    #! /usr/local/bin/ruby -w
    require 'RMagick'

    # Demonstrate the Image#edge method

    jj = Magick::Image.read('images/Jean_Jacket.jpg').first
    jj.scale!(250.0/jj.rows)

    jj2 = jj.edge(5)

    # Make a before-and-after composite
    jj2.crop!(jj2.columns/2, 0, jj2.columns/2, jj2.rows)
    jj = jj.composite(jj2, Magick::EastGravity, Magick::OverCompositeOp)
    jj = jj.border(1,1,'black')

    #jj.display
    jj.write('edge.jpg')
    exit