MixerBoard.cpp

Go to the documentation of this file.

/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  MixerBoard.cpp
 
  Vaughan Johnson, January 2007
  Dominic Mazzoni
 
**********************************************************************/
 
 
#include "MixerBoard.h"
 
 
 
#include <cfloat>
#include <math.h>
 
#include <wx/setup.h> // for wxUSE_* macros
 
#include <wx/app.h>
#include <wx/bmpbuttn.h>
#include <wx/dcclient.h>
#include <wx/icon.h>
#include <wx/settings.h> // for wxSystemSettings::GetColour and wxSystemSettings::GetMetric
 
#include "AColor.h"
#include "AllThemeResources.h"
#include "AudioIO.h"
 
#ifdef USE_MIDI
#include "NoteTrack.h"
#endif
 
#include "AudioSegmentSampleView.h"
#include "CommonCommandFlags.h"
#include "KeyboardCapture.h"
#include "prefs/GUISettings.h" // for RTL_WORKAROUND
#include "PendingTracks.h"
#include "Project.h"
#include "ProjectAudioIO.h"
#include "ProjectAudioManager.h"
#include "ProjectHistory.h"
#include "ProjectFileIO.h"
#include "ProjectWindow.h"
#include "ProjectWindows.h"
#include "SelectUtilities.h"
#include "Theme.h"
#include "TrackPanel.h"
#include "TrackUtilities.h"
#include "UndoManager.h"
#include "Viewport.h"
#include "WaveTrack.h"
 
#include "widgets/AButton.h"
#include "widgets/MeterPanel.h"
#include "widgets/auStaticText.h"
 
 
#include "../images/MusicalInstruments.h"
#ifdef __WXMSW__
   #include "../images/AudacityLogo.xpm"
#else
   #include "../images/AudacityLogo48x48.xpm"
#endif
 
#include "MenuCreator.h"
 
#include <numeric> // accumulate
 
#define AudacityMixerBoardTitle XO("Audacity Mixer%s")
 
// class MixerTrackSlider
 
BEGIN_EVENT_TABLE(MixerTrackSlider, ASlider)
   EVT_MOUSE_EVENTS(MixerTrackSlider::OnMouseEvent)
 
   EVT_SET_FOCUS(MixerTrackSlider::OnFocus)
   EVT_KILL_FOCUS(MixerTrackSlider::OnFocus)
   EVT_COMMAND(wxID_ANY, EVT_CAPTURE_KEY, MixerTrackSlider::OnCaptureKey)
 
END_EVENT_TABLE()
 
MixerTrackSlider::MixerTrackSlider(wxWindow * parent,
                                    wxWindowID id,
                                    const TranslatableString &name,
                                    const wxPoint & pos,
                                    const wxSize & size,
                                    const ASlider::Options &options)
: ASlider(parent, id, name, pos, size, options)
{
}
 
void MixerTrackSlider::OnMouseEvent(wxMouseEvent &event)
{
   ASlider::OnMouseEvent(event);
 
   if (event.ButtonUp())
   {
      MixerTrackCluster* pMixerTrackCluster = (MixerTrackCluster*)(this->GetParent());
      switch (mStyle)
      {
      case DB_SLIDER: pMixerTrackCluster->HandleSliderGain(true); break;
      case PAN_SLIDER: pMixerTrackCluster->HandleSliderPan(true); break;
      default: break; // no-op
      }
   }
}
 
void MixerTrackSlider::OnFocus(wxFocusEvent &event)
{
   KeyboardCapture::OnFocus( *this, event );
}
 
void MixerTrackSlider::OnCaptureKey(wxCommandEvent &event)
{
   wxKeyEvent *kevent = (wxKeyEvent *)event.GetEventObject();
   int keyCode = kevent->GetKeyCode();
 
   // Pass LEFT/RIGHT/UP/DOWN/PAGEUP/PAGEDOWN through for input/output sliders
   if (keyCode == WXK_LEFT || keyCode == WXK_RIGHT ||
       keyCode == WXK_UP || keyCode == WXK_DOWN ||
       keyCode == WXK_PAGEUP || keyCode == WXK_PAGEDOWN) {
      return;
   }
 
   event.Skip();
 
   return;
}
 
 
 
// class MixerTrackCluster
 
const int kInset = 4;
const int kDoubleInset    = (2 * kInset);
const int kTripleInset    = (3 * kInset);
const int kQuadrupleInset = (4 * kInset);
 
const int TRACK_NAME_HEIGHT                   = 18;
const int MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH = 48;
const int MUTE_SOLO_HEIGHT                    = 19;
const int  PAN_HEIGHT                         = 24;
 
const int kLeftSideStackWidth     = MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH - kDoubleInset; //vvv Change when numbers shown on slider scale.
const int kRightSideStackWidth    = MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH + kDoubleInset;
const int kMixerTrackClusterWidth = kLeftSideStackWidth + kRightSideStackWidth + kQuadrupleInset; // kDoubleInset margin on both sides
 
enum {
   ID_BITMAPBUTTON_MUSICAL_INSTRUMENT = 13000,
   ID_SLIDER_PAN,
   ID_SLIDER_GAIN,
   ID_SLIDER_VELOCITY,
   ID_TOGGLEBUTTON_MUTE,
   ID_TOGGLEBUTTON_SOLO,
};
 
BEGIN_EVENT_TABLE(MixerTrackCluster, wxPanelWrapper)
   EVT_MOUSE_EVENTS(MixerTrackCluster::OnMouseEvent)
   EVT_PAINT(MixerTrackCluster::OnPaint)
 
   EVT_BUTTON(ID_BITMAPBUTTON_MUSICAL_INSTRUMENT, MixerTrackCluster::OnButton_MusicalInstrument)
   EVT_SLIDER(ID_SLIDER_PAN, MixerTrackCluster::OnSlider_Pan)
   EVT_SLIDER(ID_SLIDER_GAIN, MixerTrackCluster::OnSlider_Gain)
   EVT_SLIDER(ID_SLIDER_VELOCITY, MixerTrackCluster::OnSlider_Velocity)
   //v EVT_COMMAND_SCROLL(ID_SLIDER_GAIN, MixerTrackCluster::OnSliderScroll_Gain)
   EVT_COMMAND(ID_TOGGLEBUTTON_MUTE, wxEVT_COMMAND_BUTTON_CLICKED, MixerTrackCluster::OnButton_Mute)
   EVT_COMMAND(ID_TOGGLEBUTTON_SOLO, wxEVT_COMMAND_BUTTON_CLICKED, MixerTrackCluster::OnButton_Solo)
END_EVENT_TABLE()
 
MixerTrackCluster::MixerTrackCluster(wxWindow* parent,
   MixerBoard* grandParent, AudacityProject* project,
   PlayableTrack &track,
   const wxPoint& pos /*= wxDefaultPosition*/,
   const wxSize& size /*= wxDefaultSize*/)
: wxPanelWrapper(parent, -1, pos, size)
, mTrack{ track.SharedPointer<PlayableTrack>() }
{
   mMixerBoard = grandParent;
   mProject = project;
   assert(mTrack);
 
   SetName( Verbatim( mTrack->GetName() ) );
 
   //this->SetBackgroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE));
   this->SetBackgroundColour( theTheme.Colour( clrMedium ) );
   // Not sure why, but sizers weren't getting offset vertically,
   // probably because not using wxDefaultPosition,
   // so positions are calculated explicitly below, and sizers code was removed.
   // (Still available in Audacity_UmixIt branch off 1.2.6.)
 
