macOS: Change drag copy shortcut from Command to Option (#7325)

macOS: Replace Command + Drag shortcut key with Option + Drag
Add new header `KeyboardShortcuts.h` for platform-specific keyboard mappings

---------

Co-authored-by: Michael Gregorius <michael.gregorius.git@arcor.de>

include/KeyboardShortcuts.h

@@ -0,0 +1,77 @@
+/*
+ * KeyboardShortcuts.h - Cross-platform handling of keyboard modifier keys
+ *
+ * Copyright (c) 2025 Michael Gregorius
+ * Copyright (c) 2025 Tres Finocchiaro <tres.finocchiaro/at/gmail.com>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef LMMS_KEYBOARDSHORTCUTS_H
+#define LMMS_KEYBOARDSHORTCUTS_H
+
+#include "lmmsconfig.h"
+
+#include "qnamespace.h"
+
+
+namespace lmms
+{
+
+// Qt on macOS maps:
+//  - ControlModifier --> Command keys
+//  - MetaModifier value --> Control keys
+//  - Qt::AltModifier --> Option keys
+//
+// Our UI hints need to be adjusted to accommodate for this
+constexpr const char* UI_CTRL_KEY =
+#ifdef LMMS_BUILD_APPLE
+"⌘";
+#else
+"Ctrl";
+#endif
+
+constexpr const char* UI_ALT_KEY =
+#ifdef LMMS_BUILD_APPLE
+"Option";
+#else
+"Alt";
+#endif
+
+// UI hint for copying OR linking a UI component
+// this MUST be consistent with KBD_COPY_MODIFIER
+constexpr const char* UI_COPY_KEY =
+#ifdef LMMS_BUILD_APPLE
+UI_ALT_KEY;
+#else
+UI_CTRL_KEY;
+#endif
+
+// Shortcut for copying OR linking a UI component
+// this MUST be consistent with UI_COPY_KEY
+constexpr Qt::KeyboardModifier KBD_COPY_MODIFIER =
+#ifdef LMMS_BUILD_APPLE
+Qt::AltModifier;
+#else
+Qt::ControlModifier;
+#endif
+
+} // namespace lmms
+
+#endif // LMMS_KEYBOARDSHORTCUTS_H

include/lmms_basics.h

@@ -69,15 +69,6 @@ constexpr char LADSPA_PATH_SEPERATOR =
 #define LMMS_STRINGIFY(s) LMMS_STR(s)
 #define LMMS_STR(PN)	#PN
 
-// Abstract away GUI CTRL key (linux/windows) vs ⌘ (apple)
-constexpr const char* UI_CTRL_KEY =
-#ifdef LMMS_BUILD_APPLE
-"⌘";
-#else
-"Ctrl";
-#endif
-
-
 } // namespace lmms
 
 #endif // LMMS_TYPES_H

src/core/AutomationClip.cpp

@@ -29,6 +29,7 @@
 #include "AutomationNode.h"
 #include "AutomationClipView.h"
 #include "AutomationTrack.h"
+#include "KeyboardShortcuts.h"
 #include "LocaleHelper.h"
 #include "Note.h"
 #include "PatternStore.h"
@@ -952,7 +953,7 @@ QString AutomationClip::name() const
 	{
 		return m_objects.front()->fullDisplayName();
 	}
-	return tr( "Drag a control while pressing <%1>" ).arg(UI_CTRL_KEY);
+	return tr( "Drag a control while pressing <%1>" ).arg(UI_COPY_KEY);
 }
 
