[needs-docs] Mouse wheeling over font buttons can change font size

With ctrl+mouse wheel changing in smaller size increments

python/gui/qgsfontbutton.sip

@@ -188,6 +188,9 @@ class QgsFontButton : QToolButton
     virtual void dropEvent( QDropEvent *e );
 
 
+    virtual void wheelEvent( QWheelEvent *event );
+
+
 };
 
 /************************************************************************

src/gui/qgsfontbutton.cpp

@@ -305,6 +305,53 @@ void QgsFontButton::dropEvent( QDropEvent *e )
   updatePreview();
 }
 
+void QgsFontButton::wheelEvent( QWheelEvent *event )
+{
+  double size = 0;
+  switch ( mMode )
+  {
+    case ModeTextRenderer:
+      size = mFormat.size();
+      break;
+
+    case ModeQFont:
+      size = mFont.pointSizeF();
+      break;
+  }
+
+  double increment = event->modifiers() & Qt::ControlModifier ? 0.1 : 1;
+  if ( event->delta() > 0 )
+  {
+    size += increment;
+  }
+  else
+  {
+    size -= increment;
+  }
+  size = qMax( size, 1.0 );
+
+  switch ( mMode )
+  {
+    case ModeTextRenderer:
+    {
+      QgsTextFormat newFormat = mFormat;
+      newFormat.setSize( size );
+      setTextFormat( newFormat );
+      break;
+    }
+
+    case ModeQFont:
+    {
+      QFont newFont = mFont;
+      newFont.setPointSizeF( size );
+      setCurrentFont( newFont );
+      break;
+    }
+  }
+
+  event->accept();
+}
+
 QPixmap QgsFontButton::createColorIcon( const QColor &color ) const
 {
   //create an icon pixmap

src/gui/qgsfontbutton.h

@@ -199,6 +199,8 @@ class GUI_EXPORT QgsFontButton : public QToolButton
     // Reimplemented to accept dropped colors
     void dropEvent( QDropEvent *e ) override;
 
+    void wheelEvent( QWheelEvent *event ) override;
+
   private slots:
 
     void showSettingsDialog();