   // track name
   wxPoint ctrlPos(kDoubleInset, kDoubleInset);
   wxSize ctrlSize(size.GetWidth() - kQuadrupleInset, TRACK_NAME_HEIGHT);
   mStaticText_TrackName =
      safenew auStaticText(this, mTrack->GetName());
   //v Useful when different tracks are different colors, but not now.
   //    mStaticText_TrackName->SetBackgroundColour(this->GetTrackColor());
   mStaticText_TrackName->SetForegroundColour(theTheme.Colour(clrMedium));
   mStaticText_TrackName->SetForegroundColour(theTheme.Colour(clrTrackPanelText));
   mStaticText_TrackName->SetSize( ctrlSize );
   mStaticText_TrackName->SetPosition( ctrlPos );
 
 
   // volume and velocity sliders at left (both in same place)
   ctrlPos.x = kDoubleInset;
   ctrlPos.y += TRACK_NAME_HEIGHT + kDoubleInset;
   const int nGainSliderHeight =
      size.GetHeight() - ctrlPos.y - kQuadrupleInset;
   ctrlSize.Set(kLeftSideStackWidth - kQuadrupleInset, nGainSliderHeight);
 
   mSlider_Volume =
      safenew MixerTrackSlider(
            this, ID_SLIDER_GAIN,
            /* i18n-hint: title of the Volume slider, used to adjust the volume */
            XO("Volume"),
            ctrlPos, ctrlSize,
            ASlider::Options{}
               .Style( DB_SLIDER )
               .Orientation( wxVERTICAL ));
   mSlider_Volume->SetName(_("Volume"));
 
   mSlider_Velocity =
      safenew MixerTrackSlider(
            this, ID_SLIDER_VELOCITY,
            /* i18n-hint: title of the MIDI Velocity slider */
            XO("Velocity"),
            ctrlPos, ctrlSize,
            ASlider::Options{}
               .Style( VEL_SLIDER )
               .Orientation( wxVERTICAL ));
   mSlider_Velocity->SetName(_("Velocity"));
 
   // other controls and meter at right
 
   // musical instrument image
   ctrlPos.x += kLeftSideStackWidth + kInset; // + kInset to center it in right side stack
   ctrlSize.Set(MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH, MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH);
   wxBitmap* bitmap = mMixerBoard->GetMusicalInstrumentBitmap(mTrack.get());
   wxASSERT(bitmap);
   mBitmapButton_MusicalInstrument =
      safenew wxBitmapButton(this, ID_BITMAPBUTTON_MUSICAL_INSTRUMENT, *bitmap,
                           ctrlPos, ctrlSize,
                           wxBU_AUTODRAW, wxDefaultValidator,
                           _("Musical Instrument"));
   mBitmapButton_MusicalInstrument->SetName(_("Musical Instrument"));
 
 
   // pan slider
   ctrlPos.x -= kInset; // Remove inset for instrument, so Pan is at leftmost of left side stack.
   ctrlPos.y += MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH + kDoubleInset;
   ctrlSize.Set(kRightSideStackWidth, PAN_HEIGHT);
 
   // The width of the pan slider must be odd (don't ask).
   if (!(ctrlSize.x & 1))
      ctrlSize.x--;
 
   mSlider_Pan =
      safenew MixerTrackSlider(
            this, ID_SLIDER_PAN,
            /* i18n-hint: Title of the Pan slider, used to move the sound left or right */
            XO("Pan"),
            ctrlPos, ctrlSize,
            ASlider::Options{}.Style( PAN_SLIDER ));
   mSlider_Pan->SetName(_("Pan"));
 
   // mute/solo buttons stacked below Pan slider
   ctrlPos.y += PAN_HEIGHT + kDoubleInset;
   ctrlSize.Set(mMixerBoard->mMuteSoloWidth, MUTE_SOLO_HEIGHT);
   mToggleButton_Mute =
      safenew AButton(this, ID_TOGGLEBUTTON_MUTE,
                  ctrlPos, ctrlSize,
                  *(mMixerBoard->mImageMuteUp), *(mMixerBoard->mImageMuteOver),
                  *(mMixerBoard->mImageMuteDown), *(mMixerBoard->mImageMuteDown),
                  *(mMixerBoard->mImageMuteDisabled),
                  true); // toggle button
   mToggleButton_Mute->SetName(_("Mute"));
   mToggleButton_Mute->SetAlternateImages(
      1,
      *(mMixerBoard->mImageMuteUp), *(mMixerBoard->mImageMuteOver),
      *(mMixerBoard->mImageMuteDown), *(mMixerBoard->mImageMuteDown),
      *(mMixerBoard->mImageMuteDisabled));
 
   ctrlPos.y += MUTE_SOLO_HEIGHT;
   mToggleButton_Solo =
      safenew AButton(this, ID_TOGGLEBUTTON_SOLO,
                  ctrlPos, ctrlSize,
                  *(mMixerBoard->mImageSoloUp), *(mMixerBoard->mImageSoloOver),
                  *(mMixerBoard->mImageSoloDown), *(mMixerBoard->mImageSoloDown),
                  *(mMixerBoard->mImageSoloDisabled),
                  true); // toggle button
   mToggleButton_Solo->SetName(_("Solo"));
 
 
   // meter
   ctrlPos.y += MUTE_SOLO_HEIGHT + kDoubleInset;
   const int nMeterHeight =
      nGainSliderHeight -
      (MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH + kDoubleInset) -
      (PAN_HEIGHT + kDoubleInset) -
      (MUTE_SOLO_HEIGHT + MUTE_SOLO_HEIGHT + kDoubleInset);
   ctrlSize.Set(kRightSideStackWidth, nMeterHeight);
 
   mMeter.Release();
   if (GetWave()) {
      mMeter =
         safenew MeterPanel(mProject, // AudacityProject* project,
                   this, -1, // wxWindow* parent, wxWindowID id,
                   false, // bool isInput
                   ctrlPos, ctrlSize, // const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize,
                   MeterPanel::MixerTrackCluster); // Style style = HorizontalStereo,
      mMeter->SetName(XO("Signal Level Meter"));
   }
 
   #if wxUSE_TOOLTIPS
      mStaticText_TrackName->SetToolTip(mTrack->GetName());
      mToggleButton_Mute->SetToolTip(XO("Mute"));
      mToggleButton_Solo->SetToolTip(XO("Solo"));
      if (GetWave())
         mMeter->SetToolTip(XO("Signal Level Meter"));
   #endif // wxUSE_TOOLTIPS
 
   UpdateForStateChange();
 
   #ifdef __WXMAC__
      wxSizeEvent event(GetSize(), GetId());
      event.SetEventObject(this);
      GetEventHandler()->ProcessEvent(event);
   #endif
}
 
WaveTrack *MixerTrackCluster::GetWave() const
{
   return dynamic_cast< WaveTrack * >( mTrack.get() );
}
 
WaveChannel *MixerTrackCluster::GetRight() const
{
  // TODO: more-than-two-channels
   auto left = GetWave();
   if (left) {
      auto channels = left->Channels();
      if (channels.size() > 1)
         return (* ++ channels.first).get();
   }
   return nullptr;
}
 
NoteTrack *MixerTrackCluster::GetNote() const
{
   return dynamic_cast< NoteTrack * >( mTrack.get() );
}
 
