Now implement scrubbing default to unpinned, see commit ac1017e...

... This was motivated by punch and roll recording:  it appears most convenient
to pin the head for recording purposes, and drag it near the right, but when
stopping and finding the splice point for the correction, it is better to
scrub unpinned.

src/prefs/PlaybackPrefs.cpp

@@ -49,6 +49,18 @@ void PlaybackPrefs::Populate()
    // ----------------------- End of main section --------------
 }
 
+namespace {
+   const char *UnpinnedScrubbingPreferenceKey()
+   {
+      return "/AudioIO/UnpinnedScrubbing";
+   }
+   bool UnpinnedScrubbingPreferenceDefault()
+   {
+      return true;
+   }
+   int iPreferenceUnpinned = -1;
+}
+
 void PlaybackPrefs::PopulateOrExchange(ShuttleGui & S)
 {
    wxTextCtrl *w;
@@ -126,7 +138,9 @@ void PlaybackPrefs::PopulateOrExchange(ShuttleGui & S)
 
       S.StartTwoColumn();
       {
-         S.TieCheckBox(_("Always scrub un&pinned"), "/AudioIO/UnpinnedScrubbing", true);
+         S.TieCheckBox(_("Always scrub un&pinned"),
+            UnpinnedScrubbingPreferenceKey(),
+            UnpinnedScrubbingPreferenceDefault());
       }
       S.EndTwoColumn();
    }
@@ -137,8 +151,21 @@ void PlaybackPrefs::PopulateOrExchange(ShuttleGui & S)
 
 }
 
+bool PlaybackPrefs::GetUnpinnedScrubbingPreference()
+{
+   if ( iPreferenceUnpinned >= 0 )
+      return iPreferenceUnpinned == 1;
+   bool bResult = gPrefs->ReadBool(
+      UnpinnedScrubbingPreferenceKey(),
+      UnpinnedScrubbingPreferenceDefault());
+   iPreferenceUnpinned = bResult ? 1: 0;
+   return bResult;
+}
+
 bool PlaybackPrefs::Commit()
 {
+   iPreferenceUnpinned = -1;
+
    ShuttleGui S(this, eIsSavingToPrefs);
    PopulateOrExchange(S);
 

src/prefs/PlaybackPrefs.h

@@ -28,6 +28,8 @@ class PlaybackPrefs final : public PrefsPanel
    bool Commit() override;
    wxString HelpPageName() override;
    void PopulateOrExchange(ShuttleGui & S) override;
+   
+   static bool GetUnpinnedScrubbingPreference();
 
  private:
    void Populate();

src/toolbars/ControlToolBar.cpp

@@ -1505,9 +1505,20 @@ void ControlToolBar::UpdateStatusBar(AudacityProject *pProject)
    pProject->GetStatusBar()->SetStatusText(StateForStatusBar(), stateStatusBarField);
 }
 
+bool ControlToolBar::IsTransportingPinned()
+{
+   if (!TracksPrefs::GetPinnedHeadPreference())
+      return false;
+   const auto &scrubber = ::GetActiveProject()->GetScrubber();
+   return
+     !(scrubber.HasMark() &&
+       !scrubber.WasSpeedPlaying() &&
+       !Scrubber::ShouldScrubPinned());
+}
+
 void ControlToolBar::StartScrollingIfPreferred()
 {
-   if (TracksPrefs::GetPinnedHeadPreference())
+   if (IsTransportingPinned())
       StartScrolling();
 #ifdef __WXMAC__
    else if (::GetActiveProject()->GetScrubber().HasMark()) {

src/toolbars/ControlToolBar.h

@@ -51,6 +51,8 @@ class ControlToolBar final : public ToolBar {
    ControlToolBar();
    virtual ~ControlToolBar();
 
+   static bool IsTransportingPinned();
+
    void Create(wxWindow *parent) override;
 
    void UpdatePrefs() override;

src/tracks/ui/Scrubbing.cpp

@@ -17,6 +17,7 @@ Paul Licameli split from TrackPanel.cpp
 #include "../../Project.h"
 #include "../../TrackPanel.h"
 #include "../../TrackPanelCell.h"
+#include "../../prefs/PlaybackPrefs.h"
 #include "../../prefs/TracksPrefs.h"
 #include "../../toolbars/ControlToolBar.h"
 #include "../../toolbars/ScrubbingToolBar.h"
@@ -162,6 +163,12 @@ auto Scrubber::ScrubPollerThread::Entry() -> ExitCode
 
 #endif
 
+bool Scrubber::ShouldScrubPinned()
+{
+   return TracksPrefs::GetPinnedHeadPreference() &&
+      !PlaybackPrefs::GetUnpinnedScrubbingPreference();
+}
+
 class Scrubber::ScrubPoller : public wxTimer
 {
 public:
@@ -997,7 +1004,7 @@ void Scrubber::DoScrub(bool seek)
    if( !CanScrub() )
       return;
    const bool wasScrubbing = HasMark() || IsScrubbing();
-   const bool scroll = TracksPrefs::GetPinnedHeadPreference();
+   const bool scroll = ShouldScrubPinned();
    if (!wasScrubbing) {
       auto tp = mProject->GetTrackPanel();
       wxCoord xx = tp->ScreenToClient(::wxGetMouseState().GetPosition()).x;

src/tracks/ui/Scrubbing.h

@@ -72,6 +72,8 @@ public:
    
    Scrubber(AudacityProject *project);
    ~Scrubber();
+
+   static bool ShouldScrubPinned();
    
    // Assume xx is relative to the left edge of TrackPanel!
    void MarkScrubStart(wxCoord xx, bool smoothScrolling, bool seek);

src/widgets/Ruler.cpp

@@ -2210,7 +2210,7 @@ public:
    static std::shared_ptr<PlayheadHandle>
    HitTest( const AudacityProject *pProject, wxCoord xx )
    {
-      if( TracksPrefs::GetPinnedHeadPreference() &&
+      if( ControlToolBar::IsTransportingPinned() &&
           pProject->IsAudioActive() )
       {
          const auto targetX = GetPlayHeadX( pProject );
@@ -2373,7 +2373,7 @@ private:
             if (!scrubber.HasMark()) {
                // Asynchronous scrub poller gets activated here
                scrubber.MarkScrubStart(
-                  event.event.m_x, TracksPrefs::GetPinnedHeadPreference(), false);
+                  event.event.m_x, Scrubber::ShouldScrubPinned(), false);
             }
          }
       }
@@ -3287,6 +3287,8 @@ void AdornedRulerPanel::UpdateButtonStates()
    };
 
    {
+      // The button always reflects the pinned head preference, even though
+      // there is also a Playback preference that may overrule it for scrubbing
       bool state = TracksPrefs::GetPinnedHeadPreference();
       auto pinButton = static_cast<AButton*>(FindWindow(OnTogglePinnedStateID));
       if( !state )
@@ -3664,7 +3666,7 @@ void AdornedRulerPanel::DoDrawIndicator
       dc->DrawPolygon( 3, tri );
    }
    else {
-      bool pinned = TracksPrefs::GetPinnedHeadPreference();
+      bool pinned = ControlToolBar::IsTransportingPinned();
       wxBitmap & bmp = theTheme.Bitmap( pinned ? 
          (playing ? bmpPlayPointerPinned : bmpRecordPointerPinned) :
          (playing ? bmpPlayPointer : bmpRecordPointer)