import matplotlib.pyplot as plt
from matplotlib.widgets import RectangleSelector
import functools

_, ax = plt.subplots()
ax.plot([1, 2, 3])


def dummy_callback(*args):
    pass


def onselect_callback(event, selector):
    print('## onselect callback ##')
    if not selector.ignore(event):
        print('   ', selector.extents)
        return
    print('   event ignored')


def onmove_callback(event, selector):
    print('## onmove callback ##')
    if not selector.ignore(event) and selector._eventpress:
        print('   ', selector.extents)
        return
    print('   event ignored')


tool = RectangleSelector(ax, dummy_callback, interactive=True,
                         drag_from_anywhere=True,)
tool.extents = (1.2, 2.0, 1.0, 1.6)

# alternative to onselect
rectangle_onselect_callback = functools.partial(onselect_callback, selector=tool)
tool.connect_event('button_release_event', rectangle_onselect_callback)

# alternative to onmove_callback (SpanSelector only)
rectangle_onmove_callback = functools.partial(onmove_callback, selector=tool)
tool.connect_event('motion_notify_event', rectangle_onmove_callback)