// Old approach modified things in situ.
// However with a theme change there is so much to modify, it is easier
// to recreate.
#if 0
void MixerTrackCluster::UpdatePrefs()
{
   this->SetBackgroundColour( theTheme.Colour( clrMedium ) );
   mStaticText_TrackName->SetForegroundColour(theTheme.Colour(clrTrackPanelText));
   HandleResize(); // in case TracksBehaviorsSolo changed
}
#endif
 
void MixerTrackCluster::HandleResize() // For wxSizeEvents, update volume slider and meter.
{
   wxSize scrolledWindowClientSize = this->GetParent()->GetClientSize();
   const int newClusterHeight =
      scrolledWindowClientSize.GetHeight() - kDoubleInset - // nClusterHeight from MixerBoard::UpdateTrackClusters
      wxSystemSettings::GetMetric(wxSYS_HSCROLL_Y) + // wxScrolledWindow::GetClientSize doesn't account for its scrollbar size.
      kDoubleInset;
 
   this->SetSize(-1, newClusterHeight);
 
   // Change only the heights of mSlider_Volume and mMeter.
   // But update shown status of mToggleButton_Solo, which affects top of mMeter.
   const int nGainSliderHeight =
      newClusterHeight -
      (kInset + // margin above mStaticText_TrackName
         TRACK_NAME_HEIGHT + kDoubleInset) - // mStaticText_TrackName + margin
      kQuadrupleInset; // margin below volume slider
   mSlider_Volume->SetSize(-1, nGainSliderHeight);
   mSlider_Velocity->SetSize(-1, nGainSliderHeight);
 
   const int nRequiredHeightAboveMeter =
      MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH + kDoubleInset +
      PAN_HEIGHT + kDoubleInset +
      MUTE_SOLO_HEIGHT + MUTE_SOLO_HEIGHT + kDoubleInset;
   const int nMeterY =
      kDoubleInset + // margin at top
      TRACK_NAME_HEIGHT + kDoubleInset +
      nRequiredHeightAboveMeter;
   const int nMeterHeight = nGainSliderHeight - nRequiredHeightAboveMeter;
   if (mMeter)
      mMeter->SetSize(-1, nMeterY, -1, nMeterHeight);
}
 
void MixerTrackCluster::HandleSliderGain(const bool bWantPushState /*= false*/)
{
   float fValue = mSlider_Volume->Get();
   if (GetWave())
      GetWave()->SetVolume(fValue);
 
   // Update the TrackPanel correspondingly.
   TrackPanel::Get( *mProject ).RefreshTrack(mTrack.get());
   if (bWantPushState)
      ProjectHistory::Get( *mProject )
         .PushState(XO("Moved volume slider"), XO("Volume"), UndoPush::CONSOLIDATE );
}
 
void MixerTrackCluster::HandleSliderVelocity(const bool bWantPushState /*= false*/)
{
   float fValue = mSlider_Velocity->Get();
   if (GetNote())
      GetNote()->SetVelocity(fValue);
 
   // Update the TrackPanel correspondingly.
   TrackPanel::Get( *mProject ).RefreshTrack(mTrack.get());
   if (bWantPushState)
      ProjectHistory::Get( *mProject )
         .PushState(XO("Moved velocity slider"), XO("Velocity"),
            UndoPush::CONSOLIDATE);
}
 
void MixerTrackCluster::HandleSliderPan(const bool bWantPushState /*= false*/)
{
   float fValue = mSlider_Pan->Get();
   if (GetWave()) // test in case track is a NoteTrack
      GetWave()->SetPan(fValue);
 
   // Update the TrackPanel correspondingly.
   TrackPanel::Get( *mProject ).RefreshTrack(mTrack.get());
 
   if (bWantPushState)
      ProjectHistory::Get( *mProject )
         .PushState(XO("Moved pan slider"), XO("Pan"),
            UndoPush::CONSOLIDATE );
}
 
void MixerTrackCluster::ResetMeter(const bool bResetClipping)
{
   if (mMeter)
      mMeter->Reset(GetWave()->GetRate(), bResetClipping);
   // Release view to allow cache eviction after/before playback.
   mSampleView.clear();
}
 
 
// Update appearance to match the state of the track
void MixerTrackCluster::UpdateForStateChange()
{
   const wxString newName = mTrack->GetName();
   if (newName != GetName()) {
      SetName( Verbatim( newName ) );
      mStaticText_TrackName->SetLabel(newName);
      mStaticText_TrackName->SetName(newName);
#if wxUSE_TOOLTIPS
         mStaticText_TrackName->SetToolTip(newName);
#endif
      mBitmapButton_MusicalInstrument->SetBitmapLabel(
         *(mMixerBoard->GetMusicalInstrumentBitmap(mTrack.get())));
   }
 
   mToggleButton_Mute->SetAlternateIdx(mTrack->GetSolo() ? 1 : 0);
   if (mTrack->GetMute())
      mToggleButton_Mute->PushDown();
   else
      mToggleButton_Mute->PopUp();
 
   bool bIsSolo = mTrack->GetSolo();
   if (bIsSolo)
      mToggleButton_Solo->PushDown();
   else
      mToggleButton_Solo->PopUp();
   mToggleButton_Mute->SetAlternateIdx(bIsSolo ? 1 : 0);
 
   if (!GetWave())
      mSlider_Pan->Hide();
   else
      mSlider_Pan->Set(GetWave()->GetPan());
 
   if (!GetWave())
      mSlider_Volume->Hide();
   else
      mSlider_Volume->Set(GetWave()->GetVolume());
 
   if (!GetNote())
      mSlider_Velocity->Hide();
   else
      mSlider_Velocity->Set(GetNote()->GetVelocity());
}
 
namespace {
size_t GetNumSamplesInView(const ChannelSampleView& view)
{
   return std::accumulate(
      view.begin(), view.end(), 0,
      [](size_t total, const AudioSegmentSampleView& segmentView) {
         return total + segmentView.GetSampleCount();
      });
}
 
// Assumes that buffer has capacity >= GetNumSamplesInView(view)
void FillBufferWithSampleView(float* buffer, const ChannelSampleView& view)
{
   size_t copiedSamples = 0;
   for (const auto& segmentView : view)
   {
      const auto sampleCount = segmentView.GetSampleCount();
      segmentView.Copy(buffer + copiedSamples, sampleCount);
      copiedSamples += sampleCount;
   }
}
}
 
void MixerTrackCluster::UpdateMeter(const double t0, const double t1)
{
   // NoteTracks do not (currently) register on meters. It would probably be
   // a good idea to display 16 channel "active" lights rather than a meter
   if (!GetWave())
      return;
 
   if ((t0 < 0.0) || (t1 < 0.0) || (t0 >= t1) || // bad time value or nothing to show
         ((mMixerBoard->HasSolo() || mTrack->GetMute()) && !mTrack->GetSolo())
      )
   {
      //v Vaughan, 2011-02-25: Moved the update back to TrackPanel::OnTimer() as it helps with
      //    playback issues reported by Bill and noted on Bug 258, so no assert.
      // Vaughan, 2011-02-04: Now that we're updating all meters from audacityAudioCallback,
      //    this causes an assert if you click Mute while playing, because ResetMeter() resets
      //    the timer, and wxTimerbase says that can only be done from main thread --
      //    but it seems to work fine.
      this->ResetMeter(false);
      return;
   }
 
   // Vaughan, 2010-11-27:
   // This commented out code is flawed. Mistaken understanding of "frame" vs "window".
   // Caused me to override MeterPanel::UpdateDisplay().
   // But I think it's got a good idea, of calling WaveTracks' GetMinMax and GetRMS
   // instead of passing in all the data and asking the meter to derive peak and rms.
   // May be worth revisiting as I think it should perform better, because it uses the min/max/rms
   // stored in sample blocks, rather than calculating them, but for now, changing it to use the
   // original MeterPanel::UpdateDisplay(). New code is below the previous (now commented out).
   //
   //const size_t kFramesPerBuffer = 4;
   //float min; // dummy, since it's not shown in meters
   //Floats maxLeft{kFramesPerBuffer};
   //Floats rmsLeft{kFramesPerBuffer};
   //Floats maxRight{kFramesPerBuffer};
   //Floats rmsRight{kFramesPerBuffer};
   //
   //   bool bSuccess = (GetWave() != nullptr);
 
