.. _widgets-rectangle_selector:

widgets example code: rectangle_selector.py
===========================================

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

::

    """
    Do a mouseclick somewhere, move the mouse to some destination, release
    the button.  This class gives click- and release-events and also draws
    a line or a box from the click-point to the actual mouseposition
    (within the same axes) until the button is released.  Within the
    method 'self.ignore()' it is checked wether the button from eventpress
    and eventrelease are the same.
    
    """
    from matplotlib.widgets import RectangleSelector
    import numpy as np
    import matplotlib.pyplot as plt
    
    def line_select_callback(eclick, erelease):
        'eclick and erelease are the press and release events'
        x1, y1 = eclick.xdata, eclick.ydata
        x2, y2 = erelease.xdata, erelease.ydata
        print "(%3.2f, %3.2f) --> (%3.2f, %3.2f)" % (x1, y1, x2, y2)
        print " The button you used were: ", eclick.button, erelease.button
    
    def toggle_selector(event):
        print ' Key pressed.'
        if event.key in ['Q', 'q'] and toggle_selector.RS.active:
            print ' RectangleSelector deactivated.'
            toggle_selector.RS.set_active(False)
        if event.key in ['A', 'a'] and not toggle_selector.RS.active:
            print ' RectangleSelector activated.'
            toggle_selector.RS.set_active(True)
    
    
    current_ax = plt.subplot(111)                    # make a new plotingrange
    N = 100000                                       # If N is large one can see
    x = np.linspace(0.0, 10.0, N)                    # improvement by use blitting!
    
    plt.plot(x, +np.sin(.2*np.pi*x), lw=3.5, c='b', alpha=.7)  # plot something
    plt.plot(x, +np.cos(.2*np.pi*x), lw=3.5, c='r', alpha=.5)
    plt.plot(x, -np.sin(.2*np.pi*x), lw=3.5, c='g', alpha=.3)
    
    print "\n      click  -->  release"
    
    # drawtype is 'box' or 'line' or 'none'
    toggle_selector.RS = RectangleSelector(current_ax, line_select_callback,
                                           drawtype='box', useblit=True,
                                           button=[1,3], # don't use middle button
                                           minspanx=5, minspany=5,
                                           spancoords='pixels')
    plt.connect('key_press_event', toggle_selector)
    plt.show()
    

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