Qt: Resize borderless widget

Question

My question is basically the same as this one, but applied to the Qt C++ framework.

I am implementing a popup window by inheriting QWidget with flags Qt::QPopup | Qt::QWindow. I would like this window to be moveable and resizeable, I'm currently achieving this by using the mouse events in the following code:

void TextPopup::mousePressEvent(QMouseEvent* event)
{
    offset = event->pos();
    QWidget::mousePressEvent(event);
}

void TextPopup::mouseMoveEvent(QMouseEvent* event)
{
    if(event->buttons() & Qt::LeftButton)
        if(resizeMode) {
            QPoint p = mapToGlobal(event->pos()) - geometry().topLeft();
            resize(p.x(), p.y());
        } else
            move(mapToParent(event->pos() - offset));
    else {
        QPoint diff = geometry().bottomRight() - mapToGlobal(event->pos());
        if(diff.x() <= 6 && diff.y() <= 6) {
            if(!resizeMode) {
                setCursor(Qt::SizeFDiagCursor);
                resizeMode = true;
            }
        } else {
            if(resizeMode) {
                setCursor(Qt::SizeAllCursor);
                resizeMode = false;
            }
        }
    }
}

void TextPopup::mouseReleaseEvent(QMouseEvent* event)
{
    offset = QPoint();
    QWidget::mouseReleaseEvent(event);
}

I have a few problems with this. For one, I'm guessing there's a better way to do it. And more importantly, I would like the resize symbol at the bottom right as in this image] (taken from the post mentioned above). Any suggestions for achieving this?

Answer 1

You can add the resize grip by calling QDialog's or QStatusBar's function setSizeGripEnabled (or directly in QtCreator form designer).

For custom widgets the simplest way probably is to use QSizeGrip. I didn't use it myself but you can check the Qt source code on git for QStatusBar or QDialog.