'Set the mouse interaction mode. *mode* must be either ViewBox.PanMode or ViewBox.RectMode.
In PanMode, the left mouse button pans the view and the right button scales.
In RectMode, the left button draws a rectangle which updates the visible region (this mode is more suitable for single-button mice)'

def setMouseMode(self, mode):

    if (mode not in [ViewBox.PanMode, ViewBox.RectMode]):
        raise Exception('Mode    must    be    ViewBox.PanMode    or    ViewBox.RectMode')
    self.state['mouseMode'] = mode
    self.sigStateChanged.emit(self)
