# cbezier1.rb

    #!/usr/local/bin/ruby18 -w
    require 'RMagick'

    imgl = Magick::ImageList.new
    imgl.new_image(390, 140, Magick::HatchFill.new('white','lightcyan2'))
    gc = Magick::Draw.new

    # Draw Bezier curve
    gc.stroke('red')
    gc.stroke_width(2)
    gc.fill_opacity(0)
    gc.bezier(20,120, 20,20, 320, 20, 320,120)

    # Draw circles around endpoints
    gc.fill_opacity(0)
    gc.stroke('gray50').stroke_width(1)
    gc.circle(20,120, 23, 123)
    gc.circle(320,120, 323, 123)

    # Draw filled circles around control points
    gc.line(20,120, 20,20)
    gc.line(320,120, 320,20)
    gc.fill_opacity(1)
    gc.fill('gray50')
    gc.circle(20,20, 23,23)
    gc.circle(320,20, 323,23)

    # Annotate
    gc.font_weight(Magick::NormalWeight)
    gc.font_style(Magick::NormalStyle)
    gc.fill('black')
    gc.stroke('transparent')
    gc.text(27,120, "'20,120'")
    gc.text(27,20, "'20,20'")
    gc.text(327,120, "'320,120'")
    gc.text(327,20, "'320,20'")
    gc.draw(imgl)

    imgl.border!(1, 1, "lightcyan2")
    imgl.write('cbezier1.gif')
    exit(0)

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