From 9819cdb11722b2b579b61c1fc74df0dc0489ac8c Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 17 Dec 2022 12:37:32 +0100
Subject: [PATCH] GUI support for per region polarity invert

---
 gtk2_ardour/audio_region_editor.cc | 20 +++++++++++++++++---
 gtk2_ardour/audio_region_editor.h  |  7 +++++--
 gtk2_ardour/audio_region_view.cc   |  5 +++--
 gtk2_ardour/editor_ops.cc          |  5 +++--
 4 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/gtk2_ardour/audio_region_editor.cc b/gtk2_ardour/audio_region_editor.cc
index 78b4462e89..f6ef07c1c1 100644
--- a/gtk2_ardour/audio_region_editor.cc
+++ b/gtk2_ardour/audio_region_editor.cc
@@ -55,7 +55,8 @@ _peak_amplitude_thread (void* arg)
 AudioRegionEditor::AudioRegionEditor (Session* s, boost::shared_ptr<AudioRegion> r)
 	: RegionEditor (s, r)
 	, _audio_region (r)
-	, gain_adjustment(accurate_coefficient_to_dB(_audio_region->scale_amplitude()), -40.0, +40.0, 0.1, 1.0, 0)
+	, gain_adjustment(accurate_coefficient_to_dB(fabsf (_audio_region->scale_amplitude())), -40.0, +40.0, 0.1, 1.0, 0)
+	, _polarity_toggle (_("Invert"))
 	, _peak_channel (false)
 {
 
@@ -84,9 +85,16 @@ AudioRegionEditor::AudioRegionEditor (Session* s, boost::shared_ptr<AudioRegion>
 	_table.attach (*b, 1, 2, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
 	++_table_row;
 
+	_polarity_label.set_name ("AudioRegionEditorLabel");
+	_polarity_label.set_text (_("Polarity:"));
+	_table.attach (_polarity_label, 0, 1, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
+	_table.attach (_polarity_toggle, 1, 2, _table_row, _table_row + 1, Gtk::FILL, Gtk::FILL);
+	++_table_row;
+
 	gain_changed ();
 
 	gain_adjustment.signal_value_changed().connect (sigc::mem_fun (*this, &AudioRegionEditor::gain_adjustment_changed));
+	_polarity_toggle.signal_toggled().connect (sigc::mem_fun (*this, &AudioRegionEditor::gain_adjustment_changed));
 
 	_peak_amplitude.property_editable() = false;
 	_peak_amplitude.set_text (_("Calculating..."));
@@ -123,16 +131,22 @@ AudioRegionEditor::region_changed (const PBD::PropertyChange& what_changed)
 void
 AudioRegionEditor::gain_changed ()
 {
-	float const region_gain_dB = accurate_coefficient_to_dB (_audio_region->scale_amplitude());
+	const gain_t scale_amplitude = _audio_region->scale_amplitude();
+
+	float const region_gain_dB = accurate_coefficient_to_dB (fabsf (scale_amplitude));
 	if (region_gain_dB != gain_adjustment.get_value()) {
 		gain_adjustment.set_value(region_gain_dB);
 	}
+	_polarity_toggle.set_active (scale_amplitude < 0);
 }
 
 void
 AudioRegionEditor::gain_adjustment_changed ()
 {
-	float const gain = dB_to_coefficient (gain_adjustment.get_value());
+	float gain = dB_to_coefficient (gain_adjustment.get_value());
+	if (_polarity_toggle.get_active ()) {
+		gain *= -1;
+	}
 	if (_audio_region->scale_amplitude() != gain) {
 		_audio_region->set_scale_amplitude (gain);
 	}
diff --git a/gtk2_ardour/audio_region_editor.h b/gtk2_ardour/audio_region_editor.h
index 6433ee7112..78ac74a3c0 100644
--- a/gtk2_ardour/audio_region_editor.h
+++ b/gtk2_ardour/audio_region_editor.h
@@ -28,7 +28,7 @@
 #include <gtkmm/label.h>
 #include <gtkmm/entry.h>
 #include <gtkmm/box.h>
-#include <gtkmm/togglebutton.h>
+#include <gtkmm/checkbutton.h>
 #include <gtkmm/button.h>
 #include <gtkmm/arrow.h>
 #include <gtkmm/frame.h>
@@ -69,10 +69,13 @@ private:
 
 	boost::shared_ptr<ARDOUR::AudioRegion> _audio_region;
 
-	Gtk::Label gain_label;
+	Gtk::Label      gain_label;
 	Gtk::Adjustment gain_adjustment;
 	Gtk::SpinButton gain_entry;
 
+	Gtk::Label        _polarity_label;
+	Gtk::CheckButton  _polarity_toggle;
+
 	Gtk::Label _peak_amplitude_label;
 	Gtk::Entry _peak_amplitude;
 
diff --git a/gtk2_ardour/audio_region_view.cc b/gtk2_ardour/audio_region_view.cc
index c976f1f874..45fdfd0c6f 100644
--- a/gtk2_ardour/audio_region_view.cc
+++ b/gtk2_ardour/audio_region_view.cc
@@ -416,9 +416,10 @@ AudioRegionView::region_renamed ()
 	}
 
 	boost::shared_ptr<AudioRegion> ar (audio_region());
-	if (ar->scale_amplitude() != 1.0) {
+	const gain_t scale_amplitude = ar->scale_amplitude();
+	if (scale_amplitude != 1.0) {
 		char tmp[32];
-		snprintf (tmp, 32, " (%.1fdB)", accurate_coefficient_to_dB (ar->scale_amplitude()));
+		snprintf (tmp, 32, " (%.1fdB%s)", accurate_coefficient_to_dB (fabsf (scale_amplitude)), scale_amplitude < 0 ? " Ø" : "");
 		str += tmp;
 	}
 
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 00c769c211..6f920ac6a1 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -5769,7 +5769,8 @@ Editor::adjust_region_gain (bool up)
 
 		arv->region()->clear_changes ();
 
-		double dB = accurate_coefficient_to_dB (arv->audio_region()->scale_amplitude ());
+		gain_t scale_amplitude = arv->audio_region()->scale_amplitude ();
+		double dB = accurate_coefficient_to_dB (fabsf (scale_amplitude));
 
 		if (up) {
 			dB += 1;
@@ -5777,7 +5778,7 @@ Editor::adjust_region_gain (bool up)
 			dB -= 1;
 		}
 
-		arv->audio_region()->set_scale_amplitude (dB_to_coefficient (dB));
+		arv->audio_region()->set_scale_amplitude (dB_to_coefficient (dB) * (scale_amplitude < 0 ? -1. : 1.));
 
 		if (!in_command) {
 				begin_reversible_command ("adjust region gain");