Qlabel with transparent mask does not update background?

[ianni67]

Hallo everyone,
I'm a noob for QT and I'm trying to develop a program for my research work.

I'm trying to produce a QLabel with a transparent background and a transparent mask, in order to be able to click "through" the background of the label and see what happens.
I managed to set a transparent mask for a label but then its background is not updated, so if something happens below the label I do not see it happening.

Please, help! ?(

Here is my code:


#include <QApplication>
#include <QtGui>

void delay()
{
QTime dieTime= QTime::currentTime().addSecs(5);
while( QTime::currentTime() < dieTime )
QCoreApplication::processEvents(QEventLoop::AllEve nts, 100);
}

int main(int argc, char* argv[])
{
QApplication a(argc, argv);
QMainWindow* window = new QMainWindow;
QPixmap pixmap(40,40);

//window->setWindowFlags(Qt::WindowStaysOnTopHint);
pixmap.fill(Qt::transparent);
QPainter p(&pixmap);
p.setPen(Qt::blue);
p.drawLine(5,5, 40, 40);
p.end();
QLabel label;
label.setPixmap(pixmap);
label.setMask(pixmap.mask());
label.setWindowFlags(Qt::WindowStaysOnTopHint);
label.setAttribute(Qt::WA_TranslucentBackground);
// label.setAutoFillBackground(true);
label.show();
//QCursor::setPos(40, 40);
delay();

label.move(40,40);
return a.exec();
}