Add Midi Reversing (#7606)

Adds the ability to reverse the selected midi notes in the PianoRoll.

The tool is located under the wrench icon in the PianoRoll and can also be triggered with Shift-R.

---------

Co-authored-by: szeli1 <143485814+szeli1@users.noreply.github.com>

include/MidiClip.h

@@ -79,6 +79,9 @@ public:
 	Note * addStepNote( int step );
 	void setStep( int step, bool enabled );
 
+	//! Horizontally flip the positions of the given notes.
+	void reverseNotes(const NoteVector& notes);
+
 	// Split the list of notes on the given position
 	void splitNotes(const NoteVector& notes, TimePos pos);
 

include/PianoRoll.h

@@ -248,6 +248,7 @@ protected slots:
 	void clearGhostClip();
 	void glueNotes();
 	void fitNoteLengths(bool fill);
+	void reverseNotes();
 	void constrainNoteLengths(bool constrainMax);
 
 	void changeSnapMode();

src/gui/editors/PianoRoll.cpp

@@ -786,6 +786,20 @@ void PianoRoll::constrainNoteLengths(bool constrainMax)
 	Engine::getSong()->setModified();
 }
 
+void PianoRoll::reverseNotes()
+{
+	if (!hasValidMidiClip()) { return; }
+
+	const NoteVector selectedNotes = getSelectedNotes();
+	const auto& notes = selectedNotes.empty() ? m_midiClip->notes() : selectedNotes;
+
+	m_midiClip->reverseNotes(notes);
+
+	update();
+	getGUI()->songEditor()->update();
+	Engine::getSong()->setModified();
+}
+
 
 void PianoRoll::loadMarkedSemiTones(const QDomElement & de)
 {
@@ -5035,6 +5049,10 @@ 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 reverseAction = new QAction(embed::getIconPixmap("flip_x"), tr("Reverse Notes"), noteToolsButton);
+	connect(reverseAction, &QAction::triggered, [this](){ m_editor->reverseNotes(); });
+	reverseAction->setShortcut(combine(Qt::SHIFT, Qt::Key_R));
+
 	noteToolsButton->addAction(glueAction);
 	noteToolsButton->addAction(knifeAction);
 	noteToolsButton->addAction(strumAction);
@@ -5042,6 +5060,7 @@ PianoRollWindow::PianoRollWindow() :
 	noteToolsButton->addAction(cutOverlapsAction);
 	noteToolsButton->addAction(minLengthAction);
 	noteToolsButton->addAction(maxLengthAction);
+	noteToolsButton->addAction(reverseAction);
 
 	notesActionsToolBar->addWidget(noteToolsButton);
 

src/tracks/MidiClip.cpp

@@ -314,6 +314,25 @@ void MidiClip::setStep( int step, bool enabled )
 
 
 
+void MidiClip::reverseNotes(const NoteVector& notes)
+{
+	addJournalCheckPoint();
+
+	// Find the very first start position and the very last end position of all the notes.
+	TimePos firstPos = (*std::min_element(notes.begin(), notes.end(), [](const Note* n1, const Note* n2){ return Note::lessThan(n1, n2); }))->pos();
+	TimePos lastPos = (*std::max_element(notes.begin(), notes.end(), [](const Note* n1, const Note* n2){ return n1->endPos() < n2->endPos(); }))->endPos();
+
+	for (auto note : notes)
+	{
+		TimePos newStart = lastPos - (note->pos() - firstPos) - note->length();
+		note->setPos(newStart);
+	}
+
+	rearrangeAllNotes();
+	emit dataChanged();
+}
+
+
 
 void MidiClip::splitNotes(const NoteVector& notes, TimePos pos)
 {