Addition, deletion, sort of Labels communicated by events...

... and LabelTrack listens to its own events, to update certain state.

This is roundabout for now, but that state is view-related and will move into
another class.

src/LabelTrack.cpp

@@ -76,6 +76,10 @@ for drawing different aspects of the label and its text box.
 #include "widgets/AudacityMessageBox.h"
 #include "widgets/ErrorDialog.h"
 
+wxDEFINE_EVENT(EVT_LABELTRACK_ADDITION, LabelTrackEvent);
+wxDEFINE_EVENT(EVT_LABELTRACK_DELETION, LabelTrackEvent);
+wxDEFINE_EVENT(EVT_LABELTRACK_PERMUTED, LabelTrackEvent);
+
 enum
 {
    OnCutSelectedTextID = 1,      // OSX doesn't like a 0 menu id
@@ -131,6 +135,10 @@ LabelTrack::LabelTrack(const std::shared_ptr<DirManager> &projDirManager):
 
    // reset flags
    ResetFlags();
+
+   Bind( EVT_LABELTRACK_ADDITION, &LabelTrack::OnLabelAdded, this );
+   Bind( EVT_LABELTRACK_DELETION, &LabelTrack::OnLabelDeleted, this );
+   Bind( EVT_LABELTRACK_PERMUTED, &LabelTrack::OnLabelPermuted, this );
 }
 
 LabelTrack::LabelTrack(const LabelTrack &orig) :
@@ -806,7 +814,7 @@ namespace {
       if (target) {
          auto handle = dynamic_cast<LabelGlyphHandle*>( target.get() );
          if (handle)
-            return &handle->mHit;
+            return &*handle->mpHit;
       }
       return nullptr;
    }
@@ -1581,7 +1589,7 @@ bool LabelTrack::HandleGlyphDragRelease
          //the NEW size of the label.
          *newSel = mLabels[mSelIndex].selectedRegion;
       }
-      SortLabels( &hit );
+      SortLabels();
    }
 
    return false;
@@ -2802,8 +2810,17 @@ int LabelTrackView::AddLabel(const SelectedRegion &selectedRegion,
    return pos;
 }
 
-void LabelTrack::OnLabelAdded( const wxString &title, int pos )
+void LabelTrack::OnLabelAdded( LabelTrackEvent &e )
 {
+   e.Skip();
+   if ( e.mpTrack.lock().get() != this )
+      return;
+
+   const auto &title = e.mTitle;
+   const auto pos = e.mPresentPosition;
+
+   mInitialCursorPos = mCurrentCursorPos = title.length();
+
    // restoreFocus is -2 e.g. from Nyquist label creation, when we should not
    // even lose the focus and open the label to edit in the first place.
    // -1 means we don't need to restore it to anywhere.
@@ -2824,8 +2841,6 @@ void LabelTrack::OnLabelAdded( const wxString &title, int pos )
    //      If the label is added during actions like import, then the
    //      mDrawCursor flag will be reset once the action is complete.
    mDrawCursor = true;
-
-   mInitialCursorPos = mCurrentCursorPos = title.length();
 }
 
 
@@ -2842,7 +2857,10 @@ int LabelTrack::AddLabel(const SelectedRegion &selectedRegion,
 
    mLabels.insert(mLabels.begin() + pos, l);
 
-   OnLabelAdded( title, pos );
+   // wxWidgets will own the event object
+   QueueEvent( safenew LabelTrackEvent{
+      EVT_LABELTRACK_ADDITION, SharedPointer<LabelTrack>(), title, -1, pos
+   } );
 
    return pos;
 }
@@ -2850,7 +2868,24 @@ int LabelTrack::AddLabel(const SelectedRegion &selectedRegion,
 void LabelTrack::DeleteLabel(int index)
 {
    wxASSERT((index < (int)mLabels.size()));
-   mLabels.erase(mLabels.begin() + index);
+   auto iter = mLabels.begin() + index;
+   const auto title = iter->title;
+   mLabels.erase(iter);
+
+   // wxWidgets will own the event object
+   QueueEvent( safenew LabelTrackEvent{
+      EVT_LABELTRACK_DELETION, SharedPointer<LabelTrack>(), title, index, -1
+   } );
+}
+
+void LabelTrack::OnLabelDeleted( LabelTrackEvent &e )
+{
+   e.Skip();
+   if ( e.mpTrack.lock().get() != this )
+      return;
+
+   auto index = e.mFormerPosition;
+
    // IF we've deleted the selected label
    // THEN set no label selected.
    if( mSelIndex== index )
@@ -2866,6 +2901,23 @@ void LabelTrack::DeleteLabel(int index)
    }
 }
 
