Implement drag-scrub, compatibly with the existing move-scrub...

... Start scrub by click or double click on the scrub head; release button or
not; then move.

If you release before moving, you get scrubbing as before, controlled by
motion.  Click or drag to switch in and out of seeking.  Stop with ESC,
spacebar, etc.  No change of selection.

But now if you drag, then scrubbing contines until you release the mouse or
otherwise stop with a key.

If by release of the mouse, then the selection changes as if by a click at
the last play position.  If you hold shift, then, as if by shift-click.

If drag begins with a double-click, then the play head remains centered and
the track moves.

src/AudioIO.cpp

@@ -402,6 +402,14 @@ struct AudioIO::ScrubQueue
    }
    ~ScrubQueue() {}
 
+   double LastTimeInQueue() const
+   {
+      // Needed by the main thread sometimes
+      wxCriticalSectionLocker locker(mUpdating);
+      const Entry &previous = mEntries[(mLeadingIdx + Size - 1) % Size];
+      return previous.mS1 / mRate;
+   }
+
    bool Producer(double end, double maxSpeed, bool bySpeed, bool maySkip)
    {
       // Main thread indicates a scrubbing interval
@@ -670,7 +678,7 @@ private:
    const double mRate;
    const long mMinStutter;
    wxLongLong mLastScrubTimeMillis;
-   wxCriticalSection mUpdating;
+   mutable wxCriticalSection mUpdating;
 };
 #endif
 
@@ -2426,6 +2434,15 @@ bool AudioIO::EnqueueScrubBySignedSpeed(double speed, double maxSpeed, bool mayS
    else
       return false;
 }
+
+double AudioIO::GetLastTimeInScrubQueue() const
+{
+   if (mScrubQueue)
+      return mScrubQueue->LastTimeInQueue();
+   else
+      return -1.0;
+}
+
 #endif
 
 bool AudioIO::IsBusy()

src/AudioIO.h

@@ -208,6 +208,10 @@ class AUDACITY_DLL_API AudioIO final {
    * Return true if some work was really enqueued.
    */
    bool EnqueueScrubBySignedSpeed(double speed, double maxSpeed, bool maySkip);
+
+   /** \brief return the ending time of the last enqueued scrub interval.
+   */
+   double GetLastTimeInScrubQueue() const;
 #endif
 
    /** \brief  Returns true if audio i/o is busy starting, stopping, playing,

src/Menus.cpp

@@ -2281,8 +2281,13 @@ void AudacityProject::OnRecordAppend()
    GetControlToolBar()->OnRecord(evt);
 }
 
-// The code for "OnPlayStopSelect" is simply the code of "OnPlayStop" and "OnStopSelect" merged.
 void AudacityProject::OnPlayStopSelect()
+{
+   DoPlayStopSelect(false, false);
+}
+
+// The code for "OnPlayStopSelect" is simply the code of "OnPlayStop" and "OnStopSelect" merged.
+void AudacityProject::DoPlayStopSelect(bool click, bool shift)
 {
    wxCommandEvent evt;
    ControlToolBar *toolbar = GetControlToolBar();
@@ -2291,7 +2296,36 @@ void AudacityProject::OnPlayStopSelect()
    if (gAudioIO->IsStreamActive(GetAudioIOToken())) {
       toolbar->SetPlay(false);        //Pops
       toolbar->SetStop(true);         //Pushes stop down
-      mViewInfo.selectedRegion.setT0(gAudioIO->GetStreamTime(), false);
+
+      // change the selection
+      auto time = gAudioIO->GetStreamTime();
+      auto &selection = mViewInfo.selectedRegion;
+      if (shift && click) {
+         // Change the region selection, as if by shift-click at the play head
+         auto t0 = selection.t0(), t1 = selection.t1();
+         if (time < t0)
+            // Grow selection
+            t0 = time;
+         else if (time > t1)
+            // Grow selection
+            t1 = time;
+         else {
+            // Shrink selection, changing the nearer boundary
+            if (fabs(t0 - time) < fabs(t1 - time))
+               t0 = time;
+            else
+               t1 = time;
+         }
+         selection.setTimes(t0, t1);
+      }
+      else if (click)
+         // Set a point selection, as if by a click at the play head
+         selection.setTimes(time, time);
+      else
+         // How stop and set cursor always worked
+         // -- change t0, collapsing to point only if t1 was greater
+         selection.setT0(time, false);
+
       ModifyState(false);           // without bWantsAutoSave
       toolbar->OnStop(evt);
    }

src/Menus.h

@@ -80,6 +80,7 @@ void OnSeekRightLong();
 
 bool MakeReadyToPlay(bool loop = false, bool cutpreview = false); // Helper function that sets button states etc.
 void OnPlayStop();
+void DoPlayStopSelect(bool click, bool shift);
 void OnPlayStopSelect();
 void OnPlayOneSecond();
 void OnPlayToSelection();

src/tracks/ui/Scrubbing.cpp

@@ -230,6 +230,9 @@ bool Scrubber::MaybeStartScrubbing(wxCoord xx)
    if (IsScrubbing())
       return false;
    else {
+      const auto state = ::wxGetMouseState();
+      mDragging = state.LeftIsDown();
+
       const bool busy = gAudioIO->IsBusy();
       if (busy && gAudioIO->GetNumCaptureChannels() > 0) {
          // Do not stop recording, and don't try to start scrubbing after
@@ -259,6 +262,14 @@ bool Scrubber::MaybeStartScrubbing(wxCoord xx)
                mScrubStartPosition = position;
             }
 
