Function EffectPreview

src/effects/EffectPreview.cpp:24–221

#include "WaveTrack.h"

void EffectPreview(EffectBase &effect,
   EffectSettingsAccess &access, std::function<void()> updateUI, bool dryOnly)
{
   auto cleanup0 = effect.BeginPreview(access.Get());

   // These are temporary state in the Effect object that are meant be moved to
   // a new class EffectContext
   const auto numTracks = effect.mNumTracks;
   const auto rate = effect.mProjectRate;
   const auto &factory = effect.mFactory;
   auto &mT0 = effect.mT0;
   auto &mT1 = effect.mT1;
   auto &mTracks = effect.mTracks;
   auto &mProgress = effect.mProgress;
   auto &mIsPreview = effect.mIsPreview;

   // Get certain immutable properties of the effect
   const auto previewFullSelection = effect.PreviewsFullSelection();
   const auto isLinearEffect = effect.IsLinearEffect();

   if (numTracks == 0) { // nothing to preview
      return;
   }

   auto gAudioIO = AudioIO::Get();
   if (gAudioIO->IsBusy()) {
      return;
   }

   const auto FocusDialog = BasicUI::FindFocus();
   assert(FocusDialog); // postcondition

   double previewDuration;
   bool isNyquist = effect.GetFamily() == NYQUISTEFFECTS_FAMILY;
   bool isGenerator = effect.GetType() == EffectTypeGenerate;

   // Mix a few seconds of audio from all of the tracks
   double previewLen;
   gPrefs->Read(wxT("/AudioIO/EffectsPreviewLen"), &previewLen, 6.0);

   const auto &settings = access.Get();
   if (isNyquist && isGenerator)
      previewDuration = effect.CalcPreviewInputLength(settings, previewLen);
   else
      previewDuration = std::min(settings.extra.GetDuration(),
         effect.CalcPreviewInputLength(settings, previewLen));

   double t1 = mT0 + previewDuration;

   if ((t1 > mT1) && !isGenerator) {
      t1 = mT1;
   }

   if (t1 <= mT0)
      return;

   bool success = true;