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

    # Demonstrate the Image#level method

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

    # Allow the white-point argument to default.
    # This is really a very small adjustment.
    after = before.level(0,1.25)

    # Make a before-and-after composite
    after.crop!(after.columns/2, 0, after.columns/2, after.rows)
    result = before.composite(after, Magick::EastGravity, Magick::OverCompositeOp)

    # Draw a black line between the before and after parts.
    line = Magick::Draw.new
    line.line(result.columns/2, 0, result.columns/2, result.rows)
    line.draw(result)

    #result.display
    result.write('level.jpg')
    exit