View images with the matplotlib library

imv.py

#!/usr/bin/env python
# Use the power of matplotlib to display an image file
# This can be helpful when logged in to a remote server 
# and you need more power than xview, or may xview hasn't 
# been installed.
# 2012 Derek Ashley Thomas

import matplotlib as mpl
import matplotlib.image as mpimg
import matplotlib.pyplot as plt
import numpy as np

from os.path import expanduser
import sys

def load_image(fname):
    fname = expanduser(fname)
    # load image
    img = mpimg.imread(fname)

    return img

def plot_img(data):
    fig = plt.figure(frameon=False)
    ax = plt.Axes(fig, [0., 0., 1., 1.])
    ax.set_axis_off()
    fig.add_axes(ax)

    ax.imshow(data, aspect='normal')
    plt.show()

def test_save(fname=None):
    if not fname:
        fname = "/tmp/test.png"

    x = np.arange(100)
    y = x**2

    plt.plot(x,y)
    plt.savefig(fname)

    plt.close()
    return fname

def print_usage(err=1):
    print "USAGE: imv [filename]"
    sys.exit(err)

if __name__ == "__main__":

    try:
        img_file = sys.argv[1]
        if img_file == "--test":
            img_file = test_save()
            print "*** Using test value"
    except IndexError:
        print_usage()

    img = load_image(img_file)
    plot_img(img)