Transpose midi clips in song editor (#6409)

* Transpose midi clips in song editor

* Fix undo stupidity

* Check boundries when transposing clips

and move transpose function to NoteVector

* Avoid update if nothing has changed

* Make getNoteBounds a separate function

* Rename getNoteBounds to boundsForNotes

* bool operator instead of optional + qobject_cast

* Revert "bool operator instead of optional + qobject_cast"

This reverts commit 98c56a96cf.

* qobject_cast and nullopt

include/MidiClipView.h

@@ -73,6 +73,7 @@ protected slots:
 
 	void resetName();
 	void changeName();
+	void transposeSelection();
 
 
 protected:

include/Note.h

@@ -26,6 +26,7 @@
 #ifndef NOTE_H
 #define NOTE_H
 
+#include <optional>
 #include <QVector>
 
 #include "volume.h"
@@ -252,6 +253,18 @@ private:
 typedef QVector<Note *> NoteVector;
 
 
+struct NoteBounds
+{
+	TimePos start;
+	TimePos end;
+	int lowest;
+	int highest;
+};
+
+
+std::optional<NoteBounds> boundsForNotes(const NoteVector& notes);
+
+
 } // namespace lmms
 
 #endif

src/core/Note.cpp

@@ -237,4 +237,33 @@ bool Note::withinRange(int tickStart, int tickEnd) const
 }
 
 
+
+
+/*! \brief Get the start/end/bottom/top positions of notes in a vector
+ *
+ *  Returns no value if there are no notes
+ */
+std::optional<NoteBounds> boundsForNotes(const NoteVector& notes)
+{
+	if (notes.empty()) { return std::nullopt; }
+
+	TimePos start = notes.front()->pos();
+	TimePos end = start;
+	int lower = notes.front()->key();
+	int upper = lower;
+
+	for (const Note* note: notes)
+	{
+		// TODO should we assume that NoteVector is always sorted correctly,
+		// so first() always has the lowest time position?
+		start = std::min(start, note->pos());
+		end = std::max(end, note->endPos());
+		lower = std::min(lower, note->key());
+		upper = std::max(upper, note->key());
+	}
+
+	return NoteBounds{start, end, lower, upper};
+}
+
+
 } // namespace lmms

src/gui/clips/MidiClipView.cpp

@@ -27,6 +27,7 @@
 
 #include <cmath>
 #include <QApplication>
+#include <QInputDialog>
 #include <QMenu>
 #include <QPainter>
 
@@ -36,6 +37,7 @@
 #include "MidiClip.h"
 #include "PianoRoll.h"
 #include "RenameDialog.h"
+#include "TrackView.h"
 
 namespace lmms::gui
 {
@@ -144,8 +146,66 @@ void MidiClipView::changeName()
 
 
 
+void MidiClipView::transposeSelection()
+{
+	const auto selection = getClickedClips();
+
+	// Calculate the key boundries for all clips
+	int highest = 0;
+	int lowest = NumKeys - 1;
+	for (ClipView* clipview: selection)
+	{
+		if (auto mcv = qobject_cast<MidiClipView*>(clipview))
+		{
+			if (auto bounds = boundsForNotes(mcv->getMidiClip()->notes()))
+			{
+				lowest = std::min(bounds->lowest, lowest);
+				highest = std::max(bounds->highest, highest);
+			}
+		}
+	}
+
+	int semitones = QInputDialog::getInt(this, tr("Transpose"), tr("Semitones to transpose by:"),
+		/*start*/ 0, /*min*/ -lowest, /*max*/ (NumKeys - 1 - highest));
+
+	if (semitones == 0) { return; }
+
+	// TODO make this not crash
+	// Engine::getSong()->addJournalCheckPoint();
+
+	QSet<Track*> m_changedTracks;
+	for (ClipView* clipview: selection)
+	{
+		auto mcv = qobject_cast<MidiClipView*>(clipview);
+		if (!mcv) { continue; }
+
+		auto clip = mcv->getMidiClip();
+		if (clip->notes().empty()) { continue; }
+
+		auto track = clipview->getTrackView()->getTrack();
+		if (!m_changedTracks.contains(track))
+		{
+			track->addJournalCheckPoint();
+			m_changedTracks.insert(track);
+		}
+
+		for (Note* note: clip->notes())
+		{
+			note->setKey(note->key() + semitones);
+		}
+		emit clip->dataChanged();
+	}
+	// At least one clip must have notes to show the transpose dialog, so something *has* changed
+	Engine::getSong()->setModified();
+}
+
+
+
+
 void MidiClipView::constructContextMenu( QMenu * _cm )
 {
+	bool isBeat = m_clip->type() == MidiClip::BeatClip;
+
 	QAction * a = new QAction( embed::getIconPixmap( "piano" ),
 					tr( "Open in piano-roll" ), _cm );
 	_cm->insertAction( _cm->actions()[0], a );
@@ -163,6 +223,10 @@ void MidiClipView::constructContextMenu( QMenu * _cm )
 
 	_cm->addAction( embed::getIconPixmap( "edit_erase" ),
 			tr( "Clear all notes" ), m_clip, SLOT(clear()));
+	if (!isBeat)
+	{
+		_cm->addAction(embed::getIconPixmap("scale"), tr("Transpose"), this, &MidiClipView::transposeSelection);
+	}
 	_cm->addSeparator();
 
 	_cm->addAction( embed::getIconPixmap( "reload" ), tr( "Reset name" ),
@@ -171,7 +235,7 @@ void MidiClipView::constructContextMenu( QMenu * _cm )
 						tr( "Change name" ),
 						this, SLOT(changeName()));
 
-	if ( m_clip->type() == MidiClip::BeatClip )
+	if (isBeat)
 	{
 		_cm->addSeparator();
 
@@ -622,4 +686,4 @@ void MidiClipView::paintEvent( QPaintEvent * )
 }
 
 
-} // namespace lmms::gui
+} // namespace lmms::gui