QListView resize icon dynamically

[Alundra]

Hi all,
I want to resize icon dynamically when the view resize.
Here the actual code who works :

virtual void resizeEvent( QResizeEvent* e )
{
  QFileSystemModel* Model = static_cast< QFileSystemModel* >( model() );
  QDir RootDir = QDir( Model->filePath( rootIndex() ) );
  RootDir.setFilter( Model->filter() );
  RootDir.setNameFilters( Model->nameFilters() );
  RootDir.refresh();
  const int ItemSize = 128 + 16;
  const int ItemRow = std::ceil( (float)e->size().width() / (float)ItemSize );
  if( ItemRow > (int)RootDir.count() )
  {
    setIconSize( QSize( 128, 128 ) );
  }
  else
  {
    if( ItemRow > 0 )
    {
      const int SizeOffset = ( ItemSize - ( e->size().width() % ItemSize ) ) / ItemRow;
      const int IconSize = ( 128 - SizeOffset <= 0 ) ? 128 : 128 - SizeOffset;
      setIconSize( QSize( IconSize, IconSize ) );
    }
    else
    {
      setIconSize( QSize( 32, 32 ) );
    }
  }
  QListView::resizeEvent( e );
}

virtual void resizeEvent( QResizeEvent* e )
{
  QFileSystemModel* Model = static_cast< QFileSystemModel* >( model() );
  QDir RootDir = QDir( Model->filePath( rootIndex() ) );
  RootDir.setFilter( Model->filter() );
  RootDir.setNameFilters( Model->nameFilters() );
  RootDir.refresh();
  const int ItemSize = 128 + 16;
  const int ItemRow = std::ceil( (float)e->size().width() / (float)ItemSize );
  if( ItemRow > (int)RootDir.count() )
  {
    setIconSize( QSize( 128, 128 ) );
  }
  else
  {
    if( ItemRow > 0 )
    {
      const int SizeOffset = ( ItemSize - ( e->size().width() % ItemSize ) ) / ItemRow;
      const int IconSize = ( 128 - SizeOffset <= 0 ) ? 128 : 128 - SizeOffset;
      setIconSize( QSize( IconSize, IconSize ) );
    }
    else
    {
      setIconSize( QSize( 32, 32 ) );
    }
  }
  QListView::resizeEvent( e );
}

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Can it be better ? One flickering can be seen who is not good.
This flickering is because I only set icon 128x128 or it's problem of the code ?
The max icon size is 128x128 and I add 16 to have it correct about margin :

const int ItemSize = 128 + 16;

const int ItemSize = 128 + 16;

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Can the item size can be computed by code without hard coded values ?
Thanks for the help