def __init__(self, parent=None):
super(GraphicsView, self).__init__(parent)
assert self.dragMode() == QGraphicsView.NoDrag
self.setRenderHint(QPainter.Antialiasing)
self.setRenderHint(QPainter.TextAntialiasing)
self.freehandTool = FreehandTool(view=self)
self.setMouseTracking(True)
