Persist meter state across toolbar resets and fix clipping indicator

This will fix the clipping indicator turning on after a toolbar reset
and, as a bonus, the timers now only run if playing, capturing, or
monitoring.  Will (slightly) reduce the CPU consumption.

src/toolbars/MeterToolBar.cpp

@@ -81,6 +81,36 @@ void MeterToolBar::Create(wxWindow * parent)
    OnSize(dummy);
 }
 
+void MeterToolBar::ReCreateButtons()
+{
+   void *playState = NULL;
+   void *recordState = NULL;
+
+   if (mPlayMeter && mProject->GetPlaybackMeter() == mPlayMeter)
+   {
+      mProject->SetPlaybackMeter( NULL );
+      playState = mPlayMeter->SaveState();
+   }
+
+   if (mRecordMeter && mProject->GetCaptureMeter() == mRecordMeter)
+   {
+      mProject->SetCaptureMeter( NULL );
+      recordState = mRecordMeter->SaveState();
+   }
+
+   ToolBar::ReCreateButtons();
+
+   if (playState)
+   {
+      mPlayMeter->RestoreState(playState);
+   }
+
+   if (recordState)
+   {
+      mRecordMeter->RestoreState(recordState);
+   }
+}
+
 void MeterToolBar::Populate()
 {
    mSizer = new wxGridBagSizer();

src/toolbars/MeterToolBar.h

@@ -39,6 +39,7 @@ class MeterToolBar:public ToolBar {
    void Create(wxWindow *parent);
 
    virtual void Populate();
+   virtual void ReCreateButtons();
    virtual void Repaint(wxDC * WXUNUSED(dc)) {};
    virtual void EnableDisableButtons() {};
    virtual void UpdatePrefs();

src/widgets/Meter.cpp

@@ -248,7 +248,6 @@ Meter::Meter(AudacityProject *project,
                      this);
 
    if (mIsInput) {
-      // Register for AudioIO Monitor events
       wxTheApp->Connect(EVT_AUDIOIO_MONITOR,
                         wxCommandEventHandler(Meter::OnAudioIOStatus),
                         NULL,
@@ -266,6 +265,12 @@ Meter::Meter(AudacityProject *project,
 //      mDarkPen   = wxPen(   theTheme.Colour( clrMeterInputDarkPen     ), 1, wxSOLID);
    }
    else {
+      // Register for AudioIO events
+      wxTheApp->Connect(EVT_AUDIOIO_PLAYBACK,
+                        wxCommandEventHandler(Meter::OnAudioIOStatus),
+                        NULL,
+                        this);
+
       mPen       = wxPen(   theTheme.Colour( clrMeterOutputPen        ), 1, wxSOLID);
       mBrush     = wxBrush( theTheme.Colour( clrMeterOutputBrush      ), wxSOLID);
       mRMSBrush  = wxBrush( theTheme.Colour( clrMeterOutputRMSBrush   ), wxSOLID);
@@ -313,7 +318,7 @@ Meter::~Meter()
 {
    if (mIsInput)
    {
-      // Unregister for AudioIO Monitor events
+      // Unregister for AudioIO events
       wxTheApp->Disconnect(EVT_AUDIOIO_MONITOR,
                            wxCommandEventHandler(Meter::OnAudioIOStatus),
                            NULL,
@@ -323,6 +328,13 @@ Meter::~Meter()
                            NULL,
                            this);
    }
+   else
+   {
+      wxTheApp->Disconnect(EVT_AUDIOIO_PLAYBACK,
+                           wxCommandEventHandler(Meter::OnAudioIOStatus),
+                           NULL,
+                           this);
+   }
 
    // Unregister for our preference update event
    wxTheApp->Disconnect(EVT_METER_PREFERENCES_CHANGED,
@@ -379,8 +391,6 @@ void Meter::UpdatePrefs()
 
    Reset(mRate, false);
 
-   mTimer.Start(1000 / mMeterRefreshRate);
-
    mLayoutValid = false;
 }
 
@@ -674,7 +684,6 @@ void Meter::OnMouse(wxMouseEvent &evt)
       else {
          Reset(mRate, true);
       }
-
    }
 }
 
@@ -701,14 +710,14 @@ void Meter::Reset(double sampleRate, bool resetClipping)
 
    // wxTimers seem to be a little unreliable - sometimes they stop for
    // no good reason, so this "primes" it every now and then...
-   mTimer.Stop();
+//   mTimer.Stop();
 
    // While it's stopped, empty the queue
    mQueue.Clear();
 
    mLayoutValid = false;
 
-   mTimer.Start(1000 / mMeterRefreshRate);
+//   mTimer.Start(1000 / mMeterRefreshRate);
 
    Refresh(false);
 }
@@ -755,14 +764,8 @@ void Meter::UpdateDisplay(int numChannels, int numFrames, float *sampleData)
    int num = intmin(numChannels, mNumBars);
    MeterUpdateMsg msg;
 
+   memset(&msg, 0, sizeof(msg));
    msg.numFrames = numFrames;
-   for(j=0; j<mNumBars; j++) {
-      msg.peak[j] = 0;
-      msg.rms[j] = 0;
-      msg.clipping[j] = false;
-      msg.headPeakCount[j] = 0;
-      msg.tailPeakCount[j] = 0;
-   }
 
    for(i=0; i<numFrames; i++) {
       for(j=0; j<num; j++) {
@@ -1718,6 +1721,8 @@ void Meter::OnAudioIOStatus(wxCommandEvent &evt)
       {
          mActive = true;
 
+         mTimer.Start(1000 / mMeterRefreshRate);
+
          if (evt.GetEventType() == EVT_AUDIOIO_MONITOR)
          {
             mMonitoring = mActive;
@@ -1725,11 +1730,15 @@ void Meter::OnAudioIOStatus(wxCommandEvent &evt)
       }
       else
       {
+         mTimer.Stop();
+
          mMonitoring = false;
       }
    }
    else
    {
+      mTimer.Stop();
+
       mMonitoring = false;
    }
 
@@ -1740,6 +1749,31 @@ void Meter::OnAudioIOStatus(wxCommandEvent &evt)
    }
 }
 
+// SaveState() and RestoreState() exist solely for purpose of recreating toolbars
+// They should really be quering the project for current audio I/O state, but there
+// isn't a clear way of doing that just yet.  (It should NOT query AudioIO.)
+void *Meter::SaveState()
+{
+   bool *state = new bool[2];
+   state[0] = mMonitoring;
+   state[1] = mActive;
+
+   return state;
+}
+
+void Meter::RestoreState(void *state)
+{
+   mMonitoring = ((bool *)state)[0];
+   mActive = ((bool *)state)[1];
+
+   if (mActive)
+   {
+      mTimer.Start(1000 / mMeterRefreshRate);
+   }
+
+   delete [] state;
+}
+
 //
 // Pop-up menu handlers
 //

src/widgets/Meter.h

@@ -171,6 +171,10 @@ class Meter : public wxPanel
 
    void StartMonitoring();
 
+   // These exist solely for the purpose of reseting the toolbars
+   void *SaveState();
+   void RestoreState(void *state);
+
  private:
    //
    // Event handlers