From Pokechu22: Rename gain to velocity on note tracks

"Velocity" is the technical term, and it's the term that's used everywhere.
"Gain" was probably only used because "gain" is used on wave tracks; since
note tracks aren't wave tracks (and shouldn't be treated as them) the
corresponding variables should be named velocity.

src/AudioIO.cpp

@@ -3790,7 +3790,7 @@ void AudioIO::OutputEvent()
          data1 = mNextEvent->get_pitch();
          if (mNextIsNoteOn) {
             data2 = mNextEvent->get_loud(); // get velocity
-            int offset = mNextEventTrack->GetGain();
+            int offset = mNextEventTrack->GetVelocity();
             data2 += offset; // offset comes from per-track slider
             // clip velocity to insure a legal note-on value
             data2 = (data2 < 0 ? 1 : (data2 > 127 ? 127 : data2));

src/MixerBoard.cpp

@@ -395,7 +395,7 @@ void MixerTrackCluster::HandleSliderGain(const bool bWantPushState /*= false*/)
       mLeftTrack->SetGain(fValue);
 #ifdef EXPERIMENTAL_MIDI_OUT
    else
-      mNoteTrack->SetGain(fValue);
+      mNoteTrack->SetVelocity(fValue);
 #endif
    if (mRightTrack)
       mRightTrack->SetGain(fValue);
@@ -512,7 +512,7 @@ void MixerTrackCluster::UpdateGain()
 #ifdef EXPERIMENTAL_MIDI_OUT
    if (mNoteTrack) {
       mSlider_Gain->SetStyle(VEL_SLIDER);
-      mSlider_Gain->Set(mNoteTrack->GetGain());
+      mSlider_Gain->Set(mNoteTrack->GetVelocity());
       return;
    }
    mSlider_Gain->SetStyle(DB_SLIDER);

src/NoteTrack.cpp

@@ -113,7 +113,7 @@ Track(projDirManager)
    mSerializationLength = 0;
 
 #ifdef EXPERIMENTAL_MIDI_OUT
-   mGain = 0;
+   mVelocity = 0;
 #endif
    mBottomNote = 24;
    mPitchHeight = 5;
@@ -160,7 +160,7 @@ Track::Holder NoteTrack::Duplicate() const
    duplicate->mVisibleChannels = mVisibleChannels;
    duplicate->SetOffset(GetOffset());
 #ifdef EXPERIMENTAL_MIDI_OUT
-   duplicate->SetGain(GetGain());
+   duplicate->SetVelocity(GetVelocity());
 #endif
    // This std::move is needed to "upcast" the pointer type
    return std::move(duplicate);
@@ -782,7 +782,7 @@ bool NoteTrack::HandleXMLTag(const wxChar *tag, const wxChar **attrs)
          else if (!wxStrcmp(attr, wxT("velocity")) &&
                   XMLValueChecker::IsGoodString(strValue) &&
                   Internat::CompatibleToDouble(strValue, &dblValue))
-            mGain = (float) dblValue;
+            mVelocity = (float) dblValue;
 #endif
          else if (!wxStrcmp(attr, wxT("bottomnote")) &&
                   XMLValueChecker::IsGoodInt(strValue) && strValue.ToLong(&nValue))
@@ -838,7 +838,7 @@ void NoteTrack::WriteXML(XMLWriter &xmlFile) const
    xmlFile.WriteAttr(wxT("isSelected"), this->GetSelected());
 
 #ifdef EXPERIMENTAL_MIDI_OUT
-   xmlFile.WriteAttr(wxT("velocity"), (double) saveme->mGain);
+   xmlFile.WriteAttr(wxT("velocity"), (double) saveme->mVelocity);
 #endif
    xmlFile.WriteAttr(wxT("bottomnote"), saveme->mBottomNote);
    xmlFile.WriteAttr(wxT("data"), wxString(data.str().c_str(), wxConvUTF8));

src/NoteTrack.h

@@ -98,8 +98,8 @@ class AUDACITY_DLL_API NoteTrack final : public Track {
    bool Shift(double t) /* not override */;
 
 #ifdef EXPERIMENTAL_MIDI_OUT
-   float GetGain() const { return mGain; }
+   float GetVelocity() const { return mVelocity; }
-   void SetGain(float gain) { mGain = gain; }
+   void SetVelocity(float velocity) { mVelocity = velocity; }
 #endif
 
    double NearestBeatTime(double time, double *beat) const;
@@ -202,7 +202,7 @@ class AUDACITY_DLL_API NoteTrack final : public Track {
    long mSerializationLength;
 
 #ifdef EXPERIMENTAL_MIDI_OUT
-   float mGain; // velocity offset
+   float mVelocity; // velocity offset
 #endif
 
    // mBottom is the Y offset of pitch 0 (normally off screen)

src/TrackPanel.cpp

@@ -4963,7 +4963,7 @@ void TrackPanel::HandleSliders(wxMouseEvent &event, bool pan)
      // mCapturedTrack is not wave...
       if (!pan) {
          // .. so assume it is note
-         static_cast<NoteTrack*>(mCapturedTrack)->SetGain(newValue);
+         static_cast<NoteTrack*>(mCapturedTrack)->SetVelocity(newValue);
 #ifdef EXPERIMENTAL_MIXER_BOARD
             if (pMixerBoard)
                // probably should modify UpdateGain to take a track that is
@@ -9377,7 +9377,7 @@ void TrackInfo::DrawVelocitySlider(wxDC *dc, NoteTrack *t, wxRect rect) const
        auto &gain = mGain; // mGains[index];
        gain->SetStyle(VEL_SLIDER);
        GainSlider(index)->Move(wxPoint(gainRect.x, gainRect.y));
-       GainSlider(index)->Set(t->GetGain());
+       GainSlider(index)->Set(t->GetVelocity());
        GainSlider(index)->OnPaint(*dc
           // , t->GetSelected()
        );