>>> """
=============
Span Selector
=============

The SpanSelector is a mouse widget to select a xmin/xmax range and plot the
detail view of the selected region in the lower axes
"""
... import numpy as np
... import matplotlib.pyplot as plt
... from matplotlib.widgets import SpanSelector
... 
... # Fixing random state for reproducibility
... np.random.seed(19680801)
... 
... fig, (ax1, ax2) = plt.subplots(2, figsize=(8, 6))
... 
... x = np.arange(0.0, 5.0, 0.01)
... y = np.sin(2 * np.pi * x) + 0.5 * np.random.randn(len(x))
... 
... ax1.plot(x, y)
... ax1.set_ylim(-2, 2)
... ax1.set_title('Press left mouse button and drag '
...               'to select a region in the top graph')
... 
... line2, = ax2.plot([], [])
... 
... 
... def onselect(xmin, xmax):
...     indmin, indmax = np.searchsorted(x, (xmin, xmax))
...     indmax = min(len(x) - 1, indmax)
... 
...     region_x = x[indmin:indmax]
...     region_y = y[indmin:indmax]
... 
...     if len(region_x) >= 2:
...         line2.set_data(region_x, region_y)
...         ax2.set_xlim(region_x[0], region_x[-1])
...         ax2.set_ylim(region_y.min(), region_y.max())
...         fig.canvas.draw_idle()
... 
... 
... #############################################################################
... # .. note::
... #
... #    If the SpanSelector object is garbage collected you will lose the
... #    interactivity.  You must keep a hard reference to it to prevent this.
... #
... 
... 
... span = SpanSelector(
...     ax1,
...     onselect,
...     "horizontal",
...     useblit=True,
...     props=dict(alpha=0.5, facecolor="tab:blue"),
...     interactive=True,
...     drag_from_anywhere=True
... )
... # Set useblit=True on most backends for enhanced performance.
... 
... 
... plt.show()
... 
... #############################################################################
... #
... # .. admonition:: References
... #
... #    The use of the following functions, methods, classes and modules is shown
... #    in this example:
... #
... #    - `matplotlib.widgets.SpanSelector`
...