   //const double dFrameInterval = (t1 - t0) / (double)kFramesPerBuffer;
   //double dFrameT0 = t0;
   //double dFrameT1 = t0 + dFrameInterval;
   //int i = 0;
   //while (bSuccess && (i < kFramesPerBuffer))
   //{
   //   bSuccess &=
   //      mTrack->GetMinMax(&min, &(maxLeft[i]), dFrameT0, dFrameT1) &&
   //      mTrack->GetRMS(&(rmsLeft[i]), dFrameT0, dFrameT1);
   //   if (bSuccess && mRightTrack)
   //      bSuccess &=
   //         mRightTrack->GetMinMax(&min, &(maxRight[i]), dFrameT0, dFrameT1) &&
   //         mRightTrack->GetRMS(&(rmsRight[i]), dFrameT0, dFrameT1);
   //   else
   //   {
   //      // Mono: Start with raw values same as left.
   //      // To be modified by bWantPostFadeValues and channel pan/gain.
   //      maxRight[i] = maxLeft[i];
   //      rmsRight[i] = rmsLeft[i];
   //   }
   //   dFrameT0 += dFrameInterval;
   //   dFrameT1 += dFrameInterval;
   //   i++;
   //}
   //
   //const bool bWantPostFadeValues = true; //v Turn this into a checkbox on MixerBoard? For now, always true.
   //if (bSuccess && bWantPostFadeValues)
   //if (bSuccess)
   //{
   //   for (i = 0; i < kFramesPerBuffer; i++)
   //   {
   //      float gain = mTrack->GetChannelVolume(0);
   //      maxLeft[i] *= gain;
   //      rmsLeft[i] *= gain;
   //      if (mRightTrack)
   //         gain = mRightTrack->GetChannelVolume(1);
   //      maxRight[i] *= gain;
   //      rmsRight[i] *= gain;
   //   }
   //   if ( mMeter ) mMeter->UpdateDisplay(
   //      2, // If mono, show left track values in both meters, as in MeterToolBar, rather than nChannels.
   //      kFramesPerBuffer,
   //      maxLeft, rmsLeft,
   //      maxRight, rmsRight,
   //      mTrack->TimeToLongSamples(t1 - t0));
   //}
   //
 
   // PRL: TODO:  don't fetch from wave tracks at calculated times, for update
   // of the meter display, but instead consult PlaybackPolicy
 
   const auto pTrack = GetWave();
 
   // Don't throw on read error in this drawing update routine
   constexpr auto mayThrow = false;
 
   // Not sure how to prove satisfaction of the invariant of GetSampleView
   mSampleView = pTrack->GetSampleView(t0, t1, mayThrow);
 
   // Expect that the difference of t1 and t0 is the part of a track played
   // in about 1/20 second (ticks of TrackPanel timer), so this won't overflow,
   // unless stretch ratio is extremely low.
   const auto nFrames = GetNumSamplesInView(mSampleView[0]);
 
   Floats tempFloatsArray;
   try {
      tempFloatsArray.reinit(nFrames);
   }
   catch (const std::bad_alloc&) {
      // Just in case we did not satisfy GetSampleView and computed a bogus
      // size_t value
      return;
   }
   FillBufferWithSampleView(tempFloatsArray.get(), mSampleView[0]);
 
   decltype(tempFloatsArray) meterFloatsArray;
   // We always pass a stereo sample array to the meter, as it shows 2 channels.
   // Mono shows same in both meters.
   // Since we're not mixing, need to duplicate same signal for "right" channel in mono case.
   try {
      meterFloatsArray.reinit(2 * nFrames );
   }
   catch (const std::bad_alloc&) {
      // Just in case we did not satisfy GetSampleView and computed a bogus
      // size_t value
      return;
   }
 
   // Interleave for stereo. Left/mono first.
   for (unsigned int index = 0; index < nFrames; index++)
      meterFloatsArray[2 * index] = tempFloatsArray[index];
 
   if (mSampleView.size() > 1u)
      FillBufferWithSampleView(tempFloatsArray.get(), mSampleView[1]);
 
   // Interleave right channel, or duplicate same signal for "right" channel in mono case.
   for (unsigned int index = 0; index < nFrames; index++)
      meterFloatsArray[(2 * index) + 1] = tempFloatsArray[index];
 
   //const bool bWantPostFadeValues = true; //v Turn this into a checkbox on MixerBoard? For now, always true.
   //if (bSuccess && bWantPostFadeValues)
   //vvv Need to apply envelope, too? See Mixer::MixSameRate.
   float volume = pTrack->GetChannelVolume(0);
   for (unsigned int index = 0; index < nFrames; index++)
      meterFloatsArray[2 * index] *= volume;
   volume = pTrack->GetChannelVolume(1);
   for (unsigned int index = 0; index < nFrames; index++)
      meterFloatsArray[(2 * index) + 1] *= volume;
   // Clip to [-1.0, 1.0] range.
   for (unsigned int index = 0; index < 2 * nFrames; index++)
      if (meterFloatsArray[index] < -1.0)
         meterFloatsArray[index] = -1.0;
      else if (meterFloatsArray[index] > 1.0)
         meterFloatsArray[index] = 1.0;
 
   if (mMeter)
      mMeter->UpdateDisplay(2, nFrames, meterFloatsArray.get());
}
 
// private
 
wxColour MixerTrackCluster::GetTrackColor()
{
   return wxColour(102, 255, 102); // same as Meter playback color
}
 
 
// event handlers
 
void MixerTrackCluster::HandleSelect(bool bShiftDown, bool bControlDown)
{
   SelectUtilities::DoListSelection(*mProject,
      *mTrack, bShiftDown, bControlDown, true);
}
 
void MixerTrackCluster::OnMouseEvent(wxMouseEvent& event)
{
   if (event.ButtonUp())
      this->HandleSelect(event.ShiftDown(), event.ControlDown());
   else
      event.Skip();
}
 
void MixerTrackCluster::OnPaint(wxPaintEvent & WXUNUSED(event))
{
   UpdateForStateChange();
 
   auto selected = mTrack->GetSelected();
 
   wxColour col = theTheme.Colour(selected ? clrTrackInfoSelected : clrTrackInfo) ;
   SetBackgroundColour( col );
   if (mMeter)
      mMeter->SetBackgroundColour( col );
   mStaticText_TrackName->SetBackgroundColour( col );
   mSlider_Volume->SetBackgroundColour( col );
   mSlider_Pan->SetBackgroundColour( col );
 
   wxPaintDC dc(this);
 
   AColor::MediumTrackInfo(&dc, selected);
   dc.DrawRectangle(this->GetClientRect());
 
   wxSize clusterSize = this->GetSize();
   wxRect bev(0, 0, clusterSize.GetWidth() - 1, clusterSize.GetHeight() - 1);
 
   //bev.Inflate(-1, -1);
   AColor::Bevel(dc, true, bev);// same bevel whether selected or not.
}
 
 
void MixerTrackCluster::OnButton_MusicalInstrument(wxCommandEvent& WXUNUSED(event))
{
   const auto &state = ::wxGetMouseState();
   this->HandleSelect(state.ShiftDown(), state.ControlDown());
}
 
void MixerTrackCluster::OnSlider_Gain(wxCommandEvent& WXUNUSED(event))
{
   this->HandleSliderGain();
}
 
void MixerTrackCluster::OnSlider_Velocity(wxCommandEvent& WXUNUSED(event))
{
   this->HandleSliderVelocity();
}
 
void MixerTrackCluster::OnSlider_Pan(wxCommandEvent& WXUNUSED(event))
{
   this->HandleSliderPan();
}
 
void MixerTrackCluster::OnButton_Mute(wxCommandEvent& WXUNUSED(event))
{
   TrackUtilities::DoTrackMute(
      *mProject, *mTrack, mToggleButton_Mute->WasShiftDown());
   mToggleButton_Mute->SetAlternateIdx(mTrack->GetSolo() ? 1 : 0);
 