+void LabelTrack::OnLabelPermuted( LabelTrackEvent &e )
+{
+   e.Skip();
+   if ( e.mpTrack.lock().get() != this )
+      return;
+
+   auto former = e.mFormerPosition;
+   auto present = e.mPresentPosition;
+
+   if ( mSelIndex == former )
+      mSelIndex = present;
+   else if ( former < mSelIndex && mSelIndex <= present )
+      -- mSelIndex;
+   else if ( former > mSelIndex && mSelIndex >= present )
+      ++ mSelIndex;
+}
+
 wxBitmap & LabelTrack::GetGlyph( int i)
 {
    return theTheme.Bitmap( i + bmpLabelGlyph0);
@@ -3013,7 +3065,7 @@ static bool IsGoodLabelEditKey(const wxKeyEvent & evt)
 /// This function is called often (whilst dragging a label)
 /// We expect them to be very nearly in order, so insertion
 /// sort (with a linear search) is a reasonable choice.
-void LabelTrack::SortLabels( LabelTrackHit *pHit )
+void LabelTrack::SortLabels()
 {
    const auto begin = mLabels.begin();
    const auto nn = (int)mLabels.size();
@@ -3039,20 +3091,12 @@ void LabelTrack::SortLabels( LabelTrackHit *pHit )
          begin + i + 1
       );
 
-      // Various indices need to be updated with the moved items...
+      // Let listeners update their stored indices
-      auto update = [=](int &index) {
+      // wxWidgets will own the event object
-         if( index <= i ) {
+      QueueEvent( safenew LabelTrackEvent{
-            if( index == i )
+         EVT_LABELTRACK_PERMUTED, SharedPointer<LabelTrack>(),
-               index = j;
+         mLabels[j].title, i, j
-            else if( index >= j)
+      } );
-               ++index;
-         }
-      };
-      if ( pHit ) {
-         update( pHit->mMouseOverLabelLeft );
-         update( pHit->mMouseOverLabelRight );
-      }
-      update(mSelIndex);
    }
 }
 

src/LabelTrack.h

@@ -31,6 +31,7 @@ class DirManager;
 class TimeWarper;
 class ZoomInfo;
 
+class LabelTrackEvent;
 
 struct LabelTrackHit;
 struct TrackPanelDrawingContext;
@@ -102,7 +103,9 @@ const int NUM_GLYPH_CONFIGS = 3;
 const int NUM_GLYPH_HIGHLIGHTS = 4;
 const int MAX_NUM_ROWS =80;
 
-class AUDACITY_DLL_API LabelTrack final : public Track
+class AUDACITY_DLL_API LabelTrack final
+   : public Track
+   , public wxEvtHandler
 {
    friend class LabelTrackView;
    friend class LabelStruct;
@@ -253,7 +256,8 @@ public:
    int FindPrevLabel(const SelectedRegion& currentSelection);
 
  public:
-   void SortLabels(LabelTrackHit *pHit = nullptr);
+   void SortLabels();
+
  private:
    TrackKind GetKind() const override { return TrackKind::Label; }
 
@@ -296,6 +300,10 @@ private:
    void calculateFontHeight(wxDC & dc) const;
    void RemoveSelectedText();
 
+   void OnLabelAdded( LabelTrackEvent& );
+   void OnLabelDeleted( LabelTrackEvent& );
+   void OnLabelPermuted( LabelTrackEvent& );
+
    static wxFont msFont;
 
 protected:
@@ -303,4 +311,44 @@ protected:
    std::shared_ptr<TrackControls> DoGetControls() override;
 };
 
