suggest a fix for precision on knob dragging (#3075)

* fixes precision on knob dragging

* fixes precision on fader dragging

* diaplay a rounded float on knobs

* enter rounded value on fader

* add getRoundedValue() and getDigitCount() to floatmodel

* whitespace

include/AutomatableModel.h

@@ -406,7 +406,8 @@ public:
 		AutomatableModel( Float, val, min, max, step, parent, displayName, defaultConstructed )
 	{
 	}
-
+	float getRoundedValue() const;
+	float getDigitCount();
 	defaultTypedMethods(float);
 
 } ;

src/core/AutomatableModel.cpp

@@ -275,9 +275,10 @@ float AutomatableModel::inverseScaledValue( float value ) const
 
 QString AutomatableModel::displayValue( const float val ) const
 {
+	const FloatModel *floatmodel = dynamic_cast<const FloatModel*>( this );
 	switch( m_dataType )
 	{
-		case Float: return QString::number( castValue<float>( scaledValue( val ) ) );
+		case Float: return QString::number( castValue<float>( scaledValue( floatmodel->getRoundedValue() ) ) );
 		case Integer: return QString::number( castValue<int>( scaledValue( val ) ) );
 		case Bool: return QString::number( castValue<bool>( scaledValue( val ) ) );
 	}
@@ -713,6 +714,23 @@ float AutomatableModel::globalAutomationValueAt( const MidiTime& time )
 	}
 }
 
+float FloatModel::getRoundedValue() const
+{
+	return static_cast<float>( static_cast<int>( value() / step<float>() + 0.5 ) ) * step<float>();
+}
 
 
 
+
+float FloatModel::getDigitCount()
+{
+	float steptemp = step<float>();
+	int digits = 0;
+	while ( steptemp < 1 )
+	{
+		steptemp = steptemp / 0.1f;
+		digits++;
+	}
+	return digits;
+}
+

src/gui/widgets/Fader.cpp

@@ -174,7 +174,9 @@ void Fader::mouseMoveEvent( QMouseEvent *mouseEvent )
 
 		float delta = dy * ( model()->maxValue() - model()->minValue() ) / (float) ( height() - ( *m_knob ).height() );
 
-		model()->setValue( m_startValue + delta );
+		const float step = model()->step<float>();
+		float newValue = static_cast<float>( static_cast<int>( ( m_startValue + delta ) / step + 0.5 ) ) * step;
+		model()->setValue( newValue );
 
 		updateTextFloat();
 	}
@@ -215,7 +217,6 @@ void Fader::mouseDoubleClickEvent( QMouseEvent* mouseEvent )
 {
 	bool ok;
 	float newValue;
-
 	// TODO: dbV handling
 	if( m_displayConversion )
 	{
@@ -223,9 +224,9 @@ void Fader::mouseDoubleClickEvent( QMouseEvent* mouseEvent )
 					tr( "Please enter a new value between %1 and %2:" ).
 							arg( model()->minValue() * 100 ).
 							arg( model()->maxValue() * 100 ),
-						model()->value() * 100,
+						model()->getRoundedValue() * 100,
 						model()->minValue() * 100,
-						model()->maxValue() * 100, 4, &ok ) * 0.01f;
+						model()->maxValue() * 100, model()->getDigitCount(), &ok ) * 0.01f;
 	}
 	else
 	{
@@ -233,9 +234,9 @@ void Fader::mouseDoubleClickEvent( QMouseEvent* mouseEvent )
 					tr( "Please enter a new value between %1 and %2:" ).
 							arg( model()->minValue() ).
 							arg( model()->maxValue() ),
-						model()->value(),
+						model()->getRoundedValue(),
 						model()->minValue(),
-						model()->maxValue(), 4, &ok );
+						model()->maxValue(), model()->getDigitCount(), &ok );
 	}
 
 	if( ok )

src/gui/widgets/Knob.cpp

@@ -51,7 +51,6 @@
 #include "templates.h"
 #include "TextFloat.h"
 
-
 TextFloat * Knob::s_textFloat = NULL;
 
 
@@ -729,6 +728,7 @@ void Knob::setPosition( const QPoint & _p )
 	const float oldValue = model()->value();
 
 
+
 	if( model()->isScaleLogarithmic() ) // logarithmic code
 	{
 		const float pos = model()->minValue() < 0
@@ -738,7 +738,8 @@ void Knob::setPosition( const QPoint & _p )
 		float newValue = value * ratio;
 		if( qAbs( newValue ) >= step )
 		{
-			model()->setValue( oldValue - newValue );
+			float roundedValue = static_cast<float>( static_cast<int>( ( oldValue - newValue ) / step + 0.5 ) ) * step;
+			model()->setValue( roundedValue );
 			m_leftOver = 0.0f;
 		}
 		else
@@ -747,12 +748,12 @@ void Knob::setPosition( const QPoint & _p )
 		}
 	}
 
-
 	else // linear code
 	{
 		if( qAbs( value ) >= step )
 		{
-			model()->setValue( oldValue - value );
+			float roundedValue = static_cast<float>( static_cast<int>( ( oldValue - value ) / step + 0.5 ) ) * step;
+			model()->setValue( roundedValue );
 			m_leftOver = 0.0f;
 		}
 		else
@@ -769,6 +770,7 @@ void Knob::enterValue()
 {
 	bool ok;
 	float new_val;
+
 	if( isVolumeKnob() &&
 		ConfigManager::inst()->value( "app", "displaydbfs" ).toInt() )
 	{
@@ -776,8 +778,8 @@ void Knob::enterValue()
 			this, windowTitle(),
 			tr( "Please enter a new value between "
 					"-96.0 dBFS and 6.0 dBFS:" ),
-				20.0 * log10( model()->value() / 100.0 ),
-							-96.0, 6.0, 4, &ok );
+				20.0 * log10( model()->getRoundedValue() / 100.0 ),
+							-96.0, 6.0, model()->getDigitCount(), &ok );
 		if( new_val <= -96.0 )
 		{
 			new_val = 0.0f;
@@ -795,9 +797,9 @@ void Knob::enterValue()
 						"%1 and %2:" ).
 						arg( model()->minValue() ).
 						arg( model()->maxValue() ),
-					model()->value(),
+					model()->getRoundedValue(),
 					model()->minValue(),
-					model()->maxValue(), 4, &ok );
+					model()->maxValue(), model()->getDigitCount(), &ok );
 	}
 
 	if( ok )
@@ -828,11 +830,11 @@ QString Knob::displayValue() const
 		ConfigManager::inst()->value( "app", "displaydbfs" ).toInt() )
 	{
 		return m_description.trimmed() + QString( " %1 dBFS" ).
-				arg( 20.0 * log10( model()->value() / volumeRatio() ),
+				arg( 20.0 * log10( model()->getRoundedValue() / volumeRatio() ),
 								3, 'f', 2 );
 	}
 	return m_description.trimmed() + QString( " %1" ).
-					arg( model()->value() ) + m_unit;
+					arg( model()->getRoundedValue() ) + m_unit;
 }