+            if (mDragging && mSmoothScrollingScrub) {
+               auto delta = time0 - time1;
+               time0 = std::max(0.0, std::min(maxTime,
+                  (viewInfo.h + mProject->GetScreenEndTime()) / 2
+               ));
+               time1 = time0 + delta;
+            }
+
             AudioIOStartStreamOptions options(mProject->GetDefaultPlayOptions());
             options.timeTrack = NULL;
             options.scrubDelay = (kTimerInterval / 1000.0);
@@ -272,8 +283,10 @@ bool Scrubber::MaybeStartScrubbing(wxCoord xx)
                p->GetTranscriptionToolBar()->GetPlaySpeed();
             }
 #else
-            // That idea seems unpopular... just make it one
+            // That idea seems unpopular... just make it one for move-scrub,
-            mMaxScrubSpeed = options.maxScrubSpeed = 1.0;
+            // but big for drag-scrub
+            mMaxScrubSpeed = options.maxScrubSpeed =
+               mDragging ? AudioIO::GetMaxScrubSpeed() : 1.0;
 #endif
             options.maxScrubTime = mProject->GetTracks()->GetEndTime();
             ControlToolBar::PlayAppearance appearance =
@@ -300,6 +313,7 @@ bool Scrubber::MaybeStartScrubbing(wxCoord xx)
       if (IsScrubbing()) {
          mProject->GetPlaybackScroller().Activate(mSmoothScrollingScrub);
          mScrubHasFocus = true;
+         mLastScrubPosition = xx;
       }
 
       // Return true whether we started scrub, or are still waiting to decide.
@@ -309,13 +323,19 @@ bool Scrubber::MaybeStartScrubbing(wxCoord xx)
 
 void Scrubber::ContinueScrubbing()
 {
+   const wxMouseState state(::wxGetMouseState());
+
+   if (mDragging && !state.LeftIsDown()) {
+      // Stop and set cursor
+      mProject->DoPlayStopSelect(true, state.ShiftDown());
+      return;
+   }
 
    // Thus scrubbing relies mostly on periodic polling of mouse and keys,
    // not event notifications.  But there are a few event handlers that
    // leave messages for this routine, in mScrubSeekPress and in mScrubHasFocus.
 
    // Seek only when the pointer is in the panel.  Else, scrub.
-   const wxMouseState state(::wxGetMouseState());
    TrackPanel *const trackPanel = mProject->GetTrackPanel();
 
    // Decide whether to skip play, because either mouse is down now,
@@ -333,13 +353,21 @@ void Scrubber::ContinueScrubbing()
    }
 
    const wxPoint position = trackPanel->ScreenToClient(state.GetPosition());
-   // When we don't have focus, enqueue silent scrubs until we regain focus.
+   const auto &viewInfo = mProject->GetViewInfo();
+
    bool result = false;
    if (!mScrubHasFocus)
+      // When we don't have focus, enqueue silent scrubs until we regain focus.
       result = gAudioIO->EnqueueScrubBySignedSpeed(0, mMaxScrubSpeed, false);
+   else if (mDragging && mSmoothScrollingScrub) {
+      const auto lastTime = gAudioIO->GetLastTimeInScrubQueue();
+      const auto delta = mLastScrubPosition - position.x;
+      const double time = viewInfo.OffsetTimeByPixels(lastTime, delta);
+      result = gAudioIO->EnqueueScrubByPosition(time, mMaxScrubSpeed, false);
+      mLastScrubPosition = position.x;
+   }
    else {
-      const double time = mProject->GetViewInfo().PositionToTime(position.x, trackPanel->GetLeftOffset());
+      const double time = viewInfo.PositionToTime(position.x, trackPanel->GetLeftOffset());
-
       if (seek)
          // Cause OnTimer() to suppress the speed display
          mScrubSpeedDisplayCountdown = 1;
@@ -372,6 +400,7 @@ void Scrubber::StopScrubbing()
 
    mScrubStartPosition = -1;
    mProject->GetPlaybackScroller().Activate(false);
+   mDragging = false;
 
    if (!IsScrubbing())
    {
@@ -382,6 +411,11 @@ void Scrubber::StopScrubbing()
    }
 
    mProject->GetRulerPanel()->HideQuickPlayIndicator();
+
+   // Need this in case ruler gets the mouse-up event after escaping scrubbing:
+   // prevent reappearance of the
+   // quick play guideline
+   mProject->GetRulerPanel()->IgnoreMouseUp();
 }
 
