From a4b4cf1e285c59adac1950602c46388c053fc5f0 Mon Sep 17 00:00:00 2001
From: regulus79 <117475203+regulus79@users.noreply.github.com>
Date: Sun, 16 Feb 2025 19:47:36 -0500
Subject: [PATCH] Initial Implementation

---
 include/PianoRoll.h           |  1 +
 src/gui/editors/PianoRoll.cpp | 46 +++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/include/PianoRoll.h b/include/PianoRoll.h
index e9939101c3f..f100ef87920 100644
--- a/include/PianoRoll.h
+++ b/include/PianoRoll.h
@@ -247,6 +247,7 @@ protected slots:
 	void clearGhostClip();
 	void glueNotes();
 	void fitNoteLengths(bool fill);
+	void invertSelection(bool up);
 	void constrainNoteLengths(bool constrainMax);
 
 	void changeSnapMode();
diff --git a/src/gui/editors/PianoRoll.cpp b/src/gui/editors/PianoRoll.cpp
index cbd68e7ff4f..562bf9fb732 100644
--- a/src/gui/editors/PianoRoll.cpp
+++ b/src/gui/editors/PianoRoll.cpp
@@ -765,6 +765,42 @@ void PianoRoll::fitNoteLengths(bool fill)
 	Engine::getSong()->setModified();
 }
 
+void PianoRoll::invertSelection(bool up)
+{
+	if (!hasValidMidiClip()) { return; }
+	m_midiClip->addJournalCheckPoint();
+
+	// Notes to edit
+	const NoteVector selectedNotes = getSelectedNotes();
+	const auto& notes = selectedNotes.empty() ? m_midiClip->notes() : selectedNotes;
+
+	const auto [minNote, maxNote] = std::minmax_element(notes.begin(), notes.end(), [](Note* n1, Note* n2) { return n1->key() < n2->key(); });
+	const int minKey = (*minNote)->key();
+	const int maxKey = (*maxNote)->key();
+
+	const auto microtuner = m_midiClip->instrumentTrack()->microtuner();
+	const int octaveSize = microtuner->enabled() ? microtuner->octaveSize() : 12;
+	const int numOctaves = (maxKey - minKey) / octaveSize + 1;
+
+	for (Note* note : notes)
+	{
+		if (up)
+		{
+			if (note->key() == minKey)
+			{
+				note->setKey(minKey + numOctaves * octaveSize);
+			}
+		}
+		else
+		{
+			if (note->key() == maxKey)
+			{
+				note->setKey(maxKey - numOctaves * octaveSize);
+			}
+		}
+	}
+}
+
 
 void PianoRoll::constrainNoteLengths(bool constrainMax)
 {
@@ -4869,12 +4905,22 @@ PianoRollWindow::PianoRollWindow() :
 	auto maxLengthAction = new QAction(embed::getIconPixmap("max_length"), tr("Max length as last"), noteToolsButton);
 	connect(maxLengthAction, &QAction::triggered, [this](){ m_editor->constrainNoteLengths(true); });
 
+	auto upwardInversionAction = new QAction(embed::getIconPixmap("flip_y"), tr("Upward Inversion"), noteToolsButton);
+	connect(upwardInversionAction, &QAction::triggered, [this](){ m_editor->invertSelection(true); });
+	upwardInversionAction->setShortcut(combine(Qt::SHIFT, Qt::Key_I));
+
+	auto downwardInversionAction = new QAction(embed::getIconPixmap("flip_y"), tr("Downward Inversion"), noteToolsButton);
+	connect(downwardInversionAction, &QAction::triggered, [this](){ m_editor->invertSelection(false); });
+	downwardInversionAction->setShortcut(combine(Qt::SHIFT, Qt::Key_U));
+
 	noteToolsButton->addAction(glueAction);
 	noteToolsButton->addAction(knifeAction);
 	noteToolsButton->addAction(fillAction);
 	noteToolsButton->addAction(cutOverlapsAction);
 	noteToolsButton->addAction(minLengthAction);
 	noteToolsButton->addAction(maxLengthAction);
+	noteToolsButton->addAction(upwardInversionAction);
+	noteToolsButton->addAction(downwardInversionAction);
 
 	notesActionsToolBar->addWidget(noteToolsButton);