   // Update the TrackPanel correspondingly.
   if (TracksBehaviorsSolo.ReadEnum() == SoloBehaviorSimple)
      Viewport::Get(*mProject).Redraw();
   else
      // Update only the changed track.
      TrackPanel::Get( *mProject ).RefreshTrack(mTrack.get());
}
 
void MixerTrackCluster::OnButton_Solo(wxCommandEvent& WXUNUSED(event))
{
   TrackUtilities::DoTrackSolo(
      *mProject, *mTrack, mToggleButton_Solo->WasShiftDown());
   bool bIsSolo = mTrack->GetSolo();
   mToggleButton_Mute->SetAlternateIdx(bIsSolo ? 1 : 0);
 
   // Update the TrackPanel correspondingly.
   // Bug 509: Must repaint all, as many tracks can change with one Solo change.
   Viewport::Get(*mProject).Redraw();
}
 
 
// class MusicalInstrument
 
MusicalInstrument::MusicalInstrument(std::unique_ptr<wxBitmap> &&pBitmap, const wxString & strXPMfilename)
{
   mBitmap = std::move(pBitmap);
 
   int nUnderscoreIndex;
   wxString strFilename = strXPMfilename;
   strFilename.MakeLower(); // Make sure, so we don't have to do case insensitive comparison.
   wxString strKeyword;
   while ((nUnderscoreIndex = strFilename.Find(wxT('_'))) != -1)
   {
      strKeyword = strFilename.Left(nUnderscoreIndex);
      mKeywords.push_back(strKeyword);
      strFilename = strFilename.Mid(nUnderscoreIndex + 1);
   }
   if (!strFilename.empty()) // Skip trailing underscores.
      mKeywords.push_back(strFilename); // Add the last one.
}
 
MusicalInstrument::~MusicalInstrument()
{
   mKeywords.clear();
}
 
 
// class MixerBoardScrolledWindow
 
// wxScrolledWindow ignores mouse clicks in client area,
// but they don't get passed to Mixerboard.
// We need to catch them to deselect all track clusters.
 
BEGIN_EVENT_TABLE(MixerBoardScrolledWindow, wxScrolledWindow)
   EVT_MOUSE_EVENTS(MixerBoardScrolledWindow::OnMouseEvent)
END_EVENT_TABLE()
 
MixerBoardScrolledWindow::MixerBoardScrolledWindow(AudacityProject* project,
                                                   MixerBoard* parent, wxWindowID id /*= -1*/,
                                                   const wxPoint& pos /*= wxDefaultPosition*/,
                                                   const wxSize& size /*= wxDefaultSize*/,
                                                   long style /*= wxHSCROLL | wxVSCROLL*/)
: wxScrolledWindow(parent, id, pos, size, style)
{
   mMixerBoard = parent;
   mProject = project;
}
 
MixerBoardScrolledWindow::~MixerBoardScrolledWindow()
{
}
 
void MixerBoardScrolledWindow::OnMouseEvent(wxMouseEvent& event)
{
   if (event.ButtonUp())
   {
      //v Even when I implement MixerBoard::OnMouseEvent and call event.Skip()
      // here, MixerBoard::OnMouseEvent never gets called.
      // So, added mProject to MixerBoardScrolledWindow and just directly do what's needed here.
      SelectUtilities::SelectNone( *mProject );
   }
   else
      event.Skip();
}
 
 
// class MixerBoard
 
#define MIXER_BOARD_MIN_HEIGHT      460
 
// Min width is one cluster wide, plus margins.
#define MIXER_BOARD_MIN_WIDTH       kTripleInset + kMixerTrackClusterWidth*2 + kTripleInset
 
 
BEGIN_EVENT_TABLE(MixerBoard, wxWindow)
   EVT_PAINT(MixerBoard::OnPaint)
   EVT_SIZE(MixerBoard::OnSize)
END_EVENT_TABLE()
 
MixerBoard::MixerBoard(AudacityProject* pProject,
                        wxFrame* parent,
                        const wxPoint& pos /*= wxDefaultPosition*/,
                        const wxSize& size /*= wxDefaultSize*/)
: wxWindow(parent, -1, pos, size)
{
   // public data members
 
   // mute & solo button images
   // Create once and store on MixerBoard for use in all MixerTrackClusters.
   mImageMuteUp = NULL;
   mImageMuteOver = NULL;
   mImageMuteDown = NULL;
   mImageMuteDownWhileSolo = NULL;
   mImageMuteDisabled = NULL;
   mImageSoloUp = NULL;
   mImageSoloOver = NULL;
   mImageSoloDown = NULL;
   mImageSoloDisabled = NULL;
 
   mMuteSoloWidth = kRightSideStackWidth - kInset; // correct for max width, but really set in MixerBoard::CreateMuteSoloImages
 
   // private data members
   this->LoadMusicalInstruments(); // Set up mMusicalInstruments.
   mProject = pProject;
 
   wxASSERT(pProject); // to justify safenew
   mScrolledWindow =
      safenew MixerBoardScrolledWindow(
         pProject, // AudacityProject* project,
         this, -1, // wxWindow* parent, wxWindowID id = -1,
         this->GetClientAreaOrigin(), // const wxPoint& pos = wxDefaultPosition,
         size, // const wxSize& size = wxDefaultSize,
         wxHSCROLL); // long style = wxHSCROLL | wxVSCROLL, const wxString& name = "scrolledWindow")
 
   // Set background color to same as TrackPanel background.
//      mScrolledWindow->SetBackgroundColour(this->GetParent()->GetBackgroundColour());
   mScrolledWindow->SetBackgroundColour( theTheme.Colour( clrMedium ) );
   RTL_WORKAROUND(mScrolledWindow);
 
   mScrolledWindow->SetScrollRate(10, 0); // no vertical scroll
   mScrolledWindow->SetVirtualSize(size);
 
   /* This doesn't work to make the mScrolledWindow automatically resize, so do it explicitly in OnSize.
         auto pBoxSizer = std::make_unique<wxBoxSizer>(wxVERTICAL);
         pBoxSizer->push_back(mScrolledWindow, 0, wxExpand, 0);
         this->SetAutoLayout(true);
         this->SetSizer(pBoxSizer);
         pBoxSizer->Fit(this);
         pBoxSizer->SetSizeHints(this);
      */
 
   mPrevT1 = 0.0;
   mTracks = &TrackList::Get( *mProject );
 
   // Events from the project don't propagate directly to this other frame, so...
   mPlaybackScrollerSubscription =
   ProjectWindow::Get( *mProject ).GetPlaybackScroller()
      .Subscribe(*this, &MixerBoard::OnTimer);
 
   mTrackPanelSubscription =
   PendingTracks::Get(*mProject).Subscribe([this](const TrackListEvent &event){
      switch (event.mType) {
      case TrackListEvent::SELECTION_CHANGE:
      case TrackListEvent::TRACK_DATA_CHANGE:
         OnTrackChanged(event); break;
      case TrackListEvent::PERMUTED:
      case TrackListEvent::ADDITION:
      case TrackListEvent::DELETION:
         OnTrackSetChanged(); break;
      default:
         break;
      }
   });
 
   mAudioIOSubscription =
      AudioIO::Get()->Subscribe(*this, &MixerBoard::OnStartStop);
}
 
