Add two commands to move the cursor/selection to next/prev label

The two commands are "selection to next label" and "selection to previous label". They have default shortcuts alt+right and alt+left. Primary motivation is for use by screen readers. They use the first label track, if any, starting at the focused track.
DavidBailes · Oct 18, 2016 · b04a98e · b04a98e
1 parent d5a6b83
commit b04a98e
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Showing 8 changed files with 239 additions and 69 deletions.
diff --git a/src/LabelTrack.cpp b/src/LabelTrack.cpp
@@ -105,7 +105,8 @@ LabelTrack::LabelTrack(const std::shared_ptr<DirManager> &projDirManager):
    mMouseOverLabelRight(-1),
    mRestoreFocus(-1),
    mClipLen(0.0),
-   mIsAdjustingLabel(false)
+   mIsAdjustingLabel(false),
+   miLastLabel(-1)
 {
    SetDefaultName(_("Label Track"));
    SetName(GetDefaultName());
@@ -2849,3 +2850,55 @@ wxString LabelTrack::GetTextOfLabels(double t0, double t1) const
 
    return retVal;
 }
+
+int LabelTrack::FindNextLabel(const SelectedRegion& currentRegion)
+{
+   int i = -1;
+
+   if (!mLabels.empty()) {
+      int len = (int) mLabels.size();
+      if (miLastLabel >= 0 && miLastLabel + 1 < len
+         && currentRegion.t0() == mLabels[miLastLabel].getT0()
+         && currentRegion.t0() == mLabels[miLastLabel + 1].getT0() ) {
+         i = miLastLabel + 1;
+      }
+      else {
+         i = 0;
+         if (currentRegion.t0() < mLabels[len - 1].getT0()) {
+            while (i < len &&
+                  mLabels[i].getT0() <= currentRegion.t0()) {
+               i++;
+            }
+         }
+      }
+   }
+
+   miLastLabel = i;
+   return i;
+}
+
+ int LabelTrack::FindPrevLabel(const SelectedRegion& currentRegion)
+{
+   int i = -1;
+
+   if (!mLabels.empty()) {
+      int len = (int) mLabels.size();
+      if (miLastLabel > 0 && miLastLabel < len
+         && currentRegion.t0() == mLabels[miLastLabel].getT0()
+         && currentRegion.t0() == mLabels[miLastLabel - 1].getT0() ) {
+         i = miLastLabel - 1;
+      }
+      else {
+         i = len - 1;
+         if (currentRegion.t0() > mLabels[0].getT0()) {
+            while (i >=0  &&
+                  mLabels[i].getT0() >= currentRegion.t0()) {
+               i--;
+            }
+         }
+      }
+   }
+
+   miLastLabel = i;
+   return i;
+}
diff --git a/src/LabelTrack.h b/src/LabelTrack.h
@@ -232,6 +232,9 @@ class AUDACITY_DLL_API LabelTrack final : public Track
    // Returns tab-separated text of all labels completely within given region
    wxString GetTextOfLabels(double t0, double t1) const;
 
+   int FindNextLabel(const SelectedRegion& currentSelection);
+   int FindPrevLabel(const SelectedRegion& currentSelection);
+
  public:
    void SortLabels();
    //These two are used by a TrackPanel KLUDGE, which is why they are public.
@@ -268,6 +271,8 @@ class AUDACITY_DLL_API LabelTrack final : public Track
    // Set in copied label tracks
    double mClipLen;
 
+   int miLastLabel;                 // used by FindNextLabel and FindPrevLabel
+
    void ComputeLayout(const wxRect & r, const ZoomInfo &zoomInfo) const;
    void ComputeTextPosition(const wxRect & r, int index) const;
 

diff --git a/src/Menus.cpp b/src/Menus.cpp
@@ -1251,6 +1251,11 @@ void AudacityProject::CreateMenusAndCommands()
    c->AddCommand(wxT("PlaySpeedInc"), _("Increase playback speed"), FN(OnPlaySpeedInc));
    c->AddCommand(wxT("PlaySpeedDec"), _("Decrease playback speed"), FN(OnPlaySpeedDec));
 
+   c->AddCommand(wxT("SelToNextLabel"), _("Selection to next label"), FN(OnSelToNextLabel), wxT("Alt+Right"),
+      AudioIONotBusyFlag, AudioIONotBusyFlag);
+   c->AddCommand(wxT("SelToPrevLabel"), _("Selection to previous label"), FN(OnSelToPrevLabel), wxT("Alt+Left"),
+      AudioIONotBusyFlag, AudioIONotBusyFlag);
+
 #ifdef __WXMAC__
    /* i8n-hint: Shrink all project windows to icons on the Macintosh tooldock */
    c->AddCommand(wxT("MacMinimizeAll"), _("Minimize all projects"),
@@ -2656,6 +2661,51 @@ void AudacityProject::OnSelToEnd()
    ModifyState(false);
 }
 
+void AudacityProject::OnSelToNextLabel()
+{
+   OnSelToLabel(true);
+}
+
+void AudacityProject::OnSelToPrevLabel()
+{
+   OnSelToLabel(false);
+}
+
+void AudacityProject::OnSelToLabel(bool next)
+{
+   Track* t = mTrackPanel->GetFocusedTrack();
+
+   // find first label track, if any, starting at the focused track
+   while (t && t->GetKind() != Track::Label) {
+      t = mTracks->GetNext(t, true);
+   }
+
+   if (t) {
+      LabelTrack* lt = static_cast<LabelTrack*>(t);
+      int i;
+      if (next)
+         i = lt->FindNextLabel(GetSelection());
+      else
+         i = lt->FindPrevLabel(GetSelection());
+
+      if (i >= 0) {
+         const LabelStruct* label = lt->GetLabel(i);
+         GetViewInfo().selectedRegion = label->selectedRegion;
+         RedrawProject();
+
+         wxString message;
+         message.Printf(wxT("%s %d of %d"), label->title, i + 1, lt->GetNumLabels() );
+         mTrackPanel->MessageForScreenReader(message);
+      }
+      else {
+         mTrackPanel->MessageForScreenReader(_("no labels in label track"));
+      }
+   }
+   else {
+      mTrackPanel->MessageForScreenReader(_("no label track"));
+   }
+}
+
 void AudacityProject::OnCursorUp()
 {
    mTrackPanel->OnPrevTrack( false );

diff --git a/src/Menus.h b/src/Menus.h
@@ -170,6 +170,10 @@ void OnSetRightSelection();
 void OnSelToStart();
 void OnSelToEnd();
 
+void OnSelToNextLabel();
+void OnSelToPrevLabel();
+void OnSelToLabel(bool next);
+
 void OnZeroCrossing();
 
 void OnLockPlayRegion();

diff --git a/src/TrackPanel.cpp b/src/TrackPanel.cpp
@@ -2408,6 +2408,12 @@ void TrackPanel::UpdateAccessibility()
       mAx->Updated();
 }
 
+void TrackPanel::MessageForScreenReader(const wxString& message)
+{
+   if (mAx)
+      mAx->MessageForScreenReader(message);
+}
+
 #ifdef EXPERIMENTAL_SPECTRAL_EDITING
 namespace {
 

diff --git a/src/TrackPanel.h b/src/TrackPanel.h
@@ -308,6 +308,7 @@ class AUDACITY_DLL_API TrackPanel final : public OverlayPanel {
 
 public:
    virtual void UpdateAccessibility();
+   void MessageForScreenReader(const wxString& message);
 
 #ifdef EXPERIMENTAL_SPECTRAL_EDITING
 public: