QT Round Edges Rectangle

Question

Im using following code for making the edges of rectangle round... but getting the top left and right different from the bottom left and right.

How can I fix this?

   QRegion ErrorCallout::roundRect(const QRect& rect, int r)
{
    QRegion region;

    // middle and borders
    region += rect.adjusted(r, 0, -r, 0);
    region += rect.adjusted(0, r, 0, -r);

    // top left
    QRect corner(rect.topLeft(), QSize(r*2, r*2));
    region += QRegion(corner, QRegion::Ellipse);

    // top right
    corner.moveTopRight(rect.topRight());
    region += QRegion(corner, QRegion::Ellipse);

    // bottom left
    corner.moveBottomLeft(rect.bottomLeft());
    region += QRegion(corner, QRegion::Ellipse);

    // bottom right
    corner.moveBottomRight(rect.bottomRight());
    region += QRegion(corner, QRegion::Ellipse);

    return region;
}

this->roundRect(rect,5);

Like below: