.. _widgets-span_selector:

widgets example code: span_selector.py
======================================

[`source code <span_selector.py>`_]

::

    #!/usr/bin/env python
    """
    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 npy
    from pylab import figure, show
    from matplotlib.widgets import SpanSelector
    
    fig = figure(figsize=(8,6))
    ax = fig.add_subplot(211, axisbg='#FFFFCC')
    
    x = npy.arange(0.0, 5.0, 0.01)
    y = npy.sin(2*npy.pi*x) + 0.5*npy.random.randn(len(x))
    
    ax.plot(x, y, '-')
    ax.set_ylim(-2,2)
    ax.set_title('Press left mouse button and drag to test')
    
    ax2 = fig.add_subplot(212, axisbg='#FFFFCC')
    line2, = ax2.plot(x, y, '-')
    
    
    def onselect(xmin, xmax):
        indmin, indmax = npy.searchsorted(x, (xmin, xmax))
        indmax = min(len(x)-1, indmax)
    
        thisx = x[indmin:indmax]
        thisy = y[indmin:indmax]
        line2.set_data(thisx, thisy)
        ax2.set_xlim(thisx[0], thisx[-1])
        ax2.set_ylim(thisy.min(), thisy.max())
        fig.canvas.draw()
    
    # set useblit True on gtkagg for enhanced performance
    span = SpanSelector(ax, onselect, 'horizontal', useblit=True,
                        rectprops=dict(alpha=0.5, facecolor='red') )
    
    
    show()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)