 

src/gui/AutomatableModelView.cpp

@@ -31,6 +31,7 @@
 #include "ControllerConnection.h"
 #include "embed.h"
 #include "GuiApplication.h"
+#include "KeyboardShortcuts.h"
 #include "MainWindow.h"
 #include "StringPairDrag.h"
 #include "Clipboard.h"
@@ -171,7 +172,7 @@ void AutomatableModelView::unsetModel()
 
 void AutomatableModelView::mousePressEvent( QMouseEvent* event )
 {
-	if( event->button() == Qt::LeftButton && event->modifiers() & Qt::ControlModifier )
+	if (event->button() == Qt::LeftButton && event->modifiers() & KBD_COPY_MODIFIER)
 	{
 		new gui::StringPairDrag( "automatable_model", QString::number( modelUntyped()->id() ), QPixmap(), widget() );
 		event->accept();

src/gui/FileBrowser.cpp

@@ -52,6 +52,7 @@
 #include "Instrument.h"
 #include "InstrumentTrack.h"
 #include "InstrumentTrackWindow.h"
+#include "KeyboardShortcuts.h"
 #include "MainWindow.h"
 #include "PatternStore.h"
 #include "PluginFactory.h"

src/gui/ProjectNotes.cpp

@@ -40,6 +40,7 @@
 #include "embed.h"
 #include "Engine.h"
 #include "GuiApplication.h"
+#include "KeyboardShortcuts.h"
 #include "MainWindow.h"
 #include "Song.h"
 

src/gui/StringPairDrag.cpp

@@ -61,7 +61,7 @@ StringPairDrag::StringPairDrag( const QString & _key, const QString & _value,
 	auto m = new QMimeData();
 	m->setData( mimeType( MimeType::StringPair ), txt.toUtf8() );
 	setMimeData( m );
-	exec( Qt::LinkAction, Qt::LinkAction );
+	exec( Qt::CopyAction, Qt::CopyAction );
 }
 
 

src/gui/clips/ClipView.cpp

@@ -41,6 +41,7 @@
 #include "GuiApplication.h"
 #include "InstrumentTrack.h"
 #include "InstrumentTrackView.h"
+#include "KeyboardShortcuts.h"
 #include "MidiClip.h"
 #include "MidiClipView.h"
 #include "Note.h"
@@ -633,7 +634,7 @@ void ClipView::mousePressEvent( QMouseEvent * me )
 		auto pClip = dynamic_cast<PatternClip*>(m_clip);
 		const bool knifeMode = m_trackView->trackContainerView()->knifeMode();
 
-		if ( me->modifiers() & Qt::ControlModifier && !(sClip && knifeMode) )
+		if (me->modifiers() & KBD_COPY_MODIFIER && !(sClip && knifeMode))
 		{
 			if( isSelected() )
 			{
@@ -726,7 +727,7 @@ void ClipView::mousePressEvent( QMouseEvent * me )
 			QString hint = m_action == Action::Move || m_action == Action::MoveSelection
 						? tr( "Press <%1> and drag to make a copy." )
 						: tr( "Press <%1> for free resizing." );
-			m_hint = TextFloat::displayMessage( tr( "Hint" ), hint.arg(UI_CTRL_KEY),
+			m_hint = TextFloat::displayMessage( tr( "Hint" ), hint.arg(UI_COPY_KEY),
 					embed::getIconPixmap( "hint" ), 0 );
 		}
 	}
@@ -824,7 +825,7 @@ void ClipView::mouseMoveEvent( QMouseEvent * me )
 		}
 	}
 
-	if( me->modifiers() & Qt::ControlModifier )
+	if (me->modifiers() & KBD_COPY_MODIFIER)
 	{
 		delete m_hint;
 		m_hint = nullptr;

src/gui/editors/PianoRoll.cpp

@@ -57,6 +57,7 @@
 #include "GuiApplication.h"
 #include "FontHelper.h"
 #include "InstrumentTrack.h"
+#include "KeyboardShortcuts.h"
 #include "MainWindow.h"
 #include "MidiClip.h"
 #include "PatternStore.h"

src/gui/editors/TimeLineWidget.cpp

@@ -37,6 +37,7 @@
 #include "ConfigManager.h"
 #include "embed.h"
 #include "GuiApplication.h"
+#include "KeyboardShortcuts.h"
 #include "NStateButton.h"
 #include "TextFloat.h"
 

