#include <QtWidgets>

class MySlider : public QSlider
{
public:
    using QSlider::QSlider;

    void initStyleOption(QStyleOptionSlider* option) const override
    {
        QSlider::initStyleOption(option);
        if (m_adjustRect) {
            const auto w = option->rect.width() / 10.;
            const auto h = option->rect.height() / 10.;
            if (option->orientation == Qt::Horizontal)
                option->rect.adjust(w, 0, -2 * w, 0);
            else
                option->rect.adjust(0, h, 0, -2 * h);
        }
    }
    bool m_adjustRect = true;
};

int main(int argc, char** argv)
{
    // call with '-style windows' and also '-reverse' to test all 
    QApplication app(argc, argv);

    QWidget w;
    QGridLayout* lay = new QGridLayout(&w);
    {
        QSlider* slider = new MySlider;
        slider->setRange(0, 100);
        slider->setOrientation(Qt::Horizontal);
        slider->setTickPosition(QSlider::TicksAbove);
        lay->addWidget(slider, 0, 0);
    }
    {
        QSlider* slider = new MySlider;
        slider->setRange(0, 100);
        slider->setOrientation(Qt::Horizontal);
        slider->setTickPosition(QSlider::TicksBelow);
        lay->addWidget(slider, 0, 1);
    }
    {
        QSlider* slider = new MySlider;
        slider->setRange(0, 100);
        slider->setOrientation(Qt::Horizontal);
        slider->setTickPosition(QSlider::TicksBothSides);
        lay->addWidget(slider, 0, 2);
    }
    {
        QSlider* slider = new MySlider;
        slider->setRange(0, 100);
        slider->setOrientation(Qt::Vertical);
        slider->setTickPosition(QSlider::TicksLeft);
        lay->addWidget(slider, 2, 0);
    }
    {
        QSlider* slider = new MySlider;
        slider->setRange(0, 100);
        slider->setOrientation(Qt::Vertical);
        slider->setTickPosition(QSlider::TicksRight);
        lay->addWidget(slider, 2, 1);
    }
    {
        QSlider* slider = new MySlider;
        slider->setRange(0, 100);
        slider->setOrientation(Qt::Vertical);
        slider->setTickPosition(QSlider::TicksBothSides);
        lay->addWidget(slider, 2, 2);
    }
    w.show();
    return app.exec();
}