Update envelope properly for TimeTrack and WaveTrack editing...

... Formerly this was done correctly only for cut and delete from WaveTrack,
paste into WaveTrack, and sync-lock adjustment of WaveTrack (either lengthening
or shortening).

Now also properly done for TimeTrack cut and paste, and also for:

Split cut
Split delete
Trim

src/Envelope.cpp

@@ -606,34 +606,60 @@ bool EnvelopeEditor::MouseEvent(const wxMouseEvent & event, wxRect & r,
    return false;
 }
 
-void Envelope::CollapseRegion(double t0, double t1)
+void Envelope::CollapseRegion( double t0, double t1, double sampleTime )
 // NOFAIL-GUARANTEE
 {
-   // This gets called when somebody clears samples.  All of the
-   // control points within the region disappear and the points
-   // to the right get shifted over.
+   // This gets called when somebody clears samples.
 
-   t0 -= mOffset;
-   t1 -= mOffset;
+   // Snip points in the interval (t0, t1), shift values left at times after t1.
+   // For the boundaries of the interval, preserve the left-side limit at the
+   // start and right-side limit at the end.
 
-   t0 = std::max(0.0, std::min(mTrackLen, t0));
-   t1 = std::max(0.0, std::min(mTrackLen, t1));
+   const auto epsilon = sampleTime / 2;
+   t0 = std::max( 0.0, std::min( mTrackLen, t0 - mOffset ) );
+   t1 = std::max( 0.0, std::min( mTrackLen, t1 - mOffset ) );
 
-   int len = mEnv.size();
-   int i;
-
-   // Remove points in deleted region.
-   for (i = 0; i < len - 0; i++)
-      if (mEnv[i].GetT() >= t0 && mEnv[i].GetT() < t1) {
-         Delete(i);
-         len--;
-         i--;
+   // Determine the start of the range of points to remove from the array.
+   auto range0 = EqualRange( t0, 0 );
+   auto begin = range0.first;
+   if ( begin == range0.second ) {
+      if ( t0 > epsilon ) {
+         // There was no point exactly at t0;
+         // insert a point to preserve the value.
+         auto val = GetValueRelative( t0 );
+         InsertOrReplaceRelative( t0, val );
+         ++begin;
       }
+   }
+   else
+      // We will keep the first (or only) point that was at t0.
+      ++begin;
+
+   // We want end to be the index one past the range of points to remove from
+   // the array.
+   // At first, find index of the first point after t1:
+   auto range1 = EqualRange( t1, 0 );
+   auto end = range1.second;
+   if ( range1.first == end ) {
+      if ( mTrackLen - t1 > epsilon ) {
+         // There was no point exactly at t1; insert a point to preserve the value.
+         auto val = GetValueRelative( t1 );
+         InsertOrReplaceRelative( t1, val );
+         // end is now the index of this NEW point and that is correct.
+      }
+   }
+   else
+      // We will keep the last (or only) point that was at t1.
+      --end;
+
+   mEnv.erase( mEnv.begin() + begin, mEnv.begin() + end );
 
    // Shift points left after deleted region.
-   for (i = 0; i < len; i++)
-      if (mEnv[i].GetT() >= t1)
-         mEnv[i].SetT(mEnv[i].GetT() - (t1 - t0));
+   auto len = mEnv.size();
+   for ( size_t i = begin; i < len; ++i ) {
+      auto &point = mEnv[i];
+      point.SetT( point.GetT() - (t1 - t0) );
+   }
 
    mTrackLen -= ( t1 - t0 );
 }

src/Envelope.h

@@ -118,8 +118,11 @@ public:
       float zoomMin, float zoomMax, bool mirrored) const;
 
    // Handling Cut/Copy/Paste events
-   void CollapseRegion(double t0, double t1);
+   // sampleTime determines when the endpoint of the collapse is near enough
+   // to an endpoint of the domain, that an extra control point is not needed.
+   void CollapseRegion(double t0, double t1, double sampleTime);
    void Paste(double t0, const Envelope *e);
+
    void InsertSpace(double t0, double tlen);
    void RemoveUnneededPoints(double time = -1, double tolerence = 0.001);
 

src/TimeTrack.cpp

@@ -22,6 +22,7 @@
 #include "widgets/Ruler.h"
 #include "Envelope.h"
 #include "Prefs.h"
+#include "Project.h"
 #include "Internat.h"
 #include "ViewInfo.h"
 #include "AllThemeResources.h"
@@ -108,7 +109,8 @@ Track::Holder TimeTrack::Copy( double t0, double t1, bool ) const
 
 void TimeTrack::Clear(double t0, double t1)
 {
-   mEnvelope->CollapseRegion(t0, t1);
+   auto sampleTime = 1.0 / GetActiveProject()->GetRate();
+   mEnvelope->CollapseRegion( t0, t1, sampleTime );
 }
 
 void TimeTrack::Paste(double t, const Track * src)

src/WaveClip.cpp

@@ -1676,7 +1676,8 @@ void WaveClip::Clear(double t0, double t1)
    }
 
    // Collapse envelope
-   GetEnvelope()->CollapseRegion(t0, t1);
+   auto sampleTime = 1.0 / GetRate();
+   GetEnvelope()->CollapseRegion( t0, t1, sampleTime );
    if (t0 < GetStartTime())
       Offset(-(GetStartTime() - t0));
 
@@ -1728,7 +1729,8 @@ void WaveClip::ClearAndAddCutLine(double t0, double t1)
    GetSequence()->Delete(s0, s1-s0);
 
    // Collapse envelope
-   GetEnvelope()->CollapseRegion(t0, t1);
+   auto sampleTime = 1.0 / GetRate();
+   GetEnvelope()->CollapseRegion( t0, t1, sampleTime );
    if (t0 < GetStartTime())
       Offset(-(GetStartTime() - t0));
 

src/WaveTrack.cpp

@@ -1138,26 +1138,7 @@ void WaveTrack::HandleClear(double t0, double t1,
                clipsToDelete.push_back( clip.get() );
                auto newClip = make_movable<WaveClip>( *clip, mDirManager, true );
 
-               /* We are going to DELETE part of the clip here. The clip may
-                * have envelope points, and we need to ensure that the envelope
-                * outside of the cleared region is not affected. This means
-                * putting in "glue" points where the clip enters and leaves the
-                * region being cleared. If one of the ends of the clip is inside
-                * the region, then one of the glue points will be redundant. */
                // clip->Clear keeps points < t0 and >= t1 via Envelope::CollapseRegion
-               if (clip->GetEnvelope()->GetNumberOfPoints() > 0) {   // don't insert env pts if none exist
-                  double val;
-                  if (clip->WithinClip(t0)) {
-                     // start of region within clip
-                     val = clip->GetEnvelope()->GetValue(t0);
-                     newClip->GetEnvelope()->InsertOrReplace(t0 - 1.0 / clip->GetRate(), val);
-                     }
-                  if (clip->WithinClip(t1))
-                     {  // end of region within clip
-                     val = clip->GetEnvelope()->GetValue(t1);
-                     newClip->GetEnvelope()->InsertOrReplace(t1 , val);
-                     }
-               }
                newClip->Clear(t0,t1);
                newClip->GetEnvelope()->RemoveUnneededPoints(t0);