def _resizeSouthwest(self, pos, offset):
        dw = pos.x() - offset.x()
        dh = pos.y() - self.height() + offset.y()
        size = self.size()
        min_size = self.minimumSizeHint()
        if size.width() - dw < min_size.width():
            dw = size.width() - min_size.width()
        rect = self.geometry()
        rect.setX(rect.x() + dw)
        rect.setHeight(rect.height() + dh)
        self.setGeometry(rect)
A resize handler for southwest resizing.
dataset/ETHPy150Open ContinuumIO/ashiba/enaml/enaml/qt/docking/q_dock_frame.py/QDockFrame._resizeSouthwest