 
 
 
void MixerBoard::UpdatePrefs()
{
   // Destroys this:
   static_cast<MixerBoardFrame*>(GetParent())->Recreate( mProject );
 
// Old approach modified things in situ.
// However with a theme change there is so much to modify, it is easier
// to recreate.
#if 0
   mScrolledWindow->SetBackgroundColour( theTheme.Colour( clrMedium ) );
   if( mImageMuteUp ){
      mImageMuteUp.reset();
      mImageMuteOver.reset();
      mImageMuteDown.reset();
      mImageMuteDownWhileSolo.reset();
      mImageMuteDisabled.reset();
      mImageSoloUp.reset();
      mImageSoloOver.reset();
      mImageSoloDown.reset();
      mImageSoloDisabled.reset();
   }
   for (unsigned int nClusterIndex = 0; nClusterIndex < mMixerTrackClusters.size(); nClusterIndex++)
      mMixerTrackClusters[nClusterIndex]->UpdatePrefs();
   Refresh();
#endif
}
 
// Reassign mixer input strips (MixerTrackClusters) to Track Clusters
// both have the same order.
// Note Tracks appear in the mixer,
// and we must be able to convert and reuse a MixerTrackCluster
// from audio to midi or midi to audio. This task is handled by
// UpdateForStateChange().
//
void MixerBoard::UpdateTrackClusters()
{
   if (!mImageMuteUp)
      this->CreateMuteSoloImages();
 
   const int nClusterHeight = mScrolledWindow->GetClientSize().GetHeight() - kDoubleInset;
   size_t nClusterCount = mMixerTrackClusters.size();
   unsigned int nClusterIndex = 0;
   MixerTrackCluster* pMixerTrackCluster = NULL;
 
   for (auto pPlayableTrack: mTracks->Any<PlayableTrack>()) {
      // TODO: more-than-two-channels
      auto spTrack = pPlayableTrack->SharedPointer<PlayableTrack>();
      // Track iterations always yield non-null pointers; maintain invariant
      // when reassigning
      assert(spTrack);
      if (nClusterIndex < nClusterCount)
      {
         // Already showing it.
         // Track clusters are maintained in the same order as the WaveTracks.
         // Track pointers can change for the "same" track for different states
         // on the undo stack, so update the pointers and display name.
         mMixerTrackClusters[nClusterIndex]->mTrack = spTrack;
         // Assume linked track is wave or null
         mMixerTrackClusters[nClusterIndex]->UpdateForStateChange();
      }
      else
      {
         // Not already showing it. Add a NEW MixerTrackCluster.
         wxPoint clusterPos(
            kInset + nClusterIndex * kMixerTrackClusterWidth,
            kInset);
         wxSize clusterSize(kMixerTrackClusterWidth, nClusterHeight);
         pMixerTrackCluster =
            safenew MixerTrackCluster(mScrolledWindow, this, mProject,
               *spTrack, clusterPos, clusterSize);
         if (pMixerTrackCluster)
            mMixerTrackClusters.push_back(pMixerTrackCluster);
      }
      nClusterIndex++;
   }
 
   if (pMixerTrackCluster)
   {
      // Added at least one MixerTrackCluster.
      this->UpdateWidth();
      this->ResizeTrackClusters();
   }
   else while (nClusterIndex < nClusterCount)
   {
      // We've got too many clusters.
      // This can happen only on things like Undo New Audio Track or Undo Import
      // that don't call RemoveTrackCluster explicitly.
      // We've already updated the track pointers for the clusters to the left, so just remove all the rest.
      // Successively DELETE from right to left.
      RemoveTrackCluster(--nClusterCount);
   }
}
 
int MixerBoard::GetTrackClustersWidth()
{
   return
      kInset +                                     // extra margin at left for first one
      (mMixerTrackClusters.size() *            // number of tracks times
         (kInset + kMixerTrackClusterWidth)) +     // left margin and width for each
      kDoubleInset;                                // plus final right margin
}
 
void MixerBoard::RemoveTrackCluster(size_t nIndex)
{
   auto pMixerTrackCluster = mMixerTrackClusters[nIndex];
   mMixerTrackClusters.erase(mMixerTrackClusters.begin() + nIndex);
   pMixerTrackCluster->Destroy(); // DELETE is unsafe on wxWindow.
 
   // Close the gap, if any.
   wxPoint pos;
   int targetX;
   for (unsigned int i = nIndex; i < mMixerTrackClusters.size(); i++)
   {
      pos = mMixerTrackClusters[i]->GetPosition();
      targetX =
         kInset +                                     // extra inset to left for first one, so it's double
         (i * (kInset + kMixerTrackClusterWidth)) +   // left margin and width for each
         kInset;                                      // plus left margin for this cluster
      if (pos.x != targetX)
         mMixerTrackClusters[i]->Move(targetX, pos.y);
   }
 
   this->UpdateWidth();
}
 
 
wxBitmap* MixerBoard::GetMusicalInstrumentBitmap(const Track* pTrack)
{
   if (mMusicalInstruments.empty())
      return NULL;
 
   // random choice:    return mMusicalInstruments[(int)pTrack % mMusicalInstruments.size()].mBitmap;
 
   const wxString strTrackName(
      wxString{ pTrack->GetName() }.MakeLower());
   size_t nBestItemIndex = 0;
   unsigned int nBestScore = 0;
   unsigned int nInstrIndex = 0;
   unsigned int nKeywordIndex;
   unsigned int nNumKeywords;
   unsigned int nPointsPerMatch;
   unsigned int nScore;
   for (nInstrIndex = 0; nInstrIndex < mMusicalInstruments.size(); nInstrIndex++)
   {
      nScore = 0;
 
      nNumKeywords = mMusicalInstruments[nInstrIndex]->mKeywords.size();
      if (nNumKeywords > 0)
      {
         nPointsPerMatch = 10 / nNumKeywords;
         for (nKeywordIndex = 0; nKeywordIndex < nNumKeywords; nKeywordIndex++)
            if (strTrackName.Contains(mMusicalInstruments[nInstrIndex]->mKeywords[nKeywordIndex]))
            {
               nScore +=
                  nPointsPerMatch +
                  // Longer keywords get more points.
                  (2 * mMusicalInstruments[nInstrIndex]->mKeywords[nKeywordIndex].length());
            }
      }
 
      // Choose later one if just matching nBestScore, for better variety,
      // and so default works as last element.
      if (nScore >= nBestScore)
      {
         nBestScore = nScore;
         nBestItemIndex = nInstrIndex;
      }
   }
   return mMusicalInstruments[nBestItemIndex]->mBitmap.get();
}
 
bool MixerBoard::HasSolo()
{
   return
      !(mTracks->Any<PlayableTrack>() + &PlayableTrack::GetSolo).empty();
}
 
void MixerBoard::RefreshTrackClusters(bool bEraseBackground /*= true*/)
{
   for (unsigned int i = 0; i < mMixerTrackClusters.size(); i++)
      mMixerTrackClusters[i]->Refresh(bEraseBackground);
}
 
void MixerBoard::ResizeTrackClusters()
{
   for (unsigned int nClusterIndex = 0; nClusterIndex < mMixerTrackClusters.size(); nClusterIndex++)
      mMixerTrackClusters[nClusterIndex]->HandleResize();
}
 
void MixerBoard::ResetMeters(const bool bResetClipping)
{
   mPrevT1 = BAD_STREAM_TIME;
 
   if (!this->IsShown())
      return;
 
   for (unsigned int i = 0; i < mMixerTrackClusters.size(); i++)
      mMixerTrackClusters[i]->ResetMeter(bResetClipping);
}
 
void MixerBoard::UpdateMeters(const double t1, const bool bLoopedPlay)
{
   if (!this->IsShown() || (t1 == BAD_STREAM_TIME))
      return;
 
   if (mPrevT1 == BAD_STREAM_TIME)
   {
      mPrevT1 = t1;
      return;
   }
 
   // PRL:  TODO:  reexamine the assumptions below
 
   // In loopedPlay mode, at the end of the loop, mPrevT1 is set to
   // selection end, so the next t1 will be less, but we do want to
   // keep updating the meters.
   if (t1 <= mPrevT1)
   {
      if (bLoopedPlay)
         mPrevT1 = t1;
      return;
   }
 
   for (unsigned int i = 0; i < mMixerTrackClusters.size(); i++)
      mMixerTrackClusters[i]->UpdateMeter(mPrevT1, t1);
 
   mPrevT1 = t1;
}
 
 
void MixerBoard::UpdateWidth()
{
   int newWidth = this->GetTrackClustersWidth();
 
   // Min width is one cluster wide, plus margins.
   if (newWidth < MIXER_BOARD_MIN_WIDTH)
      newWidth = MIXER_BOARD_MIN_WIDTH;
 
   mScrolledWindow->SetVirtualSize(newWidth, -1);
   this->GetParent()->SetSize(newWidth + kDoubleInset, -1);
}
 
//
// private methods
//
 
 
void MixerBoard::MakeButtonBitmap( wxMemoryDC & dc, wxBitmap & WXUNUSED(bitmap), wxRect & bev, const TranslatableString & str, bool up )
{
 
   const auto translation = str.Translation();
   int textWidth, textHeight;
 
   int fontSize = 10;
   #ifdef __WXMSW__
      fontSize = 8;
   #endif
   wxFont font(fontSize, wxFONTFAMILY_SWISS, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_NORMAL);
   GetTextExtent(translation, &textWidth, &textHeight, NULL, NULL, &font);
 
   AColor::UseThemeColour( &dc, clrMedium );
   dc.DrawRectangle(bev);
 
   AColor::Bevel2( dc, up, bev, false );
 
   wxCoord x = bev.x + (bev.width - textWidth) / 2;
   wxCoord y = bev.y + (bev.height - textHeight) / 2;
   dc.SetFont(font);
   dc.SetTextForeground(theTheme.Colour(clrTrackPanelText));
   dc.SetBackgroundMode(wxTRANSPARENT);
   dc.DrawText(translation, x, y);
//   dc.DrawText(translation, 0, 0);
}
 
void MixerBoard::CreateMuteSoloImages()
{
   // Much of this is similar to TrackInfo::MuteOrSoloDrawFunction.
   wxMemoryDC dc;
   auto str = XO("Mute");
 
   //mMuteSoloWidth = textWidth + kQuadrupleInset;
   //if (mMuteSoloWidth < kRightSideStackWidth - kInset)
   mMuteSoloWidth = kRightSideStackWidth - kInset;
 
   wxBitmap bitmap(mMuteSoloWidth, MUTE_SOLO_HEIGHT,24);
   dc.SelectObject(bitmap);
   wxRect bev(0, 0, mMuteSoloWidth, MUTE_SOLO_HEIGHT);
 
   const bool up=true;
   const bool down=false;
 
   MakeButtonBitmap( dc, bitmap, bev, str, up );
   mImageMuteUp = std::make_unique<wxImage>(bitmap.ConvertToImage());
   mImageMuteOver = std::make_unique<wxImage>(bitmap.ConvertToImage()); // Same as up, for now.
 
   MakeButtonBitmap( dc, bitmap, bev, str, down );
   //AColor::Bevel(dc, false, bev);
   mImageMuteDown = std::make_unique<wxImage>(bitmap.ConvertToImage());
 
   MakeButtonBitmap( dc, bitmap, bev, str, down );
   mImageMuteDownWhileSolo = std::make_unique<wxImage>(bitmap.ConvertToImage());
 
   mImageMuteDisabled = std::make_unique<wxImage>(mMuteSoloWidth, MUTE_SOLO_HEIGHT); // Leave empty because unused.
 
   str = XO("Solo");
   MakeButtonBitmap( dc, bitmap, bev, str, up );
   mImageSoloUp = std::make_unique<wxImage>(bitmap.ConvertToImage());
   mImageSoloOver = std::make_unique<wxImage>(bitmap.ConvertToImage()); // Same as up, for now.
 
   MakeButtonBitmap( dc, bitmap, bev, str, down );
   mImageSoloDown = std::make_unique<wxImage>(bitmap.ConvertToImage());
 
   mImageSoloDisabled = std::make_unique<wxImage>(mMuteSoloWidth, MUTE_SOLO_HEIGHT); // Leave empty because unused.
}
 
int MixerBoard::FindMixerTrackCluster(const PlayableTrack* pTrack,
                                        MixerTrackCluster** hMixerTrackCluster) const
{
   *hMixerTrackCluster = NULL;
   for (unsigned int i = 0; i < mMixerTrackClusters.size(); i++)
   {
      if (mMixerTrackClusters[i]->mTrack.get() == pTrack)
      {
         *hMixerTrackCluster = mMixerTrackClusters[i];
         return i;
      }
   }
   return -1;
}
 
void MixerBoard::LoadMusicalInstruments()
{
   const struct Data { const char * const *bitmap; wxString name; } table[] = {
      {acoustic_guitar_gtr_xpm, wxT("acoustic_guitar_gtr")},
      {acoustic_piano_pno_xpm, wxT("acoustic_piano_pno")},
      {back_vocal_bg_vox_xpm, wxT("back_vocal_bg_vox")},
      {clap_xpm, wxT("clap")},
      {drums_dr_xpm, wxT("drums_dr")},
      {electric_bass_guitar_bs_gtr_xpm, wxT("electric_bass_guitar_bs_gtr")},
      {electric_guitar_gtr_xpm, wxT("electric_guitar_gtr")},
      {electric_piano_pno_key_xpm, wxT("electric_piano_pno_key")},
      {kick_xpm, wxT("kick")},
      {loop_xpm, wxT("loop")},
      {organ_org_xpm, wxT("organ_org")},
      {perc_xpm, wxT("perc")},
      {sax_xpm, wxT("sax")},
      {snare_xpm, wxT("snare")},
      {string_violin_cello_xpm, wxT("string_violin_cello")},
      {synth_xpm, wxT("synth")},
      {tambo_xpm, wxT("tambo")},
      {trumpet_horn_xpm, wxT("trumpet_horn")},
      {turntable_xpm, wxT("turntable")},
      {vibraphone_vibes_xpm, wxT("vibraphone_vibes")},
      {vocal_vox_xpm, wxT("vocal_vox")},
 
      // This one must be last, so it wins when best score is 0.
      {_default_instrument_xpm, wxEmptyString},
   };
 
   wxRect bev(1, 1, MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH - 2, MUSICAL_INSTRUMENT_HEIGHT_AND_WIDTH - 2);
   wxMemoryDC dc;
 
   for (const auto &data : table) {
      auto bmp = std::make_unique<wxBitmap>(data.bitmap);
      dc.SelectObject(*bmp);
      AColor::Bevel(dc, false, bev);
      mMusicalInstruments.push_back(std::make_unique<MusicalInstrument>(
         std::move(bmp), data.name
      ));
   };
}
 
// event handlers
 
void MixerBoard::OnPaint(wxPaintEvent& evt)
{
   if (!mUpToDate) {
      mUpToDate = true;
      UpdateTrackClusters();
      Refresh();
   }
   // Does the base class do anything for repainting?
   evt.Skip();
}
 
void MixerBoard::OnSize(wxSizeEvent &evt)
{
   // this->FitInside() doesn't work, and it doesn't happen automatically. Is wxScrolledWindow wrong?
   mScrolledWindow->SetSize(evt.GetSize());
 
   this->ResizeTrackClusters();
   this->RefreshTrackClusters(true);
}
 
void MixerBoard::OnTimer(Observer::Message)
{
   // PRL 12 Jul 2015:  Moved the below (with comments) out of TrackPanel::OnTimer.
 
