- Qt 5.15
- Qt Quick Controls
- High-DPI Support in Qt Quick Controls
- Qt 5.15.19 Reference Documentation

# High-DPI Support in Qt Quick Controls

Qt Quick Controls support Qt's cross-platform high-DPI scaling introduced in Qt 5.6. The feature is opt-in, and can be enabled by setting the `Qt::AA_EnableHighDpiScaling` application attribute in C++ before QGuiApplication is constructed:

     #include <QGuiApplication>
     #include <QQmlApplicationEngine>

     int main(int argc, char *argv[])
     {
         QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling); // <--
         QGuiApplication app(argc, argv);
         QQmlApplicationEngine engine;
         engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
         return app.exec();
     }

Alternatively, an environment variable `QT_AUTO_SCREEN_SCALE_FACTOR=1` can be set to enable automatic high-DPI scaling.

Warning: Qt Quick Controls 1.x are not compatible with Qt's automatic high-DPI scaling. There is currently no available solution for high-DPI support in applications wishing to mix Qt Quick Controls and Qt Quick Controls.

## Related Information

- High DPI Displays
- Scalability