From 3605d73d1233ff044cbe1897f73e2d3d71afcb3b Mon Sep 17 00:00:00 2001
From: Leland Lucius <github@homerow.net>
Date: Fri, 18 Sep 2020 09:00:50 -0500
Subject: [PATCH] Bug 2534 - Change Speed merges selected clip with adjacent
 clips

---
 src/effects/ChangeSpeed.cpp | 38 +++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/effects/ChangeSpeed.cpp b/src/effects/ChangeSpeed.cpp
index 1833b6cae..7df513d5b 100644
--- a/src/effects/ChangeSpeed.cpp
+++ b/src/effects/ChangeSpeed.cpp
@@ -32,6 +32,7 @@
 #include "../widgets/valnum.h"
 
 #include "TimeWarper.h"
+#include "../WaveClip.h"
 #include "../WaveTrack.h"
 
 enum
@@ -551,9 +552,42 @@ bool EffectChangeSpeed::ProcessOne(WaveTrack * track,
    double newLength = outputTrack->GetEndTime();
    if (bResult)
    {
+       // Silenced samples will be inserted in gaps between clips, so capture where these
+      // gaps are for later deletion
+      std::vector<std::pair<double, double>> gaps;
+      double last = 0.0;
+      auto clips = track->SortedClipArray();
+      auto front = clips.front();
+      auto back = clips.back();
+      for (auto &clip : clips) {
+         auto st = clip->GetStartTime();
+         auto et = clip->GetEndTime();
+
+         if (st >= mCurT0 || et < mCurT1) {
+            if (mCurT0 < st && clip == front) {
+               gaps.push_back(std::make_pair(mCurT0, st));
+            }
+            if (mCurT1 > et && clip == back) {
+               gaps.push_back(std::make_pair(et, mCurT1));
+            }
+            if (last >= mCurT0) {
+               gaps.push_back(std::make_pair(last, st));
+            }
+         }
+         last = et;
+      }
+
       LinearTimeWarper warper { mCurT0, mCurT0, mCurT1, mCurT0 + newLength };
-      track->ClearAndPaste(
-         mCurT0, mCurT1, outputTrack.get(), true, false, &warper);
+
+      // Take the output track and insert it in place of the original sample data
+      track->ClearAndPaste(mCurT0, mCurT1, outputTrack.get(), true, true, &warper);
+
+      // Finally, recreate the gaps
+      for (auto gap : gaps) {
+         auto st = track->LongSamplesToTime(track->TimeToLongSamples(gap.first));
+         auto et = track->LongSamplesToTime(track->TimeToLongSamples(gap.second));
+         track->SplitDelete(warper.Warp(st), warper.Warp(et));
+      }
    }
 
    if (newLength > mMaxNewLength)