+struct LabelTrackEvent : TrackListEvent
+{
+   explicit
+   LabelTrackEvent(
+      wxEventType commandType, const std::shared_ptr<LabelTrack> &pTrack,
+      const wxString &title,
+      int formerPosition,
+      int presentPosition
+   )
+   : TrackListEvent{ commandType, pTrack }
+   , mTitle{ title }
+   , mFormerPosition{ formerPosition }
+   , mPresentPosition{ presentPosition }
+   {}
+
+   LabelTrackEvent( const LabelTrackEvent& ) = default;
+   wxEvent *Clone() const override {
+      // wxWidgets will own the event object
+      return safenew LabelTrackEvent(*this); }
+
+   wxString mTitle;
+
+   // invalid for addition event
+   int mFormerPosition{ -1 };
+
+   // invalid for deletion event
+   int mPresentPosition{ -1 };
+};
+
+// Posted when a label is added.
+wxDECLARE_EXPORTED_EVENT(AUDACITY_DLL_API,
+                         EVT_LABELTRACK_ADDITION, LabelTrackEvent);
+
+// Posted when a label is deleted.
+wxDECLARE_EXPORTED_EVENT(AUDACITY_DLL_API,
+                         EVT_LABELTRACK_DELETION, LabelTrackEvent);
+
+// Posted when a label is repositioned in the sequence of labels.
+wxDECLARE_EXPORTED_EVENT(AUDACITY_DLL_API,
+                         EVT_LABELTRACK_PERMUTED, LabelTrackEvent);
 #endif

src/Track.h

@@ -1081,7 +1081,9 @@ struct TrackListEvent : public wxCommandEvent
 
    TrackListEvent( const TrackListEvent& ) = default;
 
-   wxEvent *Clone() const override { return new TrackListEvent(*this); }
+   wxEvent *Clone() const override {
+      // wxWidgets will own the event object
+      return safenew TrackListEvent(*this); }
 
    std::weak_ptr<Track> mpTrack;
    int mCode;

src/tracks/labeltrack/ui/LabelGlyphHandle.cpp

@@ -22,10 +22,46 @@ Paul Licameli split from TrackPanel.cpp
 #include <wx/cursor.h>
 #include <wx/translation.h>
 
+LabelTrackHit::LabelTrackHit( const std::shared_ptr<LabelTrack> &pLT )
+   : mpLT{ pLT }
+{
+   pLT->Bind(
+      EVT_LABELTRACK_PERMUTED, &LabelTrackHit::OnLabelPermuted, this );
+}
+
+LabelTrackHit::~LabelTrackHit()
+{
+   // Must do this because this sink isn't wxEvtHandler
+   mpLT->Unbind(
+      EVT_LABELTRACK_PERMUTED, &LabelTrackHit::OnLabelPermuted, this );
+}
+
+void LabelTrackHit::OnLabelPermuted( LabelTrackEvent &e )
+{
+   e.Skip();
+   if ( e.mpTrack.lock() != mpLT )
+      return;
+
+   auto former = e.mFormerPosition;
+   auto present = e.mPresentPosition;
+
+   auto update = [=]( int &index ){
+      if ( index == former )
+         index = present;
+      else if ( former < index && index <= present )
+         -- index;
+      else if ( former > index && index >= present )
+         ++ index;
+   };
+   
+   update( mMouseOverLabelLeft );
+   update( mMouseOverLabelRight );
+}
+
 LabelGlyphHandle::LabelGlyphHandle
 (const std::shared_ptr<LabelTrack> &pLT,
- const wxRect &rect, const LabelTrackHit &hit)
+ const wxRect &rect, const std::shared_ptr<LabelTrackHit> &pHit)
-   : mHit{ hit }
+   : mpHit{ pHit }
    , mpLT{ pLT }
    , mRect{ rect }
 {
@@ -39,7 +75,7 @@ void LabelGlyphHandle::Enter(bool)
 UIHandle::Result LabelGlyphHandle::NeedChangeHighlight
 (const LabelGlyphHandle &oldState, const LabelGlyphHandle &newState)
 {
-   if (oldState.mHit.mEdge != newState.mHit.mEdge)
+   if (oldState.mpHit->mEdge != newState.mpHit->mEdge)
       // pointer moves between the circle and the chevron
       return RefreshCode::RefreshCell;
    return 0;
@@ -61,14 +97,18 @@ UIHandlePtr LabelGlyphHandle::HitTest
  const wxMouseState &state,
  const std::shared_ptr<LabelTrack> &pLT, const wxRect &rect)
 {
-   LabelTrackHit hit{};
+   // Allocate on heap because there are pointers to it when it is bound as
-   pLT->OverGlyph(hit, state.m_x, state.m_y);
+   // an event sink, therefore it's not copyable; make it shared so
+   // LabelGlyphHandle can be copyable:
+   auto pHit = std::make_shared<LabelTrackHit>( pLT );
+
+   pLT->OverGlyph(*pHit, state.m_x, state.m_y);
 
