How to center a QProgressBar's chunk? - qt

Question

I have this audio viewer that, for lack of a better widget, uses QProgressBars to display the overall volume and the volume of each RTA bin, in addition to selecting a range of "interesting" bins:
The parent widget has a stylesheet of "background-color: DimGray;"; I don't know if that has anything to do with the problem or not. The progressbars themselves are set up like this:
AudioMeter::AudioMeter(..., QWidget* parent) :
QWidget(parent)
{
...
meter = new QProgressBar(this);
meter->setOrientation(Qt::Vertical);
meter->setFormat("");
meter->setGeometry(...);
meter->setRange(FixedPoint::Zero, FixedPoint::One);
}
and used like this:
void AudioMeter::setValue(int value)
{
meter->setValue(value);
}
The problem is that the chunks (in light blue) seem to be offset to the left by a few pixels and up by one or two, so it just doesn't look right. This is true on Lubuntu 16.04 LTS (pictured) and on Ubuntu 16.04 LTS. How can I center them?
Or if there's a better widget to use (with straightforward code, not a custom thing with 20 re-implemented methods like I've seen in some examples), I'm open to that too.

Answer 1

http://doc.qt.io/qt-4.8/stylesheet-examples.html#customizing-qprogressbar
http://doc.qt.io/qt-5/stylesheet-examples.html#customizing-qprogressbar
http://doc.qt.io/qt-5/stylesheet-customizing.html#the-box-model
https://www.w3schools.com/css/css_padding.asp
It looks like the right padding is probably off for some reason.
// try this and see if it helps
meter->setStyleSheet("padding: 0;");
// or just zero out the right padding
meter->setStyleSheet("padding-right: 0;");
If not, you will probably need to do some iterations of stylesheet editing...
Use a stylesheet.css file in the same path as your program:
http://doc.qt.io/qt-5/qapplication.html#QApplication
-stylesheet= stylesheet, sets the application styleSheet. The value must be a path to a file that contains the Style Sheet.
So you run your program with
meters -stylesheet=./stylesheet.css
and fill in stylesheet.css with:
QProgressBar {
/* attempt at fix by removing all padding */
padding: 0;
/* Another style to try out sometime:
QProgressBar {
border: 2px solid grey;
border-radius: 5px;
}
QProgressBar::chunk {
background-color: #05B8CC;
width: 20px;
}*/
}
I've also done prototyping of stylesheets by connecting it's reload to an application wide hotkey or a pushbutton in your program.
QString stylesheet;
QFile f("stylesheet.css");
if (f.open(QFile::ReadOnly | QFile::Text))
{
QTextStream in(&f);
stylesheet = in.readAll();
}
qApp->setStyleSheet(stylesheet);
qApp->style()->unpolish(qApp);
qApp->style()->polish(qApp);
Hope that helps.