Change zoom in SongEditor to a Slider Zoom (#6664)

Co-authored-by: Dalton Messmer <33463986+messmerd@users.noreply.github.com>
Co-authored-by: Alex <allejok96@gmail.com>

include/SongEditor.h

@@ -26,6 +26,7 @@
 #ifndef LMMS_GUI_SONG_EDITOR_H
 #define LMMS_GUI_SONG_EDITOR_H
 
+#include "AutomatableModel.h"
 #include "Editor.h"
 #include "TrackContainerView.h"
 
@@ -69,7 +70,6 @@ public:
 	void saveSettings( QDomDocument& doc, QDomElement& element ) override;
 	void loadSettings( const QDomElement& element ) override;
 
-	ComboBoxModel *zoomingModel() const;
 	ComboBoxModel *snappingModel() const;
 	float getSnapSize() const;
 	QString getSnapSizeString() const;
@@ -120,10 +120,12 @@ private:
 	bool allowRubberband() const override;
 	bool knifeMode() const override;
 
+	int calculatePixelsPerBar() const;
+	int calculateZoomSliderValue(int pixelsPerBar) const;
+
 	int trackIndexFromSelectionPoint(int yPos);
 	int indexOfTrackView(const TrackView* tv);
 
-
 	Song * m_song;
 
 	QScrollBar * m_leftRightScroll;
@@ -141,12 +143,10 @@ private:
 
 	PositionLine * m_positionLine;
 
-	ComboBoxModel* m_zoomingModel;
+	IntModel* m_zoomingModel;
 	ComboBoxModel* m_snappingModel;
 	bool m_proportionalSnap;
 
-	static const QVector<float> m_zoomLevels;
-
 	bool m_scrollBack;
 	bool m_smoothScroll;
 
@@ -158,14 +158,14 @@ private:
 	QPoint m_mousePos;
 	int m_rubberBandStartTrackview;
 	TimePos m_rubberbandStartTimePos;
-	int m_currentZoomingValue;
+	int m_rubberbandPixelsPerBar; //!< pixels per bar when selection starts
 	int m_trackHeadWidth;
 	bool m_selectRegion;
 
 	friend class SongEditorWindow;
 
 signals:
-	void zoomingValueChanged( float );
+	void pixelsPerBarChanged(float);
 } ;
 
 
@@ -213,7 +213,7 @@ private:
 	QAction* m_selectModeAction;
 	QAction* m_crtlAction;
 
-	ComboBox * m_zoomingComboBox;
+	AutomatableSlider * m_zoomingSlider;
 	ComboBox * m_snappingComboBox;
 	QLabel* m_snapSizeLabel;
 
@@ -221,7 +221,6 @@ private:
 	QAction* m_removeBarAction;
 };
 
-
 } // namespace gui
 
 } // namespace lmms