from matplotlib.widgets import  RectangleSelector
from pylab import *


def onselect(eclick, erelease):
    # eclick and erelease are matplotlib events at press and release
    global x_new
    global y_new
    print ' startposition : (%f, %f)' % (eclick.xdata, eclick.ydata)
    print ' endposition   : (%f, %f)' % (erelease.xdata, erelease.ydata)
    print ' used button   : ', eclick.button
    xmin = min(eclick.xdata, erelease.xdata)
    xmax = max(eclick.xdata, erelease.xdata)
    ymin = min(eclick.ydata, erelease.ydata)
    ymax = max(eclick.ydata, erelease.ydata)
    indices = (x >= xmin) & (x <= xmax) & (y >= ymin) & (y <= ymax)
    x_new = x[indices]
    y_new = y[indices]
    fig_new = figure()
    plot(x_new, y_new)
    fig_new.show()

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)

x = arange(100)/(99.0)
y = sin(x)
fig = figure
ax = subplot(111)
ax.plot(x,y)

toggle_selector.RS = RectangleSelector(ax, onselect, drawtype='box')
connect('key_press_event', toggle_selector)
show()