How to get size of QSlider-handle?

Question

QSliders are displayed differently on different platforms. How can I get the width and height of the handle of a QSlider, being it styled using CSS or not? I am only aware of methods to retrieve the size of the whole QWidget, but not the handle?

Answer 1

There is a terrible way, which may not have to work correctly, but it still works:

QSize sliderHandleSize( const QSlider& slider )
{
    const QSize _minSize = slider.minimumSizeHint();
    
    switch( slider.orientation() )
    {
        case Qt::Orientation::Horizontal:
            return QSize( _minSize.width() - 1, _minSize.height() );
        case Qt::Orientation::Vertical:
            return QSize( _minSize.width(), _minSize.height() - 1 );
        default:
            Q_ASSERT_X( false, "sliderHandleSize", "Today is a bad day" );
    }
    
    return _minSize;
}

Answer 2

Check QSlider Stylesheet example:

QSlider::groove:horizontal
{
    border: 1px solid #bbb;
    background: white;
    height: 10px;
    border-radius: 4px;
}

QSlider::sub-page:horizontal
{
    background: qlineargradient(x1: 0, y1: 0,    x2: 0, y2: 1,
        stop: 0 #66e, stop: 1 #bbf);
    background: qlineargradient(x1: 0, y1: 0.2, x2: 1, y2: 1,
        stop: 0 #bbf, stop: 1 #55f);
    border: 1px solid #777;
    height: 10px;
    border-radius: 4px;
}

QSlider::add-page:horizontal
{
    background: #fff;
    border: 1px solid #777;
    height: 10px;
    border-radius: 4px;
}

QSlider::handle:horizontal
{
    background: qlineargradient(x1:0, y1:0, x2:1, y2:1,
        stop:0 #eee, stop:1 #ccc);
    border: 1px solid #777;
    width: 13px;
    margin-top: -2px;
    margin-bottom: -2px;
    border-radius: 4px;
}

QSlider::handle:horizontal:hover
{
    background: qlineargradient(x1:0, y1:0, x2:1, y2:1,
        stop:0 #fff, stop:1 #ddd);
    border: 1px solid #444;
    border-radius: 4px;
}

QSlider::sub-page:horizontal:disabled
{
    background: #bbb;
    border-color: #999;
}

QSlider::add-page:horizontal:disabled
{
    background: #eee;
    border-color: #999;
}

QSlider::handle:horizontal:disabled
{
    background: #eee;
    border: 1px solid #aaa;
    border-radius: 4px;
}