def METHOD_NAME(self, key, default=None):
    limit = AbstractMatplotlib2DViewer.METHOD_NAME(self, key, default=default)
    if limit is None:
        X, Y = self.vars[0].mesh.faceCenters
        if 'xmin' in key:
            limit = float(min(X))
        elif 'ymin' in key:
            limit = float(min(Y))
        if 'xmax' in key:
            limit = float(max(X))
        elif 'ymax' in key:
            limit = float(max(Y))
    return limit