    // IF edge!=0 THEN we've set the cursor and we're done.
    // signal this by setting the tip.
-   if ( hit.mEdge & 3 )
+   if ( pHit->mEdge & 3 )
    {
-      auto result = std::make_shared<LabelGlyphHandle>( pLT, rect, hit );
+      auto result = std::make_shared<LabelGlyphHandle>( pLT, rect, pHit );
       result = AssignUIHandlePtr(holder, result);
       return result;
    }
@@ -89,9 +129,9 @@ UIHandle::Result LabelGlyphHandle::Click
 
    auto &viewInfo = ViewInfo::Get( *pProject );
    mpLT->HandleGlyphClick
-      (mHit, event, mRect, viewInfo, &viewInfo.selectedRegion);
+      (*mpHit, event, mRect, viewInfo, &viewInfo.selectedRegion);
 
-   if (! mHit.mIsAdjustingLabel )
+   if (! mpHit->mIsAdjustingLabel )
    {
       // The positive hit test should have ensured otherwise
       //wxASSERT(false);
@@ -119,7 +159,7 @@ UIHandle::Result LabelGlyphHandle::Drag
    const wxMouseEvent &event = evt.event;
    auto &viewInfo = ViewInfo::Get( *pProject );
    mpLT->HandleGlyphDragRelease
-      (mHit, event, mRect, viewInfo, &viewInfo.selectedRegion);
+      (*mpHit, event, mRect, viewInfo, &viewInfo.selectedRegion);
 
    // Refresh all so that the change of selection is redrawn in all tracks
    return result | RefreshCode::RefreshAll | RefreshCode::DrawOverlays;
@@ -128,7 +168,7 @@ UIHandle::Result LabelGlyphHandle::Drag
 HitTestPreview LabelGlyphHandle::Preview
 (const TrackPanelMouseState &, const AudacityProject *)
 {
-   return HitPreview( (mHit.mEdge & 4 )!=0);
+   return HitPreview( (mpHit->mEdge & 4 )!=0);
 }
 
 UIHandle::Result LabelGlyphHandle::Release
@@ -140,7 +180,7 @@ UIHandle::Result LabelGlyphHandle::Release
    const wxMouseEvent &event = evt.event;
    auto &viewInfo = ViewInfo::Get( *pProject );
    if (mpLT->HandleGlyphDragRelease
-          (mHit, event, mRect, viewInfo, &viewInfo.selectedRegion)) {
+          (*mpHit, event, mRect, viewInfo, &viewInfo.selectedRegion)) {
       ProjectHistory::Get( *pProject ).PushState(_("Modified Label"),
          _("Label Edit"),
          UndoPush::CONSOLIDATE);

src/tracks/labeltrack/ui/LabelGlyphHandle.h

@@ -15,6 +15,7 @@ Paul Licameli split from TrackPanel.cpp
 
 class wxMouseState;
 class LabelTrack;
+class LabelTrackEvent;
 
 /// mEdge:
 /// 0 if not over a glyph,
@@ -26,12 +27,20 @@ class LabelTrack;
 ///   mMouseLabelLeft - index of any left label hit
 ///   mMouseLabelRight - index of any right label hit
 ///
-struct LabelTrackHit {
+struct LabelTrackHit
+{
+   LabelTrackHit( const std::shared_ptr<LabelTrack> &pLT );
+   ~LabelTrackHit();
+
    int mEdge{};
    int mMouseOverLabelLeft{ -1 };    /// Keeps track of which left label the mouse is currently over.
    int mMouseOverLabelRight{ -1 };   /// Keeps track of which right label the mouse is currently over.
    bool mbIsMoving {};
    bool mIsAdjustingLabel {};
+
+   std::shared_ptr<LabelTrack> mpLT {};
+
+   void OnLabelPermuted( LabelTrackEvent &e );
 };
 
 class LabelGlyphHandle final : public LabelDefaultClickHandle
@@ -41,7 +50,7 @@ class LabelGlyphHandle final : public LabelDefaultClickHandle
 public:
    explicit LabelGlyphHandle
       (const std::shared_ptr<LabelTrack> &pLT,
-       const wxRect &rect, const LabelTrackHit &hit);
+       const wxRect &rect, const std::shared_ptr<LabelTrackHit> &pHit);
 
    LabelGlyphHandle &operator=(const LabelGlyphHandle&) = default;
    
@@ -72,7 +81,7 @@ public:
 
    bool StopsOnKeystroke() override { return true; }
 
-   LabelTrackHit mHit{};
+   std::shared_ptr<LabelTrackHit> mpHit{};
 
    static UIHandle::Result NeedChangeHighlight
       (const LabelGlyphHandle &oldState, const LabelGlyphHandle &newState);