 bool Scrubber::IsScrubbing() const
@@ -400,6 +434,9 @@ bool Scrubber::IsScrubbing() const
 
 bool Scrubber::ShouldDrawScrubSpeed()
 {
+   if (mDragging)
+      return false;
+
    return IsScrubbing() &&
       mScrubHasFocus && (
       // Draw for (non-scroll) scrub, sometimes, but never for seek
@@ -419,6 +456,10 @@ double Scrubber::FindScrubSpeed(bool seeking, double time) const
 
 void Scrubber::HandleScrollWheel(int steps)
 {
+   if (mDragging)
+      // Not likely you would spin it with the left button down, but...
+      return;
+
    const int newLogMaxScrubSpeed = mLogMaxScrubSpeed + steps;
    static const double maxScrubSpeedBase =
       pow(2.0, 1.0 / ScrubSpeedStepsPerOctave);
@@ -450,7 +491,8 @@ void Scrubber::Forwarder::OnMouse(wxMouseEvent &event)
    if (isScrubbing && !event.HasAnyModifiers()) {
       if(event.LeftDown() ||
          (event.LeftIsDown() && event.Dragging())) {
-         scrubber.mScrubSeekPress = true;
+         if (!scrubber.mDragging)
+            scrubber.mScrubSeekPress = true;
          auto xx = ruler->ScreenToClient(::wxGetMousePosition()).x;
          ruler->UpdateQuickPlayPos(xx);
          ruler->ShowQuickPlayIndicator();
@@ -541,12 +583,13 @@ void ScrubbingOverlay::OnTimer(wxCommandEvent &event)
    auto position = ::wxGetMousePosition();
 
    {
-      auto xx = ruler->ScreenToClient(position).x;
+      if(scrubber.HasStartedScrubbing()) {
-      ruler->UpdateQuickPlayPos(xx);
+         auto xx = ruler->ScreenToClient(position).x;
+         ruler->UpdateQuickPlayPos(xx);
 
-      if(!isScrubbing && scrubber.HasStartedScrubbing()) {
+         if (!isScrubbing)
-         // Really start scrub if motion is far enough
+            // Really start scrub if motion is far enough
-         scrubber.MaybeStartScrubbing(xx);
+            scrubber.MaybeStartScrubbing(xx);
       }
 
       if (!isScrubbing) {
@@ -627,7 +670,7 @@ Scrubber &ScrubbingOverlay::GetScrubber()
 
 bool Scrubber::PollIsSeeking()
 {
-   return mAlwaysSeeking || ::wxGetMouseState().LeftIsDown();
+   return !mDragging && (mAlwaysSeeking || ::wxGetMouseState().LeftIsDown());
 }
 
 void Scrubber::DoScrub(bool scroll, bool seek)

src/tracks/ui/Scrubbing.h

@@ -109,10 +109,12 @@ private:
    bool mScrubHasFocus;
    int mScrubSpeedDisplayCountdown;
    wxCoord mScrubStartPosition;
+   wxCoord mLastScrubPosition {};
    double mMaxScrubSpeed;
    bool mScrubSeekPress;
    bool mSmoothScrollingScrub;
-   bool mAlwaysSeeking{};
+   bool mAlwaysSeeking {};
+   bool mDragging {};
 
 #ifdef EXPERIMENTAL_SCRUBBING_SCROLL_WHEEL
    int mLogMaxScrubSpeed;

src/widgets/Ruler.cpp

@@ -2582,6 +2582,17 @@ bool AdornedRulerPanel::IsWithinMarker(int mousePosX, double markerTime)
 
 void AdornedRulerPanel::OnMouseEvents(wxMouseEvent &evt)
 {
+   if (mIgnoreMouseUp) {
+      if (evt.Dragging())
+         return;
+      else if (evt.ButtonUp()) {
+         mIgnoreMouseUp = false;
+         return;
+      }
+      else
+         mIgnoreMouseUp = false;
+   }
+
    // PRL:  why do I need these two lines on Windows but not on Mac?
    if (evt.ButtonDown(wxMOUSE_BTN_ANY))
       SetFocus();
@@ -2910,10 +2921,12 @@ void AdornedRulerPanel::HandleQPRelease(wxMouseEvent &evt)
    if (mDoubleClick)
       return;
 
-   HideQuickPlayIndicator();
-
    if (HasCapture())
       ReleaseMouse();
+   else
+      return;
+
+   HideQuickPlayIndicator();
 
    mCaptureState = CaptureState{};
 

src/widgets/Ruler.h

@@ -350,6 +350,7 @@ public:
    void ShowQuickPlayIndicator();
    void HideQuickPlayIndicator();
    void UpdateQuickPlayPos(wxCoord &mousPosX);
+   void IgnoreMouseUp() { mIgnoreMouseUp = true; }
 
 private:
    void OnCapture(wxCommandEvent & evt);
@@ -531,6 +532,7 @@ private:
    mutable wxFont mButtonFont;
 
    bool mDoubleClick {};
+   bool mIgnoreMouseUp {};
 
    DECLARE_EVENT_TABLE()