Adding proportional scrolling (#7476)

Add proportional scrolling to the song editor, piano roll and automation editor. Proportional scrolling means that if for example a certain measure is on the right side of the song editor then it will take a certain number of mouse wheel moves to get it to the left side of the editor. It is the same number of wheel moves regardless of the zoom level.

include/AutomationEditor.h

@@ -241,6 +241,8 @@ protected slots:
 	QScrollBar * m_leftRightScroll;
 	QScrollBar * m_topBottomScroll;
 
+	void adjustLeftRightScoll(int value);
+
 	TimePos m_currentPosition;
 
 	Action m_action;

include/PianoRoll.h

@@ -374,6 +374,8 @@ protected slots:
 	QScrollBar * m_leftRightScroll;
 	QScrollBar * m_topBottomScroll;
 
+	void adjustLeftRightScoll(int value);
+
 	TimePos m_currentPosition;
 	bool m_recording;
 	bool m_doAutoQuantization{false};

include/SongEditor.h

@@ -128,6 +128,8 @@ private slots:
 
 	QScrollBar * m_leftRightScroll;
 
+	void adjustLeftRightScoll(int value);
+
 	LcdSpinBox * m_tempoSpinBox;
 
 	TimeLineWidget * m_timeLine;

src/gui/editors/AutomationEditor.cpp

@@ -1560,7 +1560,11 @@ void AutomationEditor::resizeEvent(QResizeEvent * re)
 	update();
 }
 
-
+void AutomationEditor::adjustLeftRightScoll(int value)
+{
+	m_leftRightScroll->setValue(m_leftRightScroll->value() -
+							value * 0.3f / m_zoomXLevels[m_zoomingXModel.value()]);
+}
 
 
 // TODO: Move this method up so it's closer to the other mouse events
@@ -1625,13 +1629,11 @@ void AutomationEditor::wheelEvent(QWheelEvent * we )
 	// FIXME: Reconsider if determining orientation is necessary in Qt6.
 	else if(abs(we->angleDelta().x()) > abs(we->angleDelta().y())) // scrolling is horizontal
 	{
-		m_leftRightScroll->setValue(m_leftRightScroll->value() -
-							we->angleDelta().x() * 2 / 15);
+		adjustLeftRightScoll(we->angleDelta().x());
 	}
 	else if(we->modifiers() & Qt::ShiftModifier)
 	{
-		m_leftRightScroll->setValue(m_leftRightScroll->value() -
-							we->angleDelta().y() * 2 / 15);
+		adjustLeftRightScoll(we->angleDelta().y());
 	}
 	else
 	{

src/gui/editors/PianoRoll.cpp

@@ -3743,6 +3743,12 @@ void PianoRoll::resizeEvent(QResizeEvent* re)
 }
 
 
+void PianoRoll::adjustLeftRightScoll(int value)
+{
+	m_leftRightScroll->setValue(m_leftRightScroll->value() -
+							value * 0.3f / m_zoomLevels[m_zoomingModel.value()]);
+}
+
 
 
 void PianoRoll::wheelEvent(QWheelEvent * we )
@@ -3875,13 +3881,11 @@ void PianoRoll::wheelEvent(QWheelEvent * we )
 	// FIXME: Reconsider if determining orientation is necessary in Qt6.
 	else if(abs(we->angleDelta().x()) > abs(we->angleDelta().y())) // scrolling is horizontal
 	{
-		m_leftRightScroll->setValue(m_leftRightScroll->value() -
-							we->angleDelta().x() * 2 / 15);
+		adjustLeftRightScoll(we->angleDelta().x());
 	}
 	else if(we->modifiers() & Qt::ShiftModifier)
 	{
-		m_leftRightScroll->setValue(m_leftRightScroll->value() -
-							we->angleDelta().y() * 2 / 15);
+		adjustLeftRightScoll(we->angleDelta().y());
 	}
 	else
 	{

src/gui/editors/SongEditor.cpp

@@ -516,6 +516,12 @@ void SongEditor::keyPressEvent( QKeyEvent * ke )
 
 
 
+void SongEditor::adjustLeftRightScoll(int value)
+{
+	m_leftRightScroll->setValue(m_leftRightScroll->value()
+						- value * DEFAULT_PIXELS_PER_BAR / pixelsPerBar());
+}
+
 
 void SongEditor::wheelEvent( QWheelEvent * we )
 {
@@ -544,13 +550,11 @@ void SongEditor::wheelEvent( QWheelEvent * we )
 	// FIXME: Reconsider if determining orientation is necessary in Qt6.
 	else if (std::abs(we->angleDelta().x()) > std::abs(we->angleDelta().y())) // scrolling is horizontal
 	{
-		m_leftRightScroll->setValue(m_leftRightScroll->value()
-							- we->angleDelta().x());
+		adjustLeftRightScoll(we->angleDelta().x());
 	}
 	else if (we->modifiers() & Qt::ShiftModifier)
 	{
-		m_leftRightScroll->setValue(m_leftRightScroll->value()
-							- we->angleDelta().y());
+		adjustLeftRightScoll(we->angleDelta().y());
 	}
 	else
 	{