src/gui/tracks/TrackOperationsWidget.cpp

@@ -40,6 +40,7 @@
 #include "embed.h"
 #include "Engine.h"
 #include "InstrumentTrackView.h"
+#include "KeyboardShortcuts.h"
 #include "PixmapButton.h"
 #include "Song.h"
 #include "StringPairDrag.h"
@@ -180,9 +181,8 @@ TrackOperationsWidget::TrackOperationsWidget( TrackView * parent ) :
  */
 void TrackOperationsWidget::mousePressEvent( QMouseEvent * me )
 {
-	if( me->button() == Qt::LeftButton &&
-		me->modifiers() & Qt::ControlModifier &&
-			m_trackView->getTrack()->type() != Track::Type::Pattern)
+	if (me->button() == Qt::LeftButton && me->modifiers() & KBD_COPY_MODIFIER &&
+		m_trackView->getTrack()->type() != Track::Type::Pattern)
 	{
 		DataFile dataFile( DataFile::Type::DragNDropData );
 		m_trackView->getTrack()->saveState( dataFile, dataFile.content() );

src/gui/widgets/Fader.cpp

@@ -55,6 +55,7 @@
 #include "embed.h"
 #include "CaptionMenu.h"
 #include "ConfigManager.h"
+#include "KeyboardShortcuts.h"
 #include "SimpleTextFloat.h"
 
 namespace lmms::gui
@@ -125,7 +126,7 @@ void Fader::mouseMoveEvent(QMouseEvent* mouseEvent)
 void Fader::mousePressEvent(QMouseEvent* mouseEvent)
 {
 	if (mouseEvent->button() == Qt::LeftButton &&
-			!(mouseEvent->modifiers() & Qt::ControlModifier))
+			!(mouseEvent->modifiers() & KBD_COPY_MODIFIER))
 	{
 		AutomatableModel* thisModel = model();
 		if (thisModel)

src/gui/widgets/FloatModelEditorBase.cpp

@@ -33,6 +33,7 @@
 #include "CaptionMenu.h"
 #include "ControllerConnection.h"
 #include "GuiApplication.h"
+#include "KeyboardShortcuts.h"
 #include "LocaleHelper.h"
 #include "MainWindow.h"
 #include "ProjectJournal.h"
@@ -155,7 +156,7 @@ void FloatModelEditorBase::dropEvent(QDropEvent * de)
 void FloatModelEditorBase::mousePressEvent(QMouseEvent * me)
 {
 	if (me->button() == Qt::LeftButton &&
-			! (me->modifiers() & Qt::ControlModifier) &&
+			! (me->modifiers() & KBD_COPY_MODIFIER) &&
 			! (me->modifiers() & Qt::ShiftModifier))
 	{
 		AutomatableModel *thisModel = model();

src/gui/widgets/LcdFloatSpinBox.cpp

@@ -42,6 +42,7 @@
 #include "embed.h"
 #include "GuiApplication.h"
 #include "FontHelper.h"
+#include "KeyboardShortcuts.h"
 #include "MainWindow.h"
 #include "lmms_math.h"
 
@@ -139,7 +140,7 @@ void LcdFloatSpinBox::mousePressEvent(QMouseEvent* event)
 	m_intStep = event->x() < m_wholeDisplay.width();
 
 	if (event->button() == Qt::LeftButton &&
-		!(event->modifiers() & Qt::ControlModifier) &&
+		!(event->modifiers() & KBD_COPY_MODIFIER) &&
 		event->y() < m_wholeDisplay.cellHeight() + 2)
 	{
 		m_mouseMoving = true;

src/gui/widgets/LcdSpinBox.cpp

@@ -28,6 +28,7 @@
 #include <QInputDialog>
 
 #include "LcdSpinBox.h"
+#include "KeyboardShortcuts.h"
 #include "CaptionMenu.h"
 
 
@@ -79,7 +80,7 @@ void LcdSpinBox::contextMenuEvent(QContextMenuEvent* event)
 void LcdSpinBox::mousePressEvent( QMouseEvent* event )
 {
 	if( event->button() == Qt::LeftButton &&
-		! ( event->modifiers() & Qt::ControlModifier ) &&
+		! (event->modifiers() & KBD_COPY_MODIFIER) &&
 						event->y() < cellHeight() + 2  )
 	{
 		m_mouseMoving = true;