#include <QtWidgets>

int main(int argc, char** argv)
{
    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);

    QApplication app(argc, argv);

    QWidget* window = new QWidget();
    Qt::WindowFlags flags = window->windowFlags() | Qt::FramelessWindowHint;
    window->setWindowFlags(flags);
    window->setAttribute(Qt::WA_TranslucentBackground, true);

    window->show();

    window->resize(400, 300);
    window->move(0, 0);

    QBoxLayout* buttonLayout = new QBoxLayout(QBoxLayout::LeftToRight, window);
    QPushButton* toggleFullscreenButton = new QPushButton("Toggle fullscreen", window);
    QObject::connect(toggleFullscreenButton, &QPushButton::clicked, window, [window]
    {
        if (!window->isFullScreen())
            window->showFullScreen();
        else
            window->showNormal();
    });
    buttonLayout->addWidget(toggleFullscreenButton);

    QPushButton* moveButton = new QPushButton("Move 100px", window);
    QObject::connect(moveButton, &QPushButton::clicked, window, [window]
    {
        window->move(window->pos() + QPoint(100, 100));
    });
    buttonLayout->addWidget(moveButton);

    return app.exec();
}