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

    # Demonstrate the Image#crop method

    lighthouse = Magick::Image.read('images/Lighthouse.jpg')[0]
    lighthouse = lighthouse.scale(250.0/lighthouse.rows)

    # Crop the specified rectangle out of the lighthouse.
    chopped = lighthouse.crop(78, 66, 90, 110)

    # Go back to the original and highlight the area
    # corresponding to the retained rectangle.
    rect = Magick::Draw.new
    rect.stroke('transparent')
    rect.fill('white')
    rect.fill_opacity(.25)
    rect.rectangle(78, 66, 90+78, 110+66)
    rect.draw(lighthouse)

    # Create a image to use as a background for
    # the "before & after" images.
    bg = Magick::Image.new(lighthouse.columns*2, lighthouse.rows) {
        self.background_color = 'black'
        }

    # Composite the "before" image on the left side
    # and the "after" (chopped) image on the right.
    bg = bg.composite(lighthouse, Magick::WestGravity, Magick::OverCompositeOp)
    bg = bg.composite(chopped, lighthouse.columns+78, 66, Magick::OverCompositeOp)

    bg.write('crop.jpg')
    #bg.display
    exit