Method onMenuZoomTo50

YUViewLib/src/ui/Mainwindow.h:109–114

      v->zoomOut(checked);
  }
  void onMenuZoomTo50(bool checked)
  {
    const auto v = this->getCurrentActiveView();
    if (v)
      v->zoomTo50(checked);
  }
  void onMenuZoomTo100(bool checked)
  {
    const auto v = this->getCurrentActiveView();