Function DoAlign

src/menus/TrackMenus.cpp:169–295

const size_t kAlignLabelsCount(){ return alignLabels().size(); }

void DoAlign(AudacityProject &project, int index, bool moveSel)
{
   auto &tracks = TrackList::Get( project );
   auto &selectedRegion = ViewInfo::Get( project ).selectedRegion;
   auto &viewport = Viewport::Get(project);

   TranslatableString action, shortAction;
   double delta = 0.0;
   double newPos = -1.0;

   auto trackRange = tracks.Selected<AudioTrack>();

   auto FindOffset =
      [](const Track *pTrack) { return pTrack->GetStartTime(); };

   auto firstTrackOffset = [&]{ return FindOffset( *trackRange.begin() ); };
   auto minOffset = [&]{ return trackRange.min( FindOffset ); };
   auto avgOffset = [&]{
      return trackRange.sum( FindOffset ) /
                             std::max( size_t(1), trackRange.size() ); };

   auto maxEndOffset = [&]{
      return std::max(0.0, trackRange.max(&Track::GetEndTime)); };

   switch(index) {
   case kAlignStartZero:
      delta = -minOffset();
      action = moveSel
         /* i18n-hint: In this and similar messages describing editing actions,
            the starting or ending points of tracks are re-"aligned" to other
            times, and the time selection may be "moved" too.  The first
            noun -- "start" in this example -- is the object of a verb (not of
            an implied preposition "from"). */
         ? XO("Aligned/Moved start to zero")
         : XO("Aligned start to zero");
      shortAction = moveSel
         /* i18n-hint: This and similar messages give shorter descriptions of
            the aligning and moving editing actions */
         ? XO("Align/Move Start")
         : XO("Align Start");
      break;
   case kAlignStartSelStart:
      delta = selectedRegion.t0() - minOffset();
      action = moveSel
         ? XO("Aligned/Moved start to cursor/selection start")
         : XO("Aligned start to cursor/selection start");
      shortAction = moveSel
         ? XO("Align/Move Start")
         : XO("Align Start");
      break;
   case kAlignStartSelEnd:
      delta = selectedRegion.t1() - minOffset();
      action = moveSel
         ? XO("Aligned/Moved start to selection end")
         : XO("Aligned start to selection end");
      shortAction = moveSel
         ? XO("Align/Move Start")
         : XO("Align Start");