Change zoom in SongEditor to a Slider Zoom

data/themes/classic/style.css

@@ -418,6 +418,25 @@ lmms--gui--AutomatableSlider::handle:vertical {
 	margin: -4px -12px -2px;
 }
 
+/* main horizontal sliders (zoom) */
+
+lmms--gui--AutomatableSlider::groove:horizontal {
+	background: rgba(0,0,0, 128);
+	border: 1px inset rgba(100,100,100, 64);
+	border-radius: 2px;
+	height: 2px;
+	margin: 2px;
+}
+
+lmms--gui--AutomatableSlider::handle:horizontal {
+	background: none;
+	border-image: url(resources:horizontal_slider.png);
+	width: 10px;
+	height: 26px;
+	border-radius: 2px;
+	margin: -12px -2px;
+}
+
 /* about dialog */
 QTabWidget, QTabWidget QWidget {
 	background: #5b6571;

data/themes/default/style.css

@@ -443,6 +443,25 @@ lmms--gui--AutomatableSlider::handle:vertical {
 	margin: -4px -12px -2px;
 }
 
+/* main horizontal sliders (zoom) */
+
+lmms--gui--AutomatableSlider::groove:horizontal {
+	background: #040506;
+	border: none;
+	border-radius: 2px;
+	height: 2px;
+	margin: 2px;
+}
+
+lmms--gui--AutomatableSlider::handle:horizontal {
+	background: none;
+	border-image: url(resources:horizontal_slider.png);
+	width: 10px;
+	height: 26px;
+	border-radius: 2px;
+	margin: -12px -2px;
+}
+
 /* window that shows up when you add effects */
 
 lmms--gui--EffectSelectDialog QScrollArea {

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 @@ class SongEditor : public TrackContainerView
 	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 slots:
 	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 slots:
 
 	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 slots:
 	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);
 } ;
 
 
@@ -213,15 +213,14 @@ protected slots:
 	QAction* m_selectModeAction;
 	QAction* m_crtlAction;
 
-	ComboBox * m_zoomingComboBox;
+	AutomatableSlider * m_zoomingSlider;
 	ComboBox * m_snappingComboBox;
 	QLabel* m_snapSizeLabel;
 
 	QAction* m_insertBarAction;
 	QAction* m_removeBarAction;
 };
 
-
 } // namespace gui
 
 } // namespace lmms

src/gui/clips/ClipView.cpp

@@ -125,7 +125,7 @@ ClipView::ClipView( Clip * clip,
 
 	connect( m_clip, SIGNAL(lengthChanged()),
 			this, SLOT(updateLength()));
-	connect( getGUI()->songEditor()->m_editor->zoomingModel(), SIGNAL(dataChanged()), this, SLOT(updateLength()));
+	connect(getGUI()->songEditor()->m_editor, &SongEditor::pixelsPerBarChanged, this, &ClipView::updateLength);
 	connect( m_clip, SIGNAL(positionChanged()),
 			this, SLOT(updatePosition()));
 	connect( m_clip, SIGNAL(destroyedClip()), this, SLOT(close()));
@@ -314,10 +314,9 @@ void ClipView::updateLength()
 	}
 	else
 	{
-		setFixedWidth(
-		static_cast<int>( m_clip->length() * pixelsPerBar() /
-					TimePos::ticksPerBar() ) + 1 /*+
-						BORDER_WIDTH * 2-1*/ );
+		// this std::max function is needed for clips that do not start or end on the beat, otherwise, they "disappear" when zooming to min 
+		// 3 is the minimun width needed to make a clip visible
+		setFixedWidth(std::max(static_cast<int>(m_clip->length() * pixelsPerBar() / TimePos::ticksPerBar() + 1), 3));
 	}
 	m_trackView->trackContainerView()->update();
 }