qtqslider

Coloring QSlider for a particular range


I have a QSlider, with a range of 0 to 100,

What I need is to color the background of its groove from the range 20 to 80 only.

enter image description here


Solution

  • I suggest you to subclass QSlider and reimplement paintEvent as the following:

    void My_slider::paintEvent(QPaintEvent *ev) {
      QStyleOptionSlider opt;
      initStyleOption(&opt);
    
      opt.subControls = QStyle::SC_SliderGroove | QStyle::SC_SliderHandle;
      if (tickPosition() != NoTicks) {
        opt.subControls |= QStyle::SC_SliderTickmarks;
      }
    
      QRect groove_rect = style()->subControlRect(QStyle::CC_Slider, &opt, QStyle::SC_SliderGroove, this);
      qDebug() << groove_rect;
      QSlider::paintEvent(ev);
      QRect rect(groove_rect.left() + 0.2 * groove_rect.width(), groove_rect.top(), 0.6 * groove_rect.width(), groove_rect.height());
      QPainter painter(this);
      painter.fillRect(rect, QBrush(Qt::red));
    }