.. _pylab_examples-image_slices_viewer:

pylab_examples example code: image_slices_viewer.py
===================================================



.. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/pylab_examples/image_slices_viewer.py

::

    from __future__ import print_function
    import numpy
    import matplotlib.pyplot as plt
    
    
    class IndexTracker(object):
        def __init__(self, ax, X):
            self.ax = ax
            ax.set_title('use scroll wheel to navigate images')
    
            self.X = X
            rows, cols, self.slices = X.shape
            self.ind = self.slices//2
    
            self.im = ax.imshow(self.X[:, :, self.ind])
            self.update()
    
        def onscroll(self, event):
            print("%s %s" % (event.button, event.step))
            if event.button == 'up':
                self.ind = numpy.clip(self.ind + 1, 0, self.slices - 1)
            else:
                self.ind = numpy.clip(self.ind - 1, 0, self.slices - 1)
            self.update()
    
        def update(self):
            self.im.set_data(self.X[:, :, self.ind])
            ax.set_ylabel('slice %s' % self.ind)
            self.im.axes.figure.canvas.draw()
    
    
    fig, ax = plt.subplots(1, 1)
    
    X = numpy.random.rand(20, 20, 40)
    
    tracker = IndexTracker(ax, X)
    
    
    fig.canvas.mpl_connect('scroll_event', tracker.onscroll)
    plt.show()
    

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