   // Vaughan, 2011-01-28: No longer doing this on timer.
   //   Now it's in AudioIO::SetMeters() and AudioIO::StopStream(), as with Meter Toolbar meters.
   //if (pMixerBoard)
   //   pMixerBoard->ResetMeters(false);
 
   //v Vaughan, 2011-02-25: Moved this update back here from audacityAudioCallback.
   //    See note there.
   // Vaughan, 2010-01-30:
   //    Since all we're doing here is updating the meters, I moved it to
   //    audacityAudioCallback where it calls gAudioIO->mOutputMeter->UpdateDisplay().
   if (ProjectAudioIO::Get( *mProject ).IsAudioActive())
   {
      auto gAudioIO = AudioIO::Get();
      UpdateMeters(
         gAudioIO->GetStreamTime(),
         (ProjectAudioManager::Get( *mProject ).GetLastPlayMode()
            == PlayMode::loopedPlay)
      );
   }
}
 
void MixerBoard::OnTrackChanged(const TrackListEvent &evt)
{
   auto pTrack = evt.mpTrack.lock();
   auto pPlayable = dynamic_cast<PlayableTrack*>( pTrack.get() );
   if ( pPlayable ) {
      MixerTrackCluster *pMixerTrackCluster;
      FindMixerTrackCluster( pPlayable, &pMixerTrackCluster );
      if ( pMixerTrackCluster )
         pMixerTrackCluster->Refresh();
   }
}
 
void MixerBoard::OnTrackSetChanged()
{
   mUpToDate = false;
   UpdateTrackClusters();
   Refresh();
}
 
void MixerBoard::OnStartStop(AudioIOEvent evt)
{
   if (evt.type == AudioIOEvent::PLAYBACK)
      ResetMeters( evt.on );
}
 
// class MixerBoardFrame
 
BEGIN_EVENT_TABLE(MixerBoardFrame, wxFrame)
   EVT_KEY_DOWN(MixerBoardFrame::OnKeyEvent)
   EVT_CLOSE(MixerBoardFrame::OnCloseWindow)
   EVT_MAXIMIZE(MixerBoardFrame::OnMaximize)
   EVT_SIZE(MixerBoardFrame::OnSize)
END_EVENT_TABLE()
 
// Default to fitting one track.
const wxSize kDefaultSize =
   wxSize(MIXER_BOARD_MIN_WIDTH, MIXER_BOARD_MIN_HEIGHT);
 
MixerBoardFrame::MixerBoardFrame(AudacityProject* parent)
:  wxFrame( &GetProjectFrame( *parent ), -1, wxString{},
            wxDefaultPosition, kDefaultSize,
            wxDEFAULT_FRAME_STYLE | wxFRAME_FLOAT_ON_PARENT)
   , mProject(parent)
{
   SetWindowTitle();
   mTitleChangeSubscription = ProjectFileIO::Get(*parent)
      .Subscribe([this](ProjectFileIOMessage message){
         if (message == ProjectFileIOMessage::ProjectTitleChange)
            SetWindowTitle();
      });
 
   mMixerBoard = safenew MixerBoard(parent, this, wxDefaultPosition, kDefaultSize);
 
   this->SetSizeHints(MIXER_BOARD_MIN_WIDTH, MIXER_BOARD_MIN_HEIGHT);
 
   mMixerBoard->UpdateTrackClusters();
 
   // loads either the XPM or the windows resource, depending on the platform
#if !defined(__WXMAC__) && !defined(__WXX11__)
   {
#ifdef __WXMSW__
      wxIcon ic{ wxICON(AudacityLogo) };
#else
      wxIcon ic{wxICON(AudacityLogo48x48)};
#endif
      SetIcon(ic);
   }
#endif
   Center();
}
 
MixerBoardFrame::~MixerBoardFrame()
{
}
 
 
// event handlers
void MixerBoardFrame::OnCloseWindow(wxCloseEvent &WXUNUSED(event))
{
   // Fix for bug #2175.
   //
   // If the mixerboard enters fullscreen, the main project will be
   // "lowered", so ensure it's visible after the mixerboard closes.
#if defined(__WXMAC__)
   dynamic_cast<wxFrame*>(GetParent())->Raise();
#endif
 
   this->Hide();
}
 
void MixerBoardFrame::OnMaximize(wxMaximizeEvent &event)
{
   // Update the size hints to show all tracks before skipping to let default handling happen.
   mMixerBoard->UpdateWidth();
   event.Skip();
}
 
void MixerBoardFrame::OnSize(wxSizeEvent & WXUNUSED(event))
{
   mMixerBoard->SetSize(this->GetClientSize());
}
 
void MixerBoardFrame::OnKeyEvent(wxKeyEvent & event)
{
   if (auto project = mMixerBoard->mProject)
      MenuCreator::FilterKeyEvent(*project, event, true);
}
 
void MixerBoardFrame::Recreate( AudacityProject *pProject )
{
   wxPoint  pos = mMixerBoard->GetPosition();
   wxSize siz = mMixerBoard->GetSize();
   wxSize siz2 = this->GetSize();
 
   //wxLogDebug("Got rid of board %p", mMixerBoard );
   mMixerBoard->Destroy();
   mMixerBoard = NULL;
   mMixerBoard = safenew MixerBoard(pProject, this, pos, siz);
   //wxLogDebug("Created NEW board %p", mMixerBoard );
   mMixerBoard->UpdateTrackClusters();
   mMixerBoard->SetSize( siz );
 
   this->SetSize( siz2 );
   SetWindowTitle();
}
 
void MixerBoardFrame::SetWindowTitle()
{
   wxString name = mProject->GetProjectName();
   if (!name.empty())
   {
      name.Prepend(wxT(" - "));
   }
 
   SetTitle(AudacityMixerBoardTitle.Format(name).Translation());
}
 
// Remaining code hooks this add-on into the application
#include "CommandContext.h"
 
namespace {
 
const ReservedCommandFlag&
   PlayableTracksExistFlag() { static ReservedCommandFlag flag{
      [](const AudacityProject &project){
         auto &tracks = TrackList::Get( project );
         return
            !tracks.Any<const NoteTrack>().empty()
         ||
            !tracks.Any<const WaveTrack>().empty()
         ;
      }
   }; return flag; }
 
// Mixer board window attached to each project is built on demand by:
AttachedWindows::RegisteredFactory sMixerBoardKey{
   []( AudacityProject &parent ) -> wxWeakRef< wxWindow > {
      return safenew MixerBoardFrame( &parent );
   }
};
 
// Define our extra menu item that invokes that factory
void OnMixerBoard(const CommandContext &context)
{
   auto &project = context.project;
 
   auto mixerBoardFrame = &GetAttachedWindows(project).Get(sMixerBoardKey);
   mixerBoardFrame->Show();
   mixerBoardFrame->Raise();
   mixerBoardFrame->SetFocus();
}
 
// Register that menu item
 
using namespace MenuRegistry;
AttachedItem sAttachment{
   Command( wxT("MixerBoard"), XXO("&Mixer"), OnMixerBoard,
      PlayableTracksExistFlag()),
   wxT("View/Windows")
};
 
}