wheelEvent handling improved

src/controls/QskBoundedInput.cpp

@@ -207,7 +207,7 @@ void QskBoundedInput::wheelEvent( QWheelEvent* event )
         return;
     }
 
-    auto offset = qskWheelSteps( event ) * m_stepSize;
+    auto offset = qskWheelIncrement( event ) * m_stepSize;
     if ( event->modifiers() & ( Qt::ControlModifier | Qt::ShiftModifier ) )
         offset *= m_pageSize;
 

src/controls/QskEvent.cpp

@@ -87,52 +87,31 @@ QPointF qskWheelPosition( const QWheelEvent* event )
 
 #ifndef QT_NO_WHEELEVENT
 
-qreal qskWheelSteps( const QWheelEvent* event, int orientation )
+qreal qskWheelSteps( const QWheelEvent* event )
 {
-    qreal delta = 0.0;
-
-    // what about event->pixelDelta()
-    auto aDelta = event->angleDelta();
-
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 7, 0 )
-    if ( event->inverted() )
-        aDelta.setY( -aDelta.y() );
-#endif
-
-    switch( orientation )
-    {
-        case Qt::Horizontal:
-            delta = aDelta.x();
-            break;
-
-        case Qt::Vertical:
-            delta = aDelta.y();
-            break;
-
-        default:
-            delta = aDelta.y() ? aDelta.y() : aDelta.x();
-    }
+    const auto angleDelta = event->angleDelta();
 
+    const qreal delta = angleDelta.y() ? angleDelta.y() : angleDelta.x();
     return delta / QWheelEvent::DefaultDeltasPerStep; 
 }
 
+qreal qskWheelIncrement( const QWheelEvent* event )
+{
+    /*
+        Some controls ( f.e a spin box ) are interpreting the wheel to
+        in/decrease a value. For those the physical direction is not relevant
+        and we might have to invert the y delta.
+     */
+
+    auto angleDelta = event->angleDelta();
+
+#if QT_VERSION >= QT_VERSION_CHECK( 5, 7, 0 )
+    if ( event->inverted() )
+        angleDelta.setY( -angleDelta.y() );
 #endif
 
-#ifndef QT_NO_WHEELEVENT
-
-QPointF qskScrollIncrement( const QWheelEvent* event )
-{
-    QPointF increment = event->pixelDelta();
-
-    if ( increment.isNull() )
-    {
-        increment = event->angleDelta() / QWheelEvent::DefaultDeltasPerStep;
-
-        constexpr qreal stepSize = 20.0; // how to find this value ???
-        increment *= stepSize;
-    }
-
-    return increment;
+    const qreal delta = angleDelta.y() ? angleDelta.y() : angleDelta.x();
+    return delta / QWheelEvent::DefaultDeltasPerStep; 
 }
 
 #endif

src/controls/QskEvent.h

@@ -143,10 +143,8 @@ QSK_EXPORT QPointF qskHoverPosition( const QHoverEvent* );
 #ifndef QT_NO_WHEELEVENT
 
 QSK_EXPORT QPointF qskWheelPosition( const QWheelEvent* );
-QSK_EXPORT qreal qskWheelSteps(
-    const QWheelEvent*, int orientation = 0 );
-
-QSK_EXPORT QPointF qskScrollIncrement( const QWheelEvent* );
+QSK_EXPORT qreal qskWheelSteps( const QWheelEvent* );
+QSK_EXPORT qreal qskWheelIncrement( const QWheelEvent* );
 
 #endif
 

src/controls/QskScrollBox.cpp

@@ -402,11 +402,21 @@ void QskScrollBox::gestureEvent( QskGestureEvent* event )
 
 QPointF QskScrollBox::scrollOffset( const QWheelEvent* event ) const
 {
+    QPointF offset;
+
     const auto pos = qskWheelPosition( event );
     if ( viewContentsRect().contains( pos ) )
-        return qskScrollIncrement( event );
+    {
+        offset = event->pixelDelta();
 
-    return QPointF();
+        if ( offset.isNull() )
+        {
+            offset = event->angleDelta() / QWheelEvent::DefaultDeltasPerStep;
+            offset *= 20.0; // how to find such a value ???
+        }
+    }
+
+    return offset;
 }
 
 void QskScrollBox::wheelEvent( QWheelEvent* event )

src/controls/QskScrollView.cpp

@@ -8,6 +8,9 @@
 #include "QskBoxBorderMetrics.h"
 #include "QskEvent.h"
 
+#include <qguiapplication.h>
+#include <qstylehints.h>
+
 QSK_SUBCONTROL( QskScrollView, Panel )
 QSK_SUBCONTROL( QskScrollView, Viewport )
 QSK_SUBCONTROL( QskScrollView, HorizontalScrollBar )
@@ -18,6 +21,15 @@ QSK_SUBCONTROL( QskScrollView, VerticalScrollHandle )
 QSK_SYSTEM_STATE( QskScrollView, VerticalHandlePressed, QskAspect::FirstSystemState << 1 )
 QSK_SYSTEM_STATE( QskScrollView, HorizontalHandlePressed, QskAspect::FirstSystemState << 2 )
 
+static int qskScrollLines()
+{
+#if QT_VERSION >= QT_VERSION_CHECK( 5, 9, 0 )
+    return QGuiApplication::styleHints()->wheelScrollLines();
+#else
+    return 3;
+#endif
+}
+
 class QskScrollView::PrivateData
 {
   public:
@@ -217,24 +229,13 @@ QPointF QskScrollView::scrollOffset( const QWheelEvent* event ) const
 
     if ( subControlRect( VerticalScrollBar ).contains( pos ) )
     {
-        const auto increment = qskScrollIncrement( event );
-        offset.setY( increment.y() );
+        const auto steps = qskWheelSteps( event );
+        offset.setY( steps * qskScrollLines() );
     }
     else if ( subControlRect( HorizontalScrollBar ).contains( pos ) )
     {
-        const auto increment = qskScrollIncrement( event );
-
-        qreal dx = increment.x();
-        if ( dx == 0 )
-        {
-            dx = increment.y();
-
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 7, 0 )
-            if ( event->inverted() )
-                dx = -dx;
-#endif
-        }
-        offset.setX( dx );
+        const auto steps = qskWheelSteps( event );
+        offset.setX( steps * qskScrollLines() );
     }
     else
     {