#include <QApplication>
#include <QGuiApplication>

#include <QString>

#include <QWidget>
#include <QComboBox>

#include <QHBoxLayout>


int main(int argc, char *argv[])
{ // High-DPI scale factor rounding
  // !! test this on screen with a normally a device pixel ratio of 1.5 !!
  QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::Floor); // problem
//  QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::Ceil); // okay
//  QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough); // okay

  // application
  QApplication app(argc,argv);

  // combox contents too narrow
  // 4K screen under Windows 10 with (normally) a device pixel ratio 1.5,
  // but rounded down to 1.0.
  QComboBox *combobox = new QComboBox();
  combobox->addItem(QStringLiteral("Z"));

  QHBoxLayout *layout = new QHBoxLayout();
  layout->addStretch();
  layout->addWidget(combobox);
  layout->addStretch();

  QWidget widget;
  widget.setLayout(layout);
  widget.show();

  return QApplication::exec();
}