QProgressBar as semi-transparent overlay

So basically, I have a QToolButton filled with a large icon of a playing card, and I want to overlay a QProgressBar over it.

Unfortunately I for the life of me, can not figure out how to make the QProgressbar Semi Transparent. I tried setstylesheet, but it doesnt have the proper constructors(?did I use that term right?), and I also tried this code:

Code:

---

#include <QApplication>
#include <QProgressBar>
 
int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	QWidget	*widget = new QWidget();
	QProgressBar *progress = new QProgressBar(widget);
 
	QPalette palette(widget->palette());
	palette.setColor(widget->backgroundRole(), Qt::green);
	widget->setAutoFillBackground(true);
	widget->setPalette(palette);
 
	QPalette palette1(progress->palette());
	palette1.setColor(progress->backgroundRole(), Qt::transparent);
	progress->setAutoFillBackground(true);
	progress->setPalette(palette1);
 
	widget->show();
	return a.exec();
}

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as someone in #qt said they got it working... I can get it to work on certain objects, but not QProgressbar.

Any ideas?