# clip_path.rb

    #!/usr/local/bin/ruby18 -w

    require 'RMagick'

    points = [145, 65, 174,151, 264,151, 192,205,
              218,291, 145,240,  72,291,  98,205,
               26,151, 116,151]

    pr = Magick::Draw.new

    # Define a clip-path.
    # The name of the clip-path is "example"
    pr.define_clip_path('example') {
        pr.polygon(*points)
        }

    # Enable the clip-path
    pr.push
    pr.clip_path('example')

    # Composite the Flower Hat image over
    # the background using the clip-path
    girl = Magick::ImageList.new
    girl.read("images/Flower_Hat.jpg")

    cols = rows = nil

    # Our final image is about 290 pixels wide, so here
    # we widen our picture to fit. The change_geometry
    # method will adjust the height proportionately.

    girl.change_geometry("290") do |c,r|
        pr.composite(0,0, c, r, girl)
        cols = c
        rows = r
    end

    pr.pop

    # Create a canvas to draw on, a bit bigger than the star.
    canvas = Magick::Image.new(cols, rows)

    star = Magick::Draw.new
    star.stroke('black')
    star.fill('black')
    star.polygon(*points)
    star.draw(canvas)
    canvas = canvas.blur_image(0, 20)

    # Draw the star over the background
    pr.draw(canvas)

    # Crop away all the solid white border pixels.
    crop = canvas.bounding_box
    canvas.crop!(crop.x, crop.y, crop.width, crop.height)

    canvas.write("clip_path.gif")

    exit

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