Control play/pause buttons in slot of MainWindow via signal in Song class

The engine class as the component instance manager is the wrong place to
control the play/pause buttons. Instead emit a signal in the Song class
and update the buttons in a slot in MainWindow. This fixes problems with
GUI/pixmap operations happening outside the GUI thread when exporting a
project.

Closes #435.

include/MainWindow.h

@@ -107,6 +107,8 @@ public slots:
 	void togglePianoRollWin();
 	void toggleControllerRack();
 
+	void updatePlayPauseIcons();
+
 	void undo();
 	void redo();
 

include/engine.h

@@ -147,8 +147,6 @@ public:
 		return s_controllerRackView;
 	}
 
-	static void updatePlayPauseIcons();
-
 	static float framesPerTick()
 	{
 		return s_framesPerTick;

include/song.h

@@ -360,6 +360,7 @@ private:
 
 signals:
 	void projectLoaded();
+	void playbackStateChanged();
 	void lengthChanged( int _tacts );
 	void tempoChanged( bpm_t _new_bpm );
 	void timeSignatureChanged( int _old_ticks_per_tact,

src/core/engine.cpp

@@ -146,42 +146,6 @@ void engine::destroy()
 
 
 
-void engine::updatePlayPauseIcons()
-{
-	s_songEditor->setPauseIcon( false );
-	s_automationEditor->setPauseIcon( false );
-	s_bbEditor->setPauseIcon( false );
-	s_pianoRoll->setPauseIcon( false );
-
-	if( s_song->isPlaying() )
-	{
-		switch( s_song->playMode() )
-		{
-			case song::Mode_PlaySong:
-				s_songEditor->setPauseIcon( true );
-				break;
-
-			case song::Mode_PlayAutomationPattern:
-				s_automationEditor->setPauseIcon( true );
-				break;
-
-			case song::Mode_PlayBB:
-				s_bbEditor->setPauseIcon( true );
-				break;
-
-			case song::Mode_PlayPattern:
-				s_pianoRoll->setPauseIcon( true );
-				break;
-
-			default:
-				break;
-		}
-	}
-}
-
-
-
-
 void engine::updateFramesPerTick()
 {
 	s_framesPerTick = s_mixer->processingSampleRate() * 60.0f * 4 /

src/core/song.cpp

@@ -404,10 +404,7 @@ void song::playSong()
 
 	savePos();
 
-	if( QApplication::type() != QApplication::Tty )
-	{
-		engine::updatePlayPauseIcons();
-	}
+	emit playbackStateChanged();
 }
 
 
@@ -447,7 +444,7 @@ void song::playTrack( track * _trackToPlay )
 
 	savePos();
 
-	engine::updatePlayPauseIcons();
+	emit playbackStateChanged();
 }
 
 
@@ -468,7 +465,7 @@ void song::playBB()
 
 	savePos();
 
-	engine::updatePlayPauseIcons();
+	emit playbackStateChanged();
 }
 
 
@@ -493,7 +490,7 @@ void song::playPattern( pattern * _patternToPlay, bool _loop )
 
 	savePos();
 
-	engine::updatePlayPauseIcons();
+	emit playbackStateChanged();
 }
 
 
@@ -546,7 +543,7 @@ void song::togglePause()
 
 	m_vstSyncController.setPlaybackState( m_playing );
 
-	engine::updatePlayPauseIcons();
+	emit playbackStateChanged();
 }
 
 
@@ -605,9 +602,7 @@ void song::stop()
 
 	m_playMode = Mode_None;
 
-	if(QApplication::type() != QApplication::Tty) {
-		engine::updatePlayPauseIcons();
-	}
+	emit playbackStateChanged();
 }
 
 

src/gui/MainWindow.cpp

@@ -190,6 +190,9 @@ MainWindow::MainWindow() :
 		connect(&m_autoSaveTimer, SIGNAL(timeout()), this, SLOT(autoSave()));
 		m_autoSaveTimer.start(1000 * 60); // 1 minute
 	}
+
+	connect( engine::getSong(), SIGNAL( playbackStateChanged() ),
+				this, SLOT( updatePlayPauseIcons() ) );
 }
 
 
@@ -926,6 +929,42 @@ void MainWindow::toggleControllerRack()
 
 
 
+void MainWindow::updatePlayPauseIcons()
+{
+	engine::songEditor()->setPauseIcon( false );
+	engine::automationEditor()->setPauseIcon( false );
+	engine::getBBEditor()->setPauseIcon( false );
+	engine::pianoRoll()->setPauseIcon( false );
+
+	if( engine::getSong()->isPlaying() )
+	{
+		switch( engine::getSong()->playMode() )
+		{
+			case song::Mode_PlaySong:
+				engine::songEditor()->setPauseIcon( true );
+				break;
+
+			case song::Mode_PlayAutomationPattern:
+				engine::automationEditor()->setPauseIcon( true );
+				break;
+
+			case song::Mode_PlayBB:
+				engine::getBBEditor()->setPauseIcon( true );
+				break;
+
+			case song::Mode_PlayPattern:
+				engine::pianoRoll()->setPauseIcon( true );
+				break;
+
+			default:
+				break;
+		}
+	}
+}
+
+
+
+
 void MainWindow::undo()
 {
 	engine::projectJournal()->undo();