require 'sdl'

SDL.init( SDL::INIT_VIDEO )
screen = SDL::setVideoMode(640,480,16,SDL::SWSURFACE)
SDL::WM::setCaption $0, $0

screen[200,200]= screen.format.mapRGB(255,0,0)
screen[250,200]= screen.format.mapRGB(0,255,0)
screen[300,200]= screen.format.mapRGB(0,0,255)
Red=screen.format.mapRGB(255,0,0)
screen.drawLine(20,20,300,200,Red)
screen.drawRect(49,59,80,80,Red)
screen.drawCircle(100,100,50,[87,87,87])
screen.drawFilledCircle(300,300,30,Red)

screen.flip

event=SDL::Event.new

while true 
  if  event.poll != 0 then
    if event.type==SDL::Event::QUIT then
      break
    end
    if event.type==SDL::Event::KEYDOWN then
      exit
    end
  end
end