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.