QSlider mouse direct jump

Question

Instead of stepping when the user clicks somewhere on the qslider I want to make the slider jump to that position. How can this be implemented ?

Answer 1

I needed this too and tried spyke solution, but it's missing two things:

• inverted appearance
• handle picking (when the mouse is over the handle, direct jump is not necessary)

So, here's the reviewed code:

void MySlider::mousePressEvent ( QMouseEvent * event )
{
  QStyleOptionSlider opt;
  initStyleOption(&opt);
  QRect sr = style()->subControlRect(QStyle::CC_Slider, &opt, QStyle::SC_SliderHandle, this);

  if (event->button() == Qt::LeftButton &&
      sr.contains(event->pos()) == false)
  {
    int newVal;
    if (orientation() == Qt::Vertical)
       newVal = minimum() + ((maximum()-minimum()) * (height()-event->y())) / height();
    else
       newVal = minimum() + ((maximum()-minimum()) * event->x()) / width();

    if (invertedAppearance() == true)
        setValue( maximum() - newVal );
    else
        setValue(newVal);

    event->accept();
  }
  QSlider::mousePressEvent(event);
}

Answer 2

i have been trying and searching this on net and was expecting Qt for a smarter way doing this, unfortunately there was not big help (may be i was not searching properly )

well i have done this in Qt creator:

1. Add an eventFilter in header ( takes QObject and QEvent as argument ) (bool return type)
2. Initialize in constructor ..for eg .. if ur slider is HSlider then ui->HSlider->installEventFilter(this);

3. In the defination :

   a. check if the object is your slider type something like : ui->HSlider == Object

   b. Check for mouse click event something like : QEvent::MouseButtonPress == event->type

   c. if the above all passes means u have got mouse event on the slider do something like : in definition : ui->HSlider->setValue( Qcursor::pos().x() - firstval ); return QMainWindow::eventFilter(object, event);

Note: fistVal : can be taken out by printing the cursur position at 0 = initial position of the slider ( with help of QCursor::pos().x() )

hope this helps

Answer 3

I think,

the QStyle::sliderValueFromPosition() function can be used.

http://qt-project.org/doc/qt-5/qstyle.html#sliderValueFromPosition

Answer 4

Well, I doubt that Qt has a direct function for this purpose.

Try to use custom widgets. This should work!

Try the following logic

class MySlider : public QSlider
{

protected:
  void mousePressEvent ( QMouseEvent * event )
  {
    if (event->button() == Qt::LeftButton)
    {
        if (orientation() == Qt::Vertical)
            setValue(minimum() + ((maximum()-minimum()) * (height()-event->y())) / height() ) ;
        else
            setValue(minimum() + ((maximum()-minimum()) * event->x()) / width() ) ;

        event->accept();
    }
    QSlider::mousePressEvent(event);
  }
};

Answer 5

A simple method would be to derive from QSlider and reimplement mousePressEvent(....) to set the marker position using setSliderPosition(int).

Answer 6

Here is a simple implementation in python using QStyle.sliderValueFromPosition():

class JumpSlider(QtGui.QSlider):

    def mousePressEvent(self, ev):
        """ Jump to click position """
        self.setValue(QtGui.QStyle.sliderValueFromPosition(self.minimum(), self.maximum(), ev.x(), self.width()))

    def mouseMoveEvent(self, ev):
        """ Jump to pointer position while moving """
        self.setValue(QtGui.QStyle.sliderValueFromPosition(self.minimum(), self.maximum(), ev.x(), self.width()))