Width and height of QRect are off by one in the center and moveCenter methods.

Sorry, ignore this message. I had a wrong understanding of how QRect works. Even the fix is wrong. I had an issue that I thought was related to QRect and somehow modifying how the center is computed fixed it. So the issue is probably in my code.

In the center and moveCenter methods of QRect, the width and the height computed there are one less than the actual values.
This will result in the wrong computation of the center coordinates.

Example:

qDebug() << QRect(0, 0, 2, 2).center();
// Result QPoint(0, 0) should be QPoint(1, 1)
QRect a(0, 0, 2, 2);
a.moveCenter(QPoint(-1, -1));
qDebug() << a;
// Result QRect(-1,-1 2x2) should be QRect(-2,-2 2x2)

Possible fix:

// center
{ return QPoint(int((qint64(x1)+x2+1)/2), int((qint64(y1)+y2+1)/2)); }

// moveCenter
{
    int w = x2 - x1;
    int h = y2 - y1;
    x1 = p.x() - (w + 1)/2;
    y1 = p.y() - (h + 1)/2;
    x2 = x1 + w;
    y2 = y1 + h;
}