Fix Position Line gradient appearing in all editors no matter which one is playing (#7882)

Author: regulus79

include/PositionLine.h

@@ -28,6 +28,8 @@
 
 #include <QWidget>
 
+#include "Song.h"
+
 namespace lmms::gui
 {
 
@@ -37,14 +39,16 @@ class PositionLine : public QWidget
 	Q_PROPERTY(bool tailGradient MEMBER m_hasTailGradient)
 	Q_PROPERTY(QColor lineColor MEMBER m_lineColor)
 public:
-	PositionLine(QWidget* parent);
+	PositionLine(QWidget* parent, Song::PlayMode playMode);
 
 public slots:
 	void zoomChange(float zoom);
 
 private:
 	void paintEvent(QPaintEvent* pe) override;
 
+	Song::PlayMode m_playMode;
+
 	bool m_hasTailGradient;
 	QColor m_lineColor;
 };

src/gui/editors/PianoRoll.cpp

@@ -283,7 +283,7 @@ PianoRoll::PianoRoll() :
 			this, SLOT( updatePosition( const lmms::TimePos& ) ) );
 
 	// white position line follows timeline marker
-	m_positionLine = new PositionLine(this);
+	m_positionLine = new PositionLine(this, Song::PlayMode::MidiClip);
 
 	//update timeline when in step-recording mode
 	connect( &m_stepRecorderWidget, SIGNAL( positionChanged( const lmms::TimePos& ) ),

src/gui/editors/PositionLine.cpp

@@ -26,14 +26,13 @@
 
 #include <QPainter>
 
-#include "Song.h"
-
 
 namespace lmms::gui
 {
 
-PositionLine::PositionLine(QWidget* parent) :
+PositionLine::PositionLine(QWidget* parent, Song::PlayMode playMode) :
 	QWidget(parent),
+	m_playMode(playMode),
 	m_hasTailGradient(false),
 	m_lineColor(0, 0, 0, 0)
 {
@@ -64,8 +63,7 @@ void PositionLine::paintEvent(QPaintEvent* pe)
 		// If gradient is enabled, we're in focus and we're playing, enable gradient
 		if (m_hasTailGradient &&
 			Engine::getSong()->isPlaying() &&
-			(Engine::getSong()->playMode() == Song::PlayMode::Song ||
-			 Engine::getSong()->playMode() == Song::PlayMode::MidiClip))
+			(Engine::getSong()->playMode() == m_playMode))
 		{
 			c.setAlpha(60);
 			gradient.setColorAt(w, c);

src/gui/editors/SongEditor.cpp

@@ -113,7 +113,7 @@ SongEditor::SongEditor( Song * song ) :
 	// when tracks realign, adjust height of position line
 	connect(this, &TrackContainerView::tracksRealigned, this, &SongEditor::updatePositionLine);
 
-	m_positionLine = new PositionLine(this);
+	m_positionLine = new PositionLine(this, Song::PlayMode::Song);
 	static_cast<QVBoxLayout *>( layout() )->insertWidget( 1, m_timeLine );
 
 	connect( m_song, SIGNAL(playbackStateChanged()),