"""
Computing horizontal gradients with the Sobel filter
=====================================================

This example illustrates the use of the horizontal Sobel filter, to compute
horizontal gradients.
"""

from skimage import data
# scikit-image has changes its API
try:
    from skimage import filters
except ImportError:
    from skimage import filter as filters
import matplotlib.pyplot as plt

text = data.text()
hsobel_text = filters.hsobel(text)

plt.figure(figsize=(12, 3))

plt.subplot(121)
plt.imshow(text, cmap='gray', interpolation='nearest')
plt.axis('off')
plt.subplot(122)
plt.imshow(hsobel_text, cmap='spectral', interpolation='nearest')
plt.axis('off')
plt.tight_layout()
plt.show()