From 1e3100efbc7fd9c9bfd5a9ef78334bf8e42ca03c Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 8 May 2025 22:01:05 +0200
Subject: [PATCH] Stretch gain envelope and region-FX automation with region

---
 libs/ardour/rb_effect.cc  | 27 ++++++++++++++++++---------
 libs/ardour/st_stretch.cc | 26 +++++++++++++++++---------
 2 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/libs/ardour/rb_effect.cc b/libs/ardour/rb_effect.cc
index e82ed01ddf..048bbbce2f 100644
--- a/libs/ardour/rb_effect.cc
+++ b/libs/ardour/rb_effect.cc
@@ -32,6 +32,7 @@
 #include "ardour/audioregion.h"
 #include "ardour/audiosource.h"
 #include "ardour/pitch.h"
+#include "ardour/region_fx_plugin.h"
 #include "ardour/session.h"
 #include "ardour/stretch.h"
 #include "ardour/types.h"
@@ -345,6 +346,23 @@ RBEffect::run (std::shared_ptr<Region> r, Progress* progress)
 		ret = finish (region, nsrcs, new_name);
 	}
 
+
+	/* apply automation scaling before calling set_length, which trims automation */
+	if (ret == 0 && !tsr.time_fraction.is_unity()) {
+		for (auto& r : results) {
+			std::shared_ptr<AudioRegion> ar = std::dynamic_pointer_cast<AudioRegion> (r);
+			assert (ar);
+			ar->envelope ()->x_scale (tsr.time_fraction);
+			ar->foreach_plugin ([&](std::weak_ptr<RegionFxPlugin> wfx)
+			{
+				shared_ptr<RegionFxPlugin> rfx = wfx.lock ();
+				if (rfx) {
+					rfx->x_scale_automation (tsr.time_fraction);
+				}
+			});
+		}
+	}
+
 	/* now reset ancestral data for each new region */
 
 	for (vector<std::shared_ptr<Region> >::iterator x = results.begin (); x != results.end (); ++x) {
@@ -360,15 +378,6 @@ RBEffect::run (std::shared_ptr<Region> r, Progress* progress)
 		(*x)->set_whole_file (true);
 	}
 
-	/* stretch region gain envelope */
-	/* XXX: assuming we've only processed one input region into one result here */
-
-	if (ret == 0 && !tsr.time_fraction.is_unity()) {
-		std::shared_ptr<AudioRegion> result = std::dynamic_pointer_cast<AudioRegion> (results.front ());
-		assert (result);
-		result->envelope ()->x_scale (tsr.time_fraction);
-	}
-
 out:
 
 	if (buffers) {
diff --git a/libs/ardour/st_stretch.cc b/libs/ardour/st_stretch.cc
index ab37198e0a..97f5044ad6 100644
--- a/libs/ardour/st_stretch.cc
+++ b/libs/ardour/st_stretch.cc
@@ -27,6 +27,7 @@
 #include "ardour/types.h"
 #include "ardour/stretch.h"
 #include "ardour/audiofilesource.h"
+#include "ardour/region_fx_plugin.h"
 #include "ardour/session.h"
 #include "ardour/audioregion.h"
 
@@ -289,6 +290,22 @@ STStretch::run (std::shared_ptr<Region> r, Progress* progress)
 		ret = finish (region, nsrcs, new_name);
 	}
 
+	/* apply automation scaling before calling set_length, which trims automation */
+	if (ret == 0 && !tsr.time_fraction.is_unity()) {
+		for (auto& r : results) {
+			std::shared_ptr<AudioRegion> ar = std::dynamic_pointer_cast<AudioRegion> (r);
+			assert (ar);
+			ar->envelope ()->x_scale (tsr.time_fraction);
+			ar->foreach_plugin ([&](std::weak_ptr<RegionFxPlugin> wfx)
+			{
+				shared_ptr<RegionFxPlugin> rfx = wfx.lock ();
+				if (rfx) {
+					rfx->x_scale_automation (tsr.time_fraction);
+				}
+			});
+		}
+	}
+
 	/* now reset ancestral data for each new region */
 
 	for (vector<std::shared_ptr<Region> >::iterator x = results.begin (); x != results.end (); ++x) {
@@ -304,15 +321,6 @@ STStretch::run (std::shared_ptr<Region> r, Progress* progress)
 		(*x)->set_whole_file (true);
 	}
 
-	/* stretch region gain envelope */
-	/* XXX: assuming we've only processed one input region into one result here */
-
-	if (ret == 0 && tsr.time_fraction != 1) {
-		std::shared_ptr<AudioRegion> result = std::dynamic_pointer_cast<AudioRegion> (results.front ());
-		assert (result);
-		result->envelope ()->x_scale (tsr.time_fraction);
-	}
-
 out:
 
 	if (buffers) {