTrack();
    if (pTrack) {
       auto result = std::make_shared<TrackPanelResizeHandle>(
          pTrack, st.state.m_y );
@@ -36,3 +38,11 @@ std::vector<UIHandlePtr> TrackPanelResizerCell::HitTest
    }
    return results;
 }
+
+std::shared_ptr<Track> TrackPanelResizerCell::DoFindTrack()
+{
+   const auto pView = mwView.lock();
+   if ( pView )
+      return pView->FindTrack();
+   return {};
+}

src/TrackPanelResizerCell.h

@@ -14,25 +14,26 @@
 #include "tracks/ui/CommonTrackPanelCell.h"
 
 class TrackPanelResizeHandle;
+class TrackView;
 
-class TrackPanelResizerCell : public CommonTrackCell
+class TrackPanelResizerCell : public CommonTrackPanelCell
 {
    TrackPanelResizerCell(const TrackPanelResizerCell&) = delete;
    TrackPanelResizerCell &operator= (const TrackPanelResizerCell&) = delete;
 public:
 
    explicit
-   TrackPanelResizerCell( const std::shared_ptr<Track> &pTrack );
+   TrackPanelResizerCell( const std::shared_ptr<TrackView> &pView );
 
    std::vector<UIHandlePtr> HitTest
       (const TrackPanelMouseState &, const AudacityProject *) override;
 
 protected:
-   std::shared_ptr<Track> DoFindTrack() override
-   { return mpTrack.lock(); };
+   std::shared_ptr<Track> DoFindTrack() override;
 
 private:
-   std::weak_ptr<Track> mpTrack;
+   // back-pointer is weak to break a cycle
+   std::weak_ptr<TrackView> mwView;
 
    std::weak_ptr<TrackPanelResizeHandle> mResizeHandle;
 };

src/tracks/ui/TrackView.cpp

@@ -133,10 +133,15 @@ std::shared_ptr<const TrackVRulerControls> TrackView::GetVRulerControls() const
 }
 
 #include "../../TrackPanelResizeHandle.h"
-std::shared_ptr<TrackPanelCell> Track::GetResizer()
+std::shared_ptr<TrackPanelCell> TrackView::GetResizer()
 {
    if (!mpResizer)
       // create on demand
-      mpResizer = std::make_shared<TrackPanelResizerCell>( SharedPointer() );
+      mpResizer = std::make_shared<TrackPanelResizerCell>( shared_from_this() );
    return mpResizer;
 }
+
+std::shared_ptr<const TrackPanelCell> TrackView::GetResizer() const
+{
+   return const_cast<TrackView*>(this)->GetResizer();
+}

src/tracks/ui/TrackView.h

@@ -16,6 +16,7 @@ Paul Licameli split from class Track
 
 class Track;
 class TrackVRulerControls;
+class TrackPanelResizerCell;
 
 class TrackView /* not final */ : public CommonTrackCell
    , public std::enable_shared_from_this<TrackView>
@@ -37,12 +38,19 @@ public:
    std::shared_ptr<TrackVRulerControls> GetVRulerControls();
    std::shared_ptr<const TrackVRulerControls> GetVRulerControls() const;
 
+
+   // Return another, associated TrackPanelCell object that implements the
+   // click and drag to resize
+   std::shared_ptr<TrackPanelCell> GetResizer();
+   std::shared_ptr<const TrackPanelCell> GetResizer() const;
+
 protected:
    // Private factory to make appropriate object; class TrackView handles
    // memory management thereafter
    virtual std::shared_ptr<TrackVRulerControls> DoGetVRulerControls() = 0;
 
    std::shared_ptr<TrackVRulerControls> mpVRulerControls;
+   std::shared_ptr<TrackPanelResizerCell> mpResizer;
 };
 
 #endif