import graphics, sdl, sdl_image, colors
import os, strutils

var surface: graphics.PSurface = newScreenSurface(640, 480)
withEvents(surface, event):
  var x:int
  x=x+1
  while true:
    x=x+1
    surface.FillRect((0,0,640,480), colBlack);
    surface.drawCircle((x, 100), 60, colRed)
    SDL.UpdateRect(surface.s, 0, 0, 640, 480)
    sleep(20)

  case event.kind
  of sdl.QUITEV:
    break
  else: nil