screenshoter.rb

class Screenshoter
  include Java

  import java.io.File
  import java.awt.Robot
  import java.awt.Toolkit
  import java.awt.Rectangle
  import javax.imageio.ImageIO
  
  def self.shoot!(output = "screenshot.png")
    screen_size = Toolkit.default_toolkit.screen_size
    area = Rectangle.new 0, 0, screen_size.width, screen_size.height
    
    ImageIO::write Robot.new.create_screen_capture(area), "png", File.new(output)
  end
end