[FEATURE] Mouse wheel over sliders in color dialog to change value by

increments

Author: nyalldawson

python/gui/qgscolorwidgets.sip

@@ -373,6 +373,7 @@ class QgsColorRampWidget : QgsColorWidget
   protected:
 
     virtual void mouseMoveEvent( QMouseEvent *event );
+    virtual void wheelEvent( QWheelEvent* event );
     virtual void mousePressEvent( QMouseEvent *event );
     virtual void keyPressEvent( QKeyEvent * event );
 };

src/gui/qgscolorwidgets.cpp

@@ -1178,6 +1178,27 @@ void QgsColorRampWidget::mouseMoveEvent( QMouseEvent *event )
   QgsColorWidget::mouseMoveEvent( event );
 }
 
+void QgsColorRampWidget::wheelEvent( QWheelEvent *event )
+{
+  int oldValue = componentValue();
+
+  if ( event->delta() > 0 )
+  {
+    setComponentValue( componentValue() + 1 );
+  }
+  else
+  {
+    setComponentValue( componentValue() - 1 );
+  }
+
+  if ( componentValue() != oldValue )
+  {
+    //value has changed
+    emit colorChanged( mCurrentColor );
+    emit valueChanged( componentValue() );
+  }
+}
+
 void QgsColorRampWidget::mousePressEvent( QMouseEvent *event )
 {
   setColorFromPoint( event->posF() );

src/gui/qgscolorwidgets.h

@@ -515,6 +515,7 @@ class GUI_EXPORT QgsColorRampWidget : public QgsColorWidget
   protected:
 
     virtual void mouseMoveEvent( QMouseEvent *event ) override;
+    virtual void wheelEvent( QWheelEvent* event ) override;
     virtual void mousePressEvent( QMouseEvent *event ) override;
     virtual void keyPressEvent( QKeyEvent * event ) override;