Fix #5194: Fix knobs moving too fast

include/Knob.h

@@ -174,8 +174,7 @@ private slots:
 	BoolModel m_volumeKnob;
 	FloatModel m_volumeRatio;
 
-	QPoint m_mouseOffset;
-	QPoint m_origMousePos;
+	QPoint m_lastMousePos; //!< mouse position in last mouseMoveEvent
 	float m_leftOver;
 	bool m_buttonPressed;
 

include/LcdSpinBox.h

@@ -73,8 +73,9 @@ public slots:
 	virtual void mouseDoubleClickEvent( QMouseEvent * _me );
 
 private:
+	float m_remainder; //!< floating offset of spinbox in [-0.5, 0.5]
 	bool m_mouseMoving;
-	QPoint m_origMousePos;
+	QPoint m_lastMousePos; //!< mouse position in last mouseMoveEvent
 	int m_displayOffset;
 	void enterValue();
 

src/gui/widgets/Knob.cpp

@@ -497,8 +497,8 @@ float Knob::getValue( const QPoint & _p )
 {
 	float value;
 
-	// arcane mathemagicks for calculating knob movement
-	value = ( ( _p.y() + _p.y() * qMin( qAbs( _p.y() / 2.5f ), 6.0f ) ) ) / 12.0f;
+	// knob value increase is linear to mouse movement
+	value = .4f * _p.y();
 
 	// if shift pressed we want slower movement
 	if( gui->mainWindow()->isShiftPressed() )
@@ -587,13 +587,11 @@ void Knob::mousePressEvent( QMouseEvent * _me )
 		}
 
 		const QPoint & p = _me->pos();
-		m_origMousePos = p;
-		m_mouseOffset = QPoint(0, 0);
+		m_lastMousePos = p;
 		m_leftOver = 0.0f;
 
 		emit sliderPressed();
 
-		QApplication::setOverrideCursor( Qt::BlankCursor );
 		s_textFloat->setText( displayValue() );
 		s_textFloat->moveGlobal( this,
 				QPoint( width() + 2, 0 ) );
@@ -618,12 +616,13 @@ void Knob::mousePressEvent( QMouseEvent * _me )
 
 void Knob::mouseMoveEvent( QMouseEvent * _me )
 {
-	if( m_buttonPressed && _me->pos() != m_origMousePos )
+	if( m_buttonPressed && _me->pos() != m_lastMousePos )
 	{
-		m_mouseOffset = _me->pos() - m_origMousePos;
-		setPosition( m_mouseOffset );
+		// knob position is changed depending on last mouse position
+		setPosition( _me->pos() - m_lastMousePos );
 		emit sliderMoved( model()->value() );
-		QCursor::setPos( mapToGlobal( m_origMousePos ) );
+		// original position for next time is current position
+		m_lastMousePos = _me->pos();
 	}
 	s_textFloat->setText( displayValue() );
 }

src/gui/widgets/LcdSpinBox.cpp

@@ -23,6 +23,7 @@
  *
  */
 
+#include <cmath>
 #include <QApplication>
 #include <QLabel>
 #include <QMouseEvent>
@@ -40,8 +41,9 @@
 LcdSpinBox::LcdSpinBox( int numDigits, QWidget* parent, const QString& name ) :
 	LcdWidget( numDigits, parent, name ),
 	IntModelView( new IntModel( 0, 0, 0, NULL, name, true ), this ),
+	m_remainder( 0.f ),
 	m_mouseMoving( false ),
-	m_origMousePos(),
+	m_lastMousePos(),
 	m_displayOffset( 0 )
 {
 }
@@ -52,8 +54,9 @@ LcdSpinBox::LcdSpinBox( int numDigits, QWidget* parent, const QString& name ) :
 LcdSpinBox::LcdSpinBox( int numDigits, const QString& style, QWidget* parent, const QString& name ) :
 	LcdWidget( numDigits, parent, name ),
 	IntModelView( new IntModel( 0, 0, 0, NULL, name, true ), this ),
+	m_remainder( 0.f ),
 	m_mouseMoving( false ),
-	m_origMousePos(),
+	m_lastMousePos(),
 	m_displayOffset( 0 )
 {
 }
@@ -98,8 +101,7 @@ void LcdSpinBox::mousePressEvent( QMouseEvent* event )
 						event->y() < cellHeight() + 2  )
 	{
 		m_mouseMoving = true;
-		m_origMousePos = event->globalPos();
-		QApplication::setOverrideCursor( Qt::BlankCursor );
+		m_lastMousePos = event->globalPos();
 
 		AutomatableModel *thisModel = model();
 		if( thisModel )
@@ -121,15 +123,20 @@ void LcdSpinBox::mouseMoveEvent( QMouseEvent* event )
 {
 	if( m_mouseMoving )
 	{
-		int dy = event->globalY() - m_origMousePos.y();
-		if( event->modifiers() & Qt::ShiftModifier )
-			dy = qBound( -4, dy/4, 4 );
-		if( dy > 1 || dy < -1 )
+		int dy = event->globalY() - m_lastMousePos.y();
+		if( dy )
 		{
-			model()->setInitValue( model()->value() -
-						dy / 2 * model()->step<int>() );
+			float fdy = static_cast<float>(dy);
+			if( event->modifiers() & Qt::ShiftModifier ) {
+				fdy = qBound( -4.f, fdy/4.f, 4.f );
+			}
+			float floatValNotRounded =
+				model()->value() + m_remainder - fdy / 2.f * model()->step<int>();
+			float floatValRounded = roundf( floatValNotRounded );
+			m_remainder = floatValNotRounded - floatValRounded;
+			model()->setInitValue( floatValRounded );
 			emit manualChange();
-			QCursor::setPos( m_origMousePos );
+			m_lastMousePos = event->globalPos();
 		}
 	}
 }
@@ -142,10 +149,7 @@ void LcdSpinBox::mouseReleaseEvent( QMouseEvent* )
 	if( m_mouseMoving )
 	{
 		model()->restoreJournallingState();
-
-		QCursor::setPos( m_origMousePos );
 		QApplication::restoreOverrideCursor();
-
 		m_mouseMoving = false;
 	}
 }
@@ -187,5 +191,3 @@ void LcdSpinBox::enterValue()
 	}
 }
 
-
-