# File gtk/sample/misc/mouse-gesture.rb, line 49
  def update_position(x, y)
    mx = x - @prev_x
    my = y - @prev_y
    
    motion = judge_motion(mx, my)
    if motion
      @prev_x = @x = x
      @prev_y = @y = y
      if @motions.last == motion
        false
      else
        @motions << motion
        true
      end
    else
      false
    end
  end